tag:blogger.com,1999:blog-82608947942288144002024-03-13T11:47:56.895+02:00The Official VOACAP BlogAll things - even vaguely - related to VOACAP, Voice of America Coverage Analysis Program.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.comBlogger33125tag:blogger.com,1999:blog-8260894794228814400.post-90773170016902895562019-05-31T21:47:00.000+03:002019-05-31T21:47:21.882+03:00Finding the common moon window times for EME QSOs on VOACAP OnlineI am happy to announce that VOACAP Online (<a href="http://voacap.com/hf">voacap.com/hf</a>) now allows you to determine the time periods when the Moon is visible both at the Transmitter (TX) and the Receiver (RX) sites at the same time, i.e. the common moon window times for EME (Earth-Moon-Earth) QSOs.<br />
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You will just place the TX and RX markers on the map at the coordinates of your choice, select the start date from the calendar, and press the green "EME" button underneath the map.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOujeLQnC_PikgMiYJV_jFmO5t7iU_WriYGtuzyA6c-XSdQXtb5X80nk0ex0YUJ32e0WTsxaVafXTLaq4dzVILb1a3RRmKFpSRvpOtmX_eznRa7DEeneIwMs4qlYLr4cjaq7VaEN570Xk/s1600/voacap-set-calendar-date.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="283" data-original-width="425" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOujeLQnC_PikgMiYJV_jFmO5t7iU_WriYGtuzyA6c-XSdQXtb5X80nk0ex0YUJ32e0WTsxaVafXTLaq4dzVILb1a3RRmKFpSRvpOtmX_eznRa7DEeneIwMs4qlYLr4cjaq7VaEN570Xk/s1600/voacap-set-calendar-date.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Set the date in the calendar in the bottom-left corner of the map.<br />Here setting the date to October 18, 2019, the start of the VP6R Pitcairn DXpedition.</span></td></tr>
</tbody></table>
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBifafPc0xUSL7jmfuYc5uhCw3XIz5svi_iFw39TIwi3PhO07Hib86aZuqdixt2iJ5VXQCrAvCQE1ukNbmU-hsLt_60gGVIV28x-AqxIzizeV7KSWgN4BKe-lGl6HsudyM0MawA70Ccas/s1600/voacap-start-eme.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="176" data-original-width="430" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBifafPc0xUSL7jmfuYc5uhCw3XIz5svi_iFw39TIwi3PhO07Hib86aZuqdixt2iJ5VXQCrAvCQE1ukNbmU-hsLt_60gGVIV28x-AqxIzizeV7KSWgN4BKe-lGl6HsudyM0MawA70Ccas/s1600/voacap-start-eme.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">After setting the date, press the green "EME" button.</span></td></tr>
</tbody></table>
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First, the system will calculate the time periods of moon visibility, i.e. moon rise, noon and set times, for both the locations over seven days. Second, it will determine the start and the end of the overlapping time periods in those days, i.e. the times when the Moon is visible in both the QTHs at the same time. And third, within those overlapping periods, more granular calculations take place to determine the elevation over the horizon, the azimuth, and the distance to the Moon at 5-minute intervals. The results will be then displayed side by side for an easy comparison.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNDD_vfNOZ785Bq8OJ_DJsw5Onn6c9iHSBi8ej9HzPID1VE7LjklAfu2xpkS88pPrX_BZyzfZyaxM29JszyUE8LaN2u4zfYt8LAq1IjIy6OuutRh_ymPDtjkLSZ1DTQk1P5-PBdzN2edU/s1600/voacap-moon-explanations.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="773" data-original-width="1065" height="464" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNDD_vfNOZ785Bq8OJ_DJsw5Onn6c9iHSBi8ej9HzPID1VE7LjklAfu2xpkS88pPrX_BZyzfZyaxM29JszyUE8LaN2u4zfYt8LAq1IjIy6OuutRh_ymPDtjkLSZ1DTQk1P5-PBdzN2edU/s640/voacap-moon-explanations.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">A result page with a detailed analysis.<br />Click image to enlarge.</span></td></tr>
</tbody></table>
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There are still known problems to reliably handle the cases where the Moon is up all day or is not visible at all during the day. For example, this may happen if you are located far beyond the Arctic or Antarctic Circle.<br />
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I hope this will be of service to you while hunting stations via EME. Please send comments and bug reports.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0tag:blogger.com,1999:blog-8260894794228814400.post-81895239977103114842019-03-29T20:03:00.000+02:002019-03-29T20:16:32.579+02:00VOACAP Online services in a nutshell (March 2019 Update)As I am still receiving emails where people complain about the loss of some of the VOACAP Online services after the renewal of the pages last summer, let me briefly summarize the content of the current VOACAP Online portfolio.<br />
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<b>Background</b>: Last year I was forced to revamp all my VOACAP Online services, due to a change in Google Maps policies. At that time, I also consolidated all my services under the same hood, changing the URL in the process. The new URL, as you may have noticed, is now <a href="http://www.voacap.com/hf" target="_blank">http://www.voacap.com/hf</a>, and <b>it incorporates BOTH the point-to-point prediction services AND coverage area map services</b>. So, instead of reducing the VOACAP Online service portfolio, I have actually expanded it quite considerably.<br />
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To understand the new service and how it works, I warmly recommend that you read the new manual at <a href="https://voacap.blogspot.com/2018/06/voacap-online-hf-predictions-users.html" target="_blank">https://voacap.blogspot.com/2018/06/voacap-online-hf-predictions-users.html</a><br />
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Let me highlight all the services below; more detailed descriptions can be found in the aforementioned manual:<br />
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<b><span style="color: red;">(1) Prop Charts</span></b>, or Propagation Charts. Clicking the "Prop Charts" button on the right side of the map display 15 toggleable prediction charts for all amateur radio bands from 10 meters (28 MHz) to 80 meters (3.5 MHz). The charts show e.g. the probability (or, the REL parameter in the VOACAP language) for a communication contact (i.e. a QSO) between the TX and RX sites. The "REL Short-Path" chart is the default.<br />
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<b><span style="color: red;">(2) Prop Wheel</span></b>. This button on the right margin of the map will display the famous 24-hour Propagation Prediction Wheel, showcasing the REL parameter only. Keep this window open as you move the markers on the map, or change any settings. The predictions will change on the screen on-the-fly!<br />
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<b><span style="color: red;">(3) Band-by-band Prediction</span></b>, or all Prediction Charts on one page. If you wish to see all the prediction charts displayed on a single page available under the “Predictions” button on the right side of the map, click the button labeled "Band-by-band Prediction" below the map.<br />
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<b><span style="color: red;">(4) Best FREQ</span></b>. The Best FREQ button below the map provides an assessment of the Best Operating Frequencies for every hour of the day in a month for the circuit chosen. This means that all ham radio bands are being considered and, after a careful evaluation, the three best bands will be displayed, together with some VOACAP prediction data.<br />
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<b><span style="color: red;">(5) REL & SDBW</span></b>, or the original VOACAP point-to-point prediction graphs. The “REL & SDBW” graphs were the first graphs generated at the VOACAP Online Point-to-Point site, and by pressing this button, the detailed propagation prediction graphs will be calculated for the entire frequency range from 2 MHz to 30 MHz, showing the REL (Circuit reliability) and S DBW (Signal Power) graphs for the circuit.<br />
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<b><span style="color: red;">(6) All-year Prediction</span></b>, or point-to-point prediction tables for all months available at once. The All-year Prediction calculates the point-to-point predictions for the circuit (from TX to RX), covering the entire year and more if possible. The number of prediction tables generated will depend on the Sunspot Number predictions available from SIDC in Belgium. The colors in the table indicate the probability of making a contact between the TX and RX, using the TX mode selected (WSPR, FT8, CW, SSB or AM). All user-settable input parameters will be observed, except the Sunspot Number (SSN).<br />
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<b><span style="color: red;">(7) QSO Window</span></b>, know your window of opportunity to work DX! By default, on the interactive map, you will see two markers (for TX and RX). Another five markers can be revealed by clicking the triangle-shaped button on the left side of the map. These are the sites of the "competing" locations that are trying to make a QSO with the DX station, too. Now, for you to able to see your chances in relation to the other five, the QSO Window function runs five extra propagation predictions from the five sites to the DX site (RX), and displays the results as interactive charts where you can easily compare the output values to those from your location.<br />
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<b><span style="color: red;">(8) Season</span></b>. This service uses the user-entered or automatically determined Sunspot Number (SSN), and calculates the SNR (median signal-to-noise ratio), SDBW (signal power at receiver), and the REL (circuit reliability) values for each month of the year for the given circuit. The results will be displayed in a huge table band by band, together all-year averages of the three output values for each hour of the day, supporting more long-term propagation planning, or to choose the best month for a DXpedition.<br />
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<b><span style="color: red;">(9) Planner</span></b>, or the Propagation Planner is a comprehensive planning tool for HF contesters and DXers. The results can be viewed zone by zone and band by band from the TX site the user provided. The colors indicate the probability of making a QSO between the TX and the Zone in question.<br />
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<b><span style="color: red;">(10) P2P Grayline</span></b>, or sunrise/sunset times for the current and next month. The Grayline calculates a wealth of solar-related information for the Transmitter and Receiver, and for the geographical midpoint of the circuit, covering the two months: the current and the following.<br />
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<b><span style="color: red;">(11) Distance</span></b>. This graph shows how the propagation parameters of REL, MUFday, SNR, and SDBW (Signal Power) develop ALONG the Great-Circle Path from TX to RX. Work in progress.<br />
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<b><span style="color: red;">(12) REL Map & SDBW Map</span></b>. This service is able to plot coverage area maps featuring REL (circuit reliability) or SDBW (signal power) values. What is more, it can also calculate and display multiple coverage maps at one go. The input values for the coverage maps have a separate section under the “Settings” button on the right margin of the interactive map.<br />
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<b><span style="color: red;">(13) DXCC Grayline</span></b>, or sunrise/sunset/midnight times for all DXCC entities. The DXCC Grayline calculates the sunrise, sunset and midnight times for all the defined DXCC entities on the current day.<br />
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I hope this helps people understand the current offering of the services.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com2tag:blogger.com,1999:blog-8260894794228814400.post-5335991478851656322018-06-21T18:57:00.003+03:002018-06-21T18:57:41.043+03:00KH1/KH7Z Sunrise/Sunset Info and Propagation PredictionsAll times UTC. KH1 coordinates: Lat: 0.16667, Lon: -176.5. Grid: AJ10se <br />
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<b>Detailed sunrise & sunset "grayline" analysis from KH1/KH7Z to DXCC countries</b>:<br />
<a href="http://www.voacap.com/greyline/?loc=aj10se&date=2018-06-27" target="_blank">http://www.voacap.com/greyline/?loc=aj10se&date=2018-06-27</a><br />
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<b>KH1/KH7Z sunrise, sunset & midnight times (in UTC):</b><br />
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<pre>DATE DAWN RISE POST | PRE SET DUSK | MNITE
2018-06-27 17:22 17:45 18:02 | 05:36 05:53 06:15 | 11:49
2018-06-28 17:23 17:45 18:02 | 05:36 05:53 06:15 | 11:49
2018-06-29 17:23 17:45 18:02 | 05:36 05:53 06:16 | 11:49
2018-06-30 17:23 17:45 18:02 | 05:37 05:53 06:16 | 11:49
2018-07-01 17:23 17:46 18:02 | 05:37 05:53 06:16 | 11:49
2018-07-02 17:23 17:46 18:02 | 05:37 05:54 06:16 | 11:50
2018-07-03 17:24 17:46 18:03 | 05:37 05:54 06:16 | 11:50
2018-07-04 17:24 17:46 18:03 | 05:37 05:54 06:16 | 11:50
2018-07-05 17:24 17:46 18:03 | 05:38 05:54 06:17 | 11:50
2018-07-06 17:24 17:47 18:03 | 05:38 05:54 06:17 | 11:50
</pre>
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<b>Detailed HF propagation prediction</b>: <a href="http://voacap.com/hf/" target="_blank">http://voacap.com/hf/</a><br />
<br />
73 Jari OH6BGOH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0tag:blogger.com,1999:blog-8260894794228814400.post-8016740188709271982018-06-17T14:39:00.025+03:002024-01-13T20:25:58.350+02:00VOACAP Online HF Predictions, User's Manual (13 Jan 2024)<p>The <b>VOACAP Online HF Predictions service</b> (<a href="http://voacap.com/hf" target="_blank">voacap.com/hf</a>) is a replacement for and a consolidation of the previous VOACAP Online P2P (point-to-point) service at voacap.com/p2p and VOACAP Online Coverage Maps at voacap.com/area. These two previous services have been closed down.<br />
<br />
The new service uses VOACAP (Voice of America Coverage Analysis Program) as its calculation engine, requiring the use of a reasonably new web browser. For example, the latest versions of Microsoft Edge (<b>but not</b> Internet Explorer), Mozilla Firefox, and Google Chrome are known to work. The earlier versions may not be supported. If you encounter problems with the service, please try first to upgrade your browser to the latest version available.</p><p>Sometimes problems may arise if some of your input values have been saved in your browser as cookies. Be sure to clear all the cookies and re-set your input values (such as the TX/RX sites, power, antennas, etc as needed) because the site is constantly being updated, and in rare occasions new additions may interfere with your old cookies.<br /></p><p>If you think you have found a bug or if you wish to help translate the user interface into your language, please contact me at <a href="mailto:jpe@voacap.com">jpe@voacap.com</a>.<br />
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</p><h3>
1. The interactive map for setting the transmitter (TX) and receiver (RX) site coordinates</h3>
<br />
Originally, a smooth and an easy coordinate entry for the Transmitter (TX) and Receiver (RX) sites was one of the single most important design features at VOACAP Online. The stand-alone PC version of VOACAP does not offer this, and, in fact, not many other similar software do, either. Choosing an interactive map for this purpose considerably lowered the threshold of using VOACAP.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIDA-CotHNiKT4Yf6eeaQGsrWoDp8oT8tEOZv7W601WPX8lNsz63Ay4jI1oOGN9Pw2VUEue7j1wlzJZxrD6pk6iV0U5NtucL5hTa018Y5Lt22LHdu0oFhoz0sUxqPsQOPf9UWKNbr3EyM/s1600/voacap-hf-main-screen.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="789" data-original-width="1249" height="404" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIDA-CotHNiKT4Yf6eeaQGsrWoDp8oT8tEOZv7W601WPX8lNsz63Ay4jI1oOGN9Pw2VUEue7j1wlzJZxrD6pk6iV0U5NtucL5hTa018Y5Lt22LHdu0oFhoz0sUxqPsQOPf9UWKNbr3EyM/s640/voacap-hf-main-screen.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><b><span style="color: red; font-size: small;">Click to enlarge the main screen image.</span></b></td></tr>
</tbody></table>
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On the initial map, there are two markers -- red and blue -- placed on the map, placing the midpoint of the circuit at the zero longitude. The red marker signifies the transmitter's location (TX) and the blue marker is the receiver's location (RX). Perhaps typically, the transmitter is your QTH, and the blue one is the DX station, or in any way you like.<br />
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The easiest way to set the coordinates is to drag the red (TX) and blue (RX) markers to their appropriate locations on the map. Under the map, the distance calculations from TX to RX are being displayed in kilometers and miles, and the bearing in degrees from True North, via the great-circle Short Path and Long Path. If you need to zoom in or zoom out the map for better details, just scroll the mouse wheel up and down over the map, or click the plus (+) and minus (-) icons in the top-left corner of the map.<br />
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To quickly swap the TX and RX points, just double-click the blue (RX) marker. Whenever the locations have been swapped (or moved), the propagation prediction, together with other details, is re-calculated. By swapping the TX and RX locations, you will quickly see that the predictions for circuits are not always 100% reciprocal. In VOACAP calculations, this is mostly due to the different level of noise power at the RX site(s).<br />
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The coordinate input values for the TX and RX can also be set in the area above the interactive map in three different ways:<br />
<br />
<ol>
<li>by selecting a DXCC country from a pop-up menu</li>
<li>by entering a Maidenhead Grid Locator manually, or</li>
<li>by entering latitude and longitude coordinates manually</li>
</ol>
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In the TX and RX sections you can choose the location from a list of DXCC countries. The QTH pop-up menu features 483 locations around the world, including all DXCC entities. When you choose a location from this list, its name and the coordinates (latitude and longitude) will automatically be entered in their corresponding fields. Much care has been taken to find the exact coordinates of even the smallest of the islands! If you happen to find a location with wrong coordinates, drop me a note!<br />
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When you drag the markers over the map, the Maidenhead grid locator will be displayed in the Grid field. You can also enter the grid locator manually, and press the TAB key: the corresponding coordinates will then automatically be calculated from the grid locator and entered in the Latitude and Longitude fields. The latitude and longitude values can also be entered manually.<br />
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<h4>
Two great-circle paths: short-path and long-path</h4>
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There is always a solid green line and a dotted red line connecting the red and blue markers. The green line shows the great-circle Short Path and the red line great-circle Long Path between the two locations. The small blue circle along the two great-circle lines indicates the geographical midpoint between the Transmitter and Receiver along that path.<br />
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<h4>
Distance and bearing</h4>
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The details of the on-the-fly calculation of the distance between TX and RX (in kilometers and miles), and the bearing from TX to RX in degrees, calculated from True North via Short Path and Long Path can be seen under the map. Also, the geographical midpoints of the two paths are displayed there.<br />
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<h3>
2. The date and grayline terminator</h3>
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The whole concept of setting the date in VOACAP Online services has been changing over the years. Earlier, I was showing the grayline terminator that was always fixed to the current time and day -- the user was not able to set it to a specific time and day in order to see how the grayline terminator looked like at a particular point of time. I felt that a more flexible grayline zone map could be used as a way of trying to determine signal enhancements on the low bands, and therefore a new way of setting the time and day was needed.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiN7i_QrdBVxrcwizNOXYF7mPgT5DXHO1JplTZ4aSQP3RmCHi9qWy5J3x4VfS0s4femXypxKq15Ikn04c2TMeu4bq_6hbMStHiHJgdeh2TMVrLveXDIaa9VfFASoBpCoWKU3BfrwExmips/s1600/voacap-hf-calendar.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="222" data-original-width="274" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiN7i_QrdBVxrcwizNOXYF7mPgT5DXHO1JplTZ4aSQP3RmCHi9qWy5J3x4VfS0s4femXypxKq15Ikn04c2TMeu4bq_6hbMStHiHJgdeh2TMVrLveXDIaa9VfFASoBpCoWKU3BfrwExmips/s1600/voacap-hf-calendar.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The calendar is rendered differently in different browsers. In some browsers, you should click on the date field; in others, click the black downward arrow right to the date field.</span></td></tr>
</tbody></table>
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This was the reason I have again chosen to use a pop-up calendar for this purpose. This functionality requires that a reasonably new browser is being used. Any month the user will select from the calendar will be used as the date input for all propagation predictions (except for coverage area maps which have separate input values). The pop-up calendar is located in the bottom-left corner of the map, and looks like this:<br />
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To set a date, click on the calendar date field. It will prompt a calendar where the user can browse the months (and years) back and forth by pressing the left and right arrow icons. Select a month by clicking any day number in that particular month. Please note that you must select a day, any day!<br />
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The month selected will be used for propagation prediction calculations, and the day selected (and the time set by the user, using the time slider above the calendar field) will be used for drawing the grayline zone terminator over the interactive map. Please note that the day selected will not be used for propagation prediction calculations as VOACAP will not provide any daily (or near-real-time) predictions.<br />
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Again, use the time slider above the calendar to move the time of day, and see how the grayline terminator moves accordingly. The time in UTC is being displayed to the left of the time slider.<br />
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<h3>
3. Inspecting sunrise and sunset times</h3>
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The three sections of circles (colored red, green and blue) on the top part of the interactive map offer the sunrise and sunset times at Transmitter, Midpoint (via Short-Path (first row) and Long-Path (second row)), and Receiver respectively on the given day. All times are UTC.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhucctMGPz0cL1Wtr2rUyOT-bM9r2ZPeH6dy2Co4DJobwI2vg-nO76y-x_7-BcD27z-kcoZd-HCgUV_z_oVmdDokQlnkhig1-E_tfgrCO2CYPDMKmBNmitWvNimSnUYs1qznM6rZS0hfSg/s1600/voacap-hf-suntimes.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="81" data-original-width="343" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhucctMGPz0cL1Wtr2rUyOT-bM9r2ZPeH6dy2Co4DJobwI2vg-nO76y-x_7-BcD27z-kcoZd-HCgUV_z_oVmdDokQlnkhig1-E_tfgrCO2CYPDMKmBNmitWvNimSnUYs1qznM6rZS0hfSg/s1600/voacap-hf-suntimes.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="color: red; font-size: small;"><b>1) Transmitter; 2) Midpoint of the circuit (Short-Path);<br />3) Midpoint of the circuit (Long.Path); 4) Receiver</b></span></td></tr>
</tbody></table>
<br />
These calculations were originally inspired by Steve's (G0KYA) <a href="http://www.infotechcomms.co.uk/RSGB_presentation_greyline.pdf" target="_blank">more-than-15-year-old article about grayline propagation</a>. In short, the best predictions for grayline propagation or trans-terminator enhancement on low bands can probably be achieved by a close examination of grayline maps. Some also swear by <a href="http://www.qsl.net/w6elprop/" target="_blank">W6ELProp</a>. To dig deeper into sunrise and sunset times, you may also be interested in reviewing the “DXCC Grayline” button.<br />
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Please note that all the circles can be clicked on, and the interactive map will show how the terminator line will run across the map at the time clicked on. This can be very useful in determining the best times for low-band signal enhancements.<br />
<br />
<h3>
4. The input parameters for predictions</h3>
<br />
There is a number of user-adjustable parameters in the pop-up menus and buttons on the left and right sides of the interactive map that will affect all the propagation predictions.<br />
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<h4>
4.1 The left side</h4>
<div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKLMdeuhCcM8K818BBTVTK-fz_j4qErFgMK7x-eb1OKASX3osOIrPjyHffUecm_myXCgC-klxPHVj-sBS2rxPzP4n_1ds8EX0UJIr_chQI-rbXbdEVYHfyQpCCHyL7AnEEk2koECB5KcE/s1600/voacap-hf-left-side.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="217" data-original-width="498" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKLMdeuhCcM8K818BBTVTK-fz_j4qErFgMK7x-eb1OKASX3osOIrPjyHffUecm_myXCgC-klxPHVj-sBS2rxPzP4n_1ds8EX0UJIr_chQI-rbXbdEVYHfyQpCCHyL7AnEEk2koECB5KcE/s1600/voacap-hf-left-side.jpg" /></a></div><p>
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<span style="color: red;">Set Home</span>: By clicking on the <b>Set Home</b> button on the left side of the map, the Latitude and Longitude information is stored in a cookie, as well as the RX Latitude and Longitude, along with the TX and RX antenna selections. And when you press the <b>Unset Home</b> button, the cookie will be destroyed. Remember to allow your browser to set the cookie on this page if you want to allow this feature to work.<br />
<br />
<span style="color: red;">Great-Circle Path (default: SP)</span>. This is a toggleable button between Short Path (SP) and Long Path (LP). This setting will be used in many of the calculations you can choose among the 12 green buttons below the interactive map.<br />
<br />
<span style="color: red;">Es, or use of the ionospheric sporadic E layer, Es (default: NoEs)</span>. This may (or may not) prove useful during summer months when Es propagation conditions can be quite predominant. The default setting is OFF (NoEs). Please note that the use of the Es layer is otherwise discouraged as the sporadic-E model was not fully tested during the development of VOACAP. Also, the effects of the sporadic-E layer are not totally excluded in VOACAP calculations although the layer would not be set to ON.</p><p><span style="color: red;">Maidenhead Grid, or show/hide the Maidenhead locator grid overlay (default: NoM)</span>. Toggle the Maidenhead Grid overlay on the map ON and OFF. The default setting is OFF.<br />
<br />
</p><h4>
4.2 The right side</h4>
<div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuBUQLOKFFT-TJsjtj7HtZUHQZvnyXijJrmnSzyYtzTKFrrH_P0F4kKvLa_C9kNtrki-adNb7QFSSQBK-0v1JNhyn8MIY4QLWM-360Q-UQr2rRU_yqmUGl6z6YhJAsNmCxQ-dik6J1D4c/s1600/voacap-hf-right-side.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="230" data-original-width="357" height="206" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuBUQLOKFFT-TJsjtj7HtZUHQZvnyXijJrmnSzyYtzTKFrrH_P0F4kKvLa_C9kNtrki-adNb7QFSSQBK-0v1JNhyn8MIY4QLWM-360Q-UQr2rRU_yqmUGl6z6YhJAsNmCxQ-dik6J1D4c/s320/voacap-hf-right-side.jpg" width="320" /></a></div>
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</div>
<br />
<span style="color: red;">a) The Transmitting Mode pop-up menu</span>. This menu allows you to choose from WSPR, FT8, CW, SSB and AM. CW is the default setting.<br />
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<span style="color: red;">b) The Transmitting Power pop-up menu</span>. This menu allows you to select powers from 1 watt to 1500 watts at the steps given. 1500 W is the default setting. Some line loss is assumed so that the actual power used for calculations is 80% of the power chosen.<br />
<br />
<span style="color: red;">c) The “Antennas” button</span>. An antenna can be chosen for all amateur bands separately. All TX and RX antennas are artificial in the sense that they are omnidirectional, which in turn allows the user to see all possible openings to all parts of the world. In dipole-type of antennas, the height of the antenna is related to the elevation angle and the number of elements to the gain.<br />
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<div class="separator" style="clear: both; text-align: center;">
<br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjymWngW00HIIqRxDgsaMbas4Ny9u8ab3jxPUAvsewTGiaPcrNj6gQ6Gl1GYrnJJwfD1ADYMjmszihcjaD67GjTZGRPpbaKA63Q9bj9dIpm_b6Dwklql7i7uu0XccNQ_y_Jdc2-Fz4xoik/s594/voacap-antennas.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="594" data-original-width="484" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjymWngW00HIIqRxDgsaMbas4Ny9u8ab3jxPUAvsewTGiaPcrNj6gQ6Gl1GYrnJJwfD1ADYMjmszihcjaD67GjTZGRPpbaKA63Q9bj9dIpm_b6Dwklql7i7uu0XccNQ_y_Jdc2-Fz4xoik/s16000/voacap-antennas.jpg" /></a></div><p><br />
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When you choose an antenna, you should think about the elevation angles and gain, rather than the physical structure of the antenna.</p><p>Also note that the TX and RX antenna selections can be quicly swapped by clicking the "Swap TX/RX antennas" button.<br />
<br />
<span style="color: red;">d) The “Settings” button</span>. Clicking this button opens an overlay window from the left side of the map. Three parameter sections are available here: General Propagation Settings, Coverage Area Map Settings, Propagation Planner Settings, TX Antenna Analysis Settings, and Take-off Angle Analysis Settings.<br />
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</p><div class="separator" style="clear: both; text-align: center;">
<br /></div><div class="separator" style="clear: both; text-align: center;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfz7dJr_vCM-pN10LY4iFY7fkTh_qKgbV8dDIH0_s-STIfRlfCt2hWqFem8XQswQKANgBCKXMCulF9zqTOLjo7Tqs9JQG8a2Ha3hG0XLnXHoWP9iq92Ry_x68Au0nYrE87Do9Kowo7N9lZzNrE5J6v8hAxB1ocU8u3qF_TYmYC1kTbqOIxmrsadzEcJA0/s500/voacap-manual-settings.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="500" data-original-width="472" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfz7dJr_vCM-pN10LY4iFY7fkTh_qKgbV8dDIH0_s-STIfRlfCt2hWqFem8XQswQKANgBCKXMCulF9zqTOLjo7Tqs9JQG8a2Ha3hG0XLnXHoWP9iq92Ry_x68Au0nYrE87Do9Kowo7N9lZzNrE5J6v8hAxB1ocU8u3qF_TYmYC1kTbqOIxmrsadzEcJA0/s16000/voacap-manual-settings.jpg" /></a></div><br /> </div><p><br />
<br />
<b>General Propagation Settings</b><br />
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<span style="color: red;">Noise</span>. This is the option of choosing the noise level at the RX site, and the selection is used not only for point-to-point calculations but also for coverage area map calculations where a matrix of single RX site points share the same noise value. The Noise value will affect the QSO probabilities: when there is a lot of man-made noise, the probabilities are lower; when the noise level is minimal (e.g. “Quiet” (default) or “Remote”), then the probabilities are better.<br />
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<span style="color: red;">SSN, or user-settable smoothed sunspot number (default: -1)</span>. Here you can set a specific SSN (i.e. sunspot number) to be used for calculations. Note that this service knows current predicted smoothed sunspot numbers for a few months ahead so it may be advisable not to set any value to the SSN field unless you wish to conduct your own propagation experiments. The default value of -1 means that the service will automatically use the predicted values.<br />
<br />
At this point, I would like to take a few moments to discuss the pros and cons of this feature. By default, this service does internally know the current SSN to be used for approximately 6 to 9 months into the future. If no sunspot number is found for your future prediction, the SSN will be set to zero. This means you will have to set the SSN manually.</p><p>Please note that VOACAP does not operate on daily SSN figures but on smoothed monthly SSN figures which are being predicted for many months ahead and which are also re-adjusted at regular intervals.<br />
<br />
The predicted SSN figures are based on the Lincoln-McNish smoothing function, and they are currently being maintained by WDC-SILSO, Royal Observatory of Belgium in Brussels. These are the sunspot numbers used in the database reduction for the worldwide ionospheric maps used in IONCAP and now VOACAP. This is why only these figures should be used with VOACAP. <a href="http://www.voacap.com/choosingssn.html" target="_blank">Read George Lane's discussion on the sunspot numbers for VOACAP use.</a><br />
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In addition, there have been months in the past where the conditions have been well above the average for a couple of months, and a re-adjustment of SSNs would have been appropriate. Now this power has been given to the user. Just remember that, strictly theoretically speaking, entering a daily SSN value in the SSN field does not generally give you better (or more precise) predictions as VOACAP is not suited to real-time predictions at all. <a href="http://www.voacap.com/" target="_blank">Read more about the theoretical background of VOACAP in my Quick Guide.</a></p><p><span style="color: red;">Dyn SSN</span>: Check this option if you want to use the running last-three-day average of daily sunspot numbers. This can be useful when the daily sunpot numbers considerably differ from the predicted monthly smoothed sunspot number. Please note that this option is experimental. </p><p> <span style="color: red;">Method, the choice of the VOACAP propagation model: Auto, Ducted, and Ray-hop (default: Auto)</span>.<br />
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</p><ol>
<li><b>The default "Auto" or automatic model</b> refers to Method 30 in the VOACAP speak. It's a propagation model that chooses automatically either the ray-hop model or the ducted (forward-scatter) model to predict the signal power. There is also a smoothing function for ranges of 7,000 km or greater.</li>
<li><b>The (forced) "Ducted" model refers to Method 21 in the VOACAP speak</b>. Typically, this model is used for paths of 10,000 km or more. The Ducted model forces VOACAP to simulate the ducted or forward-scatter mechanisms that can prevail usually at distances having three or more hops. This model may produce unrealistic results at shorter distances where the ray-hops should occur.</li>
<li><b>The (forced) "Ray-hop" model refers to Method 22 in the VOACAP speak</b>, typically used for all circuits less than 10,000 km. It's a model that contains multiple ionospheric reflections, and includes all of the ionospheric and earth bounce losses. This model may produce extremely pessimistic predictions at the distances beyond the third ionospheric hop where ducted/forward scatter mechanisms can occur.</li>
</ol><p>
<br />
<span style="color: red;">Min. TOA, or the minimum takeoff or arrival angle for antennas</span>. This option offers angle values at the steps of 1 degree, starting from 0.1 degrees, up to 5 degrees. My default value has so far been 0.1 degrees, due to some practical reasons, but now I have chosen a new default, 3.0 degrees.</p><p>If you use a Min.TOA of 0.1 degrees with antennas of higher takeoff angles, VOACAP can miss the most reliable propagation mode which is at a higher angle. How
can this be? We have to remember that VOACAP only considers 3 modes for
each ionospheric layer. So if VOACAP starts with 2F2 mode, then only
the 3F2 mode and the 4F2 mode will be considered for the most reliable
mode. <br /></p><p>Should you have highly efficient antennas with very low take-off angles, then please use the Min.TOA of 0.1 degrees. So, setting the Min.TOA really depends on the antennas you use.<br /></p><p>In the VOACAP literature, a value of 3 degrees is also commonly recommended, as it can be a common lowest angle for arriving skywave signals due to the roughness of the terrain. Also, 3 degrees may be a good choice if your antennas are not located in a flat, unobstructed area. And if you are using isotropic antennas, you should avoid huge amounts of antenna gain at angles below 3 degrees. You are encouraged to experiment between 0.1 and 3 degrees to see differences in predictions, using different antennas.<br />
<br />
<b>Coverage Area Settings</b><br />
<br />
From the usability point of view, I feel that it makes sense to allow the user to enter some input values separately for coverage maps. You can choose the year, month, the UTC time, the plotting time range (Range), the band, as well as the TX and RX antennas.<br />
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At "UTC", choose the start time for your maps. The default is the current UTC hour.<br />
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Also for "Range", choose the time period for the maps to be plotted on screen. The default is 1, i.e. the map for the current hour. You can choose time periods of up to 12 hours, so to cover a 24-hour period, you will only need to make two runs. Unfortunately, running and plotting 24 hours, or 24 coverage maps, at one go takes a considerable amount of time and processing power, and may result in a server connection time-out, hence 12 hours is the limit. Currently, even running more than 6 hours may lead to a time-out on the server.<br />
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<b>Propagation Planner Settings</b><br />
<br />
The "DX Sites" allows you to choose from either CQ Zones or ITU Zones as well as all DXCC countries or DXCC entities by continent. Propagation Planner predictions use all the point-to-point settings as their input values, e.g. the Antennas, SP/LP selection and the Es setting, TX Mode & Power.</p><p><b>TX Antenna Analysis Settings</b></p><p>You can select a set of antennas whose performance can be evaluated against each other. Almost all of the available antennas can be evaluated. When clicking on the "Antenna" button below the world map, VOACAP will run all the TX antennas for the user-defined circuit on the given month. Note that these antenna sets are TX antennas, and the user-defined TX antennas will be overwritten; however, the used-defined RX antennas per band will be used.</p><p>The antenna codes are as follows:</p><p></p><ul><li>ISOTROPE = Isotrope, 0 dBi gain</li><li>HVD025 = Half-Wave Vertical Dipole, feed at 0.25wl AGL</li><li>V14 = 1/4 wl Vertical, with Average Ground</li><li>V14GD = 1/4 wl Vertical, with Good Ground</li><li>V32 = 3/2 wl Vertical, with Average Ground</li><li>V58 = 5/8 wl Vertical, with Average Ground</li><li>DxxM = Horizontal Half-Wave Dipole at xx meters AGL</li><li>3ELxxM = Horizontal 3-element Yagi at xx meters AGL</li><li>5ELxxM = Horizontal 5-element Yagi at xx meters AGL</li><li>8ELxxM = Horizontal 8-element Yagi at xx meters AGL</li></ul><p><b>Take-off Angle Analysis Settings</b></p><p>You can select the time period of the entire year or the current month to evaluate how the antennas you have selected for the bands will cover the take-off angles predicted for the circuit. Press the "TO Angle" button below the world map to run the take-off angle evaluation.<br /></p><p>
</p><p><br />
<span style="color: red;">e) The "Prop Charts" button</span>. This button will display 15 toggleable prediction charts for all amateur radio bands from 10 meters (28 MHz) to 80 meters (3.5 MHz). The charts show e.g. the probability (or, the REL parameter in the VOACAP language) for a communication contact (i.e. a QSO) between the TX and RX sites. See more below.<br />
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<span style="color: red;">f) The "Prop Wheel" button.</span> This button will display the famous 24-hour Propagation Prediction Wheel, showcasing the REL parameter only (REL = probability of a successful communication, see colors for the probability percentage). Keep this window open as you move the markers on the map, or change any settings. The predictions will change on the screen on-the-fly!<br />
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</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjv8CjYNFkD5zL7iPYVOmgZResiqtGrAUN4fJoZXx4y6bBIvtHcLLL3qY7yebPRbl9Bhk46rd1_mEEzDBILG31r2r1JoWDWC75aIcoC1h0eL9a_5ipiq5znrKmXOs6MTDfq-q_JO2H6i_k/s1600/voacap-propagation-wheel.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="488" data-original-width="479" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjv8CjYNFkD5zL7iPYVOmgZResiqtGrAUN4fJoZXx4y6bBIvtHcLLL3qY7yebPRbl9Bhk46rd1_mEEzDBILG31r2r1JoWDWC75aIcoC1h0eL9a_5ipiq5znrKmXOs6MTDfq-q_JO2H6i_k/s1600/voacap-propagation-wheel.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The 24-hour Propagation Prediction Wheel, displaying the REL parameter results.<br />Your quick guide to propagation ... but be sure to take a look at more detailed analysis charts, e.g. "Prop Charts", too.</span></td></tr>
</tbody></table>
<br />
<h3>
16 different propagation predictions & tools available</h3>
<br />
There are altogether 23 different point-to-point and coverage map services available as clickable buttons below the world map.<br />
<br /><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjG52l-QBcOWx1uwGVVfU0iWtJCXIEny9NUUQWJGlXiYr2InnJvd1CGnGs-DGK0qgNoG2yojB0LlHyWxRBYZSLaDbqVbei3vJei07D5-TI95a0zyMlowo7F-n73Gi07IAMJHFqt08iF1c6AV816kDLzkdjKBEFeFU4OZMq8vaUb0KoWCXHMkYFCxKat21o/s1294/voacap-manual-services.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="62" data-original-width="1294" height="30" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjG52l-QBcOWx1uwGVVfU0iWtJCXIEny9NUUQWJGlXiYr2InnJvd1CGnGs-DGK0qgNoG2yojB0LlHyWxRBYZSLaDbqVbei3vJei07D5-TI95a0zyMlowo7F-n73Gi07IAMJHFqt08iF1c6AV816kDLzkdjKBEFeFU4OZMq8vaUb0KoWCXHMkYFCxKat21o/w640-h30/voacap-manual-services.jpg" width="640" /></a></div>Any of these green prediction service buttons provide a specific prediction in its own window. Click image to enlarge.<p><br />
</p><h4>
1. “Prop Charts” button</h4>
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Clicking the "Prop Charts" button on the right side of the map display 15 toggleable prediction charts for all amateur radio bands from 10 meters (28 MHz) to 80 meters (3.5 MHz). The charts show e.g. the probability (or, the REL parameter in the VOACAP language) for a communication contact (i.e. a QSO) between the TX and RX sites. The "REL Short-Path" chart is the default. For most users, this chart may be enough for an overall understanding of the predicted propagation conditions. Other key prediction charts include SDBW (Signal Power) and MUFday. The calculations are available both via Short-Path and Long-Path.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjRDtR6pumTwUikPwxJPZ75-8iYOHOtXawgcKIsvLU0-OjUWUi92lz56lngj3MVKBlnMRWPUfSQXj3WlisT-1Nfqv7-Xu3R_7P6Tgy3GHaGw-H8hHpVPFqqQlZCZwrip2eqYKQDicdQIN4/s1600/voacap-hf-left-predictions.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="730" data-original-width="501" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjRDtR6pumTwUikPwxJPZ75-8iYOHOtXawgcKIsvLU0-OjUWUi92lz56lngj3MVKBlnMRWPUfSQXj3WlisT-1Nfqv7-Xu3R_7P6Tgy3GHaGw-H8hHpVPFqqQlZCZwrip2eqYKQDicdQIN4/s1600/voacap-hf-left-predictions.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Keep this window open, choose your output parameter, or the band of interest, and then change the TX and/or RX marker on the map. You will see the changes immediately in the prediction graph selected.</span></td></tr>
</tbody></table>
<br />
The charts visualizing multiple output parameters contribute to a better assessment of HF propagation. You can paint the big picture with a single VOACAP output parameter but, for a more accurate picture, you will need (at least) three: REL (QSO reliability), SDBW (signal power), and MUFday.<br />
<br />
Each chart offers multi-colored lines for the various parameters. And thanks to the JavaScript framework (plotly.js) used for plotting these graphs, all visible legend parameters/frequencies can be toggled on and off by clicking on the legend values on the bottom of the graphs, helping the user focus on relevant parameters/frequencies only. Also, there is a versatile toolbox on the top-right corner of each graph that allows the user to save the graph as PNG, zoom in/out, compare results data on all frequencies on mouse hover, pan the chart, and more.<br />
<br />
But let's now make a recap of what the three parameters -- REL, SDBW, and MUFday -- mean to you.<br />
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<b><span style="color: red;">The REL or Circuit Reliability</span></b>. The REL is related to VOACAP's output parameters of SNR (Signal-to-Noise Ratio) and REQ.SNR (Required Signal-to-Noise Ratio), and is defined as a circuit reliability factor. It tells us the percentage of days in the month when the SNR value (which is not shown in the charts as a separate parameter) will equal to or exceed the REQ.SNR. The REQ.SNR is an internal value set by me, related to the transmitting mode selected. For CW, the REQ.SNR is set to 19 (dB-Hz), and for SSB, it's 38 dB-Hz.<br />
<br />
<b><span style="color: red;">SDBW or Signal Power</span></b>. The Signal Power distribution tells us what levels of signal power at the receiver are to be expected over the days in the month on the given frequency at the given hour.<br />
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The SDBW indicates the dBW (the strength of a signal expressed in decibels relative to one watt) value (the green line in the chart) that can be maintained on 50% of the days (i.e. on 15 days) in the month. In a similar fashion, the SDBW90 indicates the dBW or signal strength value that can be maintained on 90% of the days (i.e. on 27 days) in the month. And finally, the SDBW10 is the dBW value that can be maintained on 10% of the days (i.e. on 3 days) in the month. However, it does not tell us which days are good or which days are bad. The SDBW10 and SDBW90 values are the top and bottom boundaries (respectively) of the light-gray area that is now always visible in all band-by-band prediction charts.<br />
<br />
<b><span style="color: red;">The MUFday</span></b> will tell us what percentage of the days in a month at that hour will be below the predicted MUF (Median Maximum Usable Frequency) for the most reliable mode (MRM). The MRM is the mode with the highest reliability of meeting the Required Signal-to-Noise Ratio, or REQ.SNR (see above).<br />
<br />
The REL and MUFday data is presented as percentages from 0 to 100 (%) whereas the Signal Power (SDBW) data is shown as dBW values from -164 to -103. The value of -164 is an extremely low noise value of my own choosing, and the next value of -157 represents a median S-meter reading of S0. The value of -103 corresponds to a median S-meter reading of S9. The steps are 6 dB or one S-meter reading step.<br />
<br />
These three output parameters are being calculated via Short-Path and Long-Path.<br />
<br />
<b>Beware of extremely wide Signal Power distributions</b><br />
<br />
Whenever you see that a Signal Power distribution is extremely wide, e.g. ranging from the S-Meter reading of S0 to S8 at any given hour, you are getting into the noise of the program, meaning that VOACAP will give predictions even when it has no idea what is going to happen. If we believe the prediction, then VOACAP is saying that 80% of the days of the month (bounded by SDBW90 and SDBW10) will have a Signal Power somewhere between S0 and S8. That is a spread of 48 dB! If the program could talk, it would tell you that it doesn't have a really good idea what is going to happen on that frequency at that hour.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi71HcE91Slj_uV746bLpqYeuG3EwSquHag8Xm7ju_UPhPFLG9lbrgj8DHeZCoTwQHTABR2GxOlidWcOxF4BSvJVakgtAavnowPxGdVv7IbYeBDZ86pg6BG3aaYa8LX8_caRZrYDuNr_pE/s1600/sdbw-distribution.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="298" data-original-width="470" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi71HcE91Slj_uV746bLpqYeuG3EwSquHag8Xm7ju_UPhPFLG9lbrgj8DHeZCoTwQHTABR2GxOlidWcOxF4BSvJVakgtAavnowPxGdVv7IbYeBDZ86pg6BG3aaYa8LX8_caRZrYDuNr_pE/s1600/sdbw-distribution.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The area filled with light-gray (= Short-Path Signal Power distribution) is bounded by the SDBW10 (top) and SDBW90 (bottom) values. Times and frequencies with extremely wide Signal Power distributions are not reliable enough. Typically, in such cases, the MUFday values are also low.</span></td></tr>
</tbody></table>
<b><span style="color: red;"><br />So, how to use these charts?</span></b> I regularly follow this sequence:<br />
<br />
<ol>
<li>Check the bands of the best REL values for the path in question. You can use the Propagation Wheel for that purpose.</li>
<li>Then go to the Propagation Charts, and check the SDBW values for the best bands.</li>
<li>When you have your candidate bands selected, then go to the specific charts for those bands.</li>
<li>In band-by-band charts, pay attention to MUFday values, and the signal power (SDBW) distribution (the light gray area). If the distribution is extremely wide, there is a chance that VOACAP unfortunately does not have a good idea of what's going on.</li>
<li>Be sure also to check the Long-Path predictions! On long-haul paths, Long-Path may bring nice surprises.</li>
</ol>
<br />
Then again, three more advanced prediction options are available, and these predictions can be calculated by clicking any of the three buttons below the Prediction Charts section:<br />
<br />
<h4>
2. Band-by-band Prediction, or all Prediction Charts on one page</h4>
<br />
If you wish to see all the prediction charts displayed on a single page available under the “Predictions” button on the right side of the map, click the button labeled "Band-by-band Prediction".<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjjoNFiK9K9RVeH2PWEMGOq6cpm1dUIwD9cLyoCz1boTIz6FcWGkDpGHcbYCzdomMmgBNPZ46RijaXmLRDZME7NnpZm9Wpo0GghztZilZRhZ-Fwv0Kil2ClAr_3ATsajR8Rt9sjqw6SWg/s1600/voacap-hf-band-by-band.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="793" data-original-width="1422" height="356" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjjoNFiK9K9RVeH2PWEMGOq6cpm1dUIwD9cLyoCz1boTIz6FcWGkDpGHcbYCzdomMmgBNPZ46RijaXmLRDZME7NnpZm9Wpo0GghztZilZRhZ-Fwv0Kil2ClAr_3ATsajR8Rt9sjqw6SWg/s640/voacap-hf-band-by-band.jpg" width="640" /></a></div>
<br />
<br />
<h4>
3. Best FREQ</h4>
<br />
The Best FREQ button provides an assessment of the Best Operating Frequencies for every hour of the day in a month for the circuit chosen. This means that all ham radio bands are being considered and, after a careful evaluation, the three best bands will be displayed, together with some VOACAP prediction data.<br />
<br />
On the output page, the best operating frequencies can be found in the rightenmost columns: FREQ1 (primary), FREQ2 (secondary), and FREQ3 (tertiary). On the left, you will have the UTC hours from 1 to 24. And the other columns from left to right are as follows:<br />
<br />
<ul>
<li><b>SDBW (or Signal Power at the receiver)</b>: the dBW (the strength of a signal expressed in decibels relative to one watt) value that can be maintained on 50% of the days (ie. on 15 days) in the month. The S-Meter Signal Strength is displayed in parentheses after the dBW value.</li>
<li><b>REL (or Circuit Reliability)</b>: percentage of days in the month when the SNR value will equal to or exceed the REQ.SNR (the threshold value for the given transmit mode); for example, the threshold value (= REQ.SNR) for CW is 24 (dB-Hz)</li>
<li><b>SNR (or Signal-to-Noise Ratio)</b>: the median dB-Hz value that can be maintained on 50% of the days (i.e. on 15 days) in the month. So, if the SNR value is lower than the threshold or REQ.SNR value for a mode (CW = 24, SSB = 38, AM = 49, etc.), then not so great propagation may be expected at all times.</li>
<li><b>MUFday</b>: percentage of the days in a month at that hour will be below the predicted MUF (Median Maximum Usable Frequency) for the most reliable mode (MRM).</li>
<li><b>FOT (or Frequency of Optimum Traffic)</b>: also known as the Optimum Working Frequency for the hourly MOF (median maximum observed frequency) distribution. At the FOT, communication can be supported on 90% of the days (27 days) in the month.</li>
<li><b>MUF (or Median Maximum Usable Frequency)</b>: the median maximum usable frequency for a given ionospheric path, month, SSN and hour. On each day of the month at this hour, there is a maximum observed frequency (MOF) for a mode. The median of this distribution is called the MUF. Therefore, here MUF is not the maximum usable frequency in terms of communications. In other words, the MUF is the frequency for which ionospheric support is predicted on 50% of the days of the month, ie. 15 days out of 30 days.</li>
<li><b>HPF (or Highest Possible Frequency)</b>: at the HPF, communication can be supported on 10% of the days (3 days) in the month.</li>
</ul>
<br />
Now, three Best Frequencies are being reported in the output. The SDBW, REL, SNR and MUFday values are reported for the Best Frequency (FREQ) only. In many cases, the Best and Second Best Frequency can be quite equal in performance so it can be hard to tell which one is actually better. However, on the other hand, the Third Best can sometimes be just a theoretical (or even an impossible) choice in practice.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXqT9qSMRSrs2y3gmMEI-HazNPQWb9Mm30wb08C21rD_dkugQVN6BeTaDwmxHIHqrZc0x1FUUnpxw11m_W07cmLwQfz7gcE9wR3qVmFeI2yx-mvOpuf262sBtKWStnRzYls44aK9XB2uo/s1600/best-operating-frequencies.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="499" data-original-width="771" height="414" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXqT9qSMRSrs2y3gmMEI-HazNPQWb9Mm30wb08C21rD_dkugQVN6BeTaDwmxHIHqrZc0x1FUUnpxw11m_W07cmLwQfz7gcE9wR3qVmFeI2yx-mvOpuf262sBtKWStnRzYls44aK9XB2uo/s640/best-operating-frequencies.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The best operating frequencies from Bouvet to my location on February 2018.<br />Primary = Best FREQ, Secondary = Second Best FREQ, Tertiary = Third Best FREQ</span></td></tr>
</tbody></table>
<br />
It should be noted, though, that FOT, MUF and HPF cannot be used alone for reliable propagation predictions. The best predictions consider Signal Power, Circuit Reliability, and Signal-to-Noise Ratio values. And this is also what the assessment of the best operating frequency for each hour is based on.<br />
<br />
Please be warned, though, that, as a consequence, there can be hours with the "best" operating frequency which does not, in reality, support any communication! The reason can be that the Signal Power, or Circuit Reliability, or Signal-to-Noise Ratio are too low at that hour.<br />
<br />
In order to indicate that there can be problems with the best operating frequency given, there can be three signs after the Best Frequency (FREQ): - (minus), + (plus), or * (star). The minus sign means that the Signal-to-Noise Ratio predicted is below zero (i.e., a negative value); the plus sign means the REL value is below 10% but the median Signal Power is still barely above the noise; the star sign means that the REL value is below 10% and the median Signal Power is also more or less under the noise.<br />
<br />
The minus, plus and star signs will be applied to the Best Frequency only. So, if the Best Frequency will be flagged with any of these signs, please note that the second best or the third best frequency will not be any better in performance but likely much worse.<br />
<br />
<h4>
4. REL | SDBW | SNR, or the original VOACAP point-to-point prediction graphs</h4><p>
<br />
The “REL | SDBW | SNR” graphs were the first graphs generated at the VOACAP Online Point-to-Point site, and by pressing this button, the detailed propagation prediction graphs will be calculated for the entire frequency range from 2 MHz to 30 MHz, showing the REL (Circuit reliability) and S DBW (Signal Power) graphs for the circuit.<br />
</p><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_awNoFpZ8YqW42x1E4O0of-49tINuWvR98oaaec37re5wlSaHiwV3Uolbs_zcPyaAyDn_dU9z39hXjvGw0rOQp0BceQS38n-AhTmk-Bkactc50dkpCAXnrwBGq-hDhmZwPbGshH0WMuE/s640/voacap-rel2.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="594" data-original-width="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_awNoFpZ8YqW42x1E4O0of-49tINuWvR98oaaec37re5wlSaHiwV3Uolbs_zcPyaAyDn_dU9z39hXjvGw0rOQp0BceQS38n-AhTmk-Bkactc50dkpCAXnrwBGq-hDhmZwPbGshH0WMuE/s16000/voacap-rel2.jpg" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">The Circuit Reliability (or REL) graph, one of the three graphs calculated for the month chosen.</td></tr></tbody></table><br /><h4>
5. All-year Prediction, or point-to-point prediction tables for all months available at once</h4>
<br />
The All-year Prediction calculates the point-to-point predictions for the circuit (from TX to RX), covering the entire year and more if possible. The number of prediction tables generated will depend on the Sunspot Number predictions available from SIDC in Belgium. The colors in the table indicate the probability of making a contact between the TX and RX, using the TX mode selected (WSPR, FT8, CW, SSB or AM). All user-settable input parameters will be observed, except the Sunspot Number (SSN).<br />
<br />
The All-Year Prediction tables are extremely informative as they nicely combine the Circuit Reliability (REL), Signal Power (S DBW) and MUFday data as well as sunrise/sunset times for TX and RX in one compact, interactive format.<br />
<br />
So, with the introduction of MUFday in all assessments, there will be more gray cells in the prediction tables from now on.<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSHtoCu_AWcJW5QT5lAGGvC_5R7Q4MqF7EKkDvYt4X9jSzlp-S7B-5IMiyK2DBAkweyzNJEFlQYUXEYcZM1luuyDbhztEdLBxULiCcmcvomm79ORL-MMdnmOhunljJyxJVSTcN9dV2Ryc/s1600/voacap-hf-all-year-prediction.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="218" data-original-width="387" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSHtoCu_AWcJW5QT5lAGGvC_5R7Q4MqF7EKkDvYt4X9jSzlp-S7B-5IMiyK2DBAkweyzNJEFlQYUXEYcZM1luuyDbhztEdLBxULiCcmcvomm79ORL-MMdnmOhunljJyxJVSTcN9dV2Ryc/s1600/voacap-hf-all-year-prediction.jpg" /></a></div>
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</div>
<div class="separator" style="clear: both; text-align: center;">
</div>
<br />
<br />
<b><span style="color: red;">On lower frequencies</span></b>, the color of gray does not indicate any probability value, in contrast to all other colors used. Instead, gray shows that, although VOACAP does not predict any probability for that specific hour (R=0% in the pop-up window), some signal power (S in the pop-up window) has been predicted which may translate into workable conditions. So, in a sense, gray indicates "a gray area" where QSOs may be possible.<br />
<br />
<b><span style="color: red;">On higher frequencies</span></b>, typically on Above-the-MUF frequencies, the color of gray is a sign of extremely poor probabilities. These are actually cases where VOACAP predicts positive REL values but unfortunately VOACAP does not know what's really happening up there. If you take a closer look at the values reported in the pop-up window over the cell (the R, S and M values), the S (Signal Power) value can be very low (e.g. -164 and below which means that there is hardly any signal in the noise).<br />
<br />
Let me again explain the nature of MUFday as concretely as possible. The value of the MUFday is the fraction of the days in a month at that hour that the operating frequency is below the MUF for the most reliable mode (that is, the mode with the highest reliability of meeting the required Signal-to-Noise Ratio, or SNR). So, on higher frequencies, I have now set the threshold to 10% for MUFday in my assessments. This means that if the MUFday value is less than 10% (or less than 3 days), then the frequency hour cell will be colored gray. And it's totally ok, as this actually means that for more than 90% of the days in a month, QSOs are likely not to happen. The odds are pretty poor.<br />
<br />
<b>Recapping the R, S and M values</b><br />
<br />
The R is VOACAP's REL or QSO probability in percentages, and the S is VOACAP's S DBW or Signal Power value in dBW. For instance, the signal power value of -164 can be considered to be on the verge of the noise in remote, extremely low-noise locations whereas the S DBW value of -103 corresponds to S9 on the S meter. Read more about translating the signal power values (S DBW) into S-meter values here: <a href="http://www.voacap.com/s-meter.html" target="_blank">http://www.voacap.com/s-meter.html</a>.<br />
<br />
And finally, the new M parameter is VOACAP's MUFday value in percentages, indicating the probability for the operating frequency on that hour being BELOW the median MUF calculated.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiex8MunhASgl_d4TZIVY_J5q_0D-JF-j9_kEUMJJbGpbc11c-ErvE27xAnY8priO7fM_j6O4kTWawWrDaM9ooYJ3P7Oe8qvJJjlXODRs-aESH-f_dT8nIOJ8LTU4aAEJwpP9fnqBv-ums/s1600/VOACAP+all-year+prediction.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="525" data-original-width="396" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiex8MunhASgl_d4TZIVY_J5q_0D-JF-j9_kEUMJJbGpbc11c-ErvE27xAnY8priO7fM_j6O4kTWawWrDaM9ooYJ3P7Oe8qvJJjlXODRs-aESH-f_dT8nIOJ8LTU4aAEJwpP9fnqBv-ums/s1600/VOACAP+all-year+prediction.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">An all-year prediction for the circuit, showcasing the months of January 2017 and February 2017.</span></td></tr>
</tbody></table>
<br />
In the table, the elements of the top row are as follows (from left):<br />
<br />
<ol>
<li>label for TX and RX,</li>
<li>Short-path (SP) or Long-path (LP),</li>
<li>the distance (kilometers & miles) of the circuit,</li>
<li>the bearing (in degrees from True North) from TX to RX, and</li>
<li>the Sunspot Number (SSN) used for calculations.</li>
</ol>
<b><span style="color: red;">Below each prediction table, the sunrise and sunset times for TX and RX locations</span></b> have been calculated and visually presented in the table cells below the UTC time row. The dark gray color denotes night-time and white day-time periods. The exact sunrise (SR) and sunset (SS) times (in UTC) will come up as you hover the mouse over the TX and RX label texts on the left column. Here, in this example, the sunrise (SR) at TX is at 0605 UTC and the sunset (SS) at 1813 UTC. The similar calculations are available for the RX site, too. The day used in the calculations is always the 15th day of the given month.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_mGlBhkDGGus5A5vNw_lo3m4gM7iVkF1LPJJtU2N8xVysi_Ez6bxXTjQs3F4VeSE-F7CSXWVkhlddX_aj_vMvWL6OrmHTIdDiEmXu0BCvr2Gbgwiy4eqgRAgSMI2A5Yj81GrH8oaL2kU/s1600/VOACAP+interactive+sun+times.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="227" data-original-width="392" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_mGlBhkDGGus5A5vNw_lo3m4gM7iVkF1LPJJtU2N8xVysi_Ez6bxXTjQs3F4VeSE-F7CSXWVkhlddX_aj_vMvWL6OrmHTIdDiEmXu0BCvr2Gbgwiy4eqgRAgSMI2A5Yj81GrH8oaL2kU/s1600/VOACAP+interactive+sun+times.jpg" /></a></div>
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<br />
<b><span style="color: red;">All colors, except gray, indicate QSO-making probabilities</span></b>. In the prediction table per se, white means 0%, blueish 10%, greenish 30-40%, yellowish 50-60%, yellow-orangeish 70-80% and orange-reddish 90%, and pure red 100%. The color of gray does not indicate any probability value. Instead, it shows that, although VOACAP does not predict any probability for that specific hour, some signal power has been predicted which may translate into workable conditions. So, in a sense, gray indicates a heads-up note -- "a gray area" where QSOs may (or may not) be possible. Typically, these gray areas can mostly be found in low-band predictions (40 to 80 meters).<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXQKNX5KuhfZi-xzAodBBwIbdz_rWsI8b5z9XdAujje1O6601v9JLFmefqI86Het_HYeMoJlHrGSNoUvVkDMBkcs3O7GWpW8TOfrxhzDjKVGJM4Im3r7zpdRW3Dl1He4stfMkiBUsxzco/s1600/VOACAP+color+scale.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="27" data-original-width="430" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXQKNX5KuhfZi-xzAodBBwIbdz_rWsI8b5z9XdAujje1O6601v9JLFmefqI86Het_HYeMoJlHrGSNoUvVkDMBkcs3O7GWpW8TOfrxhzDjKVGJM4Im3r7zpdRW3Dl1He4stfMkiBUsxzco/s1600/VOACAP+color+scale.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Propagation predictions use a color scheme from white (worst) to red (best).</span></td></tr>
</tbody></table>
<br />
<b><span style="color: red;">All predictions charts start at 01 hours UTC</span></b>. You may ask, "Why not start at 00 UTC?". Well, it's a matter of taste. All VOACAP predictions span 60 minutes but not necessarily the way you may think. A prediction for 01 UTC does not span from 01:00 to 02:00 but, in fact, from 00:30 to 01:30 UTC! So, I decided, being inspired by the original makers of VOACAP, to start at 01 UTC and end at 24 UTC. Following the same logic, 24 UTC means a time frame of 23:30 to 00:30 UTC.<br />
<br />
<h4>
6. QSO Window: know your window of opportunity to work DX!</h4>
<br />
The QSO Window offers a unique functionality for exploring the windows of QSO-making opportunities. This service was inspired by Risto OH3UU and Cesar PY2YP.<br />
<br />
By default, on the interactive map, you will see two markers (for TX and RX). Another five markers can be revealed by clicking the triangle-shaped button on the left side of the map. These are the sites of the "competing" locations that are trying to make a QSO with the DX station, too. Now, for you to able to see your chances in relation to the other five, the QSO Window function runs five extra propagation predictions from the five sites to the DX site (RX), and displays the results as interactive charts where you can easily compare the output values to those from your location.<br />
<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOD0MFK0IDVD7O1bjhg4NB-vMkn4SNpWWiRx3E6923BVdZf5_0SUz-M_5pumg-R6UjuKNqS6wsIiBdcfblFe59KxXFqUaRFORwfZzk4lk77F4S0jqXnHquBw1MXMYqsu4UtJwYpEG4KAU/s1600/voacap-hf-qso-window.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="731" data-original-width="1246" height="375" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOD0MFK0IDVD7O1bjhg4NB-vMkn4SNpWWiRx3E6923BVdZf5_0SUz-M_5pumg-R6UjuKNqS6wsIiBdcfblFe59KxXFqUaRFORwfZzk4lk77F4S0jqXnHquBw1MXMYqsu4UtJwYpEG4KAU/s640/voacap-hf-qso-window.jpg" width="640" /></a></div>
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<br />
To fully leverage the new functionality, you should set the location of the Transmitter Site (TX) to your QTH, and the location of the Receiver Site (RX) to that of the DX. The five red markers are additional Transmitter sites, too, and their default locations have been chosen to reflect perhaps a typical set-up:<br />
<br />
<ul>
<li>West Coast USA</li>
<li>East Coast USA</li>
<li>South Europe (Italy)</li>
<li>East Europe/Russia West</li>
<li>Japan</li>
</ul>
<br />
The user can freely set these markers to his/her liking on the map.<br />
<br />
When you have set up the TX and RX locations, the five extra markers, and other input values, then press the "QSO Window" button. A new window will appear with result graphs similar to those offered by the “Band-by-band Prediction”.<br />
<br />
Please note that the five "competing" stations will use the same input values you have set to the Transmitter (TX): the same antennas per band, the same power, the same mode, path, etc.<br />
<br />
<b>Finding the best QSO Windows by band</b><br />
<br />
The results will be displayed band-by-band as interactive graphs for the following VOACAP output parameters:<br />
<br />
<ul>
<li>Median Power Power (SDBW, displayed on a S-meter scale)</li>
<li>Reliability (REL)</li>
<li>Median Signal-to-Noise Radio (SNR)</li>
</ul>
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtdhcoqrWJd6zYCRTpW6qQZyJ9S3uEjKhE0QyZv3EntM642bOtfnRrNv0nCU13zJ7QvR1Vd3ShzKq5Eu_BuMuAfD_lGCVXConlHuiuc671AuswZdpCh8g-h7YM3BeDrkuyexCUbvPz7bE/s1600/qso-window-path-info.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="113" data-original-width="1422" height="50" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtdhcoqrWJd6zYCRTpW6qQZyJ9S3uEjKhE0QyZv3EntM642bOtfnRrNv0nCU13zJ7QvR1Vd3ShzKq5Eu_BuMuAfD_lGCVXConlHuiuc671AuswZdpCh8g-h7YM3BeDrkuyexCUbvPz7bE/s640/qso-window-path-info.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The header of the result page: Short/Long Path, and distance and bearing.<br />Click to enlarge.</span></td></tr>
</tbody></table>
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieueSOxymhJM2mIl6SB0BsDnO2_b_BRQLro-lfF6iZSLC62iTtzAXMqfcMlErAAIt2-LPu5XlyXBE96JFHESIDAoXVYzd6HE2mumv4BE71H63BSUZAHGumytwlBkdN_vrpqeuw5ypUeDw/s1600/qso-window-A-E-coordinates.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="113" data-original-width="1422" height="50" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieueSOxymhJM2mIl6SB0BsDnO2_b_BRQLro-lfF6iZSLC62iTtzAXMqfcMlErAAIt2-LPu5XlyXBE96JFHESIDAoXVYzd6HE2mumv4BE71H63BSUZAHGumytwlBkdN_vrpqeuw5ypUeDw/s640/qso-window-A-E-coordinates.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The header of the result page: The coordinates of the five TX stations (markers A to E).<br />Click to enlarge.</span></td></tr>
</tbody></table>
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<br />
On each graph, each station (TX and stations A to E) has a color of its own, and the legend below the graph shows which color belongs to which stations. As you have set your own QTH to the Transmitter (TX), your color is that of the TX station (typically blue).<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5D4iBafluoLqoMNInGT9P2mRt4ngx1auGdTTM_i0dJnp-njPIEUhfoA4Ssr5HL3WKX_syyxrO1uo-BftP8r6iK9TiUQDnNE_fnTgxKinkt4GXWPB5FiysB1OQ0e8dDnrM93ZsDW4ezjY/s1600/qso-window-result-graphs.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="400" data-original-width="1422" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5D4iBafluoLqoMNInGT9P2mRt4ngx1auGdTTM_i0dJnp-njPIEUhfoA4Ssr5HL3WKX_syyxrO1uo-BftP8r6iK9TiUQDnNE_fnTgxKinkt4GXWPB5FiysB1OQ0e8dDnrM93ZsDW4ezjY/s640/qso-window-result-graphs.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The result graphs for comparing the results -- and finding the best QSO windows!<br style="text-align: start;" /><span style="text-align: start;">Click to enlarge.</span></span></td></tr>
</tbody></table>
<br />
<b><span style="color: red;">All the graphs are interactive</span></b>, which means that you can hover the mouse over the graph and see the results instantly by station. At the bottom of the graph, the UTC hour will be highlighted as you compare the result values with each other. If you feel the graph is too messy and the number of the lines should be reduced, just click on the color of the line in the legend. And if you want to see the line again, just click the legend once more.<br />
<br />
In the Signal-to-Noise (SNR) section, all the graphs have a red dotted horizontal running through the graph. The line has been drawn at 19 dB/Hz, which is to indicate where the threshold for CW copy in terms of SNR has been set.<br />
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<h4>
7. Season</h4><p>
<br />
This service uses the user-entered or automatically determined Sunspot Number (SSN), and calculates the SNR (Signal-to-Noise) at 50%, 60%, 70%, 80% and 90% Reliability, SDBW (signal power at receiver) at the upper decile (10% = 3 days in a month), median (50% = 15 days), and at the lower decile (90% = 27 days) as well as the distribution spread between the lower and upper deciles for the SDBW (dP) and SNR (dS) for each month of the year for the given circuit. The results will be displayed as two overview tables and more detailed analysis tables by HOUR and by FREQUENCY.<br />
<br />
This tool is an asset for more long-term propagation planning, or to choose the best month for a DXpedition.</p><p><br />
</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg93vObjTyLkJD5uEwvttup0OY-yrPsTVTUZogy941w1wvQ74RGcOT16QStKbiCNWwnDD6GHwZ_axwLdx8xI9fW9xh4CFVmzdkBlF9VfjhKDy6_3J7LZ4WM9TxoQTuPx5y6wTN08wiVIdM/s803/voacap-best-reliability-by-hour.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="530" data-original-width="803" height="422" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg93vObjTyLkJD5uEwvttup0OY-yrPsTVTUZogy941w1wvQ74RGcOT16QStKbiCNWwnDD6GHwZ_axwLdx8xI9fW9xh4CFVmzdkBlF9VfjhKDy6_3J7LZ4WM9TxoQTuPx5y6wTN08wiVIdM/w640-h422/voacap-best-reliability-by-hour.jpg" width="640" /></a></div><br /><p><b>The Best Reliability By Hour</b> shows the maximum reliability among all the amateur radio bands from 3 to 28 MHz. For instance, for 01 UTC in January, we can see that there is at least one amateur radio band where the Mode or the Required SNR of 19 dB/Hz (= CW) can be reached 90% of the days in a month (or for 27 days). If the percentage is 80%, then the Required SNR can be reached 80% or 24 days in a month on some band. This table does not show what band would give the best probability; you will need to study the other tables on that result page. And consequently, 70% = 21 days; 60% = 18 days, and 50% = 15 days. When the percentage shows "0" on a white cell background, it means the probability of achieving the Required SNR for the Transmitting Mode is less than 50%.<br /><br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiA4lZok0EhfKGGqyLvyI4F0o5K3mKX2m1KIxUum7APBe-MVrpPclQvRPpkSnMvYG6stihLEnKYHlKfeObVEGTMNBPv50V6QAfaNcGAv8wUel-1Ocqbl-CF5SFsZvM9qhrgKGhGHh9w11M/s801/voacap-best-frequency-by-hour.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="549" data-original-width="801" height="438" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiA4lZok0EhfKGGqyLvyI4F0o5K3mKX2m1KIxUum7APBe-MVrpPclQvRPpkSnMvYG6stihLEnKYHlKfeObVEGTMNBPv50V6QAfaNcGAv8wUel-1Ocqbl-CF5SFsZvM9qhrgKGhGHh9w11M/w640-h438/voacap-best-frequency-by-hour.jpg" width="640" /></a></div><p></p><p><b>The Best Frequency By Hour</b> table shows you the best band among all the amateur radio bands, evaluated by the SNR (Signal-to-Noise ratio) at the Required Reliability of 90% (or the column "S90" in the table). The most potential cells have a specific color which indicated the performance of that hour in the given month. If the cell is white, the performance is not adequate enough. However, please note that coloring is independent of the Required SNR (or Mode) value, which means that the colors do not tell you how well that hour is with regard to the Required SNR we are investigating.</p><p>This table and the "BEST FREQ" analysis are somewhat competing with each other. However, in this table, the only criterium is the SNR at the Required Reliability of 90%, i.e. what is the SNR value which is predicted for 90% of days (or 27 days) in a month.</p><p><b>The detailed Season by Frequency and by Hour</b> tables are available as HTML and as CSV data files for a more personal analysis. The following columns are calculated for all months:</p><ul style="text-align: left;"><li>P10 = Signal Power (dBW) predicted at the upper decile (10%), or for 3 days in a month.<br /></li><li>P50 = Signal Power (dBW) predicted at the median (50%), or for 15 days in a month.</li><li>P90 = Signal Power (dBW) predicted at the lower decile (90%), or for 27 days in a month.</li><li>dP = the spread between the upper (P10) and lower decile (P90) in dB. If more than 47, beware!<br /></li><li>S10 = Signal-to-Noise predicted at the upper decile (10%), or for 3 days in a month.</li><li>S50 = Signal-to-Noise predicted at the median (50%), or for 15 days in a month.</li><li>S60 = Signal-to-Noise predicted at 60%, or for 18 days in a month.</li><li>S70 = Signal-to-Noise predicted at 70%, or for 21 days in a month.</li><li>S80 = Signal-to-Noise predicted at 80%, or for 24 days in a month.</li><li>S90 = Signal-to-Noise predicted at the lower decile (90%), or for 27 days in a month.</li><li>dS = the spread between the upper (S10) and lower decile (S90) in dB. If more than 47, beware! <br /></li></ul><p></p><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsBEtUV70f0IwbJrif9ogR6c0gam5T6SH7DS3ngU51KaJkOAAibscA7jcEXPmdeWDpqltcwg3J8ja7txWMPGBpw0uD7_nqp6tyrnpLTC0gmJUCjeRtCqL0lsIHoYRHm82aiiTbdMvUlTw/s619/voacap-detailed-season-by-frequency.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="522" data-original-width="619" height="541" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsBEtUV70f0IwbJrif9ogR6c0gam5T6SH7DS3ngU51KaJkOAAibscA7jcEXPmdeWDpqltcwg3J8ja7txWMPGBpw0uD7_nqp6tyrnpLTC0gmJUCjeRtCqL0lsIHoYRHm82aiiTbdMvUlTw/w640-h541/voacap-detailed-season-by-frequency.jpg" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Season by Frequency<br /></td></tr></tbody></table><br /> <table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilHmevfc3C4n5eTI8KTggoZx4N86ULfd-7wgnLmi8R6cx5Fm9kURjXTYd47GC7tUdkbNilgbhrJsWl9Vp7X53frupJtW6lQZv5SRdZGkwo5nEbXoRwDO_f0O6gb3LjvVqGT1vknHfqbfE/s619/voacap-detailed-season-by-hour.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="479" data-original-width="619" height="496" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilHmevfc3C4n5eTI8KTggoZx4N86ULfd-7wgnLmi8R6cx5Fm9kURjXTYd47GC7tUdkbNilgbhrJsWl9Vp7X53frupJtW6lQZv5SRdZGkwo5nEbXoRwDO_f0O6gb3LjvVqGT1vknHfqbfE/w640-h496/voacap-detailed-season-by-hour.jpg" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Season by Hour<br /></td></tr></tbody></table><br /><p></p><h4>
</h4><h4></h4><h4></h4><h4><br />8. Planner</h4>
<br />
The Propagation Planner is a comprehensive planning tool for HF contesters and DXers. Until now, the problem has been that you really must be a dedicated enthusiast to make several runs of predictions to maximize your planning effort either in contests or DXpeditions.<br />
<br />
Preparing and planning for any worldwide contest or DX expedition (or hunting a DX) require a thorough analysis of propagation predictions. The propagation predictions help you, so to speak, get a good grasp of the playing field, i.e. where to play and when. The predictions tell you when and on what bands the best openings are in the given direction at a suitable signal strength, so that the QSO rates can be maintained at their best; at what times it’s good to use those valuable long-path openings, and when to focus on working those hard-to-reach areas while the band opens elsewhere at the same time.<br />
<br />
This online version now does all heavy-lifting and number-crunching on the VOACAP server, and visualizes the results in two ways: by CQ or ITU Zones (short-path or long-path) and by band-specific zone charts (short-path or long-path, as you wish). Be warned that there are quite a number of charts to analyze but I am confident all your efforts will greatly be paid off. The tables can easily be copied to word-processing software if you wish to make them fit better on paper. I strongly recommend using the Google Chrome browser to browse the pages as I found that some of the mainstream browsers on some platforms have hard time printing (and even copying) table cells with a background color.<br />
<br />
It all boils down to making optimum use of the openings -- being in the right place at the right time. So, the better predictions you have, the better basis for operating planning. Nevertheless, we must remember that predictions are just that -- predictions, not exact science. And, due to the nature of VOACAP, you must visualize low-band openings with the help of grayline map software such as DX Atlas by Alex VE3NEA or GeoClock by Joe Ahlgren. VOACAP predictions are not so accurate there.<br />
<br />
The results can be viewed zone by zone from the TX site the user provided. The colors indicate the probability of making a QSO between the TX and the Zone in question.<br />
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<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijyq6UTBBu5zEdE7d8nOJF-qomQUBy5tcOy8_mX9keG8SHk9e75Lf4OzFUvrC4_Xqbv5cfePHne7RuK2-ORAbHUaujV5s5B4WKroINbnN7nbyiAo1-sym5fh6DDzIbxP2E0qok7THwFBs/s1600/voacap-planner-zones-solar-info.gif" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="288" data-original-width="384" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijyq6UTBBu5zEdE7d8nOJF-qomQUBy5tcOy8_mX9keG8SHk9e75Lf4OzFUvrC4_Xqbv5cfePHne7RuK2-ORAbHUaujV5s5B4WKroINbnN7nbyiAo1-sym5fh6DDzIbxP2E0qok7THwFBs/s1600/voacap-planner-zones-solar-info.gif" /></a></div>
<br />
<b><span style="color: red;">The elements of the top row are as follows (from left)</span></b>: CQ/ITU zone number, Path from TX to zone, Short-path (SP) or Long-path (LP), month and year, followed by the distance (kilometers & miles) of the circuit, and the bearing (in degrees) from TX to RX.<br />
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<b><span style="color: red;">Below each chart, the sunrise and sunset times for TX and RX locations</span></b> have been calculated and visually presented as horizontal bars. The silver color denotes night-time and white day-time. The exact sunrise (SR) and sunset (SS) times (in UTC) will come up as you hover the mouse over the TX and RX label texts on the left column. Here, in this example, the TX is "enjoying" the polar night so the sun will not rise at all. The date used in these calculations is always the 15th day of the given month.<br />
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<b><span style="color: red;">All charts are interactive</span></b>: if you hover your mouse over table cells, you will see a pop-up text, indicating the (VOACAP's REL) probability in percents, and the (VOACAP's S DBW) signal power values in dBW. For instance, the signal power value of -164 can be considered to be on the verge of the noise in remote locations whereas -103 corresponds to S9 on the S meter. Read more about translating the signal power values (S DBW) into S-meter values here:<a href="http://www.voacap.com/s-meter.html" target="_blank"> http://www.voacap.com/s-meter.html</a> .<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizMT3k6b7zvCwuAB7jGiFVoktAP-vT2lblxE84vjym0enfdvU1TQTpshNt_Xny5YgLw4Avi6qzqxS9oojsMpZ0PdnZCe5MQTdNmJOzEXhLQ_ukB9kY0bhsfk-lYhATW3lCE6ivm-5AfWA/s1600/voacap-hf-planner.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="389" data-original-width="383" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizMT3k6b7zvCwuAB7jGiFVoktAP-vT2lblxE84vjym0enfdvU1TQTpshNt_Xny5YgLw4Avi6qzqxS9oojsMpZ0PdnZCe5MQTdNmJOzEXhLQ_ukB9kY0bhsfk-lYhATW3lCE6ivm-5AfWA/s1600/voacap-hf-planner.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Predictions from KH1 (Baker & Howland Isl) to different zones in June 2018.</span></td></tr>
</tbody></table><p>
<br />
The left-hand side column shows the Zone number and the location within the zone. Many zones are geographically wide so, in many cases, a number of locations have been chosen from that zone to give a fair picture of the propagation possibilities.<br />
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<b><span style="color: red;">All colors - except gray - indicate QSO-making probabilities</span></b>. White means 0%, blueish 10%, greenish 30-40%, yellowish 50-60%, yellow-orangeish 70-80% and orange-reddish 90%, and pure red 100%. The color of gray does not indicate any probability value. Instead, it shows that, although VOACAP does not predict any probability for that specific hour, some signal power has been predicted which may translate into workable conditions. So, in a sense, gray indicates "a gray area" where QSOs may be possible. Typically, these gray areas can mostly be found in low-band predictions charts.</p><p>In addition to the cell colors that indicate the predicted RELIABILITY values, there are also three cell characters that indicate the predicted Signal Power (SDBW) and MUFday probability. This information, combined with the Reliability predictions, will help you select the most suitable time and frequency for the contact.<br /></p><pre>The cell colors reflect the predicted Reliability: red is best, white is worst
The following characters reflect the level of Signal Power: ++, + and ● </pre><pre>++ = Signal Power is S9 or more, and MUFday is 70% or more
+ = Signal Power is S6 or more, and MUFday is 50% or more
● = Signal Power is S1 or more, and MUFday is 30% or more
colored but no char = Signal is S1 or more, but MUFday is less than 30%
white = Signal Power is below or at the noise</pre><p></p><div style="text-align: left;"><h4 style="text-align: left;"><span>9. Planner DIY</span></h4></div><p>This version of the Propagation Planner offers a quick overview of propagation to five freely-adjustable locations. This service uses the same red markers as the QSO Window service.</p><p>The output is as follows (click to enlarge):</p><h4> <div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgH8lZV9x8oCLUNNz2z32iSHYwyL_iO7EMohCEMe7EHST-qGv-uBWT_o8UuA1I2JX9XKeeELwyRrljE7Z6TP0CFfrHl1poIMQtfNA0bHbpn1yF7Wzk7EI4e-95iBv6y4irLN_EMoX2BGiMOJJc5WFdshJYBoOHlGWi6WJTN_clN4tmbnfr5ORrzYnKu4HQ/s1240/voacap-manual-planner-explanation.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="928" data-original-width="1240" height="478" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgH8lZV9x8oCLUNNz2z32iSHYwyL_iO7EMohCEMe7EHST-qGv-uBWT_o8UuA1I2JX9XKeeELwyRrljE7Z6TP0CFfrHl1poIMQtfNA0bHbpn1yF7Wzk7EI4e-95iBv6y4irLN_EMoX2BGiMOJJc5WFdshJYBoOHlGWi6WJTN_clN4tmbnfr5ORrzYnKu4HQ/w640-h478/voacap-manual-planner-explanation.jpg" width="640" /></a></div><br /></h4><h4>10. P2P Grayline, or sunrise/sunset times for the current and next month</h4>
<br />
The Grayline calculates a wealth of solar-related information for the Transmitter and Receiver, and for the geographical midpoint of the circuit, covering the two months: the current and the following.<br />
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<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFGWdnhfV8_KlECxeIsQj7TTgfKAo7dTuJiza9HVEWRBhCf7ZmFan_dJQiFNnoNHFF8Dqb5sh-RIGWvljOc38GU9YV2cN_gLT6mCwyMfXV2cHv3hZsBm0yqoy3TY4gjsGVzdKqOjLgj-g/s1600/voacap-hf-p2p-grayline.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="656" data-original-width="1243" height="336" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFGWdnhfV8_KlECxeIsQj7TTgfKAo7dTuJiza9HVEWRBhCf7ZmFan_dJQiFNnoNHFF8Dqb5sh-RIGWvljOc38GU9YV2cN_gLT6mCwyMfXV2cHv3hZsBm0yqoy3TY4gjsGVzdKqOjLgj-g/s640/voacap-hf-p2p-grayline.jpg" width="640" /></a></div>
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</div>
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There are seven different times which will be calculated for each site (TX or RX): three related to sunrise, three related to sunset, and one related to solar midnight. The eight time parameter (MIDPT MNITE) is the solar midnight at the geographical midpoint of the circuit in question.<br />
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<b>Sunrise-related times</b><br />
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• DAWN = a point in time when the sun is 6 degrees below the horizon before sunrise<br />
• RISE = the sunrise time at the horizon<br />
• POST = a point in time when the sun is 3 degrees above the horizon after sunrise<br />
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<b>Sunset-related times</b><br />
<br />
• PRE = a point in time when the sun is 3 degrees above the horizon before sunset<br />
• SET = the sunset time at the horizon<br />
• DUSK = a point in time when the sun is 6 degrees below the horizon after sunset<br />
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<b>Solar midnight</b><br />
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MNITE (and MIDPT MNITE) = This is the time opposite to solar noon when the sun is closest to the nadir (the direction pointing directly below a particular location), and the night is equidistant from dusk and dawn. The solar midnight rarely coincides with midnight on a clock. Solar midnight is dependent on longitude and time of the year rather than on a time zone. [Wikipedia: https://en.wikipedia.org/wiki/Midnight]<br />
<br />
<b>POST and PRE times</b><br />
<br />
The POST and PRE times are based on an educated choice; there is no pre-meditated scientific theory behind "the 3 degrees above the horizon". We know from experience that the low-band propagation starts to deteriorate at some point after sunrise, and that the propagation starts to get enhanced before the actual sunset, and "3 degrees" was my personal choice for this purpose.<br />
<br />
There can be cases where no time is calculated but "--:--" is shown instead. This means that the sun does not reach the degree position set for the calculation.<br />
<br />
<b>Predicting probable grayline propagation enhancements</b><br />
<br />
Not going to any deeper theoretical discussions here, there are basically three periods of time when distinct propagation enhancements have been reported on low bands.<br />
<br />
These are as follows:<br />
<br />
<span style="color: red;">1. Both the Transmitter (TX) and Receiver (RX) are situated in the terminator zone.</span> In my calculations, the terminator zone has been defined as the zone limited by DAWN and POST (post-sunrise) in the morning as well as PRE (pre-sunset) and DUSK in the evening. If there is an overlap between the Transmitter's and Receiver's morning/evening terminator zones, the times will be colored as follows:<br />
<br />
a) TX DAWN-POST and RX DAWN-POST zones overlapping:<br />
<br />
TX DAWN-RISE-POST: red<br />
RX DAWN-RISE-POST: red<br />
<br />
b) TX DAWN-POST and RX PRE-DUSK zones overlapping:<br />
<br />
TX DAWN-RISE-POST: red<br />
RX PRE-SET-DUSK: blue<br />
<br />
c) TX PRE-DUSK and RX DAWN-POST zones overlapping:<br />
<br />
TX PRE-SET-DUSK: blue<br />
RX DAWN-RISE-POST: red<br />
<br />
d) TX PRE-DUSK and RX PRE-DUSK zones overlapping:<br />
<br />
TX PRE-SET-DUSK: blue<br />
RX PRE-SET-DUSK: blue<br />
<br />
<span style="color: red;">2. The Transmitter (or Receiver) is in the terminator zone and the Receiver (or Transmitter) is in darkness.</span> Whenever this condition is met, the times in the DAWN-RISE-POST and PRE-SET-DUSK columns will be colored in green. This is one of the most common cases for signal enhancement on the low bands.<br />
<br />
<span style="color: red;">3. The Transmitter (or Receiver) is in the terminator zone and the Receiver (or Transmitter) is in darkness AND the midpoint of the path is in the solar midnight.</span> This is a special case of Number 2 in this list but a very important one. Currently, the solar midnight period at the midpoint (labeled as MIDPT MNITE in the tables) is defined as a time period of plus minus 7 minutes from the time calculated and shown in table. The MIDPT MNITE time is the exact calculated solar midnight time but, in my calculations, I consider that the midpoint midnight period is plus minus 15 minutes from that time.<br />
<br />
There can be three colors for the time: black (default), red and blue. When the color is black, the midpoint midnight time does not overlap with the DAWN-RISE-POST or PRE-SET-DUSK times of neither the Transmitter not the Receiver.<br />
<br />
<b>The colors of red and blue will be assigned as follows:</b><br />
<br />
a) Midpoint midnight period and TX Terminator zone (morning or evening) overlapping: RED<br />
b) Midpoint midnight period and RX Terminator zone (morning or evening) overlapping: BLUE<br />
<br />
As a special mention, if the solar midnight period, a period of plus minus 7 minutes from the MNITE time at TX/RX, overlaps with the Midpoint Midnight period, the times in the MNITE column will be colored as follows:<br />
<br />
a) TX midnight period (MNITE) and Midpoint Midnight period overlapping: RED<br />
b) RX midnight period (MNITE) and Midpoint Midnight period overlapping: BLUE<br />
<br />
<h4>
11. Distance</h4>
<br />
This graph shows how the propagation parameters of REL, MUFday, SNR, and SDBW (Signal Power) develop along the Great-Circle Path from TX to RX.<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijioAe7jiFPZmesdGumZRojeBU6ljK2u5X11hFAmo4V4JN4J4rfqHCk6EI5kvXp4uFo79c7zk_nfYAqxOA8_ny0m39kiAmiEyMrWZq8KM0jdbN-ewNYiY7OC66ED6spSp4Itl4w8_5M_s/s1600/voacap-hf-distance.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="461" data-original-width="1022" height="288" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijioAe7jiFPZmesdGumZRojeBU6ljK2u5X11hFAmo4V4JN4J4rfqHCk6EI5kvXp4uFo79c7zk_nfYAqxOA8_ny0m39kiAmiEyMrWZq8KM0jdbN-ewNYiY7OC66ED6spSp4Itl4w8_5M_s/s640/voacap-hf-distance.jpg" width="640" /></a></div>
<br />
<br />
Choose the band of your interest from the Frequency pop-up menu, and use the time slider to change the UTC time.<br />
<br />
A more detailed explanation of the graph:<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkfgBxqO5YxXM_dbuXjrh_EtGqAd7JigPpq0H_UYNGp8GZwI2CJUA3XTqomWz6DA3Vpe_u88t-sfLZ6CG1k25CuFxmSQt7Ul1N0vnOgdYZguq3iUuNSdcTV2_sWRbRLzqe1FdGM5fGhjA/s1600/voacap-p2p-distance-explained.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="483" data-original-width="1123" height="275" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkfgBxqO5YxXM_dbuXjrh_EtGqAd7JigPpq0H_UYNGp8GZwI2CJUA3XTqomWz6DA3Vpe_u88t-sfLZ6CG1k25CuFxmSQt7Ul1N0vnOgdYZguq3iUuNSdcTV2_sWRbRLzqe1FdGM5fGhjA/s640/voacap-p2p-distance-explained.jpg" width="640" /></a></div>
<br />
<br />
<h4>
12. MUF, REL & SDBW Maps</h4>
<br />
This service is able to plot coverage area maps featuring MUF (Maximum Usable Frequency), REL (Circuit Reliability) or SDBW (Signal Power) values. What is more, it can also calculate and display multiple coverage maps at one go. The input values for the coverage maps has a separate section under the “Settings” button.<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpKviGG8xxuCb-ANKjCFDL3i4KzzcG-0YPBLadnuGX7w_QcXj7wUCfcYh_HXh3ab7Z83dqjyTw0lStfPRJqb7AomcCayWVwdLyTiaYoi2MiViNgvoPApq_vxwOYtmxe-OliYyf8yXX2zM/s800/voacap-sdbw19ut.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="360" data-original-width="800" height="288" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpKviGG8xxuCb-ANKjCFDL3i4KzzcG-0YPBLadnuGX7w_QcXj7wUCfcYh_HXh3ab7Z83dqjyTw0lStfPRJqb7AomcCayWVwdLyTiaYoi2MiViNgvoPApq_vxwOYtmxe-OliYyf8yXX2zM/w640-h288/voacap-sdbw19ut.jpg" width="640" /></a></div><br />
<br />
So when viewing the result page with the maps, you can then conveniently print that page to PDF. You may need to install some extra tools such as CutePDF Writer if this functionality is not offered to you by your operating system as standard.<br />
<br />
Please be also advised that all the coverage maps created in the service will be deleted from the server in a more frequent cycle so please do not link directly to the maps produced.<br />
<br />
<h4>
13. DXCC Grayline, or sunrise/sunset/midnight times for all DXCC entities</h4>
<br />
The DXCC Grayline calculates the sunrise, sunset and midnight times for all the defined DXCC entities on the current day. There are also other tools in this service, see more at <a href="http://voacap.blogspot.fi/2016/11/voacap-greyline-user-manual.html">http://voacap.blogspot.fi/2016/11/voacap-greyline-user-manual.html</a><br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEho8FaI8DyzgQtNM6hdB-niBzKrXxbF9nI_91TCv5dknfzoOjt_SsyS_d6vlta1-nLPdeQLXjxhVa7dgexsxb4UzyvyG4kcjKLtYv6rB4ZLEcGtvQmLxg_EBP1niaHmiv23_hEi0euqRbg/s1600/voacap-hf-dxcc-grayline.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="515" data-original-width="610" height="540" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEho8FaI8DyzgQtNM6hdB-niBzKrXxbF9nI_91TCv5dknfzoOjt_SsyS_d6vlta1-nLPdeQLXjxhVa7dgexsxb4UzyvyG4kcjKLtYv6rB4ZLEcGtvQmLxg_EBP1niaHmiv23_hEi0euqRbg/s640/voacap-hf-dxcc-grayline.jpg" width="640" /></a></div>
<br />OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com11tag:blogger.com,1999:blog-8260894794228814400.post-38649361688423239652018-04-29T12:27:00.004+03:002018-04-29T12:29:56.414+03:00Minor changes in the REQ.SNR values and new TX modes at VOACAP OnlineQuite recently, I slightly fine-tuned some of the REQ.SNR values and was inspired to add<b> FT8</b> and <b>WSPR</b> as additional TX modes in the VOACAP Online propagation prediction service after watching a YouTube video where Joe Taylor K1JT talks about WSJT-X.<br />
<br />
The video is really worth watching. Here are the details:<br />
<br />
<pre><a href="https://www.youtube.com/watch?v=j1sWCtVzzak&t=17444s" target="_blank">https://www.youtube.com/watch?v=j1sWCtVzzak&t=17444s</a>
<span style="color: red;"><b>Work the World with WSJT-X</b></span>
Joe Taylor, K1JT</pre>
<br />
On one of his slides, he shows an intriguing table, and, taking his word for it, I made slight modifications to the REQ.SNR values I had initially adopted (except for SSB). His table is this:<br />
<br />
<pre>Weak-Signal S/N Limits
Mode (B=2500 Hz)
SSB: ~+10 dB
MSK144: -8
CW: -15
FT8: -21
JT4: -23
JT65: -25
JT9: -27
QRA64: -27
WSPR: -31</pre>
<br />
As a general rule, to calculate the threshold (or minimum) SNR values for VOACAP (which are termed as "REQ.SNR"), you would use this formula:<br />
<br />
<pre>REQ.SNR [dB-Hz] = SNR [dB] + 10 * log(BW) [Hz]</pre>
<br />
According to sources, the minimum SNR for AM broadcasts is around 13 dB at the RX bandwidth (B). So, applying the formula where B=4200 Hz (quite typical a bandwidth for an AM radio), we will get:<br />
<br />
<pre>REQ.SNR = 13 dB + 10 * log(4200 Hz) = 49 dB-Hz</pre>
<br />
For SSB, people say that the minimum SNR required is around 5 dB. So, using a 2100 Hz bandwidth for SSB, we'll get:<br />
<br />
<pre>REQ.SNR = 5 dB + 10 * log(2100 Hz) = 38 dB-Hz</pre>
<br />
and, for CW, people say that a good operator can copy CW at 0 dB. So, if we use a 100 Hz bandwidth, we'll get:<br />
<br />
<pre>REQ.SNR = 0 dB + 10 * log(100 Hz) = 20 dB-Hz</pre>
<br />
Similarly, converting Joe's SNR Table values to VOACAP REQ.SNR values at dB-Hz, we'll get:<br />
<br />
<pre>SSB REQ.SNR = 10 dB + 10 * log(2500 Hz) = 44 dB-Hz
CW REQ.SNR = -15 dB + 10 * log(2500 Hz) = 19 dB-Hz
FT8 REQ.SNR = -21 dB + 10 * log(2500 Hz) = 13 dB-Hz
WSPR REQ.SNR = -31 dB + 10 * log(2500 Hz) = 3 dB-Hz</pre>
<br />
For SSB, I think +10 dB on Joe's table may be too pessimistic as the minimum limit. If he had used 5 dB, we would have been totally aligned.<br />
<br />
So, this is how the REQ.SNR values have been calculated for VOACAP. I hope this clarifies the matter.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0tag:blogger.com,1999:blog-8260894794228814400.post-70693195684044065612018-02-04T14:09:00.001+02:002018-02-04T20:34:27.983+02:00VOACAP Point-to-Point QSO Window: know your window of opportunity to work DX!I am pleased to announce that I have released a new functionality for exploring the windows of QSO-making opportunities at the VOACAP Point-to-Point (P2P) service at <a href="http://www.voacap.com/p2p" target="_blank">www.voacap.com/p2p</a>. This service has been inspired by Risto OH3UU and Cesar PY2YP.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiG60zaAES4lQIp2TUvuRCm4vcgBURk48N0Iat6HAKtt_BUks3lDVN8EGL4qrjOE8NMObHHP_6Ql2CdQh8U-wdFQkG1mkLJ7UWyps2Hw8XwhJlFhL-dI6HrYKXHEantVfH_IsyxrjGk7zo/s1600/qso-window-input-values.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="" border="0" data-original-height="718" data-original-width="1170" height="392" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiG60zaAES4lQIp2TUvuRCm4vcgBURk48N0Iat6HAKtt_BUks3lDVN8EGL4qrjOE8NMObHHP_6Ql2CdQh8U-wdFQkG1mkLJ7UWyps2Hw8XwhJlFhL-dI6HrYKXHEantVfH_IsyxrjGk7zo/s640/qso-window-input-values.jpg" title="VOACAP Point-to-Point front page" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The front page of the VOACAP Point-to-Point prediction service. The new "QSO Window" button is on the right of the page.<b> Click the image to enlarge.</b></span></td></tr>
</tbody></table>
<br />
Now, on the Google Map on the VOACAP P2P page, you will see not only two markers (for TX and RX) but also five new red (TX) markers, labelled from A to E. These are the sites of the "competing" locations that are trying to make a QSO with the DX station, too. Now, for you to able to see your chances in relation to the other five, the QSO Window function runs five extra propagation predictions from the five sites to the DX site (RX), and displays the results as interactive charts where you can easily compare the output values to those from your location.<br />
<br />
To fully leverage the new functionality, you should set the location of the Transmitter Site (TX) to your QTH, and the location of the Receiver Site (RX) to that of the DX. The five red markers are additional Transmitter sites, too, and their default locations have been chosen to reflect perhaps a typical set-up:<br />
<br />
<ul>
<li>A = West Coast USA</li>
<li>B = East Coast USA</li>
<li>C = South Europe (Italy)</li>
<li>D = East Europe/Russia West</li>
<li>E = Japan</li>
</ul>
<br />
The user can freely set these markers to his/her liking on the map.<br />
<br />
When you have set up the TX and RX locations, the five extra markers, and other input values, then press the "<b>QSO Window</b>" button. A new window will appear with results. If no results will appear, just refresh the result page. It can be that there are too many users at that particular moment.<br />
<br />
Please note that the five "competing" stations will use the same input values you have set to the Transmitter (TX): the same antennas per band, the same power, the same mode, path, etc.<br />
<br />
<h3>
Finding the best QSO Windows by band</h3>
<br />
The results will be displayed band-by-band as interactive graphs for the following VOACAP output parameters:<br />
<br />
<ul>
<li>Median Power Power (SDBW, displayed on a S-meter scale)</li>
<li>Reliability (REL)</li>
<li>Median Signal-to-Noise Radio (SNR)</li>
</ul>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmQRzkvsatOiAG0SM9yLgeK3xWfVsz0bcciJYZ8YUUUedQ-vs5mCCWKpqzzhBfb1CBgsExNDtfb9rAhTCE41M1yyLHo8T_XqBZpvzyxX7-es2MRrav8YbCC0Hr9sMB1M-hoDsE-Hz6-RA/s1600/qso-window-path-info.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="113" data-original-width="1422" height="50" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmQRzkvsatOiAG0SM9yLgeK3xWfVsz0bcciJYZ8YUUUedQ-vs5mCCWKpqzzhBfb1CBgsExNDtfb9rAhTCE41M1yyLHo8T_XqBZpvzyxX7-es2MRrav8YbCC0Hr9sMB1M-hoDsE-Hz6-RA/s640/qso-window-path-info.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The header of the result page: Short/Long Path, and distance and bearing. <b>Click to enlarge.</b></span></td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEip6I0lGxBxFtADwFttdXA_L8jdj4QnhNFqK5YiClDR8LrN6NddkkJNKyaf3rnaE8Z-X92Atgzh423E7g84hfemh9pn4zArq_VD6V2shqQnVvqKgBj3J_aO8vnApSRFZxEXLOEzCsnrulI/s1600/qso-window-A-E-coordinates.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="113" data-original-width="1422" height="50" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEip6I0lGxBxFtADwFttdXA_L8jdj4QnhNFqK5YiClDR8LrN6NddkkJNKyaf3rnaE8Z-X92Atgzh423E7g84hfemh9pn4zArq_VD6V2shqQnVvqKgBj3J_aO8vnApSRFZxEXLOEzCsnrulI/s640/qso-window-A-E-coordinates.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The header of the result page: The coordinates of the five TX stations (markers A to E). <b>Click to enlarge.</b></span></td></tr>
</tbody></table>
On each graph, each station (TX and stations A to E) has a color of its own, and the legend below the graph shows which color belongs to which stations. As you have set your own QTH to the Transmitter (TX), your color is that of the TX station (typically blue).<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwBj3547PtIBatA5ypLUw8EOXhDyE1s1jV8ZUTYPL3Num3j18Ji08XEanyDPVthfkCzoiVToCYAm1l1fHbLnJOmX5fBkvELPfu3_pea5Hzee2h_otyxZTN6EI6Y1_xE1CT3uSPBSrQhxs/s1600/qso-window-result-graphs.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="400" data-original-width="1422" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwBj3547PtIBatA5ypLUw8EOXhDyE1s1jV8ZUTYPL3Num3j18Ji08XEanyDPVthfkCzoiVToCYAm1l1fHbLnJOmX5fBkvELPfu3_pea5Hzee2h_otyxZTN6EI6Y1_xE1CT3uSPBSrQhxs/s640/qso-window-result-graphs.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The result graphs for comparing the results -- and finding the best QSO windows! <b>Click to enlarge.</b></span></td></tr>
</tbody></table>
<br />
All the graphs are interactive, which means that you can hover the mouse over the graph and see the results instantly by station. At the bottom of the graph, the UTC hour will be highlighted as you compare the result values with each other. If you feel the graph is too messy and the number of the lines should be reduced, just click on the color of the line in the legend. Adn if you want to see the line again, just click the legend once more.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrX-rwJJW-qWjXI9njFSSvVgyDLeTSaGu1A2dORvUUfImm7LP4GEjK4nM67_zJA-EYJmkTLu_Kb1scVkvBKxNaIpNtyArtISLYZZy8bcf4h0ceNdsyUskULu5CpojuUu5V_1RU3ow677A/s1600/qso-window-CW-threshold.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="400" data-original-width="476" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrX-rwJJW-qWjXI9njFSSvVgyDLeTSaGu1A2dORvUUfImm7LP4GEjK4nM67_zJA-EYJmkTLu_Kb1scVkvBKxNaIpNtyArtISLYZZy8bcf4h0ceNdsyUskULu5CpojuUu5V_1RU3ow677A/s1600/qso-window-CW-threshold.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><b>This is an example circuit from Finland to Rotuma in February 2018.</b> The SNR of the TX site (Finland) peaks at 9 UTC, with the predicted SNR value of 28 (dB/Hz). So, just about readable! However, as we can see, there can be tremendous QSO walls from sites D (East Europe/Russia West), C (Southern Europe/Italy) and E (Japan).</span></td></tr>
</tbody></table>
<br />
In the Signal-to-Noise (SNR) section, all the graphs have a red dotted horizontal running through the graph. The line has been drawn at 24 dB/Hz, which is to indicate where the threshold for CW copy in terms of SNR has been set.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com4tag:blogger.com,1999:blog-8260894794228814400.post-72134211506676331332018-01-05T17:22:00.000+02:002018-01-07T09:11:29.344+02:00Getting the best operating frequency from VOACAP P2P predictions<span style="color: red;"><b>Updated Jan 6, 2018</b></span>: Primary, Secondary and Tertiary Frequencies reported.<br />
<br />
I am happy to introduce a new functionality at the VOACAP Online P2P (point-to-point) HF propagation prediction service (<a href="http://www.voacap.com/p2p" target="_blank">http://www.voacap.com/p2p</a>), namely assessment of the Best Operating Frequencies for every hour of the day for the circuit chosen. This means that all ham radio bands are being considered and, after a careful evaluation, the three best bands will be displayed, together with some VOACAP prediction data.<br />
<br />
<b>To use the new service, just click on the new button labeled "Best FREQ", located just below the graphs on the front page.</b><br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrHuTliM6FYolz_Y1_Icl_SbfWSagwsxphlwbOlIiwDX0yocfER4VLlwW0_Vp7BH3C4BGNNi5VW5MWf_IIIVUTTjWotUaKa7N4K19_aFrP3duNO1bd8SPFF3ueUEkWM3o9lz6zstZwR90/s1600/FREQ-button.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="523" data-original-width="454" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrHuTliM6FYolz_Y1_Icl_SbfWSagwsxphlwbOlIiwDX0yocfER4VLlwW0_Vp7BH3C4BGNNi5VW5MWf_IIIVUTTjWotUaKa7N4K19_aFrP3duNO1bd8SPFF3ueUEkWM3o9lz6zstZwR90/s1600/FREQ-button.jpg" /></a></div>
<br />
<br />
On the output page, the best operating frequencies can be found in the rightenmost columns: FREQ, FREQ2, and FREQ3. On the left, you will have the UTC hours from 1 to 24. And the other columns from left to right are as follows:<br />
<br />
<ul>
<li><b>SDBW (or Signal Power at the receiver)</b>: the dBW (the strength of a signal expressed in decibels relative to one watt) value that can be maintained on 50% of the days (ie. on 15 days) in the month. The S-Meter Signal Strength is displayed in parentheses after the dBW value.</li>
<li><b>REL (or Circuit Reliability)</b>: percentage of days in the month when the SNR value will equal to or exceed the REQ.SNR (the threshold value for the given transmit mode); for example, the threshold value (= REQ.SNR) for CW is 24 (dB-Hz)</li>
<li><b>SNR (or Signal-to-Noise Ratio)</b>: the median dB-Hz value that can be maintained on 50% of the days (ie. on 15 days) in the month. So, if the SNR value is lower than the threshold or REQ.SNR value for a mode (CW = 24, SSB = 38, AM = 49, etc.), then not so great propagation may be expected at all times.</li>
<li><b>MUFday</b>: percentage of the days in a month at that hour will be below the predicted MUF (Median Maximum Usable Frequency) for the most reliable mode (MRM).</li>
<li><b>FOT (or Frequency of Optimum Traffic)</b>: also known as the Optimum Working Frequency for the hourly MOF (median maximum observed frequency) distribution. At the FOT, communication can be supported on 90% of the days (27 days) in the month.</li>
<li><b>MUF (or Median Maximum Usable Frequency)</b>: the median maximum usable frequency for a given ionospheric path, month, SSN and hour. On each day of the month at this hour, there is a maximum observed frequency (MOF) for a mode. The median of this distribution is called the MUF. Therefore, here MUF is not the maximum usable frequency in terms of communications. In other words, the MUF is the frequency for which ionospheric support is predicted on 50% of the days of the month, ie. 15 days out of 30 days.</li>
<li><b>HPF (or Highest Possible Frequency)</b>: at the HPF, communication can be supported on 10% of the days (3 days) in the month.</li>
</ul>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5io5KFG8u5xH1dwbSnVBO_rjmkRMPvljYHhqqVni7KsTaJ5o2Aaph7Mytas9H_OYuVxK3Fp9WOndgWrAGatZoUVczbL5cT-IcfbsKbiDMqPMxgd8HUWvCdPMy_RT-BQ4r2MN-lEGqLxI/s1600/best-operating-frequencies.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="499" data-original-width="771" height="414" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5io5KFG8u5xH1dwbSnVBO_rjmkRMPvljYHhqqVni7KsTaJ5o2Aaph7Mytas9H_OYuVxK3Fp9WOndgWrAGatZoUVczbL5cT-IcfbsKbiDMqPMxgd8HUWvCdPMy_RT-BQ4r2MN-lEGqLxI/s640/best-operating-frequencies.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The best operating frequencies from Bouvet to my location on February 2018.<br />Primary = Best FREQ, Secondary = Second Best FREQ, Tertiary = Third Best FREQ</span></td></tr>
</tbody></table>
<br />
Now, three Best Frequencies are being reported in the output. The SDBW, REL, SNR and MUFday values are reported for the Best Frequency (FREQ) only. In many cases, the Best and Second Best Frequency can be quite equal in performance so it can be hard to tell which one is actually better. However, on the other hand, the Third Best can sometimes be just a theoretical (or even an impossible) choice in practice.<br />
<br />
It should be noted, though, that FOT, MUF and HPF cannot be used alone for reliable propagation predictions. The best predictions consider Signal Power, Circuit Reliability, and Signal-to-Noise Ratio values. And this is also what the assessment of the best operating frequency for each hour is based on.<br />
<br />
<b>Please be warned, though, that, as a consequence, there can be hours with the "best" operating frequency which does not, in reality, support any communication! </b>The reason can be that the Signal Power, or Circuit Reliability, or Signal-to-Noise Ratio are too low at that hour.<br />
<br />
In order to indicate that there can be problems with the best operating frequency given, there can be three signs after the Best Frequency (FREQ): - (minus), + (plus), or * (star). The minus sign means that the Signal-to-Noise Ratio predicted is below zero (i.e., a negative value); the plus sign means the REL value is below 10% but the median Signal Power is still barely above the noise; the star sign means that the REL value is below 10% and the median Signal Power is also more or less under the noise.<br />
<br />
The minus, plus and star signs will be applied to the Best Frequency only. So, if the Best Frequency will be flagged with any of these signs, please note that the second best or the third best frequency will not be any better in performance but likely much worse.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com1tag:blogger.com,1999:blog-8260894794228814400.post-46105870501111331002017-07-30T23:28:00.000+03:002017-07-30T23:56:20.432+03:00VOACAP Online Point-to-Point User Interface revampedIt happened last night: the familiar 24-hour circular prediction chart was replaced by versatile and detailed propagation prediction charts, 15 charts to be exact, on the front page of the VOACAP Online P2P predictions. <b>URL: <a href="http://www.voacap.com/p2p/index.html" target="_blank">http://www.voacap.com/p2p/index.html</a></b><br />
<br />
The reason is simple: the new charts contribute to better assessment of HF propagation. You can paint the big picture with a single VOACAP output parameter but, for a more accurate picture, you will need (at least) three: <b>REL </b>(used by the earlier 24-hour circular chart which is still available via a separate link: <b><a href="http://www.voacap.com/p2p/index2.html" target="_blank">http://www.voacap.com/p2p/index2.html</a></b>) but also <b>SDBW</b> (signal power) and <b>MUFday</b>. These are now offered to the ham community, in addition to band-by-band predictions, which even visualize the signal power distribution (upper decile, median and lower decile).<br />
<br />
Each chart offers multi-colored lines for the various parameters. And thanks to the JavaScript framework (plotly.js) used for plotting these graphs, all visible legend parameters/frequencies can all be toggled on and off by clicking on the legend values on the bottom of the graphs, helping the user focus on relevant parameters/frequencies only. Also there is a versatile toolbox on the top-right corner of each graph that allows the user to save the graph as PNG, zoom in/out, compare results data on all frequencies on mouse hover, pan the chart, and more.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgas53iZO-7edrO5A83b4i3VHoR3LMzyq6eq-a8DdbuJLH5BngBcqpJ5chledMSk3Scd5AQb4L0ytG1ECY-DR18XVTqRBh_kg3HX5bKnChyqotM4pYrfYhPUl-J5M-NB5pHFEj-fXMPVJM/s1600/new-voacap-p2p-ui.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="817" data-original-width="1096" height="476" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgas53iZO-7edrO5A83b4i3VHoR3LMzyq6eq-a8DdbuJLH5BngBcqpJ5chledMSk3Scd5AQb4L0ytG1ECY-DR18XVTqRBh_kg3HX5bKnChyqotM4pYrfYhPUl-J5M-NB5pHFEj-fXMPVJM/s640/new-voacap-p2p-ui.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><b><span style="color: red;">CLICK TO ENLARGE THE IMAGE</span></b></td></tr>
</tbody></table>
<br />
But let's now make a recap of what the three parameters -- <b>REL, SDBW and MUFday</b> -- mean to you.<br />
<br />
<b><span style="color: red;">The REL or Circuit Reliability</span></b>. The REL is related to VOACAP's output parameters of SNR (Signal-to-Noise Ratio) and REQ.SNR (Required Signal-to-Noise Ratio), and is defined as a circuit reliability factor. It tells us the percentage of days in the month when the SNR value (which is not shown in the charts as a separate parameter) will equal to or exceed the REQ.SNR. The REQ.SNR is an internal value set by me, related to the transmitting mode selected. For CW, the REQ.SNR is set to 24 (dB-Hz), and for SSB, it's 38 dB-Hz.<br />
<br />
<b><span style="color: red;">SDBW or Signal Power.</span></b> The SDBW indicates the dBW (the strength of a signal expressed in decibels relative to one watt) value (the green line in the chart) that can be maintained on 50% of the days (ie. on 15 days) in the month. In a similar fashion, the SDBW90 indicates the dBW or signal strength value that can be maintained on 90% of the days (ie. on 27 days) in the month. And finally, the SDBW10 is the dbW value that can be maintained on 10% of the days (ie. on 3 days) in the month. However, it does not tell us which days are good or which days are bad. The SDBW10 and SDBW90 values are the top and bottom boundaries (respectively) of the light-gray area that is now always visible in all band-by-band prediction charts. The signal power distribution is calculated for Short-Path circuits only. The SDBW values are all translated to corresponding S-Meter readings in the charts.<br />
<br />
<ul>
<li>Read more: <a href="https://voacap.blogspot.fi/2017/07/sdbw-sdbw10-and-sdbw90-predicted-signal.html" target="_blank">Beware of extremely wide Signal Power distributions</a> </li>
</ul>
<br />
<b><span style="color: red;">The MUFday</span></b> will tell us what percentage of the days in a month at that hour will be below the predicted MUF (Median Maximum Usable Frequency) for the most reliable mode (MRM). The MRM is the mode with the highest reliability of meeting the Required Signal-to-Noise Ratio, or REQ.SNR (see above).<br />
<br />
These three output parameters are being calculated via Short-Path and Long-Path.<br />
<br />
At the same time, I changed the default setting for the Transmit & Receive Antenna and Transmit Power. Now the TX & RX antenna is a quarter-wave vertical antenna over a good ground, and the TX power is set to 1.5 kW.<br />
<br />
<b><span style="color: red;">So, how to use the new charts?</span></b> I regularly follow this sequence:<br />
<ol>
<li>Check the bands of the best REL values for the path in question.</li>
<li>Then check the SDBW values for the best bands.</li>
<li>When you have your candidate bands selected, then go to the charts for those bands.</li>
<li>In band-by-band charts, pay attention to MUFday values, and the signal power (SDBW) distribution (the light gray area). If the distribution is extremely wide, there is a chance that VOACAP unfortunately does not have a good idea of what's going on.</li>
<li>Be sure to check the Long-Path predictions, too! On long-haul paths, Long-Path may bring nice surprises.</li>
</ol>
OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com3tag:blogger.com,1999:blog-8260894794228814400.post-61466835371151836682017-07-27T12:05:00.001+03:002017-07-27T12:10:09.068+03:00SDBW, SDBW10 and SDBW90: The Predicted Signal Power DistributionDuring the past few days, two more Signal Power parameters - namely, SDBW10 and SDBW90 - were added to the VOACAP D-I-Y Charts and the similar charts at VOACAP Online Point-to-Point service. As a result, these values are being used to create an area filled with the light-gray color, showing the Signal Power distribution. It's calculated for Short-Path circuits only.<br />
<br />
<b>The Signal Power distribution</b> tells us what levels of signal power at the receiver are to be expected over the days in the month on the given frequency at the given hour.<br />
<br />
<b><span style="color: red;">The SDBW</span></b> indicates the dBW (the strength of a signal expressed in decibels relative to one watt) value (the green line in the chart) that can be maintained on 50% of the days (ie. on 15 days) in the month. In a similar fashion, <b><span style="color: red;">the SDBW90</span></b> indicates the dBW or signal strength value that can be maintained on 90% of the days (ie. on 27 days) in the month. And finally, <b><span style="color: red;">the SDBW10</span></b> is the dbW value that can be maintained on 10% of the days (ie. on 3 days) in the month. However, it does not tell us which days are good or which days are bad. The SDBW10 and SDBW90 values are the top and bottom boundaries (respectively) of the light-gray area that is now always visible in all band-by-band prediction charts.<br />
<br />
In our charts, we also display <b>the REL</b> and <b>MUFday</b> values in order to get as complete a picture as possible for the final propagation assessment. The REL is related to VOACAP's output parameters of SNR (Signal-to-Noise Ratio) and REQ.SNR (Required Signal-to-Noise Ratio), and is defined as a circuit reliability factor. It tells us the percentage of days in the month when the SNR value (which is not shown in the charts as a separate parameter) will equal to or exceed the REQ.SNR. The REQ.SNR is an internal value related to the TX mode selected. For CW, the REQ.SNR is set to 24 (dB-Hz), and for SSB, it's 38 dB-Hz. And, last but not the least, the MUFday values will tell us what percentage of the days in a month will be below the predicted MUF (Maximum Usable Frequency). These values will be calculated via Short-Path and Long-Path.<br />
<br />
<h3>
Beware of extremely wide Signal Power distributions</h3>
<br />
Whenever you see that a Signal Power distribution is extremely wide, e.g. ranging from the S-Meter reading of S0 to S8 at any given hour, you are getting into the noise of the program, meaning that VOACAP will give predictions even when it has no idea what is going to happen. If we believe the prediction, then VOACAP is saying that 80% of the days of the month (bounded by SDBW90 and SDBW10) will have a Signal Power somewhere between S0 and S8. That is a spread of 48 dB! If the program could talk, it would tell you that it doesn't have a really good idea what is going to happen on that frequency at that hour.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhut0XbdMHv2XuYpaXHPbxVkLm4-j2E70l7Jo-twfODQSbXdM5up7Hahk-5oGFW7EeU6eRdX8nqEM1NHO0SPQBWtZnGC9d0w7Yppgyi8n927hvFy6avyJqz-y_1Xtkt4rUcFEA7T9UGXgs/s1600/sdbw-distribution.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="298" data-original-width="470" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhut0XbdMHv2XuYpaXHPbxVkLm4-j2E70l7Jo-twfODQSbXdM5up7Hahk-5oGFW7EeU6eRdX8nqEM1NHO0SPQBWtZnGC9d0w7Yppgyi8n927hvFy6avyJqz-y_1Xtkt4rUcFEA7T9UGXgs/s1600/sdbw-distribution.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The area filled with light-gray (= Short-Path Signal Power distribution) is bounded by the SDBW10 (top) and SDBW90 (bottom) values. Times and frequencies with <b>extremely </b>wide Signal Power distributions are not reliable enough. Typically, in such cases, the MUFday values are also low.</span></td></tr>
</tbody></table>
<br />OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com2tag:blogger.com,1999:blog-8260894794228814400.post-85253037092332290692017-07-23T13:49:00.001+03:002017-07-23T21:10:10.306+03:00DIY VOACAP HF Propagation Predictions for DXpeditionsI am happy to announce that VOACAP Online has now an option to offer do-it-yourself HF propagation predictions, suitable for the websites of DXpeditions (and for other needs, too).<br />
<br />
If you wish to embed the propagation prediction component in your pages, just use the following code:<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5jzuRBWBO1sQYY2fqoYLubOgaDJRqOmcRIiTgs0R6Ld21fq9DWlOD3sk5R5fkvWaIOGjlIlynHUVD8MzQCh8CBaSB1Jh6DQgZji0SH-wzB5sVwp1DOBwfld3zk6rxTkfoJQbQzTdZGb4/s1600/URL1.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="48" data-original-width="710" height="42" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5jzuRBWBO1sQYY2fqoYLubOgaDJRqOmcRIiTgs0R6Ld21fq9DWlOD3sk5R5fkvWaIOGjlIlynHUVD8MzQCh8CBaSB1Jh6DQgZji0SH-wzB5sVwp1DOBwfld3zk6rxTkfoJQbQzTdZGb4/s640/URL1.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><div style="font-size: 12.8px;">
<span style="color: red; font-size: small;"><b>NOTE: the code is one big line, no linebreaks as in this example!</b></span></div>
<div style="font-size: 12.8px;">
<span style="color: red; font-size: small;"><b>CLICK IMAGE TO ENLARGE!</b></span></div>
</td></tr>
</tbody></table>
<br />
<div class="separator" style="clear: both; text-align: center;">
</div>
where:
<br />
<br />
CALLSIGN (parameter "c") = the callsign of the DXpedition (the Transmitter site)<br />
TXLOCATOR (parameter "l", like Lima) = the Maidenhead Grid Locator for the Transmitter site. To find your grid locator, please see: <b><a href="http://www.voacap.com/qth.html">www.voacap.com/qth.html</a></b><br />
YEAR (parameter "y") = the year the DXpedition is taking place, e.g. 2017<br />
MONTH-NUMBER (parameter "m") = the number of month when the DXpedition is taking place, e.g. for July, MONTH-NUMBER is 7.<br />
TXPOWER (parameter "p") = the transmitting power in kilowatts, e.g. 1.5<br />
MODE (parameter "me") = either CW or SSB. If you will use both, set this parameter to CW.<br />
<br />
So, when all the components are in place, the complete code might look like this (the example below is for the Bouvet DXpedition in February 2018):<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikntXiN03rUP8YvbIW0L3iR6iGGCdwPOKsLvj-eDs13tFwBchdjRrTr6iGcsKfQbHCeud_vXnXcjkg81BA4nbdMIbdHSZSF9-Xn7vLXFrrFHuUu17r3KNzjeP7h1ENDIkvC0A4BkVCe1U/s1600/URL2.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="46" data-original-width="709" height="40" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikntXiN03rUP8YvbIW0L3iR6iGGCdwPOKsLvj-eDs13tFwBchdjRrTr6iGcsKfQbHCeud_vXnXcjkg81BA4nbdMIbdHSZSF9-Xn7vLXFrrFHuUu17r3KNzjeP7h1ENDIkvC0A4BkVCe1U/s640/URL2.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><div style="font-size: 12.8px;">
<span style="color: red; font-size: small;"><b>NOTE: the code is one big line, no linebreaks as in this example!</b></span></div>
<div style="font-size: 12.8px;">
<span style="color: red; font-size: small;"><b>CLICK IMAGE TO ENLARGE!</b></span></div>
</td></tr>
</tbody></table>
<br />
The layout on your page will be something like this (enter your grid locator in the field, press "Run", and see the results!):<br />
<br />
<iframe frameborder="0" height="115px" src="http://www.voacap.com/charts/?c=3Y0Z&l=JD15qn&y=2018&m=2&p=1.5&me=CW" width="100%"></iframe>
The graphical predictions will be similar to this:<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieYeFEI2yBmDJfysssSgBjnPN-KBQuKEui1Q0vfNKKsmGOWRZQrpmBy0AjJnCRf-WYPTdMFYRICFPh1_rxdR019pIxTzh_l190XRO2oAm592T4fKuwgs5-Ssq49nSbpDAc7Fc-PkIf5QA/s1600/voacap-diy-propagation-prediction.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="969" data-original-width="1425" height="434" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieYeFEI2yBmDJfysssSgBjnPN-KBQuKEui1Q0vfNKKsmGOWRZQrpmBy0AjJnCRf-WYPTdMFYRICFPh1_rxdR019pIxTzh_l190XRO2oAm592T4fKuwgs5-Ssq49nSbpDAc7Fc-PkIf5QA/s640/voacap-diy-propagation-prediction.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Overview of the prediction in terms of Reliability (REL), Signal Strength (S DBW) and MUFday, followed by band-specific predictions, from 80 Meters to 10 Meters, Short-Path (SP) and Long-Path (LP). The charts are all interactive as you hover the mouse over them.</span></td></tr>
</tbody></table>
<br />
<b>The service is offered to the ham community free-of-charge.</b> If you are using this component as part of your webpages, I would like to hear from you!OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0tag:blogger.com,1999:blog-8260894794228814400.post-21764994665369262092017-07-16T23:46:00.000+03:002017-07-16T23:52:56.743+03:00Versatile charts for Reliability, Signal Power and MUFday available at VOACAP Online P2PI am happy to report that another way of visualizing three critical output parameters for HF propagation predictions at the VOACAP Online Point-to-point service is now available. These charts, namely Reliability (REL), Signal Power (S DBW) and MUFday, can be viewed at <b><a href="http://www.voacap.com/p2p/index.html">www.voacap.com/p2p/index.html</a> </b>by clicking on the "Tri-graph" button.<br />
<br />
Each chart offers multi-colored line graphs for all frequencies from 80 meters to 10 meters. And thanks to the JavaScript framework (plotly.js) used for plotting these graphs, they can all be toggled on and off by clicking on the legend values on the right, which helps the user focus on relevant graphs only. Also there are versatile tools that allow you to save the graph as PNG, zoom in/out, compare results data on all frequencies on mouse hover, pan the chart, and more.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_u4qEAXFUqVYdDg2r3keo5GeZ6rL13fngRCddHxt9DGv7JuaGQ166LKhAS1sOjHFhni1MjS9jLjkQFfK3aIZ38reCEtlNXqA8vg7lFLq-B1gkgPyFHmHFTKXsQ4zZG6hqhzhgPOcsogY/s1600/rel-3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="426" data-original-width="978" height="278" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_u4qEAXFUqVYdDg2r3keo5GeZ6rL13fngRCddHxt9DGv7JuaGQ166LKhAS1sOjHFhni1MjS9jLjkQFfK3aIZ38reCEtlNXqA8vg7lFLq-B1gkgPyFHmHFTKXsQ4zZG6hqhzhgPOcsogY/s640/rel-3.jpg" width="640" /></a></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtYaUiJxClfL5JdaXN687OY9W5U0PHlZcxy6eCnrxsjPl-Enx8yQ_WPymFosLG-W44BL86UtupWI0-RXHz-Rhjbwzks6613ICPIo0olObnh7IG7n-nCrFFxqG2db7rCeHlBDYzPm4fjGk/s1600/sdbw-3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="427" data-original-width="981" height="276" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtYaUiJxClfL5JdaXN687OY9W5U0PHlZcxy6eCnrxsjPl-Enx8yQ_WPymFosLG-W44BL86UtupWI0-RXHz-Rhjbwzks6613ICPIo0olObnh7IG7n-nCrFFxqG2db7rCeHlBDYzPm4fjGk/s640/sdbw-3.jpg" width="640" /></a></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhA8SVrSLDIq9IDqc8HEsMxrnT5sNTn-cOySJlPVxJQsbqaYTujvbVdRRQ7BjUOtWOyVlsQ0em89pOmoJXfQzQoOo2ujPxAOPQnyloEuzQAteS0OJAyYn5EiHa38PWX2kEUQCIUyf5eteA/s1600/mufday-3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="428" data-original-width="980" height="278" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhA8SVrSLDIq9IDqc8HEsMxrnT5sNTn-cOySJlPVxJQsbqaYTujvbVdRRQ7BjUOtWOyVlsQ0em89pOmoJXfQzQoOo2ujPxAOPQnyloEuzQAteS0OJAyYn5EiHa38PWX2kEUQCIUyf5eteA/s640/mufday-3.jpg" width="640" /></a></div>
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<br />
The REL and MUFday data is presented as percentages from 0 to 100 (%) whereas the Signal Power (S DBW) data is shown as dBW values from -163 to -103. The value of -163 is an extremely low noise value of my own choosing, and the next value of -157 represents a median S-meter reading of S0. The value of -103 corresponds to a median S-meter reading of S9. The steps are 6 dB or one S-meter reading step.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg32yKotyrcChBEqMNffsxhRaPCf3Z3gv11aMGP2vprcW1BDnDNkD78Hujp_EnW1A4EqxPzdX_LdQGJKRyDnLh76IiB5AP4exkWgeKPscHDdcOIucEQYG91erG5ONb4f0mUJR68xW6caFw/s1600/sdbw-3-scale.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="427" data-original-width="977" height="278" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg32yKotyrcChBEqMNffsxhRaPCf3Z3gv11aMGP2vprcW1BDnDNkD78Hujp_EnW1A4EqxPzdX_LdQGJKRyDnLh76IiB5AP4exkWgeKPscHDdcOIucEQYG91erG5ONb4f0mUJR68xW6caFw/s640/sdbw-3-scale.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">On the Signal Power graph, the Y-axis values span from -163 dBW (noise level) to -103 dBW (S-meter reading of S9).</td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj52BClfzptSJHgYCZlrP9NushDNqJf6-3Zc31YtmwGKKCOYXQ_XISRM_iTWoxQ-EXrUFfyvHY_vjTCT70F2fAogFxYoknaaFhJNfA0IWadw9TY94qLp4H8NxcBLDEfrY8q4z4Hae8Vbv0/s1600/tools-3.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="77" data-original-width="365" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj52BClfzptSJHgYCZlrP9NushDNqJf6-3Zc31YtmwGKKCOYXQ_XISRM_iTWoxQ-EXrUFfyvHY_vjTCT70F2fAogFxYoknaaFhJNfA0IWadw9TY94qLp4H8NxcBLDEfrY8q4z4Hae8Vbv0/s1600/tools-3.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The toolbox with many useful functions such as saving the graph as PNG (far left).</td></tr>
</tbody></table>
<br />
Hope you enjoy the new charts!OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0tag:blogger.com,1999:blog-8260894794228814400.post-85624483050006679522017-07-13T22:28:00.000+03:002017-07-14T00:05:11.401+03:00Adding MUFday to the equationI have been further re-factoring the code that produces the VOACAP HF propagation prediction in table format. Such tables are available e.g. on the <b>VOACAP Point-to-Point</b> page (<b><a href="http://www.voacap.com/p2p/index.html" target="_blank">www.voacap.com/p2p/index.html</a></b> > All-year prediction) and on <b>VOACAP DX Charts</b> (<b><a href="http://www.voacap.com/dx.html" target="_blank">www.voacap.com/dx.html</a></b>) or on <b>VOACAP Propagation Planner </b>(<b><a href="http://www.voacap.com/planner.html" target="_blank">www.voacap.com/planner.html</a></b>). The re-factored code has made it possible for me to add the MUFday parameter to the predictions. And it's a great enhancement, making the high-band predictions even more realistic. Be warned that the 24-hour prediction wheel I use on the VOACAP P2P front page is now "out-of-date" on Above-the-MUF frequencies!<br />
<br />
<b>So, with the introduction of MUFday in all assessments, there will be more gray cells in the prediction tables from now on. </b><br />
<br />
<b><span style="color: red;">On lower frequencies</span></b>, the color of gray does not indicate any probability value, in contrast to all other colors used. Instead, gray shows that, although VOACAP does not predict any probability for that specific hour (R=0% in the popup window), some signal power (S in the pop-up window) has been predicted which may translate into workable conditions. So, in a sense, gray indicates "a gray area" where QSOs may be possible.<br />
<br />
<b><span style="color: red;">On higher frequencies</span></b>, typically on Above-the-MUF frequencies, the color of gray is a sign of extremely poor probabilities. These are actually cases where VOACAP predicts positive REL values but unfortunately VOACAP does not know what's really happening up there. If you take a closer look at the values reported in the pop-up window over the cell (the R, S and M values), the S (Signal Power) value can be very low (e.g. -164 and below which means that there is hardly any signal in the noise).<br />
<br />
Frankly, I should have implemented the MUFday assessment much earlier. Let me explain the nature of MUFday as concretely as possible. The value of the MUFday is the fraction of the days in a month at that hour that the operating frequency is below the MUF for the most reliable mode (that is, the mode with the highest reliability of meeting the required Signal-to-Noise Ratio, or SNR). So, on higher frequencies, I have now set the threshold to 10% for MUFday in my assessments. This means that if the MUFday value is less than 10% (or less than 3 days), then the frequency hour cell will be colored gray. And it's totally ok, as this actually means that for more than 90% of the days in a month, QSOs are likely not to happen. The odds are pretty poor.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgUT0zFdgDprc3QuU8d-f_c0KUXBeBwMkm3gf3ACFHa16cBP63D-HlDZX0Y_C8qh3MSM8heZtcWemagZ8TfyoT1iz3ntWPKR-3m6CNVfMo1M1hnjvGuRMqf7jcfO3qgBbyrHG9hITBmn4/s1600/bouvet-with-mufday.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="458" data-original-width="384" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgUT0zFdgDprc3QuU8d-f_c0KUXBeBwMkm3gf3ACFHa16cBP63D-HlDZX0Y_C8qh3MSM8heZtcWemagZ8TfyoT1iz3ntWPKR-3m6CNVfMo1M1hnjvGuRMqf7jcfO3qgBbyrHG9hITBmn4/s1600/bouvet-with-mufday.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="font-size: 12.8px;">At 12 UTC on 10 Meters in February 2018 (from OH6 to 3Y0Z), VOACAP says that the REL (R or the probability for a QSO) is a good 21%! However, the Signal Power (S) is -173, way down in the noise. And what is more, the MUFday (M) is a mere 5%. So, the verdict is that there is only the slightest chance (frankly, if any) that QSOs can happen on 10 Meters with the power and antenna chosen. Therefore, the cell is rightfully colored as gray.</td></tr>
</tbody></table>
<br />
<h3>
Recapping the R, S and M values</h3>
<br />
As you know, all table charts are interactive: if you hover your mouse over table cells, you will see a pop-up text, now showing three parameter values: R, S and M.<br />
<br />
The R is VOACAP's REL or QSO probability in percentages, and the S is VOACAP's S DBW or Signal Power value in dBW. For instance, the signal power value of -164 can be considered to be on the verge of the noise in remote, extremely low-noise locations whereas the S DBW value of -93 corresponds to S9 on the S meter. Read more about translating the signal power values (S DBW) into S-meter values here: <b><a href="http://www.voacap.com/s-meter.html" target="_blank">http://www.voacap.com/s-meter.html</a></b>.<br />
<br />
And finally, the new M parameter is VOACAP's MUFday value in percentages, indicating the probability for the operating frequency on that hour being BELOW the median MUF calculated.<br />
<b><br /></b>
<b>All in all, MUFday is a much-anticipated parameter to give the wild REL values on Above-the-MUF frequencies a more realistic interpretation.</b>OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com1tag:blogger.com,1999:blog-8260894794228814400.post-11898692540613962882017-05-01T20:25:00.001+03:002018-02-04T16:34:48.869+02:00VOACAP Online Point-to-Point (P2P) User Manual (August 1, 2017 Edition)<b>URL</b>: <a href="http://www.voacap.com/p2p/index.html">http://www.voacap.com/p2p/index.html</a><br />
<b>Russian</b>: <a href="http://www.voacap.com/p2p/index-ru.html">http://www.voacap.com/p2p/index-ru.html</a><br />
<br />
<b><span style="color: red;">UPDATE February 4, 2018:<span style="color: black;"> <a href="https://voacap.blogspot.fi/2018/02/voacap-point-to-point-qso-window-know.html" target="_blank">QSO Window</a> functionality added</span></span></b><br />
<b><span style="color: red;">UPDATE January 6, 2018: <span style="color: black;"><a href="https://voacap.blogspot.fi/2018/01/getting-best-operating-frequency-in.html" target="_blank">Find best operating frequency</a> added</span></span></b><br />
<b><span style="color: red;">UPDATE August 1, 2017: <span style="color: black;">The UI of this service has been revamped considerably.</span></span></b><br />
<b><br /></b>
<b>The VOACAP Online Point-to-Point (or P2P for short) HF propagation prediction service</b> uses VOACAP (Voice of America Coverage Analysis Program) as its calculation engine, requiring that SVG (Scalable Vector Graphics) is supported in your web browser (for the prediction wheel). For example, the latest versions of Microsoft Internet Explorer, Mozilla Firefox, and Google Chrome are known to work. The earlier versions may not be supported. If you encounter problems with the page, please try first to upgrade your browser to the latest version available. If you think you have found a bug or if you wish to help translate the user interface into your language, please contact me at <a href="mailto:jpe@voacap.com"><b>jpe@voacap.com</b></a>.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPeKd2SZo7HnID-vuKl8iBLTI7QbEOgcYw5cLWtnDl90fpq2IBL9dpyDvbyx1iAkGgV9lfP-bIyKkplMooyAtpzDGXsVH4lyBd4FvyJ7YCbZe9OpEV7Xnz8hyphenhypheniTRNfcFfNmhXFEITPJs0/s1600/new-voacap-p2p-ui.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="817" data-original-width="1096" height="476" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPeKd2SZo7HnID-vuKl8iBLTI7QbEOgcYw5cLWtnDl90fpq2IBL9dpyDvbyx1iAkGgV9lfP-bIyKkplMooyAtpzDGXsVH4lyBd4FvyJ7YCbZe9OpEV7Xnz8hyphenhypheniTRNfcFfNmhXFEITPJs0/s640/new-voacap-p2p-ui.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><b><span style="color: red;">CLICK IMAGE TO ENLARGE</span></b></td></tr>
</tbody></table>
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The VOACAP P2P web interface is divided into three sections and their sub-sections as follows:<br />
<br />
<ol>
<li><b><span style="color: red;">A Google Map for setting the transmitter (TX) and receiver (RX) site coordinates</span></b>. The easiest way to set the coordinates is to drag the red (TX) and blue (RX) markers to appropriate locations on the map. Under the map, the distance from TX to RX is given in kilometers and miles, and the bearing in degrees from True North. If you need to zoom in or zoom out the map for better details, just scroll the mouse wheel up and down over the map. To quickly swap the TX and RX points, just double-click one of the markers.</li>
<li><b><span style="color: red;">A Prediction Charts section</span></b> which offers 15 different charts, including, among others, individual prediction charts for all the amateur radio bands from 10 meters (28 MHz) to 80 meters (3.5 MHz). The charts show e.g. the probability (or, the REL parameter in the VOACAP language) for a communication contact (i.e. a QSO) between the TX and RX sites. The "REL Short-Path" chart is the default. Other key prediction charts include SDBW (Signal Power) and MUFday. The calculations are available for the path both via Short-Path and Long-Path. The 24-hour prediction wheel -- which displays exactly the same prediction data as the new "REL Short-Path" chart -- is now available via a link under the "Receiver Site" section. See image above.</li>
<li><b><span style="color: red;">The input values for the prediction</span></b> can be set in the area below the Google Map and the prediction wheel. There are five sections here:</li>
</ol>
<ol>
<li>Google Map</li>
<li>Date</li>
<li>Propagation Parameters</li>
<li>Today’s Sunrise/Sunset Times</li>
<li>Transmitter Site (TX), and</li>
<li>Receiver Site (RX).</li>
</ol>
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioG7lp7NhIEFXi4xDDfB9JasLcPe8UnmyHxxOQ2aOJ1NdGXDCWLK_8TSEtmLxb3R5nWDTq6xf5RKA2fkOxhumaYvebLFVR4M7p5PFLLMepWCq-07vYMs05ypoNcZZeRnUYF6qzt7Dh34c/s1600/VOACAP+all+input+settings.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioG7lp7NhIEFXi4xDDfB9JasLcPe8UnmyHxxOQ2aOJ1NdGXDCWLK_8TSEtmLxb3R5nWDTq6xf5RKA2fkOxhumaYvebLFVR4M7p5PFLLMepWCq-07vYMs05ypoNcZZeRnUYF6qzt7Dh34c/s640/VOACAP+all+input+settings.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The input parameter sections under the Google Map and the predictions chart section.</span></td></tr>
</tbody></table>
<br />
<h4>
1. Google Map -- for smooth entry of coordinates</h4>
<br />
Originally, a smooth and an easy coordinate entry for the Transmitter (TX) and Receiver (RX) sites was one of the single most important design features at VOACAP Online. The stand-alone PC version of VOACAP does not offer this, and, in fact, not many others do, either. Choosing Google Maps for this purpose lowered the threshold of using VOACAP considerably.<br />
<br />
On the initial Google Map, there are two markers -- red and blue -- placed on the equator line in Africa. The red marker signifies the transmitter's location (TX) and the blue marker is the receiver location (RX). Perhaps typically, the transmitter is your QTH and the blue one is the DX station, or any way you like.<br />
<br />
<h3>
a) Two great-circle paths: short-path and long-path</h3>
<br />
<b>There is always a red line connecting the red and blue markers</b>, showing, by default, the great-circle path (short-path) between the two locations. A long-path great-circle line can be shown when you choose "Long-path" from the pop-up menu by the "Specials" label in the Transmitter Site section. The small red circle along the red great-circle line indicates the geographical midpoint between the Transmitter and Receiver.<br />
<br />
<h3>
b) Distance and bearing</h3>
<br />
One of the features under the Google Map is the on-the-fly calculation of the distance between TX and RX, and the bearing from TX to RX in degrees, calculated from True North. The details can be found under the map (see image below).<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHi8gk6hTi_8L4ZUQv8cE4YdHf_1KG3AcMHn2cvhLvp5bOXjCjGKkOg1xuuAa8vta9LvR_cv1TpaxB4f1NvyJfcOiLLyNG7jZbpgfhWj-8jzoak7gWkcgaq8Q0kraSGtsuYigXboQ9vTQ/s1600/VOACAP+distance+and+bearing.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHi8gk6hTi_8L4ZUQv8cE4YdHf_1KG3AcMHn2cvhLvp5bOXjCjGKkOg1xuuAa8vta9LvR_cv1TpaxB4f1NvyJfcOiLLyNG7jZbpgfhWj-8jzoak7gWkcgaq8Q0kraSGtsuYigXboQ9vTQ/s1600/VOACAP+distance+and+bearing.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Distance (in kilometers and miles) and bearing<br />(in degrees from True North, not your compass north).</span></td></tr>
</tbody></table>
<br />
And if you would like to swap the TX and RX locations, there are two ways to do it. The easiest way is to double-click on either of the markers. The bearing value will be re-calculated at once. You can also click on the "Swap TX-RX" button by the "Specials" label. Whenever the locations have been swapped (or moved), the propagation prediction is re-calculated and shown on the prediction wheel immediately.<br />
<br />
<h4>
2. The Date</h4>
<br />
The whole concept of setting the date in VOACAP Online has been changed from the original setup after I implemented the grayline terminator functionality over the Google Map, and this has been quite a while ago. Earlier, I was showing the grayline terminator but it was always fixed to the current time and day -- the user was not able to set it to a specific time and day in order to see how the grayline terminator looked like at a particular point of time. I felt that a more flexible grayline zone map could be used as a way of trying to determine signal enhancements on the low bands, and therefore a new way of setting the time and day was needed.<br />
<br />
This was the reason I chose to use a pop-up calendar for this purpose. Also, any month the user would select from the calendar for the grayline zone would also be used as input for all propagation predictions. The pop-up calendar is located just below the Google Map, and looks like this:<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCbWYE5gkS_mB8KsU4hxLlBjZnEChMQ6Bqwvu9mLfIfKYtEFrvGRxS7dK0DHtZZkewQexwd-y-0BJ2sRQmgxiuHXanWCsRBYx2XSmar5b7VVSPGpy6TCq-EG_0eI5VYzfkpTKSSe6rOKw/s1600/VOACAP+grayline+settings.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="37" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCbWYE5gkS_mB8KsU4hxLlBjZnEChMQ6Bqwvu9mLfIfKYtEFrvGRxS7dK0DHtZZkewQexwd-y-0BJ2sRQmgxiuHXanWCsRBYx2XSmar5b7VVSPGpy6TCq-EG_0eI5VYzfkpTKSSe6rOKw/s400/VOACAP+grayline+settings.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Always select a day number in the pop-up calendar, and press the <b>Set </b>button.<br />Press the <b>Reset </b>button to return to the current time and date.</span></td></tr>
</tbody></table>
<br />
<b><span style="color: red;">To set a date, click on the calendar icon on the right of the date field.</span></b> It will prompt a calendar where the user can browse the months (and years) backward and forward, by pressing the arrow icons. You select a month by picking any day number in that particular month. Please note that <b><span style="color: red;">you must select a day</span></b> (although the day selected is not used for any propagation calculations)!<br />
<br />
The month selected will be used for propagation prediction calculations, and the day selected (and the time set by the user) will be used for drawing the grayline zone terminator over the Google Map. Please note that the selected day will not be used for propagation prediction calculations as VOACAP will not calculate any daily predictions.<br />
<br />
When you have selected a month and a day, and have set the time correctly for your purposes, then press the Set button. This will finally use all the parameters set. To return to the current month, day and time, press the Reset button.<br />
<br />
<h4>
3. The Propagation Parameters</h4>
<br />
The section "Propagation Params" include a number of user-adjustable parameters that will affect propagation predictions.<br />
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<div class="separator" style="clear: both; text-align: center;">
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<br />
<b><span style="color: red;">a) Es, or setting the ionospheric sporadic E layer (Es) on and off.</span></b> This may (or may not) prove useful during summer months when Es propagation conditions are quite common. The default setting is OFF (No). Please note that the use of the Es layer is otherwise discouraged as the sporadic-E model was not fully tested during the development of VOACAP. Nevertheless, the effects of the sporadic-E layer are not totally excluded in VOACAP calculations although the layer would not be set.<br />
<b><br /></b>
<b><span style="color: red;">b) Model, or selecting the propagation model.</span></b> Three choices are available here: Auto, Ducted, and Ray-hop.<br />
<br />
<ul>
<li><b>The default "Auto" or automatic model</b> refers to Method 30 in the VOACAP speak. It's a propagation model that chooses automatically either the ray-hop model or the ducted (forward-scatter) model to predict the signal power. There is also a smoothing function for ranges of 7,000 km or greater.</li>
<li><b>The (forced) "Ducted" model</b> refers to Method 21 in the VOACAP speak. Typically, this model is used for paths of 10,000 km or more. The Ducted model forces VOACAP to simulate the ducted or forward-scatter mechanisms that can prevail usually at distances having three or more hops. This model may produce unrealistic results at shorter distances where the ray-hops should occur.</li>
<li><b>The (forced) "Ray-hop" model</b> refers to Method 22 in the VOACAP speak, typically used for all circuits less than 10,000 km. It's a model that contains multiple ionospheric reflections, and includes all of the ionospheric and earth bounce losses. This model may produce extremely pessimistic predictions at the distances beyond the third ionospheric hop where ducted/forward scatter mechanisms can occur.</li>
</ul>
<br />
<b><span style="color: red;">c) SSN, or user-settable smoothed sunspot number.</span></b> Here you can set a specific SSN (i.e. sunspot number) to be used for calculations. Note that <b>VOACAP Online knows the current predicted smoothed sunspot numbers</b> so it may be advisable not to set any value to the SSN field unless you wish to conduct your own propagation experiments. After you have entered a value in the SSN field, press the TAB key (instead of the ENTER key) to validate the number entered, and run the new prediction for the prediction wheel.<br />
<br />
At this point, I would like to take a few moments to discuss the pros and cons of this feature. By default, VOACAP Online does internally know the current SSN to be used for all the months of the years available. You can ask how can that be as the sunspot number varies day by day? The simple answer is that VOACAP does not operate on daily SSN figures but smoothed monthly SSN figures which are being predicted for many years ahead and which are re-adjusted at regular intervals.<br />
<br />
The predicted SSN figures are based on the Lincoln-McNish smoothing function, and they have been maintained by the National Geophysical Data Center (NGDC) / National Oceanic and Atmospheric Administration (NOAA). These are the sunspot numbers used in the database reduction for the worldwide ionospheric maps used in IONCAP and now VOACAP. This is why only these figures should be used with VOACAP. <a href="http://www.voacap.com/choosingssn.html" target="_blank">Read George Lane's discussion on the sunspot numbers for VOACAP use.</a><br />
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However, please note that, at the end of 2016, the NGDC/NOAA discontinued providing this invaluable predicted data, instead directing users to the SIDC website.<br />
<br />
<b>Jim Watson</b>, one of the key figures behind VOACAP Online and <a href="https://soundbytes.asia/proppy/" target="_blank">a maintainer of his own Proppy website</a>, has conducted a survey, comparing the effects of three SSN data sets: Original NOAA values, SIDC values, and adjusted SIDC values. The results indicate that VOACAP performs best with the original NOAA SSN values. Now, going forward, we will need to use 'adjusted' SIDC SSN values as a substitute. Read Jim's <a href="https://soundbytes.asia/proppy/blog/page/20/voacap-ssn-values/" target="_blank">blog post</a> or <a href="https://soundbytes.asia/proppy/static/blog/voacapssn/voacapssn.pdf" target="_blank">the full version</a> (as PDF).<br />
<br />
In addition, there have been months in the past where the conditions have been well above the average for a couple of months, and a re-adjustment of SSNs would have been appropriate. Now this power has been given to the user. Just remember that, strictly theoretically speaking, entering a daily SSN value in the SSN field does not generally give you better (or more precise) predictions as VOACAP is not suited to real-time predictions at all. <a href="http://www.voacap.com/" target="_blank">Read more about the theoretical background of VOACAP in my Quick Guide.</a><br />
<br />
<b><span style="color: red;">d) Min. TOA, or setting the minimum takeoff or arrival angle for antennas</span></b> at the steps of 1 degree, starting from 0.1 degrees (the default), up to 5 degrees. My default value has always been 0.1 degrees, due to some practical reasons. However, in the VOACAP literature, a value of 3 degrees is commonly recommended, as it can be a common lowest angle for arriving skywave signals due to the roughness of the terrain. Also, 3 degrees may be a good choice if your antennas are not located in a flat, unobstructed area. And if you are using isotropic antennas, you should avoid huge amounts of antenna gain at angles below 3 degrees. You are encouraged to experiment between 0.1 and 3 degrees to see differences in predictions, using different antennas.<br />
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<h4>
4. Sunrise and Sunset Times</h4>
<br />
The section under Propagation Parameters labeled as "<b>Today's Sunrise/Sunset Times (UTC)</b>" offers the Sun's rise and set times <b>at various regions of the ionosphere</b>, calculated at both the transmitter and the receiver coordinates. All times are UTC.<br />
<br />
These calculations were originally inspired by Steve's (G0KYA) <a href="http://www.infotechcomms.co.uk/RSGB_presentation_greyline.pdf" target="_blank">more-than-15-year-old article about grayline propagation</a>. In short, the best predictions for grayline propagation or trans-terminator enhancement on low bands can probably be achieved by a close examination of grayline maps. Some also swear by <a href="http://www.qsl.net/w6elprop/" target="_blank">W6ELProp</a>. To make this section even more informative, a new Point-to-Point prediction option - <b><span style="color: red;">All-year grayline</span></b> - has been developed. See below for more information. Also, you may be interested in <b><a href="http://www.voacap.com/greyline/index.html" target="_blank">VOACAP Greyline</a></b>.<br />
<br />
The abbreviation <b>GND (for Ground)</b> refers to sunrise and sunset at the sea level. The letter "D" refers to sunrise and sunset at the bottom of the ionospheric <b>D region</b>. Similarly, the letter "F" refers to sunrise and sunset in the ionospheric<b> F region</b>.<br />
<br />
In the summer, if you place the TX or RX marker close to the Arctic Circle, you will see that "--:--" will appear in the D and F region fields. This simply means that sunrise and sunset times cannot be calculated for those regions e.g. because the sun does not set/rise during the summer at high latitudes. Alternatively, in the winter, the sun may not rise/set.<br />
<br />
<b><span style="color: red;">Please note that all the calculated values can be clicked on</span></b> (as they are in fact buttons), and the Google Maps above will show how the terminator line will run across the map at the time clicked on. This can be very useful in determining the best times for low-band signal enhancements.<br />
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<h4>
5. The Transmitter Site</h4>
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<h3>
</h3>
<h3>
a) Selecting QTH</h3>
<br />
In the Transmitter Site (TX) section you can, besides dragging the red marker to the appropriate location on the map, choose the location from a list of DXCC countries. The QTH pop-up menu features 483 locations around the world, including all DXCC entities. When you choose a location from this list, its name and the coordinates (latitude and longitude) will automatically be entered in their corresponding fields below. Much care has been taken to find the exact coordinates of even the smallest of the islands! If you happen to find a location with wrong coordinates, drop me a note!<br />
<br />
When you drag the markers over the map, you are advised to use the Name field for entering a label for the TX site (otherwise, the Maidenhead grid locator will be used). And you can also enter the Maidenhead grid locator in the Name field, and press the "<b>Loc calc</b>" button: the corresponding coordinates will then automatically be calculated from the grid locator and entered in the Latitude and Longitude fields. The latitude and longitude values can also be entered manually. When you do that, please press the TAB key to validate them and run the prediction.<br />
<br />
<h3>
b) Selecting antenna and power</h3>
<br />
At the moment, only one antenna can be chosen for all amateur bands. If you need more freedom in selecting different antennas for different bands, you can try <b><a href="http://www.voacap.com/planner.html" target="_blank">VOACAP Propagation Planner</a></b>. In the VOACAP P2P service, the default antenna is a quarter-wave vertical over a very good ground. All TX and RX antennas are artificial in the sense that they are omnidirectional, which allows the user to see all possible openings to all parts of the world. In dipole-type of antennas, the height of the antenna is related to the elevation angle and the number of elements to the gain. When you choose an antenna, you should think about the elevation angles and gain, rather than the physical structure of the antenna.<br />
<br />
In the TX power, you can select powers from 1 watt to 1500 watts at the steps given. 1500 W is the default setting. Some line loss is assumed so that the actual power used for the calculation is 80% of the power chosen. In the TX mode, you can choose from CW, SSB and AM. CW is the default setting.<br />
<br />
<h3>
c) Short-path and long-path, and specials</h3>
<br />
You can decide whether you want the predictions to be calculated via <b>Short-Path </b>or <b>Long-Path</b>. Short-path means the shortest distance between the TX and RX, and this so-called great-circle path is visualized with a red line on the Google Map. If you set this to Long-path, you will go from TX to RX in the opposite way: the longest great-circle path. On the red great-circle line, the geographical midpoint of the path is shown as a small red circle.<br />
<br />
Last but not the least, there are three buttons:<br />
<br />
<ul>
<li>Swap TX-RX,</li>
<li>Set Home, and</li>
<li>Unset Home.</li>
</ul>
<b><span style="color: red;"><br /></span></b>
<b><span style="color: red;">If you click on the Swap TX-RX button</span></b>, the TX and RX locations will be swapped: the current TX location becomes the RX location, and the RX location becomes the TX location. You can accomplish the same effect by double-clicking the red (TX) or blue (RX) marker on the map. In this way, you will see that the predictions for circuits are not always 100% reciprocal. In VOACAP calculations, this is mostly due to the different level of noise power in the RX site.<br />
<br />
<span style="color: red;"><b>By clicking on the Set Home button</b></span>, the TX Name, Latitude and Longitude information is stored in a cookie, as well as the RX Name, RX Latitude and Longitude, along with the TX and RX antenna selections. And when you press the <b>Unset Home button</b>, the cookie will be destroyed. Remember to allow your browser to set the cookie on this page if you want to allow this feature to work.<br />
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<h4>
6. The Receiver Site</h4>
<div>
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In the Receiver Site (RX) section, the input options are similar to those of the Transmitter Site. The RX location can be selected from the pre-defined DXCC list, or coordinates can be entered manually in the Latitude and Longitude fields. If you enter the values manually, please then remember to press the TAB key.<br />
<br />
The Name field is used to give a label for this site, or alternatively you can enter a Maidenhead grid locator in this field and press the "Loc calc" button, and the latitude and longitude values will be calculated automatically.<br />
<br />
Also the receiving antenna selection is exactly the same as for the Transmitter Site. Also, there is an option of choosing the noise level at the RX site. This will affect the QSO probabilities: when there is a lot of man-made noise, the probabilities are lower; when the noise level is minimal (e.g. “Quiet” (default) or “Remote”), then the probabilities are better.<br />
<br />
<h4>
Five types of P2P predictions available</h4>
<br />
So, after setting all the input parameters properly, you can always see the immediate results on the prediction charts section on the right of the Google Map. For most users, the first of the charts -- REL Short-Path -- may be enough for an overall understanding of the predicted propagation conditions.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSO4T-U4cJpgxWmJXl56bDTUFX9s40mTvlz18Yub7DAcrTtErDpRAgcfCpNaeECLm4AKTpE88aTPNLtR3rSnfbLhnJVY0P3fSmOhAxqQcsPA7KsAwYAcOnowXLGMoYHkAs1iwYFqkuflU/s1600/voacap-p2p-prediction-charts.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="515" data-original-width="446" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSO4T-U4cJpgxWmJXl56bDTUFX9s40mTvlz18Yub7DAcrTtErDpRAgcfCpNaeECLm4AKTpE88aTPNLtR3rSnfbLhnJVY0P3fSmOhAxqQcsPA7KsAwYAcOnowXLGMoYHkAs1iwYFqkuflU/s1600/voacap-p2p-prediction-charts.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The new Prediction Charts section, replacing the previous 24-hour circular prediction wheel, shown below. The circular wheel is now on a page of its own.</span></td></tr>
</tbody></table>
<br />
<h3>
Why change to new charts?</h3>
<br />
The reason is simple: the new charts contribute to a better assessment of HF propagation. You can paint the big picture with a single VOACAP output parameter but, for a more accurate picture, you will need (at least) three: REL (used by the earlier 24-hour circular chart which is still available via a separate link: <b><a href="http://www.voacap.com/p2p/index2.html" target="_blank">http://www.voacap.com/p2p/index2.html</a></b>) but also SDBW (signal power) and MUFday. These are now offered to the ham community, in addition to band-by-band predictions, which even visualize the signal power distribution (upper decile, median and lower decile).<br />
<br />
Each chart offers multi-colored lines for the various parameters. And thanks to the JavaScript framework (plotly.js) used for plotting these graphs, all visible legend parameters/frequencies can all be toggled on and off by clicking on the legend values on the bottom of the graphs, helping the user focus on relevant parameters/frequencies only. Also there is a versatile toolbox on the top-right corner of each graph that allows the user to save the graph as PNG, zoom in/out, compare results data on all frequencies on mouse hover, pan the chart, and more.<br />
<br />
But let's now make a recap of what the three parameters -- <b>REL, SDBW and MUFday</b> -- mean to you.<br />
<br />
<span style="color: red;"><b>The REL or Circuit Reliability.</b></span> The REL is related to VOACAP's output parameters of SNR (Signal-to-Noise Ratio) and REQ.SNR (Required Signal-to-Noise Ratio), and is defined as a circuit reliability factor. It tells us the percentage of days in the month when the SNR value (which is not shown in the charts as a separate parameter) will equal to or exceed the REQ.SNR. The REQ.SNR is an internal value set by me, related to the transmitting mode selected. For CW, the REQ.SNR is set to 24 (dB-Hz), and for SSB, it's 38 dB-Hz.<br />
<b><br /></b>
<b><span style="color: red;">SDBW or Signal Power.</span> </b>The SDBW indicates the dBW (the strength of a signal expressed in decibels relative to one watt) value (the green line in the chart) that can be maintained on 50% of the days (ie. on 15 days) in the month. In a similar fashion, the SDBW90 indicates the dBW or signal strength value that can be maintained on 90% of the days (ie. on 27 days) in the month. And finally, the SDBW10 is the dbW value that can be maintained on 10% of the days (ie. on 3 days) in the month. However, it does not tell us which days are good or which days are bad. The SDBW10 and SDBW90 values are the top and bottom boundaries (respectively) of the light-gray area that is now always visible in all band-by-band prediction charts. The signal power distribution is calculated for Short-Path circuits only. The SDBW values are all translated to corresponding S-Meter readings in the charts.<br />
<br />
<ul>
<li>Read more: <a href="https://voacap.blogspot.fi/2017/07/sdbw-sdbw10-and-sdbw90-predicted-signal.html" target="_blank"><b>Beware of extremely wide Signal Power distributions</b></a> </li>
</ul>
<br />
<b><span style="color: red;">The MUFday</span></b> will tell us what percentage of the days in a month at that hour will be below the predicted MUF (Median Maximum Usable Frequency) for the most reliable mode (MRM). The MRM is the mode with the highest reliability of meeting the Required Signal-to-Noise Ratio, or REQ.SNR (see above).<br />
<br />
These three output parameters are being calculated via Short-Path and Long-Path.<br />
<br />
At the same time, I changed the default setting for the Transmit & Receive Antenna and Transmit Power. Now the TX & RX antenna is a quarter-wave vertical antenna over a good ground, and the TX power is set to 1.5 kW.<br />
<b><span style="color: red;"><br /></span></b>
<b><span style="color: red;">So, how to use the new charts? </span></b>I regularly follow this sequence:<br />
<br />
<ol>
<li>Check the bands of the best REL values for the path in question.</li>
<li>Then check the SDBW values for the best bands.</li>
<li>When you have your candidate bands selected, then go to the charts for those bands.</li>
<li>In band-by-band charts, pay attention to MUFday values, and the signal power (SDBW) distribution (the light gray area). If the distribution is extremely wide, there is a chance that VOACAP unfortunately does not have a good idea of what's going on.</li>
<li>Be sure to check the Long-Path predictions, too! On long-haul paths, Long-Path may bring nice surprises.</li>
</ol>
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMpKrDcyoZafommgPb7Lz41WY_o81Z0EZca5Z1t_cTAn9DqPE0Jtd-PRGKe2OII4glbsXfDbnSH0J2yRWTgO9L19RLbY21rDhksp5OJe_oQJd5TNP-_qjxNAapubh5EiCnUCKOqq1gRpo/s1600/24-hour+VOACAP+prediction+wheel.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMpKrDcyoZafommgPb7Lz41WY_o81Z0EZca5Z1t_cTAn9DqPE0Jtd-PRGKe2OII4glbsXfDbnSH0J2yRWTgO9L19RLbY21rDhksp5OJe_oQJd5TNP-_qjxNAapubh5EiCnUCKOqq1gRpo/s1600/24-hour+VOACAP+prediction+wheel.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The 24-hour prediction wheel shows the Circuit Reliability (or VOACAP's REL parameter). The prediction is always re-calculated as soon as any of the input parameters changes. </span><span style="font-size: small;">The colors indicate the probability of a contact (QSO) over the days of a month at the given hour, using the TX mode set.</span></td></tr>
</tbody></table>
<br />
Then again, three more advanced prediction options are available, and these predictions can be calculated by clicking any of the three buttons below the Prediction Charts section:<br />
<br />
<ol>
<li>All-year grayline</li>
<li>All-year prediction, and</li>
<li>1-month prediction</li>
<li>BxB (band-by-band predictions charts)</li>
</ol>
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<h4>
</h4>
<h4>
1. All-year grayline,<span style="font-weight: normal;"> or all-year solar info to support determining grayline propagation</span></h4>
<br />
The All-year grayline calculates a wealth of solar-related information for the Transmitter and Receiver, and for the geographical midpoint of the circuit, covering the entire year from January to December.<br />
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<br />
<b><span style="color: red;">There are seven different times which will be calculated for each site (TX or RX)</span></b>: three related to sunrise, three related to sunset, and one related to solar midnight. The eight time parameter (MIDPT MNITE) is the solar midnight at the geographical midpoint of the circuit in question.<br />
<br />
<h3>
Sunrise-related times:</h3>
<br />
<ul>
<li><b>DAWN </b>= a point in time when the sun is 6 degrees below the horizon before sunrise</li>
<li><b>RISE </b>= the sunrise time at the horizon</li>
<li><b>POST </b>= a point in time when the sun is 3 degrees above the horizon after sunrise</li>
</ul>
<br />
<h3>
Sunset-related times:</h3>
<br />
<ul>
<li><b>PRE </b>= a point in time when the sun is 3 degrees above the horizon before sunset</li>
<li><b>SET </b>= the sunset time at the horizon</li>
<li><b>DUSK </b>= a point in time when the sun is 6 degrees below the horizon after sunset</li>
</ul>
<br />
<h3>
Solar midnight</h3>
<br />
<b>MNITE </b>(and <b>MIDPT MNITE</b>) = This is the time opposite to solar noon when the sun is closest to the nadir (the direction pointing directly below a particular location), and the night is equidistant from dusk and dawn. The solar midnight rarely coincides with midnight on a clock. Solar midnight is dependent on longitude and time of the year rather than on a time zone. [Wikipedia: <a href="https://en.wikipedia.org/wiki/Midnight">https://en.wikipedia.org/wiki/Midnight</a>]<br />
<br />
<h3>
POST and PRE times </h3>
<br />
The POST and PRE times are based on an educated choice; there is no pre-meditated scientific theory behind "the 3 degrees above the horizon". We know from experience that the low-band propagation starts to deteriorate at some point after sunrise, and that the propagation starts to get enhanced before the actual sunset, and "3 degrees" was my personal choice for this purpose.<br />
<br />
There can be cases where no time is calculated but "--:--" is shown instead. This means that the sun does not reach the degree position set for the calculation.<br />
<br />
<h3>
Predicting probable grayline propagation enhancements</h3>
<br />
Not going to any deeper theoretical discussions here, there are basically three periods of time when distinct propagation enhancements have been reported on low bands.<br />
<br />
These are as follows:<br />
<br />
<b><span style="color: red;">1. Both the Transmitter (TX) and Receiver (RX) are situated in the terminator zone.</span> </b>In my calculations, the terminator zone has been defined as the zone limited by DAWN and POST (post-sunrise) in the morning as well as PRE (pre-sunset) and DUSK in the evening. If there is an overlap between the Transmitter's and Receiver's morning/evening terminator zones, the times will be colored as follows:<br />
<br />
<b>a) TX DAWN-POST and RX DAWN-POST zones overlapping:</b><br />
<br />
TX DAWN-RISE-POST: red<br />
RX DAWN-RISE-POST: red<br />
<br />
<b>b) TX DAWN-POST and RX PRE-DUSK zones overlapping:</b><br />
<br />
TX DAWN-RISE-POST: red<br />
RX PRE-SET-DUSK: blue<br />
<br />
<b>c) TX PRE-DUSK and RX DAWN-POST zones overlapping:</b><br />
<br />
TX PRE-SET-DUSK: blue<br />
RX DAWN-RISE-POST: red<br />
<br />
<b>d) TX PRE-DUSK and RX PRE-DUSK zones overlapping:</b><br />
<br />
TX PRE-SET-DUSK: blue<br />
RX PRE-SET-DUSK: blue<br />
<br />
<b><span style="color: red;">2. The Transmitter (or Receiver) is in the terminator zone and the Receiver (or Transmitter) is in darkness.</span></b> Whenever this condition is met, the times in the DAWN-RISE-POST and PRE-SET-DUSK columns will be colored in green. This is one of the most common cases for signal enhancement on the low bands.<br />
<br />
<b><span style="color: red;">3. The Transmitter (or Receiver) is in the terminator zone and the Receiver (or Transmitter) is in darkness AND the midpoint of the path is in the solar midnight. </span></b>This is a special case of Number 2 in this list but a very important one. Currently, the solar midnight period at the midpoint (labelled as MIDPT MNITE in the tables) is defined as a time period of plus minus 7 minutes from the time calculated and shown in table. The MIDPT MNITE time is the exact calculated solar midnight time but, in my calculations, I consider that the midpoint midnight period is plus minus 15 minutes from that time.<br />
<br />
There can be three colors for the time: black (default), red and blue. When the color is black, the midpoint midnight time does not overlap with the DAWN-RISE-POST or PRE-SET-DUSK times of neither the Transmitter not the Reveicer.<br />
<br />
The colors of red and blue will be assigned as follows:<br />
<br />
a) Midpoint midnight period and TX Terminator zone (morning or evening) overlapping: RED<br />
b) Midpoint midnight period and RX Terminator zone (morning or evening) overlapping: BLUE<br />
<br />
<b><span style="color: red;">As a special mention, if the solar midnight period, a period of plus minus 7 minutes from the MNITE time at TX/RX, overlaps with the Midpoint Midnight period</span></b>, the times in the MNITE column will be colored as follows:<br />
<br />
a) TX midnight period (MNITE) and Midpoint Midnight period overlapping: RED<br />
b) RX midnight period (MNITE) and Midpoint Midnight period overlapping: BLUE<br />
<br />
<h3>
Visualizing the grayline related information on a Google Map</h3>
<br />
[<b>30 June 2017</b>] The grayline related times can be investigated on a Google Map by clicking any of the days of the year.<br />
<div class="separator" style="clear: both; text-align: center;">
</div>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9APAuXJkPXu3D9zIX1Z-oRcdv3msEGLzZhXQRFgil-lvRLMkl27uha4iq0n-baffCGBhY0xyiRN92A3P0JnZK5NX9EEjykuIs_k0Lagushnng5JqUKxa4_kzP5DluGWMfpZpGhgdEMR0/s1600/all-year-grayline-list.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="642" data-original-width="972" height="422" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9APAuXJkPXu3D9zIX1Z-oRcdv3msEGLzZhXQRFgil-lvRLMkl27uha4iq0n-baffCGBhY0xyiRN92A3P0JnZK5NX9EEjykuIs_k0Lagushnng5JqUKxa4_kzP5DluGWMfpZpGhgdEMR0/s640/all-year-grayline-list.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Times of signal enhancements are marked with colors. </span><span style="font-size: small;">Click on any date in the DATE column to view the calculated times on a Google Map for better intelligibility.</span><br />
<span style="font-size: small;">[</span><b style="font-size: medium;"><span style="color: red;">Click on the image to enlarge</span></b><span style="font-size: small;">] </span></td></tr>
</tbody></table>
As soon as a date in the DATE column is clicked on, a Google Map will appear with the times of enhancements as buttons on the top of the map. Click on any of the buttons to see how the day/night terminator is running at that given time on that given day.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhGbmMqCJ6muc_KstVMjYKGOZYGSoAvRawu0la0oALDDIYISbG_WKLC2DmcLhFwhorWDmheaeG2OHmj3ujd-kRE96O-OZFFlnt1Zxe42Pxt_ZRFeasmn4Y_WbVX5XWNYiXVIHtA-caFr7s/s1600/all-year-grayline-map.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="111" data-original-width="1094" height="64" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhGbmMqCJ6muc_KstVMjYKGOZYGSoAvRawu0la0oALDDIYISbG_WKLC2DmcLhFwhorWDmheaeG2OHmj3ujd-kRE96O-OZFFlnt1Zxe42Pxt_ZRFeasmn4Y_WbVX5XWNYiXVIHtA-caFr7s/s640/all-year-grayline-map.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The times placed on the top of a Google Map as clickable buttons. Explanations of the buttons in red. </span><span style="font-size: small;">The explanations are available as tooltips over the buttons on the page.</span><br />
<span style="font-size: small;">[<b><span style="color: red;">Click on the image to enlarge</span></b>]</span></td></tr>
</tbody></table>
<br />
<h4>
2. All-year prediction, or point-to-point predictions for all months of the year at one go</h4>
<br />
The All-year Prediction calculates the point-to-point predictions for the circuit (from TX to RX), covering the entire year from January to December. The colors in the table indicate the probability of making a contact between the TX and RX, using the TX mode selected (CW, SSB or AM). All user-settable input parameters will be observed, except the Sunspot Number (SSN).<br />
<br />
<span style="color: red;">The All-Year Prediction Tables are extremely informative as they nicely combine the Circuit Reliability (REL), Signal Power (S DBW) and MUFday data as well as solar data for TX and RX in one compact, interactive format.</span><br />
<br />
<br />
<b><span id="goog_1193056564"></span><span style="background-color: yellow;"><a href="http://voacap.blogspot.fi/2017/07/adding-mufday-to-equation.html" target="_blank">Click this line to read more about the importance of the MUFday on Above-the-MUF frequencie<span id="goog_1193056565"></span>s!</a></span></b><br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhK49luexkMl4s7m7qVgSymmbYJ5bb0LBtFXvssRjVMBi2a1199xKcTFIhBncceYxpnLOWo2gYw8_1cytsRGSPjO2LFngAF2dGoOQte9QE0rSmonZA24fuykAqcldiwb_VCIA4sin_PdLc/s1600/VOACAP+all-year+prediction.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhK49luexkMl4s7m7qVgSymmbYJ5bb0LBtFXvssRjVMBi2a1199xKcTFIhBncceYxpnLOWo2gYw8_1cytsRGSPjO2LFngAF2dGoOQte9QE0rSmonZA24fuykAqcldiwb_VCIA4sin_PdLc/s1600/VOACAP+all-year+prediction.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">An all-year prediction for the circuit, showcasing the months of January 2017 and February 2017.</span></td></tr>
</tbody></table>
<br />
In the table, the elements of the top row are as follows (from left):<br />
<br />
<ol>
<li>Label for TX and RX,</li>
<li>Short-path (SP) or Long-path (LP),</li>
<li>the distance (kilometers & miles) of the circuit,</li>
<li>the bearing (in degrees from True North) from TX to RX, and</li>
<li>the Sunspot Number (SSN) used for calculations.</li>
</ol>
<br />
<b><span style="color: red;">Below each prediction table, the sunrise and sunset times for TX and RX locations</span></b> have been calculated and visually presented in the table cells below the UTC time row. The gray color denotes night-time and white day-time. The exact sunrise (SR) and sunset (SS) times (in UTC) will come up as you hover the mouse over the TX and RX label texts on the left column. Here, in this example, the sunrise (SR) at TX is at 0605 UTC and the sunset (SS) at 1813 UTC. The similar calculations are available for the RX site, too. The day used in the calculations is always the 15th day of the given month.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZgz3XH8cSoq-Qy1RhKSRZFNh6AiRNe_W184bN7S3hyphenhyphenJ2GoSTsna41y0BbUT5geebfwSuJ_BntkkiMm85O5dl7BNdXj_a-jZdu93U-8flj4iIWaI6UycA02-GNqPJW9EvvCVYnvPmaqNM/s1600/VOACAP+interactive+sun+times.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZgz3XH8cSoq-Qy1RhKSRZFNh6AiRNe_W184bN7S3hyphenhyphenJ2GoSTsna41y0BbUT5geebfwSuJ_BntkkiMm85O5dl7BNdXj_a-jZdu93U-8flj4iIWaI6UycA02-GNqPJW9EvvCVYnvPmaqNM/s1600/VOACAP+interactive+sun+times.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The sunrise and the sunset times for the Transmitter (TX) site.</span></td></tr>
</tbody></table>
<br />
<b><span style="color: red;">All charts are interactive:</span></b> if you hover your mouse over table cells, you will see a pop-up text, indicating the (VOACAP's REL) probability in percentages, and the (VOACAP's S DBW) signal power values in dBW (it’s always a negative number!). For instance in the example below, the signal power value of “-127” equals to a median signal strength of S5 whereas “-93” would correspond to S9 on the S meter. Read more about translating the signal power values (S DBW) into S-meter values here: <a href="http://www.voacap.com/s-meter.html">http://www.voacap.com/s-meter.html</a> .<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_jTvetwCHrFZqCGt82Q6QXDjQoF_7rv5AiKN0RuuS0_ZeytIiWZZR-L3O1v9ufPqD7ADwKd1FxTDlzJqrWuoyA5tfa26V_m4Ko6ityZoDPG58DEyeait6QN4utrbjAbBxbXwLFq2W3EM/s1600/VOACAP+interactive+prediction+tables.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_jTvetwCHrFZqCGt82Q6QXDjQoF_7rv5AiKN0RuuS0_ZeytIiWZZR-L3O1v9ufPqD7ADwKd1FxTDlzJqrWuoyA5tfa26V_m4Ko6ityZoDPG58DEyeait6QN4utrbjAbBxbXwLFq2W3EM/s1600/VOACAP+interactive+prediction+tables.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The pop-up window over the table cell shows the VOACAP's REL output value in percentages and the signal power as a (negative) S DBW value</span></td></tr>
</tbody></table>
<br />
<b><span style="color: red;">All colors, except grey, indicate QSO-making probabilities.</span></b> In the prediction table per se, white means 0%, blueish 10%, greenish 30-40%, yellowish 50-60%, yellow-orangeish 70-80% and orange-reddish 90%, and pure red 100%. The color of grey does not indicate any probability value. Instead, it shows that, although VOACAP does not predict any probability for that specific hour, some signal power has been predicted which may translate into workable conditions. So, in a sense, grey indicates a heads-up note -- "a grey area" where QSOs may (or may not) be possible. Typically, these grey areas can mostly be found in low-band predictions (40 to 80 meters).<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8plKatT1YLsdd-ojStP459HNm50BnfVRmp9-o00oY9IBq5ejIJ_HkiVI-GZiWyOPi2psIRj5jQt6cSWgdo0gOQ44WSrjagO_6q28IhmLx1X2fCO9GVzzl_T_D5ls5eGSZUGNXDcWCH3M/s1600/VOACAP+color+scale.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8plKatT1YLsdd-ojStP459HNm50BnfVRmp9-o00oY9IBq5ejIJ_HkiVI-GZiWyOPi2psIRj5jQt6cSWgdo0gOQ44WSrjagO_6q28IhmLx1X2fCO9GVzzl_T_D5ls5eGSZUGNXDcWCH3M/s1600/VOACAP+color+scale.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Propagation predictions use a color scheme from white (worst) to red (best).</span></td></tr>
</tbody></table>
<div class="separator" style="clear: both; text-align: center;">
</div>
<br />
<span style="color: red;"><b>All predictions charts start at 01 hours UTC.</b> </span>You may ask, "Why not start at 00 UTC?". Well, it's a matter of taste. All VOACAP predictions span 60 minutes but not necessarily the way you may think. A prediction for 01 UTC does not span from 01:00 to 02:00 but, in fact, from 00:30 to 01:30 UTC! So, I decided, being inspired by the original makers of VOACAP, to start at 01 UTC and end at 24 UTC. Following the same logic, 24 UTC means a time frame of 23:30 to 00:30 UTC.<br />
<br />
<h4>
3. 1-month prediction, or the original VOACAP P2P graphs</h4>
<br />
The button “1-month prediction” is the original button used at the VOACAP Online P2P site, but now it’s with a new name, and pressing it will calculate the detailed propagation prediction graphs for the entire frequency range from 2 MHz to 30 MHz, showing the REL (Circuit reliability) and S DBW (Signal Power) graphs for the circuit.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzdbZFTf9w_a0dxMHLUjB7FZCZkS5L_-0XIdXHRztPW0vz-dIh9oY-QqVnysWwupJfLJm7QbnLJtEyopWTdPGJHKWAtAFMQzCW3Px1DqA5eCNI9F-_UgO6yc1q2POWZzhhFvG11FYUb8o/s1600/VOACAP+circuit+reliability.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzdbZFTf9w_a0dxMHLUjB7FZCZkS5L_-0XIdXHRztPW0vz-dIh9oY-QqVnysWwupJfLJm7QbnLJtEyopWTdPGJHKWAtAFMQzCW3Px1DqA5eCNI9F-_UgO6yc1q2POWZzhhFvG11FYUb8o/s1600/VOACAP+circuit+reliability.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The Circuit Reliability graph, one of the two graphs calculated for the "1-month prediction".</span></td></tr>
</tbody></table>
<br />
<h4>
4. BxB, or all the new Prediction Charts displayed on one page</h4>
<br />
If you wish to see all the new prediction charts displayed on a single page, click the button labelled "BxB" (short for Band-by-Band).<br />
<br />
<div>
<br /></div>
OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com7tag:blogger.com,1999:blog-8260894794228814400.post-16069118325113730432016-11-18T22:35:00.000+02:002016-11-18T22:35:02.697+02:00VOACAP Greyline User ManualVOACAP Greyline is an online service that provides a number of sun-related data for any given location such as sunrise/sunset times, dawn, dusk, solar midnight, and, for circuits, the solar midnight time for the circuit's half-way point. The idea is to offer data which would help DXers/contesters leverage any "grayline" related low-band openings.<br />
<br />
The URL: <a href="http://www.voacap.com/greyline/index.html">http://www.voacap.com/greyline/index.html</a><br />
<br />
<h3>
What's in it for you?</h3>
<br />
The greyline service offers three types of solar calculations:<br />
<br />
<ol>
<li>Daily sunrise and sunset times for a wide selection of DXCC locations</li>
<li>All-year sun calendar: sunrise and sunset times for a user-defined location for every day of the year selected</li>
<li>A deep analysis of DXCC countries that are located along the grayline terminator or in darkness at sunrise and sunset in a user-defined location</li>
</ol>
<br />
<h3>
1. Daily sunrise and sunset times for a wide selection of DXCC locations</h3>
<br />
This is the default calculation when you go to the site at http://www.voacap.com/greyline/index.html. The DXCC locations are the pre-defined locations used in VOACAP Online. In reality, VOACAP Greyline offers much more than simple sunrise or sunset times. Let's look into the times calculated; all times in all calculations are UTC.<br />
<br />
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCb0UlQqcTqOmoKJPOsvaLMwnHv6NXK7anec9QCZrCGK2SW8tIQztY6xpvQOWeHLL303EvkaXHvY1hlw2SKlKxJKA752b49BmEzFLtK3ZHaHQ61mlzf9wI4F_kcgVFdH6iTujAN4zF1PI/s1600/voacap-greyline-default-view.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="222" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCb0UlQqcTqOmoKJPOsvaLMwnHv6NXK7anec9QCZrCGK2SW8tIQztY6xpvQOWeHLL303EvkaXHvY1hlw2SKlKxJKA752b49BmEzFLtK3ZHaHQ61mlzf9wI4F_kcgVFdH6iTujAN4zF1PI/s640/voacap-greyline-default-view.gif" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">CLICK TO ENLARGE</td></tr>
</tbody></table>
<br />
<br />
There are actually seven different times which will be calculated: three related to sunrise, three related to sunset, and one related to solar midnight.<br />
<br />
<h4>
Sunrise-related times:</h4>
<br />
DAWN = a point in time when the sun is 6 degrees below the horizon before sunrise<br />
RISE = the sunrise time at the horizon<br />
POST = a point in time when the sun is 3 degrees above the horizon after sunrise<br />
<br />
<h4>
Sunset-related times:</h4>
<br />
PRE = a point in time when the sun is degrees above the horizon before sunset<br />
SET = the sunset time at the horizon<br />
DUSK = a point in time when the sun is 6 degrees below the horizon after sunset<br />
<br />
<h4>
Solar midnight</h4>
<br />
MNITE = This is the time opposite to solar noon when the sun is closest to the nadir (the direction pointing directly below a particular location), and the night is equidistant from dusk and dawn. The solar midnight rarely coincides with midnight on a clock. Solar midnight is dependent on longitude and time of the year rather than on a time zone. [Wikipedia: https://en.wikipedia.org/wiki/Midnight]<br />
<br />
<br />
<h4>
POST and PRE times </h4>
<br />
The POST and PRE times are based on an educated choice; there is no conscious theory behind "the 3 degrees above the horizon". We know from experience that the low-band propagation starts to deteriorate at some point after sunrise, and that the propagation starts to get enhanced before the actual sunset, and "3 degrees" was my personal choice for this purpose. So, in effect, I am using the time periods from DAWN to POST, and from PRE to DUSK as my internal limits in my calculations when filtering the results in the deep analysis (the calculation type 3).<br />
<br />
The default date for daily calculations in the currect UTC day. If you wish to calculate times for all DXCC sites for a specific date, just select the date from the calendar, and press "Go".<br />
<br />
To make this calculation again for the current date after setting the date (or after setting a location), just press first "Reset" and then "Go".<br />
<br />
There can be cases where no time is calculated but "--:--" is shown instead. This means that the sun does not reach the degree position set for the calculation.<br />
<br />
For example, let's take some Finland locations at midsummer (June 21):<br />
<br />
<pre>CITY DAWN RISE POST | PRE SET DUSK | MNITE
OH6 Seinajoki --:-- 00:25 01:26 | 19:34 20:35 --:-- | 22:30
OH6 Vaasa --:-- 00:23 01:28 | 19:43 20:47 --:-- | 22:35
OH7 Joensuu --:-- 00:00 01:01 | 19:04 20:05 --:-- | 22:02
OH7 Kuopio --:-- 00:03 01:06 | 19:15 20:18 --:-- | 22:11
OH8 Kajaani --:-- 23:34 00:50 | 19:31 20:47 --:-- | 22:10
OH8 Oulu --:-- 23:19 00:49 | 19:50 21:20 --:-- | 22:19
</pre>
<br />
As the times for DAWN and DUSK are labelled as "--:--", it means that the sun does not reach 6 degrees before sunrise nor does it go below 6 degrees after sunset. On the other hand, for instance, if all columns are labelled as "--:--", it can mean that it's either midnight sun (polar day) or polar night.<br />
<br />
<h3>
2. All-year sun calendar: sunrise and sunset times for a user-defined location for every day of the year selected</h3>
<br />
If you wish to run the solar data above for every day of the chosen year for your own location, just enter your Maidenhead grid locator in the "Locator" field, choose any date (click on a date) in the year you are interested in, and checkmark the "Calendar" option. Then press "Go".<br />
<br />
The locator needs to be given in six characters. If you do not know your locator, please click on the "Locator" link to go to http://www.voacap.com/qth.html which shows you the coordinates and the corresponding grod locator with the precision required (6 characters).<br />
<br />
Suppose we want a all-year sun calendar for Valletta (9H) for the year 2017. Then I would first check the grid locator (JM75gv) and select any date from the calendar in 2017. Then I would checkmark the "Calendar" box, and press "Go".<br />
<br />
The result will be as follows:<br />
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhozpi6eOcG-bXANM-UdG7nvqIJycSVahWp2l72qmG-AzmdDSVtfE4IRo2ea0BGU228dxTosRvZIHUKCktZ-kZP-CiRKv9k-4hSPQfC1ClNhJnq1zhH6FTFosMXPWPBugixLkay_QJHEcM/s1600/voacap-greyline-sun-calendar-malta-2017.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="372" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhozpi6eOcG-bXANM-UdG7nvqIJycSVahWp2l72qmG-AzmdDSVtfE4IRo2ea0BGU228dxTosRvZIHUKCktZ-kZP-CiRKv9k-4hSPQfC1ClNhJnq1zhH6FTFosMXPWPBugixLkay_QJHEcM/s640/voacap-greyline-sun-calendar-malta-2017.gif" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">CLICK TO ENLARGE</td></tr>
</tbody></table>
<br />
<br />
<h3>
3. A deep analysis of DXCC countries that are located along the grayline terminator or in darkness at sunrise and sunset in a user-defined location</h3>
<br />
This calculation type is the most elaborate. First of all, it requires that you set a location (as a 6-character Maidenhead grid locator), and set a date you are interested in. Do not checkmark the "Calendar" box! Then press "Go".<br />
<br />
Two calculations will be done for all circuits from the location you set to the pre-defined locations in VOACAP Greyline's DXCC country list: sunrise and sunset calculations.<br />
<br />
<h4>
New columns</h4>
<br />
There will be a number of new columns on the result page as we are now dealing with point-to-point circuits. The columns are:<br />
<br />
<br />
<ul>
<li><b>HALFW</b> = This is the solar midnight at the half-way point along the circuit in question. This is the time ON4UN says can be one of the peak times along that circuit.</li>
<li><b>KM/SP and DEG</b> = This is the distance from the Location to the DXCC location in kilometers via short-path (SP). DEG is the corresponding bearing from Locator to the DXCC location.</li>
<li><b>KM/LP and DEG</b> = This is the distance from the Location to the DXCC location in kilometers via long-path (SP). DEG is the corresponding bearing from Locator to the DXCC location. If you want the distance in miles, divide kilometers by 1.609 ...</li>
</ul>
<br />
<br />
As said, the service calculates the sunrise and sunset times for the given Locator. Then it tries first to find the locations in DXCC countries that are along the grayline terminator. In those locations, the sun can either be rising or setting. The time frame for the terminator is determined by DAWN-POST and PRE-DUSK times. If the sun is rising, you will only see the sunrise-related times for that particular DXCC location, and consequently, if the sun is setting in that particular DXCC location, you will only see the sunset-related times.<br />
<br />
Secondly, the service finds all locations in the DXCC country list where the location is in darkness. So, this is the situation when the sun rises or sets in the Location but it's still dark in the DXCC location. Think about the morning propagation of signals from the west when the sun start to rise in your location.<br />
<br />
<h4>
An example </h4>
<br />
Let me illustrate what's happening. In the image below, this is an excerpt of the result page for my locator KP03sd on November 15, 2016.<br />
<br />
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</div>
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</div>
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</div>
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwXD-mQZea9T50kaw9mosDpTT1RN7ZbGVRbcIWP0PIrcup3rGQjbVRIPEuU1fbmaIXY6dCcaCdWTIJBmkShP1XBDisgoZ3gyuuUDzdbdArpC80TRg5RzngfBCO4v89nwmpvyqlq3c0ftU/s1600/greyline-typical-run.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="296" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwXD-mQZea9T50kaw9mosDpTT1RN7ZbGVRbcIWP0PIrcup3rGQjbVRIPEuU1fbmaIXY6dCcaCdWTIJBmkShP1XBDisgoZ3gyuuUDzdbdArpC80TRg5RzngfBCO4v89nwmpvyqlq3c0ftU/s640/greyline-typical-run.gif" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">CLICK TO ENLARGE</td></tr>
</tbody></table>
<br />
<br />
In Bullet 1, we can see that at my sunrise, the sun is rising also in 1A SMOM and in 3A Monaco. Bullet 2 reveals, on the other hand, that - at the same time - the sun is setting in 3D2/C Conway Reef and 3D2/R Rotuma. Note that in these two cases, only the sunrise or sunset times are shown, so that the user can more easily distinguish whether there is a sunset or sunrise in the DXCC location.<br />
<br />
And finally, Bullet 3 shows that there are locations which are in darkness at my sunrise. When a DXCC location is in darkness, both the sunrise and sunset times are given for the location. The darkness period is calculated to be the time period from PRE to POST in that particular DXCC location. This actually means that the darkness period also includes the twilight period.<br />
<br />
For instance, 8P Barbados is in "darkness" from 21:11 UTC (PRE) to 10:14 UTC (POST). And we can see that the twilight period for KP03sd is from 05:58 UTC (DAWN) to 07:47 UTC (POST). So, 8P is filtered to be part of the results as it's in darkness when the sun is rising in the given Location.<br />
<br />
A similar kind of analysis is made for the sunset at Locator, too.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com17tag:blogger.com,1999:blog-8260894794228814400.post-80617170559757957162016-11-12T11:14:00.000+02:002016-11-12T11:15:53.230+02:00VOACAP Online now offers multiple coverage maps at one goThe VOACAP Online Coverage Maps Service at <a href="http://www.voacap.com/area/">http://www.voacap.com/area/</a> is now able to plot multiple coverage maps at one go. This was made possible by a major code re-factoring at www.voacap.com. Earlier, only one map could be plotted at a time.<br />
<br />
In a nutshell, while entering the input values, at "Time UTC:", choose the start time for your maps. The default is the currect UTC hour. See image below.<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKmXWkDFGBBsJU20VXagaQUESwcpkBsyAMyoWvXvXSlDNI_RyM5LFmFEjLrYEpCgbJ4z1X9yIMy1WPIbn9B61GV5Vh7jUcDbmv6fOUf9JvnJIIm8TOc69tZDLkQby019OhPHxt1E7Zc40/s1600/multiple-coverage-map-voacap-online.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKmXWkDFGBBsJU20VXagaQUESwcpkBsyAMyoWvXvXSlDNI_RyM5LFmFEjLrYEpCgbJ4z1X9yIMy1WPIbn9B61GV5Vh7jUcDbmv6fOUf9JvnJIIm8TOc69tZDLkQby019OhPHxt1E7Zc40/s1600/multiple-coverage-map-voacap-online.gif" /></a></div>
<br />
Then there is a pop-up menu for "<b>Period</b>". There you will need to choose the time period for your maps, defaulting to 1, i.e. the map for the current hour. You can choose a time period up to 12 hours, so to cover a 24-hour period, you will only need to make two runs. Unfortunately, running and plotting 24 hours, or 24 coverage maps, at one go takes a considerable amount of time, resulting in a server connection time-out, hence 12 hours is the limit.<br />
<br />
So when viewing the result page with the maps, you can then conveniently print that page to PDF. You may need to install some extra tools such as <a href="http://www.cutepdf.com/" target="_blank">CutePDF Writer</a> if this functionality is not offered to you by your operating system as standard. <br />
<br />
Please be also advised that all the coverage maps created in the service will be deleted in a more frequent cycle than before so please do not link directly to the maps produced.<br />
<br />
Also, earlier this month, I added the option of choosing the noise level at RX sites. This option was also added to VOACAP Online Point-to-Point Service.<br />
<br />
Give it a spin and let me know what you think!OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0tag:blogger.com,1999:blog-8260894794228814400.post-67111988331442322452016-06-12T11:45:00.003+03:002016-06-25T20:09:54.829+03:00Introducing a text-GUI for VOACAP on Linux<span style="color: red;"><b>UPDATE: 25 June 2016: a Python version available.<span style="color: black;"> [Download <a href="http://www.voacap.com/text-gui/voatui.py">voatui.py</a>]</span> </b></span><br />
<span style="color: red;"><b>MAJOR UPDATE: 19 June 2016</b></span><br />
<br />
I have an extra computer running Developer versions of Windows 10, and creating this text-based GUI actually started with experiments with Microsoft's brand-new <b>Bash on Ubuntu on Windows 10</b>, or the Windows Subsystem for Linux (WSL). To be able to run the Bash shell on Windows 10, you will have to have a certain Developer Build, and currently the shell needs to be specifically enabled as a Windows feature, it is not activated by default. See all the vital info here:<br />
<br />
<a href="http://www.howtogeek.com/249966/how-to-install-and-use-the-linux-bash-shell-on-windows-10/">http://www.howtogeek.com/249966/how-to-install-and-use-the-linux-bash-shell-on-windows-10/</a><br />
<br />
<h2>
1. Getting Ready</h2>
<br />
Before I begin, please note that the text-based GUI should actually run on any flavor of Linux/Unix where the basic Unix tools and Perl are installed. What I want to say is that this GUI was inspired by the new Bash shell on Windows 10!<br />
<br />
So, first you will need to install the VOACAP binaries in the system. You can of course compile the VOACAP Fortran sources by yourselves but the easy way is just to grab Jim Watson's ready-made VOACAP software package, called voacapl, at <a href="http://www.qsl.net/hz1jw/voacapl/">http://www.qsl.net/hz1jw/voacapl/</a>. It's conveniently packaged also for Ubuntu so, on the WSL, you just download the package and, in the download directory, install it by typing this command:<br />
<pre><span style="color: red;"><strike>$ sudo apt-get install voacapl_0.6.5-1_amd64.deb</strike></span></pre>
<pre> </pre>
<pre><span style="color: red;">EDIT: 18 June 2016. The correct command to install this package is: </span></pre>
<pre>$ sudo dpkg -i voacapl_0.6.5-1_amd64.deb </pre>
<br />
After the installation is complete, you should run the command '<b>makeitshfbc</b>' logged in as your usual user name to create the itshfbc directory structure in your home directory.<br />
<br />
Test the installation by typing the following command:<br />
<br />
<pre>$ voacapl ~/itshfbc</pre>
<br />
You should see output similar to the following:<br />
<br />
<pre> Run Directory : /home/jpe/itshfbc/run
Opening Data File : voacapx.dat
TRANSMIT=+ 15.0 dBi[default/isotrope ]=ISOTROPE beam= 0.0 az= 344.0
RECEIVE =2-D Table [default/swwhip.voa ]=SWWhip.VOA beam= 0.0 az= 158.5
Method 30 Jun 100ssn Freqs= 6.1 7.2 9.7 11.9 13.7 15.4 17.7 21.6 25.9
</pre>
<br />
If the tests are okay, you are all ready to start!<br />
<br />
Ah, one more thing: please change the absorption model used for calculations. The absorption model will be determined at run time by the contents of the file <b>itshfbc/database/version.w32</b>. The default content of this file is: Version 14.0905W. Change this to: Version 14.0905a which implements Alex' (VE3NEA) changes to the VOACAP code using the IONCAP absorption model.<br />
<br />
<h2>
2. Moving the scripts in place</h2>
<span style="color: red;"><b>EDIT 19 June 2016:<br />Be sure to re-download the voa.sh and rel.pl scripts below as they run the entire show.</b></span><br />
Download these two scripts: <a href="http://www.voacap.com/text-gui/voa.sh">voa.sh</a> (Bash shell script) and <a href="http://www.voacap.com/text-gui/rel.pl">rel.pl</a> (Perl script), and place them into a directory of their own. <b>Use at your own risk.</b> <a href="http://www.voacap.com/disclaimer.html">Read this software disclaimer</a>.<br />
<br />
You can, for instance, create a voacap directory under your home directory:<br />
<br />
<pre>$ mkdir ~/voacap</pre>
<br />
And, provided the scripts are now in your home directory, move them to the voacap directory:<br />
<br />
<pre>$ mv voa.sh voacap
$ mv rel.pl voacap
</pre>
Go to the voacap directory, and make the scripts "executable" (chmod):<br />
<br />
<pre>$ cd voacap
$ chmod +x voa.sh
$ chmod +x rel.pl
</pre>
<h2>
3. Running the scripts voa.sh and rel.pl</h2>
<br />
Let me explain the workings of the Bash shell script <b>voa.sh</b> in more detail. This is the main script that runs the show: it prompts the user for the transmitter (TX) and receiver (RX) coordinates, and fetches the sunspot number data from the Internet if it's not already available.<br />
<br />
If you run this script for the first time, this script will get the SSN data from the Internet, and will not re-fetch it until the user deletes the SSN file. In addition, this script makes sure that the input data which is required by voacapl is formatted correctly. Then the prediction is run, and the output will be filtered and re-directed to the Perl script <b>rel.pl</b> which then creates an text-based table out of the VOACAP results.<br />
<br />
So, as said, the sunspot number data will be fetched from the Internet, so you will need an Internet connection to get that data. Otherwise, no Internet connection is required.<br />
<br />
All the necessary files are defined in voa.sh as follows:<br />
<br />
<pre># VOACAP input & output files
INP=~/itshfbc/run/voacapx.dat
OUT=~/itshfbc/run/voacapx.out
# sunspot file location
SSN=~/itshfbc/ssn.txt
# source for sunspot numbers
sunsrc="ftp://ftp.ngdc.noaa.gov/STP/space-weather/solar-data/solar-indices/
sunspot-numbers/predicted/table_international-sunspot-numbers_monthly-predicted.txt"
</pre>
<br />
The sunspot file ssn.txt will be created and located in the itshfbc directory. The VOACAP input file voacapx.dat, required for running the prediction, is located in the itshfbc/run/ directory, and the VOACAP output result file voacapx.out will be located in the same place.<br />
<br />
To run the voa.sh script, go to the voacap directory under your home directory, and type:<br />
<br />
<pre>$ ./voa.sh </pre>
<pre> </pre>
<span style="color: red;"><b>EDIT: The screenshots below reflect now the 19 June 2016 version of the text-GUI. </b></span><br />
As we don't have the sunspot data yet, first the script will fetch it by using the curl program. The text on the screen is as follows:<br />
<br />
<pre>Welcome to the VOACAP text-GUI. This script handles the most important input
values needed for running voacapl, writes the input file, runs the VOACAP
prediction, and feeds the results to the rel.pl Perl script for creating a
text-based result table.
Please wait. Fetching the sunspot number data...
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 4565 100 4565 0 0 1015 0 0:00:04 0:00:04 --:--:-- 1088
Predefined values:
TX Antenna: Isotropic, 0 dBi gain
RX Antenna: Isotropic, 0 dBi gain
Choose a year:
1) 2016
2) 2017
3) 2018
#? _</pre>
<br />
Only the input values for the TX and RX antennas are pre-defined (the 0-dBi isotropic antenna is a good starting point), and other critical input values such as the current month, year, TX power, TX mode, are user-settable.<br />
<br />
You can, of course, modify the VOACAP input file to your taste but please note, however, that the structure of the input file is column-based so care is required that the data is placed on right columns.<br />
<br />
Let's run a prediction from <b>London (G) to Christmas Island (VK9X)</b> for November 2018, using CW and 1.5 kW. The screen looks like this:<br />
<br />
<pre>Choose a year:
1) 2016
2) 2017
3) 2018
#? 3
Choose a month:
1) January 4) April 7) July 10) October
2) February 5) May 8) August 11) November
3) March 6) June 9) September 12) December
#? 11
TRANSMITTER (TX)
---------------------------
TX latitude (-90...90) : 51.5
TX longitude (-180...180) : -0.08
RECEIVER (RX)
---------------------------
RX latitude (-90...90) : -10.5
RX longitude (-180...180) : 105.67
Choose TX Power (in Watts):
1) 1500
2) 500
3) 100
4) 5
#? 1
Choose TX Mode:
1) CW
2) SSB
3) AM
#? 1
Thank you! Your input file is as follows:
LINEMAX 999 number of lines-per-page
COEFFS CCIR
TIME 1 24 1 1
MONTH 2018 11.00
SUNSPOT 11.1
LABEL TX RX
CIRCUIT 51.50N 0.08W 10.50S 105.67E S 0
SYSTEM 1. 155. 3.00 90. 24.0 3.00 0.10
FPROB 1.00 1.00 1.00 0.00
ANTENNA 1 1 2 30 0.000[samples/sample.00 ] 0.0 1.2000
ANTENNA 2 2 2 30 0.000[samples/sample.00 ] 0.0 0.0000
FREQUENCY 3.60 5.30 7.1010.1014.1018.1021.1024.9028.20 0.00 0.00
METHOD 30 0
BOTLINES 8 12 21
TOPLINES 1 2 3 4 6
EXECUTE
QUIT
Press ENTER to run the prediction...
</pre>
<br />
After you have pressed ENTER at the choice of the TX Mode, the script will show you the structure of the input file to be written to <b>~/itshfbc/run/voacapx.dat</b>. You can now visually inspect that everything is as should be. Note that the input file will be for a short-path prediction, although both the short-path and long-path circuits will be calculated and displayed. The default antennas are omnidirectional isotropics with zero dBi gain. The minimum take-off angle is set to 3 degrees.<br />
<br />
Then press ENTER to run voacapl. You will see this:<br />
<br />
<pre>Calculating Short-Path...
Calculating Long-Path... </pre>
<pre>Press ENTER to view the results...</pre>
<br />
This is where the execution of voa.sh practically ends. Now when you press ENTER, the script will extract the <b>REL (Reliability) and S DBW (Signal Power)</b> values from the VOACAP output file, and feed those values to the Perl script, rel.pl.<br />
<br />
OK, let's press ENTER and see how the Perl script massages the results into two text tables:<br />
<br />
<pre>VOACAP Prediction via Short-Path. Nov 2018: SSN 11. Power = 1.200kW, CW
TX (51.50N, 0.08W) to RX (10.50S, 105.67E): 12006 km, 7460 mi, 84 deg
| 01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|
10| f e d d d e f |10
12| d C C C C C d f |12
15| f C C C C B B B C f |15
17| d C d d C C C C B C f |17
20| e f * * C f e C C C C C d f f f f e e f |20
30| d e f * * f f C C C C C C C C C C C |30
40| d * * f f d d C C C C C C C |40
60| f * * f d C C C C d d e |60
80| * f e e d d f e f |80
| 01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|
A = 90 - 100% d = 25 - 49% * = REL 0%, but Signal Power over Noise
B = 75 - 89% e = 10 - 24%
C = 50 - 74% f = 1 - 9%
VOACAP Prediction via Long-Path. Nov 2018: SSN 11. Power = 1.200kW, CW
TX (51.50N, 0.08W) to RX (10.50S, 105.67E): 28018 km, 17410 mi, 264 deg
| 01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|
10| f f |10
12| f f e d f f |12
15| e d d C d d e |15
17| f d d d d d d e e f |17
20| f e f * f f e f f f |20
30| f f f |30
40| |40
60| |60
80| |80
| 01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|
A = 90 - 100% d = 25 - 49% * = REL 0%, but Signal Power over Noise
B = 75 - 89% e = 10 - 24%
C = 50 - 74% f = 1 - 9%</pre>
<br />
On top of the Short-Path and Long-Path tables, a good number of details are being displayed. Please note that the SSN value is not the daily sunspot number but a monthly smoothed (predicted) SSN. The band axis is the vertical one and the UTC hours run horizontally starting from 01 UTC (i.e. from 00:30 to 01:30 UTC).<br />
<br />
The letters in the table show the probability (in VOACAP parlance, the REL) values for making a QSO from London to Christmas Island from 10 meters to 80 meters. The best probabilities (A to C, or 50% to 100%) are displayed in upper case letters whereas the "less probable" slots are displayed in lower case letters (d to f). You can see the probability legends below the tables.<br />
<br />
Please note the use of the star (*). This means that the calculated probability (REL) is zero but the Signal Power (S DBW) still shows values which could be above the Noise level and could produce a detectable signal. This feature is something which is not available in the circular 24-hour (REL) prediction graph at <a href="http://www.voacap.com/prediction.html">www.voacap.com/prediction.html</a> (see below).<br />
<br />
Here's the result graph on the same circuit, Short-Path, calculated at VOACAP Online, for reference:<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjA28Mcw4WI_lFy3SyW4c1pN5akT-fTHIfTEwKnvnjOYC59GJCYKNE-refQ77wE5IxTZrVzwBCdr7Df-EwE81NG1TePliPW3OrGEoCGRnGRLRwUHidw0Y4aHgxWkfjUuAvj4ABGyWKOE2M/s1600/G-VK9X-2018.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjA28Mcw4WI_lFy3SyW4c1pN5akT-fTHIfTEwKnvnjOYC59GJCYKNE-refQ77wE5IxTZrVzwBCdr7Df-EwE81NG1TePliPW3OrGEoCGRnGRLRwUHidw0Y4aHgxWkfjUuAvj4ABGyWKOE2M/s1600/G-VK9X-2018.gif" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">VOACAP Online graphical prediction from London (G) to Christmas Isl (VK9X), November 2018. </td></tr>
</tbody></table>
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<br />OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0tag:blogger.com,1999:blog-8260894794228814400.post-64111487481003706932015-07-24T09:45:00.002+03:002018-09-01T17:52:48.465+03:00Introducing VOACAP DX Charts<b>The VOACAP DX Charts service has been upgraded in August 2018</b>. This service uses much of the same technology & ideas I created for the VOACAP Propagation Planner such as:<br />
<ul>
<li><b>interactive propagation charts</b> that show the QSO probabilities and signal power (hover the mouse over the table cells to see the values)</li>
<li><b>graphical presentation of sunrise and sunset times</b> to help predict low-band openings (hover the mouse over the 'TX' and 'RX' labels on the bottom left of the tables to see the exact sunrise and sunset times in UTC)</li>
</ul>
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjatSL06h0OZIhkZ9t5GaxSEURGFhFIbOxlWeT_qU7Wr-oY9Ihu827WMeDU5wiz0kyEixDt9qmIQBgzR3Vv0BHP6NetFBRy7isLXccyKCEidkHSh1fQOnH0QbVJkJvAOYQ1wtmTqGnu52g/s1600/voacap-prediction-table.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="264" data-original-width="388" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjatSL06h0OZIhkZ9t5GaxSEURGFhFIbOxlWeT_qU7Wr-oY9Ihu827WMeDU5wiz0kyEixDt9qmIQBgzR3Vv0BHP6NetFBRy7isLXccyKCEidkHSh1fQOnH0QbVJkJvAOYQ1wtmTqGnu52g/s1600/voacap-prediction-table.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">An example DX propagation chart.</span></td></tr>
</tbody></table>
<br />
I have deliberately kept the layout of the results page to a bare minimum to allow the user to copy the charts to word processing, and make them pretty for printing.<br />
<br />
To use this service, the user only needs to know his/her <b>Maidenhead grid locator</b> and press the "Run!" button. If you do not know your grid locator, I have created an easier-than-the-easiest map application to help you find your grid locator : <a href="http://www.voacap.com/qth.html">www.voacap.com/qth.html</a> . Just zoom into your location on the map, and your coordinates and grid locator are readily visible on the top part of the map.<br />
<br />
Furthermore, if you wish to<b> tweak the default antenna selection by band</b>, you can do so, and even save your selections (click "Save setup"), together your grid locator, for later use. Also, swapping the antenna selections between TX and RX is available with one click!<br />
<br />
<b>And, as a bonus, the option to set the sporadic E layer (Es) has been made available</b>. Use this if your location could be under the influence of the sporadic E, e.g. during the summer in the Northern hemisphere.<br />
<br />
For the predictions, I have assumed that, on 20M to 10M, the DX uses a 3-ele Yagi at 10 meters AGL, and on low-bands a 1/4 vertical over a good ground. On the user's side, a 3-ele Yagi at 20 meters AGL for 20M to 10M, and a 1/4 vertical over a good ground are assumed. The TX power is assumed as per the DXpedition in question.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_aYzE0qBfrImKp0NX6pWikW4ppasZhdbpk7h7cha-RtouhU4Hn4VVqE-XZToDyqvwVYPpEStETfBfY0EQUN3-EjWNb_ftL3u1Mypxty9g8vGHV2MLsv9-V8Ncjp56o8febnFGDDpgZsw/s1600/voacap-dx-charts-home.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="634" data-original-width="491" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_aYzE0qBfrImKp0NX6pWikW4ppasZhdbpk7h7cha-RtouhU4Hn4VVqE-XZToDyqvwVYPpEStETfBfY0EQUN3-EjWNb_ftL3u1Mypxty9g8vGHV2MLsv9-V8Ncjp56o8febnFGDDpgZsw/s1600/voacap-dx-charts-home.gif" /></a></div>
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The DX sites are currently being updated on a monthly basis, or on an "as-needed" basis. Please let me know if you find bugs, or want more DX sites added to the list.<br />
<br />
73 Jari OH6BGOH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com15tag:blogger.com,1999:blog-8260894794228814400.post-44077568315286602002015-07-18T18:16:00.000+03:002017-07-14T10:06:45.484+03:00VOACAP Propagation Planner Revisited!<b>UPDATE July 2017: MUFday assessments in place for all HF propagation
prediction tables, resulting in even better predictions on Above-the-MUF
frequencies. <a href="http://voacap.blogspot.fi/2017/07/adding-mufday-to-equation.html" target="_blank">Read more!</a></b> <br />
<br />
<a href="http://www.voacap.com/planner.html" target="_blank">VOACAP Propagation Planner</a> is a comprehensive planning tool for HF contesters and DXers. So far, the only problem has been that you really must be a dedicated enthusiast to run all the software required to maximize your efforts either in contests or DXpeditions. Now, things have changed: A new, more user-friendly version — 2.0 beta — is finally available!<br />
<br />
Preparing and planning for any worldwide contest or DX expedition (or hunting a DX) require a thorough analysis of propagation predictions. The propagation predictions help you, so to speak, get a good grasp of the playing field, i.e. where to play and when. The predictions tell you when and on what bands the best openings are in the given direction at a suitable signal strength, so that the QSO rates can be maintained at their best; at what times it’s good to use those valuable long-path openings, and when to focus on working those hard-to-reach areas while the band opens elsewhere at the same time.<br />
<br />
The new online version now does all heavy-lifting and number-crunching on the VOACAP server, and visualizes the results in two ways: by CQ or ITU Zones (short-path or long-path) and by band-specific zone charts (short-path or long-path, as you wish). Be warned that there are quite a number of charts to analyze but I am confident all your efforts will greatly be paid off. The tables can easily be copied to word-processing software if you wish to make them fit better on paper. I strongly recommend using the Google Chrome browser to browse the pages as I found that some of the mainstream browsers on some platforms have hard time printing (and even copying) table cells with a background color.<br />
<br />
It all boils down to making optimum use of the openings — being in the right place at the right time. So, the better predictions you have, the better basis for operating planning. Nevertheless, we must remember that predictions are just that — predictions, not exact science. And, due to the nature of VOACAP, you must visualize low-band openings with the help of grayline map software such as DX Atlas by Alex VE3NEA or GeoClock by Joe Ahlgren. VOACAP predictions are not so accurate there.<br />
<br />
Here are some screenshots of the renewed service:<br />
<br />
<h3>
1. VOACAP Propagation Planner, www.voacap.com/planner.html</h3>
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOWaGTqkuN8Y4PVN22rn787Vxu9Mtx3P-L-7slUn2IK7onupUCJDw8RUad3ZhzXToswzZlwvRPhq-QnC1iiZ2MdxwEhrFaJ_rPjO9Iw0rKFRXr9JkImd7i_Aziw47a3CRgo3pQVfPEF3E/s1600/voacap-propagation-planner-home.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="578" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOWaGTqkuN8Y4PVN22rn787Vxu9Mtx3P-L-7slUn2IK7onupUCJDw8RUad3ZhzXToswzZlwvRPhq-QnC1iiZ2MdxwEhrFaJ_rPjO9Iw0rKFRXr9JkImd7i_Aziw47a3CRgo3pQVfPEF3E/s640/voacap-propagation-planner-home.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The home page of VOACAP Propagation Planner. Please note that you can enter <b>your Maidenhead Grid Locator</b> into the Name ("TX") field and press the "Loc calc" button. The program will calculate the latitude and longitude values respectively.</span></td></tr>
</tbody></table>
<br />
<h3>
2. The Propagation Prediction Charts</h3>
<br />
The results can be viewed zone by zone from the TX site the user provided. The colors indicate the probability of making a QSO between the TX and the Zone in question.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiW5IsMwZA_f7EbOARwtVlWsWeOuvuE-stOVhfh0xmgKZiMhTrv7emLvMQp17WwJ6vsr6L8Hev4sybIC0hLpB42wc9Aj7-XHAnExbtlInF-8xcudveA7qH57Vg1F-pptwfKhgwCoJ5_HAI/s1600/voacap-planner-zones-solar-info.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiW5IsMwZA_f7EbOARwtVlWsWeOuvuE-stOVhfh0xmgKZiMhTrv7emLvMQp17WwJ6vsr6L8Hev4sybIC0hLpB42wc9Aj7-XHAnExbtlInF-8xcudveA7qH57Vg1F-pptwfKhgwCoJ5_HAI/s1600/voacap-planner-zones-solar-info.gif" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">A cropped example of zone-specific predictions.</span></td></tr>
</tbody></table>
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</div>
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</div>
<span style="font-size: small;">The
elements of the top row are as follows (from left): CQ/ITU zone number,
Path from TX to zone, Short-path (SP) or Long-path (LP), month and year,
followed by the distance (kilometers & miles) of the circuit, and
the bearing (in degrees) from TX to RX.</span><br />
<br />
<span style="font-size: small;">Below each chart, the sunrise and sunset times for TX and RX locations have been calculated and visually presented as horizontal bars. The silver color denotes night-time and white day-time. The exact sunrise (SR) and sunset (SS) times (in UTC) will come up as you hover the mouse over the TX and RX label texts on the left column. Here, in this example, the TX is "enjoying" the polar night so the sun will not rise at all. The date used in the calculations is always the 15th day of the given month. </span><br />
<br />
<div class="separator" style="clear: both; text-align: center;">
</div>
<b>All charts are interactive:</b> if you hover your mouse over table cells, you will see a pop-up text, indicating the (VOACAP's REL) probability in percents, and the (VOACAP's S DBW) signal power values in dBW. For instance, the signal power value of -164 can be considered to be on the verge of the noise in remote locations whereas -93 corresponds to S9 on the S meter. Read more about translating the signal power values (S DBW) into S-meter values here: <a href="http://www.voacap.com/s-meter.html">http://www.voacap.com/s-meter.html</a> .<br />
<span id="goog_1444299404"></span><span id="goog_1444299405"></span><br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKA6urtoa8CgMvF3uaBiPDRDQuCOVlhidPIEv_OlA0uFNBT0dSE_MOYS2B7xP3dEefwJmgYaFl4lbYYl79-S28IFTnTelWHYX11-4ZFUbKimBlXwsj8s4kh77P5QLCeIStdhcefwlAx1o/s1600/bands.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKA6urtoa8CgMvF3uaBiPDRDQuCOVlhidPIEv_OlA0uFNBT0dSE_MOYS2B7xP3dEefwJmgYaFl4lbYYl79-S28IFTnTelWHYX11-4ZFUbKimBlXwsj8s4kh77P5QLCeIStdhcefwlAx1o/s1600/bands.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The left-hand side column shows the Zone number and the location within the zone. Many zones are geographically wide so, in many cases, a number of locations have been chosen from that zone to give a fair picture of the propagation possibilities.</td></tr>
</tbody></table>
<br />
<b>All colors - except grey - indicate QSO-making probabilities.</b> White means 0%, blueish 10%, greenish 30-40%, yellowish 50-60%, yellow-orangeish 70-80% and orange-reddish 90%, and pure red 100%. The color of grey does not indicate any probability value. Instead, it shows that, although VOACAP does not predict any probability for that specific hour, some signal power has been predicted which may translate into workable conditions. So, in a sense, grey indicates "a grey area" where QSOs may be possible. Typically, these grey areas can mostly be found in low-band predictions charts.<br />
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhzBXt2Y0Nh9oo4WbUzgPbcFqrTk_jVO2OQyGFKOIQDDAUcqQUjuww6Fequ6zZ8eh8Z5j2BdxDkoFdOm-vr1IGrNfLP5viaVenlbLxAXsjBWCd-8fflkoBlK49LKIWlhE2FZ7oYA2byqdM/s1600/color-legend.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhzBXt2Y0Nh9oo4WbUzgPbcFqrTk_jVO2OQyGFKOIQDDAUcqQUjuww6Fequ6zZ8eh8Z5j2BdxDkoFdOm-vr1IGrNfLP5viaVenlbLxAXsjBWCd-8fflkoBlK49LKIWlhE2FZ7oYA2byqdM/s1600/color-legend.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Propagation predictions use a color scheme from white to red.</td></tr>
</tbody></table>
<br />
<b>All predictions charts start at 01 hours UTC.</b> You may ask, "Why not start at 00 UTC?". Well, it's a matter of taste. All VOACAP predictions span 60 minutes but not necessarily the way you may think. A prediction for 01 UTC does not span from 01:00 to 02:00 but, in fact, from 00:30 to 01:30 UTC! So, I decided, being inspired by the original makers of VOACAP, to start at 01 UTC and end at 24 UTC. Following the same logic, 24 UTC means a time frame of 23:30 to 00:30 UTC.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com5tag:blogger.com,1999:blog-8260894794228814400.post-88986043011049998562014-06-20T17:10:00.001+03:002014-06-21T12:09:40.709+03:00Propagation Planning for IARU/WRTC 2014<!--[if gte mso 9]><xml>
<o:OfficeDocumentSettings>
<o:AllowPNG/>
</o:OfficeDocumentSettings>
</xml><![endif]-->If you are planning to participate in this year's <a href="http://www.arrl.org/iaru-hf-championship" target="_blank">IARU HF Championship</a> contest or the <a href="http://www.wrtc2014.org/competition/wrtc-rules/" target="_blank">WRTC 2014</a> contest, you might be interested to know that I have today expanded my VOACAP Propagation Planner site at <a href="http://www.voacap.com/planner.html">www.voacap.com/planner.html</a>.<br />
<br />
Besides running batch predictions from one TX site to all CQ Zones, it's now possible also to run batch predictions to ITU Zones (short path & long path) as well. There are one analysis tool (Win & Mac) and Excel Workbooks available to make the prediction data into more readable form.<br />
<br />
Currently, more than 110 locations covering most of the ITU Zones are included.<br />
<br />
The Propagation Planner gives you a good start for planning your operating strategy, especially if you run the predictions for two different sunspot numbers (SSN): 70 and 140. For low bands, use the W6ELProp software or use grayline maps for planning the best operating times.<br />
<br />
For those who want to make predictions for WRTC 2014, use the following coordinates for the TX site: <b>42.29N, 71.57W</b>.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com1tag:blogger.com,1999:blog-8260894794228814400.post-45044638428755257182014-06-03T16:02:00.001+03:002014-06-03T23:01:07.069+03:00New features at VOACAP OnlineI have added a couple of new features (some of which are requested by users) at VOACAP Online, <a href="http://www.voacap.com/prediction.html">www.voacap.com/prediction.html</a> . The changes in the page can be seen in the screenshot below.<br />
<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgiOvDmFxfQC2ZYlgmqpkJQH_QdfN8qSR3u2IW8bCxOtG06A-RR5eigYC2wX8NvOW6aSWZ50ylM29es3zCPclQ2GwAgr8h8iI5yJ1wxQDYiYg3LPvsCLS7cLlnNKMeCPhI0q9kJ6feNk9c/s1600/voacap-online-new-features.gif" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgiOvDmFxfQC2ZYlgmqpkJQH_QdfN8qSR3u2IW8bCxOtG06A-RR5eigYC2wX8NvOW6aSWZ50ylM29es3zCPclQ2GwAgr8h8iI5yJ1wxQDYiYg3LPvsCLS7cLlnNKMeCPhI0q9kJ6feNk9c/s1600/voacap-online-new-features.gif" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">New sections at VOACAP Online: <b>Propagation Params</b> and <b>Today's
Sunrise/Sunset Times</b>.<br />
The Year/Month section has been moved below the Google
Map.</td></tr>
</tbody></table>
<br />
<div class="separator" style="clear: both; text-align: center;">
</div>
<h2>
<span style="color: red;">Propagation Parameters</span></h2>
<br />
First, there is a new section labeled "<b>Propagation Params</b>", or parameters that may affect propagation. In this section you can have access to parameters which earlier were not user-adjustable.<br />
<br />
<b>1. Es, or setting the ionospheric sporadic E layer (Es) on and off</b>. This may (or may not) prove useful during summer months when Es propagation conditions are quite common. Please note that the use of the Es layer is otherwise discouraged as the sporadic-E model was not fully tested during the development of VOACAP. Nevertheless, the effects of the sporadic-E layer are not totally excluded in VOACAP calculations although the layer is not set.<br />
<br />
<b>2. Model, or selecting the propagation model</b>. Three choices are available here: <span style="background-color: white;">Auto, Ducted, and Ray-hop</span>.<br />
<br />
<ul>
<li><span style="color: red;">The default "Auto"</span> or automatic model refers to Method 30 in the VOACAP speak. It's a propagation model that chooses automatically either the ray-hop model or the ducted (forward scatter) model to predict the signal power. There is also a smoothing function for ranges of 7,000 km or greater.</li>
<li><span style="color: red;">The (forced) "Ducted"</span> model refers to Method 21 in the VOACAP speak. Typically, this model is used for paths of 10,000 km or more. The Ducted model forces VOACAP to simulate the ducted or forward-scatter mechanisms that can prevail usually at distances having 3 or more hops. This model may produce unrealistic results at shorter distances where the ray-hops should occur.</li>
<li><span style="color: red;">The (forced) "Ray-hop"</span> model refers to Method 22 in the VOACAP speak, typically used for all circuits less than 10,000 km. It's a model that contains multiple ionospheric reflections, and includes all of the ionospheric and earth bounce losses. This model may produce extremely pessimistic predictions at the distances beyond the third ionospheric hop where ducted/forward scatter mechanisms can occur.</li>
</ul>
<br />
<b>3. SSN, or user-settable smoothed sunspot number</b>. Here you can set a specific SSN (i.e. sunspot number) to be used for calculations. Note that VOACAP Online knows about the current smoothed sunspot numbers so it may be advisable not to set any value to the SSN field unless you wish to conduct propagation experiments. After you have entered a value in the SSN field, press the TAB key (instead of the ENTER key) to run a prediction.<br />
<br />
<b>4. Min. TOA, or setting the minimum takeoff or arrival angle</b> for antennas at steps of 1 degree, starting from 0.1 degrees (the default), up to 5 degrees. My default value has always been 0.1 degrees due to practical reasons. However, in the VOACAP literature, a value of 3 degrees is commonly recommended, as it can be a common lowest angle for arriving skywave signals due to the roughness of the terrain. Also, 3 degrees may be a good choice if your antennas are not located in a flat, unobstructed area. And if you are using isotropic antennas, you should avoid huge amounts of antenna gain at angles below 3 degrees. You are encouraged to experiment between 0.1 and 3 degrees to see differences in predictions, using different antennas.<br />
<br />
<h2>
<span style="color: red;">Sunrise and Sunset Times</span></h2>
<br />
The second new section is labeled as "<b>Today's Sunrise/Sunset Times (UTC)</b>". The label itself is pretty self-explanatory per se. In this section, the Sun's rise and set times are calculated at both the transmitter and the receiver coordinates. All times are UTC.<br />
<br />
These calculations were originally inspired by Steve's (G0KYA) <a href="http://www.infotechcomms.co.uk/RSGB_presentation_greyline.pdf" target="_blank">12-year-old article about grayline propagation</a>. In short, the best predictions for grayline propagation or trans-terminator enhancement on low bands can probably be achieved by a close examination of grayline maps. Some also swear by <a href="http://www.qsl.net/w6elprop/" target="_blank">W6ELProp</a>.<br />
<br />
The abbreviation <b>GND </b>(for Ground) refers to sunrise and sunset at the sea level. The <b>letter "D"</b> refers to sunrise and sunset at the bottom of the ionospheric D region. Similarly, the <b>letter "F"</b> refers to sunrise and sunset in the ionospheric F region.<br />
<br />
In the summer, if you place the TX or RX marker close to the Arctic Circle, you will see that "--:--" will appear in the D and F region fields. This simply means that sunrise and sunset times cannot be calculated for those regions (because the sun does not set/rise during the summer at high latitudes. Alternatively, in the winter, the sun may not rise/set.).OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com4tag:blogger.com,1999:blog-8260894794228814400.post-52335637978376887032014-05-22T21:51:00.000+03:002014-05-22T21:59:00.680+03:00New version of PropPlanner software released for Windows and Intel MacsIn 2012, I opened a web-based service at voacap.com - <b>VOACAP Propagation Planner</b> (<a href="http://www.voacap.com/planner.html">www.voacap.com/planner.html</a>). This service provides VOACAP HF propagation predictions as numeric data, instead of fancy graphics. The reason is that <b>the numeric data when filtered and processed properly offer more accurate HF predictions</b>. And for this purpose you will need some extra software to help you. This is where my PropPlanner software for Windows and Intel Macs comes in. I also offer an Excel template which gives you CQ zone-specific summaries and thus helps create your own contest or DX operation plan.<br />
<br />
As you know, making predictions boils down to making optimum use of the openings — being in the right place at the right time. So, the better predictions you have, the better basis for operating planning.<br />
<br />
Nevertheless, we must remember that predictions are just that — predictions, not exact science. And in particular, due to the nature of VOACAP, you must visualize low-band openings with the help of grayline map software such as <a href="http://www.dxatlas.com/" target="_blank">DX Atlas</a> by Alex VE3NEA or <a href="http://www.mygeoclock.com/geoclock/" target="_blank">GeoClock</a> by Joe Ahlgren. VOACAP predictions are of less help there.<br />
<br />
The resources needed for successfully running VOACAP Propagation Planner are as follows:
<br />
<ol>
<li>Web site (<a href="http://www.voacap.com/planner.html">www.voacap.com/planner.html</a>) that calculates VOACAP predictions and outputs the result as numeric data, and
</li>
<li><a href="http://www.voacap.com/PropPlanner-0.94.zip">Windows</a> or <a href="http://www.voacap.com/PropPlanner-0.94.app.tar.zip">Mac</a> software called <b>PropPlanner</b> (together with <a href="http://www.voacap.com/planner/prop-planner.xltx">an Excel template</a>) that helps you work on the VOACAP prediction data on your own computer and make it more understandable.</li>
</ol>
<a href="http://www.voacap.com/planner/VOACAP-Propagation-Planner-Users-Manual.pdf" target="_blank">The VOACAP Propagation Planner manual</a> is available in PDF format.<br />
<ol>
</ol>
Give it a go, and let me know what you think.<br />
<br />
<br />
<br />OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0tag:blogger.com,1999:blog-8260894794228814400.post-70216352079749675182014-05-01T00:15:00.000+03:002014-05-01T00:15:22.902+03:00Comparing VOACAP predictions - or are we?<div class="separator" style="clear: both; text-align: center;">
</div>
Today, I happened to read <a href="https://ky6r.wordpress.com/2014/03/27/ft4ta-propagation-from-k6tu-stu/" target="_blank">KY6R's blog entry</a> about VOACAP HF predictions for a path from FT4TA (Tromelin) to his QTH. Rich was comparing VOACAP Online predictions to those of Stu K6TU. Here they are:<br />
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6rNAjZofCvUyYoINrfcxCeWyjZke1Z4aYv6m_MnGjoHyBTrcnCeXK9FlU4sIZnsi_UsG0ApPBFyn_0SwQPL6zgBmadeSlGzMoUArM5DkAWdeLp9WWn43cpv40OlUHZBbsS_CfuqIrZJA/s1600/ft4ta_ky6r_stu.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6rNAjZofCvUyYoINrfcxCeWyjZke1Z4aYv6m_MnGjoHyBTrcnCeXK9FlU4sIZnsi_UsG0ApPBFyn_0SwQPL6zgBmadeSlGzMoUArM5DkAWdeLp9WWn43cpv40OlUHZBbsS_CfuqIrZJA/s1600/ft4ta_ky6r_stu.gif" height="556" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Tromelin prediction by Stu K6TU</span></td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwcRxZk5Y7YRNFod4gm-7sW6wnuTr_zvtDMWQsJ6Ch7Jvbfvjsxd3NGTA6q-r_zd2eZtrH2FPhyphenhyphenADXLbzGowS2nKVScM_pWvG0OL8C3gkpG0DcoY6cM_L2O2pPh7sOz9wXrwgmH_wJcvk/s1600/voacap_ft4ta.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwcRxZk5Y7YRNFod4gm-7sW6wnuTr_zvtDMWQsJ6Ch7Jvbfvjsxd3NGTA6q-r_zd2eZtrH2FPhyphenhyphenADXLbzGowS2nKVScM_pWvG0OL8C3gkpG0DcoY6cM_L2O2pPh7sOz9wXrwgmH_wJcvk/s1600/voacap_ft4ta.jpg" height="640" width="596" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Tromelin prediction by VOACAP Online</span></td></tr>
</tbody></table>
<br />
To be frank, I don't know what to say after reading Rich's piece. Predictions are just predictions but, nevertheless, I felt he seemed to be convinced that Stu's VOACAP prediction is much superior to what VOACAP Online is able to produce in general, but especially on the low bands. It's of course a known fact that VOACAP cannot predict low-band long-distance propagation accurately. There are many factors involved, specifically that VOACAP does not recognize grayline propagation which will play a major role in this particular case.<br />
<br />
But what puzzles me is this: are we actually comparing apples to apples? I believe Stu's HF prediction is not at all a pure VOACAP-generated prediction on all bands. It seems to be a mixture of VOACAP-based predictions - and something else. And that "something else" is notably visible on the low bands. It would be enlightening to know where Stu's low-band openings with the predicted signal strengths are actually coming from. Is he using a tuned-up version of VOACAP?<br />
<br />
Please note that Stu's prediction strangely ignores a potential opening on 30 meters at 14-17 UTC, or on 40 meters at 15 UTC for that matter, both predicted by the latest officially released VOACAP. This is the time for grayline propagation, too.<br />
<br />
I ran a comparison prediction (the same path Rich used) with VOACAP on my PC, using extremely powerful 17-dBi isotropic antennas on both ends. This was to see whether the online version of VOACAP agrees with the PC version (yes, it does), and to see whether VOACAP can predict an opening on 80M if extremely powerful antennas are used. No, it cannot.<br />
<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIre1tLyxUxS_Z8RnSl8PLb2fPfRtfi2UQ8sEhOJx3rRo_An9N383RvqBOkPcP0OdbbIBlKUNLZ2Jv0-jYmkseNv7FO7v9TQt9DPYW_Y_jSdWRizCna8KIxk6NQ9CanBNNFmeqT-00-Js/s1600/ft4ta-cm87wv-iso17.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIre1tLyxUxS_Z8RnSl8PLb2fPfRtfi2UQ8sEhOJx3rRo_An9N383RvqBOkPcP0OdbbIBlKUNLZ2Jv0-jYmkseNv7FO7v9TQt9DPYW_Y_jSdWRizCna8KIxk6NQ9CanBNNFmeqT-00-Js/s1600/ft4ta-cm87wv-iso17.jpg" height="484" width="640" /></a></div>
<br />
The PC version was the latest version of the publicly available VOACAP
software package. The above is the result for November 2014, SSN 85.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0tag:blogger.com,1999:blog-8260894794228814400.post-66321485237631975222014-03-09T21:49:00.001+02:002014-03-09T21:49:36.990+02:00VP8ADE, Antartica's only ham radio beacon heard in FinlandToday, <b>9 March 2014 at 1900 UTC</b>, I had the pleasure of hearing the VP8ADE beacon on 28284.9 kHz (nominally 28285 kHz). VP8ADE is the only amateur radio beacon in Antarctica. The distance between VP8ADE and OH6BG is over 16,000 km.<br />
<br />
Hearing is believing, so <a href="https://app.box.com/s/ssc2ptle1sdhkszn5ui8" target="_blank">here is the recording of VP8ADE</a> at my QTH in Vaasa, Finland.<br />
<br />
This is also the first time my Skimmer Server logs this beacon. The first spot was already at 1820 UTC:<br />
<br />
<pre>OH6BG 28284.9 VP8ADE 5 dB 9 wpm 2014-03-09 18:58:00
OH6BG 28284.9 VP8ADE 6 dB 9 wpm 2014-03-09 18:38:00
OH6BG 28284.9 VP8ADE 9 dB 9 wpm 2014-03-09 18:20:00
</pre>
OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0tag:blogger.com,1999:blog-8260894794228814400.post-40557474654852317782013-07-23T17:30:00.001+03:002017-05-02T13:52:30.974+03:00VOACAP Online Next Generation: User Manual<h3>
VOACAP Online has got a face-lift, and, on this occasion, I decided to write a brief User Manual for the service.</h3>
<br />
URL: <a href="http://www.voacap.com/prediction.html">http://www.voacap.com/prediction.html</a><br />
<br />
<a href="http://voacap.blogspot.fi/2017/05/voacap-online-point-to-point-p2p-user.html" target="_blank"><span style="color: red;"><b>THIS MANUAL IS OUT OF DATE! READ THE NEW MANUAL HERE.</b></span></a><br />
<br />
VOACAP Online is a web-based HF propagation prediction service which uses VOACAP (Voice of America Coverage Analysis Program) as its calculation engine.<br />
<br />
Unlike the previous version, this new service requires that SVG (Scalable Vector Graphics) is supported in your web browser. The latest versions of Microsoft Internet Explorer, Mozilla Firefox, and Google Chrome are known to work. The earlier versions may not be supported. If you encounter problems with the page, please try first to upgrade your browser to the latest version available. If you think you have found a bug, please report it to jpe@voacap.com.<br />
<br />
The web interface is divided into three parts:<br />
<ol>
<li><b>a Google Map for setting the transmitter (TX) and receiver (RX) site coordinates</b>. The easiest way to set the coordinates is to drag the markers to appropriate locations on the map. Under the map, the distance from TX to RX is given in kilometers and miles, and the bearing in degrees from True North. If you need to zoom in or zoom out the map for better details, just scroll the mouse wheel up and down.</li>
<li><b>a circular prediction chart which is divided into 24 hours</b> and which shows all the amateur radio bands from 10 meters (28 MHz) to 80 meters (3.5 MHz). The prediction shows the probability for a QSO between the TX and RX site, illustrated as colors. The white and blue colors indicate poor probability whereas orange and red indicate good probability. The exact probabilities can be seen by hovering the mouse over the chart. The prediction details (UTC hour, band and probability (%)) will be shown in the centre of the chart.</li>
<li><b>the input values for the prediction</b> can be set in the area below the Google Map and the prediction chart. There are three sections:</li>
<ol>
<li>Date</li>
<li>Transmitter Site, and</li>
<li>Receiver Site.</li>
</ol>
</ol>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgv1Sj8ujOhcNW5UDeS86LqlbzGBbCiXaitxQUp6MYo95vDsjhAzyveWRwzCGbN9SZRmC1UK5TaMLp4Mx8gsSKe-2nQtkD3d3I5iTT7d0Zx94ojcTPsGXNVcrE0ECkTCQvNC2LwePhJ0Y0/s1600/chart.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgv1Sj8ujOhcNW5UDeS86LqlbzGBbCiXaitxQUp6MYo95vDsjhAzyveWRwzCGbN9SZRmC1UK5TaMLp4Mx8gsSKe-2nQtkD3d3I5iTT7d0Zx94ojcTPsGXNVcrE0ECkTCQvNC2LwePhJ0Y0/s1600/chart.jpg" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The new circular 24-hour prediction chart, which is updated as soon as any of the input values (coordinates, power, antenna, year, month, etc.) changes.</span></td></tr>
</tbody></table>
<br />
<h3>
The Date Section</h3>
<span style="color: red;"><b>Old info</b></span>: In the Date section you can choose the year (currently 2013, 2014, 2015) and month. In this section, it is also possible to set a specific SSN or sunspot number to be used for calculations. Note that VOACAP Online knows about the current sunspot numbers so it is advisable not to set any value to the SSN field unless you are conducting some experiments. After you have entered a value in the SSN field, press the TAB key (instead of the ENTER key) to run a prediction which is shown in the prediction chart.<br />
<br />
<span style="color: red;"><b>EDIT, 4 June 2016</b></span>: The whole concept of setting the date in VOACAP Online has been changed after I implemented the grayline terminator functionality in the service, and this has been quite awhile ago. Also, setting the SSN has been moved to a section of its own, called "Propagation Params". Let me remind you, however, that when I say that VOACAP Online knows what SSN to use, I refer to monthly smoothed sunspot numbers, not any daily value. If you wish to experiment with daily SSN values, you will need to enter them manually.<br />
<br />
The new way of setting a date and time was necessary after I found a code which allowed me to show the grayline terminator on the map. Earlier, I was also showing the grayline but it was always fixed to the current time and day -- the user was not able to set it to a specific time and day in order to see how the grayline terminator looked like on a particular point of time. I felt that the grayline map could be used as a way of predicting signal enhancements on the low bands but a new way of setting the time and day was badly needed.<br />
<br />
And this was the reason I chose to use a pop-up calendar for this particular purpose. In addition, any month the user would select for the grayline would also be used as input for all propagation predictions.<br />
<br />
The pop-up calendar is located just below the Google Map, and looks like this:<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLKK8cHfsO5tZOUm-Qxj1kv0X5RTXnogX_siUKqOq9yC_EnWDTyADhp-aG_WAB50kotYeMUx4bjLrHSYY6rbVo0LiX-7-4nwRRhwv-iMH7Uf5bkjIuCJDaE9-VcCcjPJ2M65MD5uoWcuY/s1600/grayline-voacap-online.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLKK8cHfsO5tZOUm-Qxj1kv0X5RTXnogX_siUKqOq9yC_EnWDTyADhp-aG_WAB50kotYeMUx4bjLrHSYY6rbVo0LiX-7-4nwRRhwv-iMH7Uf5bkjIuCJDaE9-VcCcjPJ2M65MD5uoWcuY/s1600/grayline-voacap-online.gif" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="color: red;">Select a day number in the pop-up calendar, and press the Set button.</span><br />
<span style="color: red;">Press the Reset button to return to the current time and date.</span></td></tr>
</tbody></table>
<br />
To set a date, click on the calendar icon on the right of the date field. It will prompt a calendar where the user can browse the months (and years) backward and forward, by pressing the arrow icons. You select a month by clicking on <b>any day number</b> in that particular month. Please note that you <b>must </b>select a day!<br />
<br />
The selected month will also be used for propagation prediction calculations, and the selected day (and the time set by the user) will be used for drawing the grayline terminator over the Google Map. Please note that the selected day <b>will not be used</b> for propagation prediction calculations as VOACAP will not calculate any daily predictions.<br />
<br />
When you have selected a month and a day, and have set the time correctly for your purposes, then press the <b>Set </b>button. This will finally use all the parameters set. To return to the current month, day and time, press the <b>Reset </b>button.<br />
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<h3>
The Transmitter Site</h3>
In the Transmitter Site section you can, besides dragging the red marker to the appropriate location on the map, choose the location from a list of DXCC countries. Basically, you use the Name field for entering a label for the TX site. But you can also enter the Maidenhead grid locator in the Name field, and press the "<b>Loc calc</b>" key: the corresponding coordinates will automatically be calculated from the grid locator and entered in the Latitude and Longitude fields. The latitude and longitude values can also be entered manually. When you do that, please press the TAB key to run the prediction.<br />
<br />
In this section, you can also select the most appropriate antenna for the TX site. At the moment, only one antenna can be chosen for all amateur bands. The default is a dipole at the height of 10 meters (33 ft) above the ground. All TX and RX antennas are artificial in the sense that they are omnidirectional, which allows the user to see all possible openings to all parts of the world. In dipole-type of antennas, the height of the antenna is related to the elevation angle and the number of elements to the gain. When you choose an antenna, you should think about the elevation angles and gain, rather than the physical structure of the antenna.<br />
<br />
In the <b>TX power</b>, you can select powers from 1 watt to 1500 watts at the given steps. 100 W is the default selection. Some line loss is assumed so that the actual power used in the calculation is 80% of the chosen power. In the <b>TX mode</b>, you can choose from CW, SSB and AM. CW is the default selection.<br />
<br />
There are also two special settings: <b>the setting of E</b>s (sporadic E) layer to on or off. The default setting is OFF (No Es). This can be set to ON (Es) during the summer time when the effects of the sporadic E layer are strongest. The second is the setting of <b>Short-Path or Long-Path</b>. Short-path means the shortest distance between the TX and RX, and this so-called great circle path is visualized with a red line on the Google Map. If you set this to Long-path, you will go from TX to RX in the opposite way: the longest great-circle path.<br />
<br />
Last but not the least, there are three buttons:<br />
<ul>
<li>Swap TX-RX,</li>
<li>Set Home, and</li>
<li>Unset Home.</li>
</ul>
If you click on the <b>Swap TX-RX button</b>, the TX and RX locations will be swapped: the current TX location becomes the RX location, and the RX location becomes the TX location. You can accomplish the same effect by double-clicking the red (TX) or blue (RX) marker on the map. In this way, you will see that the circuits are not always 100% reciprocal. In VOACAP calculations, this is mostly due to the different level of noise power in the RX site.<br />
<br />
<span style="color: red;"><b>Old Info</b></span>: By clicking on the <b>Set Home</b> button the TX Name, Latitude and Longitude will be stored in a cookie, to be used by your browser automatically when you visit VOACAP Online next time. If you press the <b>Unset Home</b> button, the cookie will be deleted from your browser.<br />
<br />
<span style="color: red;"><b>EDIT, 4 June 2016</b></span>: Now, not only the TX Name, Latitude and Longitude information is stored in a cookie, but also the RX Name, RX Latitude and Longitude as well as the TX and RX antenna selections are stored, when the <b>Set Home</b> button is pressed. And when you press the <b>Unset Home</b> button, the cookie will be destroyed. Remember to allow your browser to set the cookie on this page. <br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgvSdvISqcNuWCaVI1B8ezBkbZASmso8iZ_IgH2JtzLwd9OqSQegLdL-iR-4ZJE1FGMLYfWr7dqLX-twWvEhb_dtht1AKDtBohnL7-JnhqSlfEmbmwsjeRhUMDcG-XFtbWYB62k9cGdN-o/s1600/tx.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgvSdvISqcNuWCaVI1B8ezBkbZASmso8iZ_IgH2JtzLwd9OqSQegLdL-iR-4ZJE1FGMLYfWr7dqLX-twWvEhb_dtht1AKDtBohnL7-JnhqSlfEmbmwsjeRhUMDcG-XFtbWYB62k9cGdN-o/s1600/tx.jpg" /></a></div>
<br />
<h3>
The Receiver Site</h3>
In this section, the input options are similar to those of the Transmitter Site. The RX location can be selected from the pre-defined DXCC list, or coordinates can be entered manually in the Latitude and Longitude fields. If you enter the values manually, please remember to press the TAB key.<br />
<br />
The Name field is used to give a label for this site, or alternatively you can enter a Maidenhead grid locator in this field and press the "Loc calc" button, and the latitude and longitude values will be calculated automatically.<br />
<br />
Also the receiving antenna selection is exactly the same as for the Transmitter Site.<br />
<br />
Below the Receiver Site section there is the "<b>Run prediction!</b>" button. This will calculate the detailed propagation prediction graph for the entire frequency range from 2 MHz to 30 MHz, and show the day/night times for each location. This was the only way of getting the prediction in the previous version of VOACAP Online.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrZkwa36yCa2Kx8cmYeJXJ6NwSzv5XWZn2hIrrj1-AU2x7JlDeXeuwiwooqR4cM4fpr-e9Gc19f7wo1eoFXJayvkI2ihbtc_J_XzSARxIC5YUmzwhV5-jgCSB2PRfC0TQu6zxtS5M0ACo/s1600/rx.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrZkwa36yCa2Kx8cmYeJXJ6NwSzv5XWZn2hIrrj1-AU2x7JlDeXeuwiwooqR4cM4fpr-e9Gc19f7wo1eoFXJayvkI2ihbtc_J_XzSARxIC5YUmzwhV5-jgCSB2PRfC0TQu6zxtS5M0ACo/s1600/rx.jpg" /></a></div>
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<b>That's it ... in a nutshell!</b> If you have questions, please don't hesitate to drop me a note.OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com41tag:blogger.com,1999:blog-8260894794228814400.post-12774313196908043092013-05-16T23:26:00.001+03:002013-05-17T07:48:39.956+03:00VOACAP Online upgraded!<span style="font-size: large;">The online point-to-point HF (3-30 MHz) propagation prediction service <a href="http://www.voacap.com/prediction.html" target="_blank">VOACAP Online</a> was upgraded this week. The Google Maps portion of the site is now using the API version 3, and some new functionality was added, too.</span><br />
<br />
Perhaps it's a good time to take a more in-depth look at how VOACAP Online works. Consider the following a brief user's manual...<br />
<br />
<h3>
Google Maps for coordinate entry</h3>
<br />
Easy coordinate entry for the Transmitter (TX) and Receiver (RX) was one of the single most important design features at VOACAP Online. The stand-alone PC version of VOACAP does not offer it, and, in fact, not many others do, either. Choosing Google Maps for this purpose lowered the threshold of using VOACAP considerably.<br />
<br />
On the initial map, there are two markers - red and blue - placed on the equator line in Africa. The red marker signifies the transmitter's location and the blue marker is the receive location. Perhaps typically, the transmitter is your QTH and the blue one is the DX station.<br />
<br />
<span style="background-color: yellow;"><b>Need an easy start?</b> Just drag the markers on the map to the desired locations. </span><span style="background-color: yellow;">Zoom the map in/out with the mouse wheel and fine-tune the markers by dragging them to their exact positions.
Then press the "Run the prediction" button. That's it!</span><br />
<br />
<b>Great-circle paths: short-path and long-path</b><br />
There is always a red line between the red and blue markers, showing, by default, the great-cirle path (short-path) between the two locations. A long-path line can be shown when you choose "Long-path" from the pop-up menu by the "Specials" label. Drawing a long-path line on the map was earlier (in Google Maps API v2) not such a trivial thing. At that time, I received enormous help from Sami OH2BFO who programmed the required code. Now, in Google Maps API v3, there was a much simpler way to do it. Thanks Sami for pointing that out!<br />
<br />
<h3>
Distance and bearing</h3>
One of the new features is the on-the-fly calculation of the distance between TX and RX, and the bearing from TX to RX in degrees calculated from True North. The details can be found under the map (see image below).<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGpRKXVFDZedxmR3UIzsHFVJ3Lrq0L6kSnLIqVCOSKijoNzISoyr6HIbTZHy_7EYd5p0tWaha6mAz-TT7hGC9gOc-1qIfRr80t4CVKiRAqTUw58_NEzTdoyvFF1VT0LeH8aGB24VAEzwM/s1600/voacap-online-dist.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGpRKXVFDZedxmR3UIzsHFVJ3Lrq0L6kSnLIqVCOSKijoNzISoyr6HIbTZHy_7EYd5p0tWaha6mAz-TT7hGC9gOc-1qIfRr80t4CVKiRAqTUw58_NEzTdoyvFF1VT0LeH8aGB24VAEzwM/s1600/voacap-online-dist.gif" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Image 1. Distance and bearing.</td></tr>
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And if you would like to swap the TX and RX locations, there are two ways to do it. The easiest way is to double-click on either of the markers. The bearing value will be re-calculated at once. You can also click on the "Swap TX-RX" button by the "Specials" label.<br />
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<h3>
A closer look at the input values</h3>
The second most important design feature for VOACAP Online is that, after setting the TX and RX locations, all the input values have been pre-set as appropriately as possible so that you do not necessarily have to adjust them. You can simply press the "Run the prediction" button.<br />
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However, there are, of course, many cases where you need more control. Let's take a look at the input values (see image 2 below).<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitwoVSMrt0-HEd6GkbUwJFp1EuEkigkAfC-s0p9SlCUqCUp7AyVxvNqKh95GsUnDajpUWLFz2CcgCkZteaLYyaTnlsygOxcRpU4bR6cT0KBvtUfRuogTc9fzOjfW34GSRx_EkQdjyWwRY/s1600/voacap-online-input.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitwoVSMrt0-HEd6GkbUwJFp1EuEkigkAfC-s0p9SlCUqCUp7AyVxvNqKh95GsUnDajpUWLFz2CcgCkZteaLYyaTnlsygOxcRpU4bR6cT0KBvtUfRuogTc9fzOjfW34GSRx_EkQdjyWwRY/s1600/voacap-online-input.gif" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Image 2. The input pane on the right-hand side of the Google Maps.</td></tr>
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There are three sections in the input pane: Date, Transmitter Site, and Receiver Site.<br />
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<b>Date & Month, and SSN</b><br />
The year and month values are automatically selected (by the Javascript code on the page) to reflect the current year and the current month. If not or if you would like to change them, just choose the desired year and month from the pop-up menus. At the moment, the selection of years goes to the year 2015. I regularly (manually) update the contents of this pop-up menu.<br />
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<b>The SSN (or, Smoothed Sunspot Number) input field is a new feature</b> which has been requested by many users. Now the user can enter any value between 1 and 200. Use integer values only. <span style="background-color: yellow;">Please note that you can simply leave this field empty, and let VOACAP choose the correct SSN values.</span><br />
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At this point, I would like to take a few moments to discuss the pros and cons of this feature. By default, VOACAP Online <b>does internally know</b> the current SSN to be used for all the months of the years available. You can ask how can that be as the sunspot number varies day by day? The simple answer is that VOACAP does not operate on daily SSN figures but smoothed monthly SSN figures which are being predicted for many years ahead and which are re-adjusted at regular intervals.<br />
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The predicted SSN figures are based on the Lincoln-McNish smoothing function, and they are maintained by the National Geophysical Data Center (NOAA/NGDC). These are the sunspot numbers used in the database reduction for the worldwide ionospheric maps used in IONCAP and now VOACAP. This is why only these figures should be used with with VOACAP. <a href="http://www.voacap.com/choosingssn.html" target="_blank">Read George Lane's discussion on the sunspot numbers for VOACAP use</a>.<br />
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However, there have been months in the past where the conditions have been well above the average for a couple of months, and a re-adjustment of SSNs would have been appropriate. Now this power has been given to the user. Just remember that, strictly theoretically speaking, entering a daily SSN value in the SSN field does not generally give you better (or more precise) predictions as VOACAP is not suited to real-time predictions at all. <a href="http://www.voacap.com/" target="_blank">Read more about the theoretical background of VOACAP in my Quick Guide.</a><br />
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<b>Transmitter Site</b><br />
This section contains the input parameters for the Transmitter Site (the red marker on the map). The QTH pop-up menu features 481 locations around the world, including all DXCC entities. When you choose a location from this list, its name and the coordinates (latitude and longitude) will automatically be entered in their corresponding fields below. Much care has been taken to find the exact coordinates of even the smallest of the islands! If you happen to find a location with wrong coordinates, drop me a note!<br />
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You can also set the coordinates by entering a Maidenhead grid locator in the "Name" field and then pressing the "Loc calc" (or, Locator Calculator) button. The corresponding coordinates will be calculated and shown in their respective fields, and the TX marker will be set to those coordinates on the map.<br />
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Please note that while you are dragging any of the markers, the coordinates (latitude and longitude) will be calculated on the fly. When you release the mouse to place the marker at one particular point on the map, its Maidenhead grid locator will be calculated and shown in the "Name" field. This applies to both the TX and RX markers.<br />
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There is a huge collection of <b>pre-calculated antennas</b> to choose from. Choose the antenna that is the closest match to your particular antenna. All available antennas are tailor-made for VOACAP Online purposes: they are all omni-directional so there is no need to set the bearing to the RX location.<br />
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Then choose the transmitting power and mode. You can also experiment by adding the Sporadic E ionospheric layer to the picture by selecting "Es" from the pop-up menu to the right of the "TX mode" label. The default value is "No Es". However, especially during the summer, choosing "Es" takes the effect of the Es layer into consideration, explaining many of the short-skip contacts on higher HF bands.<br />
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Moving on. We already explained earlier the meaning of swapping TX and RX coordinates, and the choice of short-path and long-path great-circle lines on the map.<br />
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The last item in the Transmitter Site section is "Current point" with two buttons: "Set Home" and "Unset Home". If you click on the "Set Home" button, a cookie will be stored in your browser which contains the coordinates and the name of the current Transmitter site. This site will be the default start location when you use VOACAP Online next time (instead of the default coordinates of 0,0). If you want to clear the Home coordinates, just press the "Unset Home" button, and all VOACAP-related cookies will be deleted.<br />
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<b>Receiver Site</b><br />
The input parameters for the receive site (the blue marker) are much fewer but similar to those found in the Transmitter Site section. You can choose a QTH from the pop-up menu, or enter a Maidenhead grid locator in the "Name" field and press "Loc calc", or move the RX marker with the mouse on the map to the desired location. Then just select the receiving antenna.<br />
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<b>Everything is now set so press the "Run the prediction" button.</b> After a few seconds you will see the propagation prediction as a graphic. I will explain in a separate blog entry how to interpret the results and how to access the prediction data as text, too!OH6BGhttp://www.blogger.com/profile/06749763380666850551noreply@blogger.com0