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72                      >Setting up input values
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222            <div class="col-md-3">&nbsp;</div>
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224              <h3>Setting up input values for VOACAP</h3>
225            </div>
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230        <section>
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233              <h4>The main screen</h4>
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236              <p class="text-muted">
237                After you have launched VOACAP, the first and most important
238                thing is to select and enter right parameter values in the
239                program. Here we discuss the most important steps.
240              </p>
241              <p class="text-muted">
242                Below you will see the main screen with a set of reasonable
243                input values for a high-power broadcasting station with
244                transmissions to Southern Africa.
245              </p>
246              <p>
247                <img alt="" src="/2023/img/main-screen.png" />
248              </p>
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254        <hr class="my-5" />
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257        <section>
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260              <h4>Basic parameters</h4>
261            </div>
262            <div class="col-md-9 gx-5 mb-4">
263              These are the basic settings which you can initially set up as
264              follows:
265
266              <p></p>
267              <table border="0" cellpadding="2" cellspacing="2" width="600">
268                <tr valign="top" align="left" bgcolor="#ffcc33">
269                  <th>Parameter</th>
270                  <th>Recommendation</th>
271                </tr>
272
273                <tr valign="top">
274                  <td><b>Method</b></td>
275                  <td>
276                    Select Method Number 20 (Complete System Performance). If
277                    you are running circuits over 7000 km, use Method 30
278                    (Short/Long Path Smoothing).
279                  </td>
280                </tr>
281
282                <tr valign="top" bgcolor="#ebeff2">
283                  <td><b>Year</b></td>
284                  <td>
285                    This is a user-specified value. It has no effect on
286                    calculations.
287                  </td>
288                </tr>
289
290                <tr valign="top">
291                  <td><b>Coefficients</b></td>
292                  <td>
293                    Select CCIR (Oslo). This is the default for using VOACAP in
294                    long-term predictions.
295                    <b>Do not use URSI88 (Australian)</b>.
296                  </td>
297                </tr>
298
299                <tr valign="top" bgcolor="#ebeff2">
300                  <td><b>Time</b></td>
301                  <td>
302                    Select UT (Universal Coordinated Time). Local Mean Time does
303                    not mean your local time but the local sun time at the
304                    receiver.
305                  </td>
306                </tr>
307
308                <tr valign="top">
309                  <td><b>Transmitter</b></td>
310                  <td>
311                    Select the transmitter location from the pre-defined lists,
312                    sorted by city (worldwide), by nation (worldwide) and by
313                    state (USA). You can also enter the coordinates manually.
314                  </td>
315                </tr>
316
317                <tr valign="top" bgcolor="#ebeff2">
318                  <td><b>Receiver</b></td>
319                  <td>
320                    Select the receive location from the pre-defined lists,
321                    sorted by city (worldwide), by nation (worldwide) and by
322                    state (USA). You can also enter the coordinates manually.
323                  </td>
324                </tr>
325
326                <tr valign="top">
327                  <td><b>Path</b></td>
328                  <td>Select Short or Long Path. The default is Short Path.</td>
329                </tr>
330
331                <tr valign="top" bgcolor="#ebeff2">
332                  <td><b>Freq(MHz)</b></td>
333                  <td>
334                    Enter the frequencies to be used for calculation. Use the
335                    zero (0) value to remove a frequency from the set. A set of
336                    11 user-specified frequencies can be defined. Also three
337                    pre-defined frequency sets are available which can be
338                    modified if needed.
339                  </td>
340                </tr>
341
342                <tr valign="top">
343                  <td><b>Fprob</b></td>
344                  <td>
345                    Do not use all default values. Set foE to 1, foF1 to 1, foF2
346                    to 1 and foEs to 0 (zero, instead of 0.7).
347                  </td>
348                </tr>
349              </table>
350              <p><h5>
350Note about Coefficients</h5>
351
352              As noted earlier, while using VOACAP or VOAAREA,
353              <b>be sure to select the CCIR coefficients</b>. George Lane
354              explains,<br/><br/>
355                "<b>Do the URSI coefficients provide more accurate predictions?</b> We
356                do not know. What we do know is that original IONCAP using the
357                CCIR data base, corrects the predicted values by using the
358                Transmission Loss tables and determines the variability of the
359                MUF values over the month using the F-tables. These are huge
360                corrections. They are based on taking the predicted ionospheric
361                calculations using the CCIR data and subtracting them from
362                actual system performance data taken over the 1958 to 1963 time
363                period. The differences are collected into the two sets of
364                tables I just mentioned. The corrections are applied to any path
365                prediction you make using IONCAP in order to predict signal
366                power, SNR, reliability and required power gain. If you change
367                the ionospheric maps for only the F-region and do not
368                recalibrate the predictions against measurement, you do not know
369                if you made an improvement or not. Chances are you have ruined
370                the correlation."
371              </p>
372            </div>
373          </div>
374        </section>
375        <!--Section: Content-->
376
377        <hr class="my-5" />
378
379        <!--Section: Content-->
380        <section>
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382            <div class="col-md-3 gx-5 mb-4">
383              <h4>Critical parameters</h4>
384            </div>
385            <div class="col-md-9 gx-5 mb-4">
386              <p>The following are critical user-specified parameters.
387
388              <h5>Groups</h5>
389
390              <img alt="" src="/2023/img/groups.png">
391
392              <p><table border=0 cellpadding=2 cellspacing=2 width="600">
393
394              <tr valign=top align=left bgcolor="#ffcc33"><th>Parameter</th><th>Recommendation</th></tr>
395
396              <tr valign=top><td><b>Months</b></td><td>Enter the number of the month (e.g. December = 12.00). You can specify a total of 10 months at a time. The format is MM.DD (month.day). VOACAP is not, however, suitable for daily predictions. Therefore, do not specify any day since if you do, the value of Coefficients will automatically be set to URSI88.</td></tr>
397
398              <tr valign=top bgcolor="#ebeff2"><td><b>SSNs</b></td><td>Enter the monthly smoothed sunspot number for the given month.</td></tr>
399              </table></p>
400
401              <hr class="my-5" />
402              <p><h5>Choosing the correct sunspot number (SSNs)</h5></p>
403
404              <p>There are a number of sunspot resources available on the internet. However, be sure to use the values from the following resource:
405               <a href="http://sidc.oma.be/silso/FORECASTS/KFprediML.txt">Predicted Monthly Sunspot Numbers</a>, from SILSO, Royal Observatory of Belgium.
406
407
408              <hr class="my-5" />
409              <p><h5>System</h3></p>
410              <img alt="" src="/2023/img/system.png">
411
412              <p><table border=0 cellpadding=2 cellspacing=2 width="600">
413
414              <tr valign=top align=left bgcolor="#ffcc33"><th>Parameter</th><th>Recommendation</th></tr>
415
416              <tr valign=top><td><b>Man-made noise</b></td><td><b>This is a critical setting</b>. You can accept the default value of 145 (residential environment). If your receive location is in a quiet environment, you can use 155 or higher. There are still other values available, see the input help.</td></tr>
417
418              <tr valign=top bgcolor="#ebeff2"><td><b>Min. take-off angle</b></td><td>If you are a radio amateur or SWL, enter the take-off value of 3. For better antenna installations, you can use the value of 1.</td></tr>
419
420              <tr valign=top><td><b>Req'd circuit reliability</b></td><td>Accept the default value of 90%.</td></tr>
421
422              <tr valign=top bgcolor="#ebeff2"><td><b>Req'd SNR</b></td><td><b>This is a critical setting</b>. For a reasonable BC listening quality, use 67. For a reasonable CW reception quality, use 24 (or 27) and for SSB, 45.</td></tr>
423
424              <tr valign=top><td><b>Multipath power tolerance</b></td><td>Accept the default value of 3 dB.</td></tr>
425
426              <tr valign=top bgcolor="#ebeff2"><td><b>Max. tolerable time delay</b></td><td>Accept the default value of 0.10 milliseconds.</td></tr>
427
428              </table></p>
429
430              <hr class="my-5" />
431              <p><h5>Antennas</h5></p>
432
433              <p><b>Selecting the transmitter antenna</b></p>
434
435              <p><img alt="" src="/2023/img/tx-ant1.png">
436
437              <p><table border=0 cellpadding=2 cellspacing=2 width="600">
438
439              <tr valign=top align=left bgcolor="#ffcc33"><th>Parameter</th><th>Recommendation</th></tr>
440
441              <tr valign=top><td><b>TxAnt=</b></td><td>Select the transmitter antenna from the pre-defined lists. You must familiarize yourself with the available antenna patterns using the HFant program, included in the VOACAP softw
441are package. This window is the place where you can define different antennas for different frequency ranges. In the example above, we have defined one antenna for the frequency range of 2 MHz (Min) to 30 MHz (Max).</td></tr>
442
443              <tr valign=top bgcolor="#ebeff2"><td><b>MainBeam</b></td><td>Enter the main beam of the antenna (in degrees).</td></tr>
444
445              <tr valign=top><td><b>at Rx</b></td><td>Sets the main beam towards the receive location.</td></tr>
446
447              <tr valign=top bgcolor="#ebeff2"><td><b>TxPower</b></td><td>The transmitter power which is fed to the antenna. Usually, we need to assume some power losses in transmission lines, etc. so you may set this value, for instance, to 80% of the transmitter power.</td></tr>
448
449              </table>
450              <hr class="my-5" />
451              <p><h5>Selecting the receive antenna</h5></p>
452
453              <p><img alt="" src="/2023/img/rx-ant1.png"></p>
454
455              <p><table border=0 cellpadding=2 cellspacing=2 width="600">
456
457              <tr valign=top align=left bgcolor="#ffcc33"><th>Parameter</th><th>Recommendation</th></tr>
458
459              <tr valign=top><td><b>Receive Antenna=</b></td><td>Select the receive antenna from the pre-defined lists. You must familiarize yourself with the available antenna patterns using the HFant program, included in the VOACAP software package. The default antenna SWWHIP.VOA represents a typical shortwave whip antenna.</td></tr>
460
461              <tr valign=top bgcolor="#ebeff2"><td><b>Receiver bearing</b></td><td>If it is a directional antenna, enter the main beam in degrees. For non-directional antennas, enter the value of 0.</td></tr>
462
463              <tr valign=top><td><b>at Tx</b></td><td>Sets the main beam towards the transmitter location.</td></tr>
464
465              <tr valign=top bgcolor="#ebeff2"><td><b>Gain</b></td><td>This is valid only for isotropic antennas. The gain value is ignored if used with other antenna types.</td></tr>
466
467              </table></p>
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