With the 3Y0J DX-pedition to Bouvet Island coming up in February 2023, there will be no doubt be considerable interest in what propagation paths are open on the various HF bands.
Jari, OH6BG made a presentation recently on the subject to a Finnish group but the video was in Finnish. Jari has now released a shorter version of the presentation on YouTube and it can be seen below...
He writes... "This is a short video on how to find the best times and frequencies to work Bouvet, 3Y0J. I will explain two crucial prediction parameters, Signal Power and MUFday, that will determine the best openings to the island. These principles are valid for all VOACAP predictions."
You can mess about with the settings there to find the optimal time for your location. I suspect though that the biggest challenge will be trying to crack the huge pile ups rather than whether the band is open or not.
From Europe and North America on bands like 40m, 30m, 20m, 17m and 15m, the signal should be easily heard at the right time of the day.
What is VOACAP?:VOACAP(Voice of America Coverage Analysis Program) is a popular and free professional high-frequency (HF) propagation prediction software tool originally developed for the Voice of America (VOA).
Video Introduction: As part of the 2021 virtual Four Days in May (FDIM) event, Tim Snodgrass KC0DN made a presentation about the accuracy and limitations of the VOACAP programme. KC0DN along with Charley, KC0CD and Mike, AC0HB set up an extensive listening station to monitor the signals from the time standard stations WWV, WWVH and CHU.
The experiment which ran from November 2020 to February 2021 monitored all three time standard stations on a wide range of frequencies from 2.5 MHz to 25 MHz and compared the reception results against what was predicted by VOACAP.
The receive station was set up in Cedar Falls, Iowa while the time standard stations are in Fort Collins, Colorado / Ottawa, Canada & Kauai, Hawaii.
WWV Ft. Collins Colorado: Transmitting 10KW on 5, 10, 15MHz; 2.5KW on 2.5, 20 & 25MHz WWVH Kekaha, Kauai (Hawaii): Transmitting 5KW on 2.5MHz & 10KW on 5, 10, 15MHz CHU Ottawa, Ontario, Canada: 3 kW on 3.33MHz, 5KW on 14.67 MHz, & 7.85 MHz
The presentation is aimed at a US audience as it uses it uses outdated MILES for distances which mean very little for an international audience.
I have prepared a map shown below which shows the distances in kms which makes things clearer as you watch the video.
The presentation which is 45 minutes long can be seen below…
Presentation notes in PDF format can be found HERE
Findings: My own summary of the findings...
1) Like any propagation software tool, VOACAP suggests what the conditions might be like and what paths might be possible. It shouldn't be taken as fact.
2) VOACAP predictions can be too pessimistic.
3) Openings on the higher HF bands (14 MHz and above) happen more often than VOACAP predicts.
4) Lower frequencies like say 80m & 60m are underrated. They can be used 24 hours a day with modern digital techniques.
5) The 30m band is often open at night when VOACAP says it should be closed.
6) The 5 MHz band (60m) was nearly always open 24 hours a day over a 1600km path.
7) By using two bands e.g. 3.5 OR 5 MHz AND the 10 MHz band, a reliable link can be maintained over a 1600km path.
8) KC0DN advocates the use of two bands for the use of 'Store & Forward' digital traffic.
9) Circular polarization on HF can result in a significant advantage.
In Conclusion: This video by KC0DN is the summary of a significant amount of work and should be of interest to anyone with an interest in propagation on the HF bands. It's a bit unfortunate that it uses the title "Breaking Free of the Solar Cycle" on YouTube as that really doesn't describe to the casual observer what the video is about.
It should be remembered that the results are for someone in the United States and at a particular latitude. The results may not apply so readily to say someone at a more northerly latitude.
However, there is still plenty of material in the video of interest and it's worth watching.
