Tuesday, February 7, 2023

Differences calculating propagation to Bouvet

 Trying to figure out best times to work the 3Y0J DXpedtion at Bouvet Isl. I think the best way is using the VOACAP tools. Interesting but though I see some differences between best times for FT8 and SSB. Not shure wat is causing this. Understanding propagation is far more difficult as knowing about certain ionized layers that reflect our radio signals. Jari OH6BG from the VOACAP website made a dedicated page for propagation calculations to Bouvet.


Generally this is what I found for my location:

Of course you can find more on the site/prediction. Jari tells in a video, link is on the site. I suggest you watch the video for detailed info. I did watch the video and tried to find the highest SDBW90 with a MUF above 50% and as small possible difference between the SDBW10 and 90. This is what I got:

Band  -  Best time shorth path - Best time long path

10            14-17 UTC                    12 UTC

12            15-17 UTC                    12 UTC

15            17 UTC                          9-12 UTC

17            7 and 17-20 UTC           15 UTC

20            20-24 UTC                    8 and 18 UTC

30            20-24 UTC                    02 and 20 UTC

40            20-24 UTC                    -

60            21-03 UTC                    -

80            24 UTC                         -

It is interesting to compare it to the general VOACAP prediction. It is the same site but more detailed. You can choose more options like mode and power. I decided to make a FT8 and a SSB prediction for my location and antenna situation. CW will be in between I guess. I wanted to know if there are differences between the calculations.

This is what I got for FT8:

At the center are the best possible band and time to work 3Y0J.

This is what I got for SSB:

Notice the 1 hour difference in best possebility. Strange isn't it? But overall it reflects the best possible times as predicted by the dedicated page. Of course I realize that all calculations are based on past average experiences and measurements. A small change of propagation can completely change the whole prediction. Let's hope propagation will be good this month.

More info:





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