Sunday, February 12, 2023

Signals heard on the 40 MHz band - Sun 12th Feb 2023

Sunday 12th February 2023: Due to interference from some silly RTTY contest, I had to abandon listening on the 28.1246 MHz, the frequency for WSPR signals on the 10m band. Instead, I turned my attention to the 40 MHz band and had a listen there for a change.

The signals heard on FT8 over a 2-hour period are shown above including ZS6WAB and ZS6OB from South Africa. If this was on the HF bands, I'd be thinking 'whatever' but there is something special about hearing a signal from South Africa on a VHF band. And when I say 'hear', I really mean hear. Both the South African FT8 signals were audible to my ear.

All of the signals were on FT8 although I was able to hear Robbie, EI2IP and Willem, ZS6WAB have a contact on SSB as well. ZS6WAB was quite weak with me, maybe peaking 4/1 but still very audible. Robbie by contrast is 62kms away and is audible all of the time with a 5/2 signal report.

I was a bit surprised to hear the EI4GNB. EI9KP and G9PUV was well. At 200-600kms, they're in that kind of skip zone for signals. As for the mode of propagation, I think it was F2 layer backscatter. I see a lot of debate about aircraft scatter but most of these 'close in' radio signals on the 40 MHz band during the daytime can be easily explained by F2 layer back-scatter.

To close off the reception report, I had a listen for the EI1KNH 8m beacon as well and it was easy to hear, again probably via backscatter. There was no sign of EI1CAH in the west of Ireland or of GB3MCB in Cornwall.

In conclusion: An interesting day but the takeaway message here is that I was just using a simple CB type vertical half-wave antenna for reception. As it is tuned for 28 MHz, it's performance at 40 MHz probably isn't great.

I think anyone in Europe would be able to hear these 40 MHz signals with any sort of reasonable antenna and a special dedicated 40 MHz antenna is not required.

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