This is a story about why you should be very careful taking unusual VHF propagation reports at face value. Someone sent me an email to say that the PSK Reporter website had shown the reception report of CU3HN in the Azore Islands by a Dutch radio amateur on 144 MHz.
At first glance, this looked like an incredible 2m reception report with a distance of just under 3000 kms. I checked the PSK Reporter website myself this morning and it said that four stations had heard CU3HN on 144 MHz!
G8ECI 2m FT8 2635 km 22:21:44
PA3GNZ 2m FT8 2898 km 22:21:30
PA2CV 2m FT8 2969 km 22:09:15
DF8JO 2m FT8 3016 km 22:21:44
I then checked the tropo forecast from the website of Pascal, F5LEN. While there was a sign of some conditions near the Azores, it looked poor at the eastern end of the path near the Netherlands and Germany.
I then checked the PSK Reporter website to see what bands CU3HN was on by using 'All' instead of '2m' and it shows a lot of reports for 14 MHz (20m) late last night.
I sent Fábio, CU3HN an email this morning and he confirmed that he was NOT on 144 MHz last night.
So what was going on??? ...I can think of two possible reasons.
1) Someone near the Netherlands was pirating CU3HN's callsign and locator and transmitting on FT8 on 144 MHz. Maybe it's possible but I would have expected more stations to hear and report the bogus signal if that was the case.
2) Some sort of glitch in the PSK Reporter website where CU3HN was reported on the wrong band? The thing here is that some of the receive stations listed above were not reporting 20m at any stage.
I'm not 100% sure how it happened but it goes to show that you always need to be careful and question any reception report that looks out of the ordinary.
Update: See suggestion below from Kees, PA3GHQ which might be the best explanation.
"I had the same problem 2 months ago. I saw calls from Belarus, Saudi Arabia, Turkey and later from Canada on 2 mtr. After some investigation the issue was on the same time when an amateur from my region calls on 2 mtr in FT8. I’ve called him by phone and we did some tests. The issue was the audio from his 40 mtr transceiver was receiving FT8 and the audio mixed with his FT8 modulation signal when his 2 mtr transceiver was transmitting. Both radio’s worked via 1 computer and when he turned the HF radio off the problem was solved. ...Best regards/ 73 Kees PA3GHQ "
Hello John,
ReplyDeleteI was one of the stations reported CU3HN. I was surprised to see this and wrote Fabio. He wasn't QRV on 2M.
My setup was listening on 2M with a Turnstile antenna.
So, I think it was someone who want to make a joke.
73, Tjeerd (Gose)
PA3GNZ
144 MHz and 14.4 MHz are lookalikes. Issue with the decimal point ? 73 Ron PA2RF
ReplyDeleteMy guess is a transmission/decoding error in the grid locator part of the packet. I have this periodically on my WSPR beacon where I have received packets from my 0.2 watts beacon showing up in the South Atlantic or somewhere way out of EM42xk where I’m actually located. Since my WSPR beacon has a gps on it, my actual coordinates are being transmitted.
ReplyDelete2 months ago i had the same issue. On 2 mtr i saw calls from Saudie Arabia, Turkey, Belarussia and later Canada. I did some investigation and the problem was an amateur in my neighborhood was sending FT8 on 2 mtr and the same time his 40 mtr set was receiving FT8. The audio had a mix and modulated his 2 mtr transceiver. After several times i saw the same issue was going on when his call was on 2 mtr. I called him and we did some tests, after he turned off the 40 mtr set the problem was solved. So i think it’s maybe the same problem, mixed modulation on 2 mtr with the audio from (HF) bands. 73 Kees PA3GHQ
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