11 Apr 2023
6m FT8 (Tuesday)
E-field probes (EFPs)
These are tiny receive only antennas that can work extremely effectively at VLF, LF and MF where external noise is usually the dominant factor. I guess as local external noise is increasingly the dominating factor, these will be as effective as a "big" antenna at even higher frequencies. At LF they can be only a few centimetres long, but be as effective as antennas hundreds of metre long.
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| EFP on a mag mount for 2200m RX |
As the signal decreases, so does the external noise! Overall, nothing is lost. There is no advantage by using a large antenna at low frequencies for receive only. For TX efficiency, a large antenna and good earth help! A popular EFP design is that PA0RDT (Google it). I have made versions for LF and VLF with a tuned peak as shown in the circuit.
See https://sites.google.com/view/g3xbm4/home/antennas/137khz-efp-rx-antenna .
Double rainbow - NOT amateur radio
April in the UK is a strange month. Some days can be warm and sunny, whereas others can be cold. Yesterday was a mix of sunshine and showers. The photo of the double rainbow was taken in haste from the lounge window. A few minutes later it had gone.
10 Apr 2023
630m WSPR RX
At about 1940z, I switched to 630m WSPR RX with the earth-electrode "antenna" in the ground. So far, no spots.
UPDATE 2126z: Several WSPR spots of DC0DX (467km) at up to -9dB S/N.
Earth-mode paper
Someone asked for access to this file. It is now open so if you have this link you should be able to read it. It was sent to me some years ago.
See https://drive.google.com/file/d/16vtYNznORclXJTfpaT-RC7Z3IV8RKqyi/view?usp=sharing .
6m FT8 (Monday)
For about an hour, I have been on 6m FT8. So far, 13 stations have spotted me and 1 have had 1 QSO. I noticed the BNC plug was intermittent. Mending it took about an hour. In years gone by this would have taken me 5 minutes.
80m FT8 (Monday)
At 1255z, I moved from 160m FT8 (no spots) to 80m FT8 using the earth-electrode "antenna" in the ground. The FT8 frequency on 80m seems to be 3.573 MHz.




