12 years ago

Earth-mode experiments in 2011

 
This was my earth-mode signal 4.5km away from home in 2011 at 1.095 kHz using Spectran software on the PC. Strictly speaking, I suppose this is ULF!

It is a long time since I have done any earth-mode experiments, but my health has got in the way. It would be good to do some more experiments.

Sunspots - Wednesday April 12th 2023

Solar flux is 143 and the SSN 103. A=6 and K=1.

70cm activity contest

After copying no stations at all (!) I gave up. I expect the next 70cm FT8 activity contest will be much better!

80m FT8 (Tuesday)

As 6m was so poor, I QSYed to 80m FT8 using the earth-electrode "antenna" in the ground. Although I am receiving spots of my signal from right across Europe, it says I am receiving none. This is rubbish as I can see loads of stations locally. Either there is a delay with uploads from me or, more probably, my spots are not getting to PSKreporter. Shortly I shall do reset to see if this cures it.

UPDATE 1922z:  The reset did the trick with lots of spots on RX. On TX 36 unique station spots of me so far.

UPDATE 2119z:  112 stations have spotted my 10W 80m FT8 TX this evening. Now QRT on all bands.

6m FT8 (Tuesday)

In a word, hopeless. I have been on 6m FT8 for about a hour and have been spotted very strongly by just one station not too far away (50km). On RX absolutely nobody copied.

UPDATE 1708z: Still useless!  Just 2 stations have spotted me and I have spotted nobody! Soon be time to try another band. I might give 80m FT8 a go with the earth-electrode "antenna" in the ground - probably after tea.

Windmill next door - NOT amateur radio

This stunning photo of the windmill next door was taken by a neighbour K. Tingey. 

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. 

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 .

Tuesday plans

 Probably 6m FT8 later. Shopping first! 

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.

Sunspots - Tuesday April 11th 2023

Solar flux is 140 and the SSN 92. A=14 and K=0.