Hello Rick,
Michael Oexner has had good results with a mini-whip E-field probe I build
for him.
The circuit diagram is in the attachment.
The feedline is CAT5 network cable.
Note that the RF-isolating transformers in the signal path are not correct.
I have used MCL TT 1-6 parts, rated for 0.004 - 300 MHz at the -3 dB
points.
The common mode chokes are not optimum, as I used the parts I had on hand.
Type 75 or 77 ferrite should be better.
Michael used a PERSEUS SDR, which has a noise figure of about 25 dB at 9
kHz.
This is due to the fact that there is also a RF-isolating transformer in
the signal path.
It is amazing that with this not optimized set up it was possible to have
good reception over a 72 km path.
The actual capture area of the antenna is 30 x 40 mm single sided copper
clad PCB.
There are quite a few people around with a PERSEUS SDR, who are probably
interested in receiving Stefan's signal.
So a simple antenna design might help.
I have the parts for an optical link active E-field antenna, as suggested
by Stefan.
Due to other more pressing matters, I have not yet put them to good use.
I hope this helps,
Best regards,
Roelof, pa0rdt
pa0rdt-Mini-Whip CAT5.JPG
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