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John, Stefan,
we could to assign an approximate ERP to
Stefan's earth loop experiment as well.
In July, he measured DHO38 receive
voltage on his earlier 280m long earth antenna, which resulted in a
return current depth of 29 m at 23.4 kHz. Scaling this by
sqrt(f) gives 47 m at 9 kHz, and a loop area of 28000 m^2 for his new 600
m wire. The radiation resistance of this earth loop is thus
approximately 20 microohms. Assuming 0.8 amps (correct me if I'm
wrong), Stefan would have radiated 13 uW (EMRP) or 23 uW (ERP) towards
North and South.
Best regards,
Markus (DF6NM)
Am
15.12.2010 12:04, schrieb Stefan Schäfer:
Hi
John,
Am 15.12.2010 11:55, schrieb John Rabson:
I am writing a piece on VLF for the Cave Radio & Electronics
Group Journal and would like to include distance records. Can people
please confirm that the following information is correct (or not)?
Above-ground
antennas
|
Hz |
ERP mW |
From |
To |
km |
|
8970 |
58 |
Darmstadt |
Israel/Haifa |
2873 |
|
6470 |
9 |
Darmstadt |
Poland/Warshaw |
904 |
|
5170 |
5 |
Darmstadt |
Poland/Warshaw |
904 |
|
|
|
|
|
|
The QTH of SQ5BPF is
Washaw. The rest is correct.
Earth current antennas
|
Hz |
TX power W |
Electrode spacing
m |
From |
To |
km |
|
8970 |
250 |
600 |
Heidelberg |
Roschbach |
49.6 |
|
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| I did
successful tests to Roschbach just on 8970 Hz, not on 6470 and 5170. The
distance is 49.6 km (since my earth antenna QTH is different to the kite
antenna QTH).
Thanks too.
73, Stefan/DK7FC
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