On Thu, 11 Mar 2010, James Moritz wrote:
It is interesting to try to work out what might be possible by induction...
[...]
have a look at
http://www.home.pon.net/785/equipment/transmitting/VLF_transmit_2.htm
this experiment used two triangular loops of 15m high and 90m circumfrence
in a natural area (without conductors etc).
the author was able to copy a 0.5W cw signal at the distance of 3.3km!
this is much more, than what is expected from free-space calculations
mentioned in this thread. this is probably the effect of the ground
(currents induced in the ground excite some much bigger ground loops that
make up a "secondary" antenna of bigger size).
another explamantion would be that the field induced at the transmitter
site got into the 2m receiver that the author was using, but i hope that
is not the case :)
VY 73
Jacek / SQ5BPF
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