On Fri, 19 Mar 2010, Paul Nicholson wrote:
For me, the power levels for this long DX are getting worryingly
high as they will at some point start to cause interference to
research activity. [...]
a few years ago i asked people doing geophysical research if they would be
able to receive amateur transmissions at 8.9kHz. they said that the usual
research is upto a few kilohertz, and that 8.9kHz is just a little over
the range that they usually use for research (i think that they recorded
upto 7-8kHz). if the transmitter isn't soft-keyed, then key clicks might
be a problem (but would be filtered by the high Q antenna matching
network)
i don't know about lightning detection networks, they might be vulnerable,
but Stefan's ERP is a bit small compared to a lightning bolt :)
also the geophysical/atmospheric research people have a lot of experience
in avoiding 50/60/16.6Hz harmonics, powerline communications (the HV type
uses kHz frequencies, lots of power and _large_ antennas).
so it might be not so much of a big problem after all.
VY 73
Jacek / SQ5BPF
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