John,
it is a switch-mode power supply. Look at the
stronger bands every 100 Hz. May be a luminary, a
LED lamp, a CFL, a TV, a PC, a battery charger...
To locate it may be really difficult. By first,
power your radio from a battery and turn off the main switch to your home.
If it does not come from your QTH, then get a
transistor radio covering LF and MF, and try to
use the ferrite antenna to do a direction finding.
It may be hard to get a null, since the signal is
most probably conducted along mains cables and
not directly radiated, so you will find it everywhere.
You may have some success walking along the road
and listening at the energy meters of you
neighborougs; one could be "hotter" than others.
Many of us are plagued by similar QRM, from 137
kHz to microwave bands. There is little to do,
IMHO... it is a battle against windmills à la Don Quixote.
73 - Marco IK1ODO
At 20:53 13/11/2010, you wrote:
Please see attached screen print taken with Argo
at 2010 Nov 13 1941z. The frequency marks
across the top are relative to 136.0 kHz
approx. The vertical bar is an artefact of the RX.
The signal can occur at any time and drifts
across the RX passband, with occasional jumps of a few hundred Hz.
What software would people suggest for analysing
it with a view to determing its cause and perhaps locating it?
F5VLF
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