Dear LF Group,
The 73.25kHz Rugby signal has been on intermittently lately, and
sometimes when it is off I have been hearing a strange bleeping and
warbling signal, centered on about 73.315kHz. The attachment shows a couple
of minutes worth of spectrogram - the frequency span is about 1kHz, and the
signal occupies about 600Hz. The blips on the "carrier" frequency are
actually shifting up and down in frequency by a few Hz, and seem to have
some sort of modulation applied, although this is hard to see in this
screen shot.
The signal is about 20 - 30dB over the noise here - Can anyone else hear
it, or is it some strange form of local QRM? Could it be a communications
mode, or some sort of beacon? Would be interested if anyone has any ideas.
Cheers, Jim Moritz
73 de M0BMU 
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