Hello all,
For the last year or two I?ve been plagued by a rhythmic pulsating noise
that I simply can?t find or identify, and is rendering my HF station
inoperable on weak signals whenever it?s on.
This is wide-band, occurring across at least 10 MHz at a time if not more
(though rarely on 15 or 40, but wiping out 17, 20 and occasionally 30m). It
is a pulsing hash, about 4 or 5 pulses a second, and it seems to waver and
occasionally stop for a half a second to one second or so, only to start
right up again. It?s almost like a data connection or something, pulsating
regularly when idle and irregularly when active, but it?s too slow to be
data.
Additionally, it seems to sweep over a very long period of time. I don?t
have a ?scope here to see it visually, but it will louder in one part of the
band, then move very very slowly. There are random periods it?s not audible
at all, and other times it?s solid across the middle of the HF spectrum. The
noise is always loudest on the resonant antenna for whichever band I?m
operating on, and weaker on the other antennas. I?ve connected a second
transceiver up the noise appears exactly the same.
I?ve linked to an MP3 file I recorded this afternoon (9/21/09). It?s
approximately 2 minutes in length. The first minute is how it sounds with
the Mark V in ?AM? mode. At the 1 minute mark I switched over to USB mode on
the radio, then after a while back to AM.
http://dl.getdropbox.com/u/463425/W2IRT-pulsating_noise.mp3
-----------------------------------
Regards,
Peter,
W2IRT
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