[RFI] New Noise
Frank N. Haas
kb4t at arrl.net
Thu Oct 13 01:40:14 EDT 2005
If you can hear the noise during the day on 80 meters, I would be inclined
to think that the source is within the same town. I would think that it
would be easier to locate during the day when the signal seems weaker. If
that's not possible, I would try doing an "expanding circle" search while
listening to a mobile or portable receiver (assuming you can still hear it
on such a receiver.)
When I'm faced with these situations, I use an ICOM R3 with a Miracle
Ducker IL (Inline). The Miracle Ducker allows the receiver to hear much
better at low frequencies with an easily managed VHF/UHF flex antenna. The
Ducker has BNC connectors so I can't use my somewhat more sensitive
SMA-equipped IC T90a mentioned in a previous message. I also have a loop
antenna which fits nicely on top of the R3 or the Ducker. The loop is
bi-directional but it's better than no directivity at all.
Since the signal has clearly identifiable and unique characteristics it
should be easy to insure you are tracking the correct signal.
I'm curious if you can hear the signal at +/- 1.75 MHz or even +/- 875
kHz?? If so, it may be easier to hear on your car's AM radio.
In any case, take a nice drive around the neighborhood or town and see if
the signal is stronger elsewhere. If so, you may be able to mount a foot
pursuit to zero in on the source.
Frank N. Haas KB4T
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