[RFI] mystery noise

David Robbins K1TTT k1ttt at arrl.net
Sun Jul 13 21:54:42 EDT 2003

i have been hearing a noise that i just can't identify, i have narrowed
the source down to an area of 3 or 4 houses about 1/2 mile away from my
station, but need to build a directional antenna to get it down closer.
the real question is what might i be looking for????

recording at: http://www.k1ttt.net/audio/rfi4125AM.wav
this recording was made at about the loudest peak i found at 4125khz, AM
mode, 6khz wide filter.  as you can hear it is a pulsing about 2 or 3
beats per second.  this noise repeats at irregular intervals from at
least 3410 to 4365 roughly every 30-60khz, in between the peaks there is
virtually no trace of it.  the pulsing is not in sync on all the peaks.
to me this sounds like a multiple carrier fdm power line modem, but what
kind of device would be available that operates in this frequency
range??  does anyone know of a source of a noise like this??

David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net

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