[AMRadio] Odd signals in lower 80 meters

Gary Schafer garyschafer at comcast.net
Tue Dec 19 12:40:03 EST 2006

I haven't listened on 80 for those signals but I have herd similar to what
you describe in the past. A few years ago there were several companies
selling scramblers that inverted the audio. A lot of them went into South
America and were used by people for their "private" radio networks. I would
guess many were not licensed users.

You can not decode it by switching side bands. It is simply done by mixing
the speech with an audio tone and everything comes out upside down. The high
frequencies come out as low frequencies and the low frequencies come out at
high frequencies and they are offset by the mixing tone frequency. If you
listen carefully you can make out a word once in awhile.

Gary  K4FMX

> -----Original Message-----
> From: amradio-bounces at mailman.qth.net [mailto:amradio-
> bounces at mailman.qth.net] On Behalf Of A.R.S. - W5AMI
> Sent: Tuesday, December 19, 2006 12:05 PM
> To: Discussion of AM Radio in the Amateur Service
> Subject: [AMRadio] Odd signals in lower 80 meters
> Has anyone beside Don/KYV and myself heard these odd sounding voice
> signals between 3700 and about 3750 that seem to be sideband, but can
> not be tuned in either lower or upper sideband?  They seem to be all
> over the place, however no one else has said a thing about them except
> Don on amfone.net.
> They sound like inverted audio, however it would seem that going to
> the opposite sideband would allow you to tune them, but it doesn't.
> Maybe I'm not thinking clearly on "Inverted audio".  If not, would
> someone straighten me out?
> I started a thread on another list, and it's as if no one has heard
> them, and I am now getting the feeling I'm losing my marbles!
> 73
> Brian / w5ami
> --
> "There is nothing more uncommon than common sense." -- Frank Lloyd Wright
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