That is a VERY important point Joe.
"getting mixed somehow"- often occurs without fault from either of the two
mixed stations - but as a result of a nearby rectification area (the right
metal hardware (rectifiers) coupled to a antenna of some sort with good
primary RF energy from the stations) - that maybe located many miles from
both stations - but "breeds" the mix. And that is what you hear on 160 and
80.
Guys are fast to blame the AM radio stations (and "some" have problems) -
when after a deeper dive - the stations spectral purity meets or exceeds the
FCC regulations.
I have found my share of AM station "mixers" - and it is not easy - they
take on a non powered life of their own - just like the first crystal radio
I built with a razor blade and pencil lead.
My most recent mix at K3LR involved 3 AM stations. The closest one 1470 -
had their 2nd harmonic added to the next stations primary frequency - result
was booming signal (both audios) on 3.730 MHz. The 1470 2nd harmonic with
the further station added together gave a - signal on 3.510 (both audios).
Lots of DF to find the "mixer". Which was one bad power pole ground (located
close to station #1) was the problem. Ground fixed - everybody is happy.
problems gone.
73,
Tim K3LR
-----Original Message-----
From: topband-bounces@contesting.com [mailto:topband-bounces@contesting.com]
On Behalf Of Joe Giacobello, K2XX
Sent: Thursday, December 22, 2011 10:26 AM
To: richard@karlquist.com
Cc: topband@contesting.com; lrpmbt@comcast.net
Subject: Re: Topband: 1820 BCB
At this point, I'm convinced that the source of the problem
is the 24 hour station and that the WPIN and WGFC signals are getting
mixed somehow to produce the AM signal on 1840.
73, Joe
K2XX
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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