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Old January 25th 07, 01:39 AM posted to rec.radio.amateur.antenna
John Smith I John Smith I is offline
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First recorded activity by RadioBanter: Dec 2006
Posts: 1,154
Default Local station bad harmonics on 80 meters

Dave wrote:
"R. Scott" wrote in message
...
with no problems until the recent storms and the station has multiple
birdies and its in Wide FM rather than
AM ... makes me wonder.


go mobile. use a small antenna and an attenuator, maybe the one in the rig
will be enough with just a 6" antenna or something like that. if it is
indeed local to your shack it should be obvious when you get a few blocks
away, then start hunting for rectifiers. it should also be obvious if it is
from the transmitter as you drive around it. that might also find it if it
happens to be from a 3rd party, like a bad ground wire on a power pole or
something.

Also, do the test of shutting off everything at the breakers in the house...
there is an outside chance, especially with the FM symptom and extreme
width, that the AM station is getting picked up by some other device and
modulating it... it could be getting into a TV and modulating the color
burst, or a computer monitor, a old cordless phone, etc.

also check their fundamental and see if you can detect the fm on it, that
should be obvious enough also and something you could go demonstrate to the
engineer that may show him they have a problem that developed after their
certification.



Phew! That's a lot of stuff!

However, if all that fails, call Ghost Busters!

Regards,
JS