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Old January 24th 07, 05:31 AM posted to rec.radio.amateur.antenna
Michael Black Michael Black is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 322
Default Local station bad harmonics on 80 meters

"R. Scott" ) writes:
80 is basically useless. 3400 and 4000 I have a Pegged meter WFM signal
from 1380kc station here. I have mini harmonics ever 200kc that
basically makes 80meters unusable Its really annoying and the station
says they had their equipment recertified 2 months ago

This is hardly an antenna issue.

You do realize that it may not be the transmitter?

If your receiver (and you don't specify what it is) hasn't got
good strong signal-handling, the station may be overloading it
and causing the junk. And at first glance, it wouldn't be
obvious whether it's the receiver or the transmitter.

Try a different receiver.

Put an attenuator between your receiver and antenna, and see
what happens to those signals when you increase attenuation. If
it's overloadig, there will be a point where the unwanted signals
go away that can't be accounted for by the actual attenuation.

Borrow a spectrum analyzer, which should stand up well to strong
signals since it wouldn't be much use otherwise, and see what signals
are arriving at your antenna. If you do see signals that are traceable
to the broadcast station, then likely they do have a problem. But if
not, it's your receiver.

And it may not even be the receiver. There could be something acting
as a rectifier, that is picking up the transmiter signal and generating
harmonics for your receiver to pickup. A rusty rain gutter, or
a bad connection on an antenna, obviously something nearby.

You have no reason to doubt the station's word, especially since
they do have the rules to follow, and likely are in a worse
position than a ham with a bad signal. You are expecting the
transmitter to blame because you can't imagine your receiver
is at fault. But until you can actually rule out the latter,
you have no real reason to blame the transmitter.

Michael VE2BVW

Is there a place I can report this in the FCC?

The antenna is about 10 miles from me. And they are running 5kw.

They are planning and have approval for 50KW now and Im worried that
160 and 80 and possibly 40 could me useless.


Thanks
Scotty W7PSK.