> I've seen a few posts about AM BC band images at frequencies evenly
> divisible by 10 Khz ... makes sense, I guess, however I do not hear
> any of them. Should I? I'm beginning to wonder if there's something
> wrong with my receiving setup?
I would think anyone in or near the USA would hear some
harmonics, unless their noise floor is covering them up. Most of the
harmonics and spurious are fairly weak here however. I hear
multiple stations from multiple directions on 1800, 1820, 1830,
1840...although most are weak.
I also hear a few Airport NDB harmonics.
I've made it a point to identify some of the stronger stations and
report them. So far it has been a 100% hit as they've checked
stations, and found them out of spec. A few of the stronger stations
have disappeared. Several more stations are on a list for FCC
visits, including two stations in Alabama.
On the topic of reporting problems, we have to be very careful to be
sure the spurious signals we hear are actually transmitter
problems. A test would be installing a good highpass filter ahead of
any potentially non-linear devices like preamplifiers or diode
"clamps", use of a step attenuator to make sure the harmonic
decreases at the same rate as the attenuation that is added (make
sure you know your "S" meter's real accuracy), and trying a couple
different type of receivers and antennas if possible.
73, Tom W8JI
W8JI@contesting.com
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