Topband: 1610 KHz AM Channel in USA
Richard (Rick) Karlquist
richard at karlquist.com
Sun Jul 5 01:01:33 EDT 2020
On 7/4/2020 4:35 PM, Rob Atkinson wrote:
> I'm not following the reasoning here. How are listeners never
> fighting noise below 1710 kc? In some cases noise (or by noise are
> we thinking of QRM?) is worse on medium wave broadcast channels
> because noise is usually AM and so are the desired signals. Also the
> receiver passband is wide. Those TIS stations usually run only 30 to
> 50 watts and use physically small antennas.
If I listen on my 90 foot vertical, and get a noise level check
at, say, 1750 kHz and then start tuning from 1710 kHz down, there
will be no channel where the S-meter gets down to the
reference noise level at 1750 kHz. This isn't because there is
more noise below 1710 kHz; rather every channel has one or
more stations that are well out of the noise. This will be true no
matter what receiver bandwidth is used. Especially at night.
There may be signals buried in the noise, but they will
always be covered up by stronger signals. When I had my
beverages up, I remember hearing TIS stations up to 100 miles
I don't know what "noise is usually AM" means.
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