Alan Cook wrote:
> I would like to add my 25 cents worth and it is mostly about line noise.
> back in the fifties and early sixties, our local power companies were
> using 4,150 volt
> delta 3 phase supply lines. That's 2400 volts to the pole pigs. now a days,
> frequently without insulator upgrades, that voltage is 33,000 volts on
> the 3 phase transmission lines and 19.9 kv to the pigs. cross country
> lines were 115kv, now they are 670 kv. You may think
> that the old clear channel AM radio stations have packed it in in favor of
> FM, but next time you have an ice storm or hurricane, and all the AC
> service has
> been disabled, take a listen to a portable AM radio. They are still there
> in all their glory. The problem is a general increase of line noise
> averaging as much as 8 S units. and , alas unless you live on a mountain top
> or in a desert, the "good old days" are forever gone because of
> noise floor increase. Al K2MPE
>
Yeah, the AM's are still there, but the concept of a clear channel, or
even a regional channel, is long gone. For example, in the 50's and
early 60's folks here in northern Nevada could listen to WBBM in Chicago
on 780kHz but no longer. Starting in about 1964 the FCC issued licenses
here in the west on some clear channels and more and more new AM
stations were shoe-horned into the band in the ensuing years. The
resulting cacophony is sad to hear! The increase in line noise may play
a part but the population density on the AM band is a big factor as well.
Jack, W6NF
(former radio air-talent, program director and chief engineer)
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