[time-nuts] Nighttime AM reception...
Burt I. Weiner
biwa at att.net
Thu Oct 13 20:24:41 UTC 2011
Actually, from a listener standpoint it's better to offset
co-channels by 15-20 or so Hertz. That pretty much removes the
problems from deep fading by co-channel signals. It's surprising how
much a co-channel signal can interfere with even a local signal
during critical hours. We have a local classical AM station that
actually sounds pretty good on my G.E. Super Radio. At night we
would get about a 5 Hz beat between them and some other station. My
wife would complain about the funny sound, so being involved on a
consulting basis with the classical station, I moved them about 10 Hz
the other side of zero from the interfering co-channel. My wife, who
is a classical music fan (so am I) asked how I got rid of the
problem? While the 15 Hz or so beat does tend to intermodulate
program, it's far less noticeable than the rapid fading was.
At 11:45 AM 10/13/2011, time-nuts-request at febo.com wrote
>I believe the argument that was advanced for better reception through
>GPS-locking had to do with improving nighttime skywave reception. So
>the argument went, locking the carriers of co-frequency stations
>would prevent fast fading (beating). Instead, you would get only
>long fades due to atmospheric changes. I'm not sure how much of an
>advantage that would be, in practice, but it shouldn't mess up local
>coverage (which is all the FCC cares about).
Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
biwa at att.net
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