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Old Jul 25, 2005, 01:05 AM
Rem The Wasp CV-7 9/15/42
SammyB's Avatar
Santa Clarita,CA
Joined Apr 2004
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Why does AM radio reception diminish at night?

Atleast it does where I live. Right as the sun starts to go down, the radio stations will fade more and more until you hear nothing. Anyone know why?
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Old Jul 25, 2005, 01:41 AM
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Land of cajuns
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weird I know the sun's ionizes layers and the earth's atmosphere will prevents am propagation...where is this station is it day there?
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Old Jul 25, 2005, 01:41 AM
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Steve Guinn's Avatar
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"Many stations power down to 250 watts during the night. This is to protect the class A stations from interference."

Here's a link...
http://www.mcps.k12.md.us/department...s/amradio.html
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Old Jul 25, 2005, 01:42 AM
Rem The Wasp CV-7 9/15/42
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Santa Clarita,CA
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The station is based in the Los Angeles area. It is night here now.
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Old Jul 25, 2005, 01:45 AM
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Steve for like clear channles?
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Old Jul 25, 2005, 01:49 AM
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The little local station's signal travels much further at night. They cut power to keep from interfering with the big boys.
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Old Jul 25, 2005, 02:09 AM
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Helena, MT
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The reach of the signal is further at night so many stations power back their transmitters so as not to interfere with other markets. I can get LA stations on my car's AM radio when I am up in Tahoe at night.

http://www.fcc.gov/mb/audio/bickel/daytime.html better explaination from the source.
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Old Jul 25, 2005, 11:42 AM
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Jacksonville, FL
Joined Aug 2002
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I can remember as a kid growing up in Georgia, that I could pick up WLS in Chicago at night on my tabletop AM radio. That always used to fascinate me.

Rick
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Old Jul 25, 2005, 11:50 AM
Rem The Wasp CV-7 9/15/42
SammyB's Avatar
Santa Clarita,CA
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If people are getting LA stations in Tahoe, why can't I get LA stations in LA!
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Old Jul 25, 2005, 12:17 PM
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Because they are receiving the skywave signals while you are receiving the ground wave signals.

All those "powered down" stations combine to make white noise and drown everything out.
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Old Jul 25, 2005, 06:49 PM
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about 12" from my computer in Jacksonville Fl.
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Quote:
Originally Posted by SammyB
Atleast it does where I live. Right as the sun starts to go down, the radio stations will fade more and more until you hear nothing. Anyone know why?

Any Ham radio operator will tell you that the atmosphere at night is perfect for recieving radio signals.....

If you were a CB'r in the day, do you remember listening to the radio and getting "skip" from other states?

We have a 50,000 watt blow torch AM station, WOKV, here in Jacksonville, Florida that, by FCC rules, has to "power down" at 8:00pm so as to not interfere with Cuban radio. You can still hear it, but it is faint and you can hear the Cuban stations quite well.

I believe that they decrease their output so as not to bleed on another station at night due to the better reception. This is an FCC rule, not by the radio station's choice......


Still kinda neet to turn on the AM radio or the CB and Ham radio and see how far away you can hear.................


And being a Ham operator, I should know better to...

"Look out for those pesky Lightpoles!"
BB
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Old Jul 25, 2005, 08:11 PM
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Palm City, FL
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I worked the night shift at a new/motivation radio network years ago and one of the specific duties taught to me by the station manager was to turn down the station's power at a specific time.

AM will travel further at night, bouncing off the upper atmosphere, and if you don't power down you'll interfere with other stations using the same frequency in other areas of the country.

Got reamed one morning when I forgot and never forgot again... :-)
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Old Jul 25, 2005, 08:17 PM
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Hey Tim,

do you know anything about "Hot Rize" biscuits?
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Old Jul 25, 2005, 08:24 PM
Rem The Wasp CV-7 9/15/42
SammyB's Avatar
Santa Clarita,CA
Joined Apr 2004
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so because I am close to the station, when they turn it down, I can't receive it but others far away can because it bounces off the atmosphere?
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Old Jul 25, 2005, 08:51 PM
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