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Re: backcountry radio (am/fm)

Posted: Mon Sep 22, 2014 10:50 am
by John Harper
I have an old Panasonic "work" radio. I use it car camping, picking up KRHV when up in the hills is pretty cool.

Reception is generally better at night, you don't have to deal with the sun's magnetic disturbances. Probably why some AM stations lower their power at night. FM seems to be less affected.

John

Re: backcountry radio (am/fm)

Posted: Mon Sep 22, 2014 1:09 pm
by austex
Back in '86 I was driving close to dusk down 395 to the Kramer Jct split. Was wicked weather so turned on the AM to find local weather since thundershowers were on the way. Got a station; said it was clear and mild. Well after 10 mins they identified the station as being in Chicago. It's called atmospheric "skip". Way cool. I'm sure Sean or other hams have a more scientific explanation of "skip"

Re: backcountry radio (am/fm)

Posted: Mon Sep 22, 2014 2:21 pm
by longri
John Harper wrote:Reception is generally better at night, you don't have to deal with the sun's magnetic disturbances. Probably why some AM stations lower their power at night. FM seems to be less affected.
It has to do with the ionosphere, a very high layer of the atmosphere. Radio waves in the AM band are refracted and reflected by the ionosphere. This so-called bounce allows for much greater broadcast distances than would otherwise be possible. During the day there is a lower layer in the ionosphere that absorbs radio waves in the AM band. At night this layer isn't present.

The ionosphere is transparent at the frequencies used for FM radio.

Re: backcountry radio (am/fm)

Posted: Tue Sep 30, 2014 7:17 pm
by The hermit
Thanks for the replies! Got the c crane pocket. It's great so far. We'll see how it works out there.