[BC] Smallest AM Radiator

[Rob Atkinson]

I wonder what those little automated traffic information stations use, that 
are on 1610 and 530 or 540?  what kind of small tower can work well on 
540--or maybe they don't care as they don't have to get out all that far.  
must have a loading coil the size of a farm silo  :  )

rob atkinson


From: "Gary Peterson" <kzerocx at rapidcity.net>
Reply-To: Broadcasters' Mailing List <broadcast at radiolists.net>
To: <broadcast at radiolists.net>
Subject: [BC] Smallest AM Radiator
Date: Thu, 29 Jun 2006 09:35:29 -0600

" Gary,
    Were they using a folded unipole or series feed?  If it was a series
feed, yep the coverage would have been terrible. They should have used a
unipole for that application, and then they would have found the coverage
would have been much better. Sounds like to me the radials didn't do you
much good lying over the rock.  The antenna would have been great with a
unipole and a counterpoise ground system.
Scott "

The Custer AM tower was series fed.  I believe the "poopy" coverage was due
to being high on the dial and very poor ground conductivity in the locality.

Personally, I have doubts that a folded unipole feed would have done
anything to improve their situation, given all other factors remained the
same.  In 1979, I took measurements on a 1340 kHz, class IV before and after
installation of a folded unipole.  Within experimental error, the field
intensity was virtually the same, before and after, at several carefully
selected locations.  It didn't solve the static buildup problem either.  The
tower was tied directly to the radial system with three 4" copper straps.
The folded unipole feed came through a steatite bowl insulator in the wall.
You wouldn't want to be anywhere near it during a thunderstorm.  Much more
spitting, hissing, arcing and balls of fire flying than I have ever seen on
a series-fed.  There was a static drain choke from the folded unipole feed
to ground, too.

Gary, KØCX
Rapid City, SD


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