Re: [IRCA] Short antenna radials

[Dennis Gibson <wb6tnb@xxxxxxxxx>]

180 degree (or vicinity) towers are uncommon; especially on the low end of the band. Many are used by 50 KW stations. The KSTP night signal is directional with a sharp null to the east southeast to protect WFED in Washington DC. For some reason the three night towers are different heights; 216.5 degrees (184 degrees and 32.5 degrees of top loading), 184 degrees and 160 degrees. I don't know why. 

For reference 180 degrees is one half wavelength and 90 degrees (very common) is one quarter wavelength. Here's an interesting chart.

http://www.eriinc.com/Files/fc/fcec575c-5a91-455b-bcfa-5b8bf0d5ff1b.pdf

Here's a wavelength converter to change degrees to height or vice versa. All AM tower heights on the FCC website are in electrical degrees.

http://www.jampro.com/uploads/tech_calc/wavelength.htm

Date: Sun, 1 Dec 2013 13:02:30 -0600
From: Forrest Skaine <todftscytj7707@xxxxxxxxx>
To: IRCA Mailing list for the International Radio Club of America
   <irca@xxxxxxxxxxxxxxxx>
Subject: Re: [IRCA] Short antenna radials

Did you mean that KSTP night facilities?  I'm just trying to understand
because I'm just an amateur. If it is their day facilities is it because
that tower is taller than most?
Confused,
Todd in Woodbury Mn

Sent from my iPad
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