[FoxHunt] Old Homing In Article

[wolfbob]

The issue is the distortion to the antenna pattern caused by "inactive" 
antenna elements. Only one antenna is in use at any one instant and it is 
desirable to have the azimuthal pattern from that antenna be circular. If is 
is not circular then the multipath signal from the direction of highest gain 
can override the direct path and cause the doppler to make gross errors.

Joe found (using EZNEC modeling) that if the unused antenna elements are 
shorted to ground you would get some 10-20 db lobes in the antenna pattern. 
By having the unused elements open the lobing was less than 1 dB. This 
requires having a switching diode in series with the element and the more 
complex biasing arrangement.

Bob, WB6JPI


----- Original Message ----- 
From: "Charles Suprin" <hamaa1vs at gmail.com>
To: <foxhunt at mailman.qth.net>
Sent: Monday, March 08, 2010 11:10 AM
Subject: [FoxHunt] Old Homing In Article


> Hello Foxes and Hunters,
>
> I am looking for a copy of the Homing In article from April 1995.  It
> contains information on design decisions for k0ov's new Roanoake
> antenna system. Joe points the user to it at
> <http://homingin.com/newdopant.html> and Bob Simmons ( WB6EYV )
> alludes to the content at
> <http://www.silcom.com/~pelican2/PicoDopp/PICO_MORE.html>. It appears
> to deal with the need for maintaining the impedance at the antenna's
> for repeatable performance.
>
> Any insight would be appreciated.
>
> Charles
> AA1VS
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