Re: [TowerTalk] Elevated Verticals

[Terry Conboy <n6ry@arrl.net>]

On Sun Jun 12 09:49:54 EDT 2005, Jim Jarvis wrote:
> I differ on the topic of radiation pattern.  Not sure about the source of
> Tim's caution, but if we're talking about 2 resonant radials...it's just
> a bent dipole, and you WILL get high angle stuff out.

As long as the two radials are symmetrical (180 degrees apart, same slope), 
the horizontal radiation cancels quite well in the far field.  I modeled a 
40m ground plane in EZNEC with the feed at 50 feet and 45 degree sloping 
radials.  The elevation patterns with 2 and 4 radials look darn 
close.  There is a slightly oval azimuth pattern (+/- 0.2 dB) with 2 
radials.  Horizontally polarized signals were down 18 dB from the main lobe.

I believe that Brown, who worked with ground planes in the 1930's found 
that 2 radials were adequate, but it didn't "look right", so he used more.

The guys on "Team Vertical" did pretty well with only two gull wing 
elevated radials.  Yeah, the salt water might have helped a little.

73, Terry N6RY
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