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[TowerTalk] vertical antennas math & 1/2 waves

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Subject: [TowerTalk] vertical antennas math & 1/2 waves
From: K3BU@aol.com (K3BU@aol.com)
Date: Mon, 5 Nov 2001 12:08:32 EST
In a message dated 11/5/01 8:58:02 AM Eastern Standard Time, K7GCO@aol.com 
writes:

> Yuri:  I duplicated your figure  A=.026167978 WL by creating 2 "right 
>  triangles" with a line at 3 degrees bisecting the line bewteen the .25 WL 
>  tips (for further clarification).  Without a right triangle the sine 
factor 
>  is not correct.  Yuri I didn't know you were good on math also. hi  
>  
>  Actually most all this radial math nonsence goes away with 1/2 wave 
>  verticals.  With the finances of the average DXer today, I cannot see why 
> any 
>  DXer screws around with 1/4 waves.  A 1/2 wave is already resonant and 
>  doesn't need any more help in that department.  I've had great success 
with 
>  1/2 waves with just a ground rod to cool the coax shield feeding an L 
>  network.  How much E-field loss is there at the base without any radials?  
>  I'm not sure.  The higher the base of a 1/2 wave this problem reduces 
itself.
>  
>   I will run a comparison with a side by side 1/2 waves--one with a ground 
> rod 
>  and one over a good radial system.  WWVH has some radials out a ways.  I 
>  don't think they have to be a 1/4 wave although it sure can't hurt.  
>  
>  Has anyone else any 1/2 wave vertical experience?  K7GCO 

Well,
"my" formula is accurate and useful down to 1 radial(s) and cheap (free), 
practical from 3 and up and it is correct (check it out -:) no need for right 
angle triangles.

On the subject of half wave verticals, one can not overlook quality of ground 
required for effective performance at low angles. Even if the vertical 
(whatever) needs no radials, its performance is affected by the quality of 
ground. So if over land, if you put down the ground screen under the 
radialless vertical antenna, you will gain big jump in performance. I saw 
this last WW SSB contest weekend when I setup my vertical "artillery" - 4 
square and 3 el dual pol quad here behind the house, instead of the beach 
front at Cape Hatteras, they sucked!! 

When I tried to have 4 square made out of half wave vertical dipoles 
(~110ohm) using Comtek phasing unit on 10 m, there was a problem, had to 
"degrade" it to 1/4 waves with single radials, and it works as it supposed 
to. 

73 Yuri
visit 2001 Radiofest East Nov 10 at Glen Spey, NY
see www.verkhovyna.com and click on Radiofest

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