[TenTec] grounding dipoles

[n4lq]

You can have a lot of interaction between parallel dipoles. Some antenna 
current will flow the unused antennas no matter how you try to avoid it. 
Depending on which bands you try to parallel, the results will be mixed. 
Often, high swr and narrow bandwidth is the result. I have had good 
results with 80,40,20 paralleled as an inverted vee and drooping down 
around the pole like a maypole. I tried putting them all in the same 
plane and ended up with horrible swr problems. 40m and 30m can really get 
crazy. 80m and 160m will work but yields very narrow 2:1 bandwidth on 
both bands. People have been doing this since antennas were invented. 
Read any book about antennas and you'll find this covered. 
Think about this: What if we cut a dipole for every frequency between 1.8 
and 30 mhz and hooked them in parallel? We would end up with two big 
sheets of metal about 250 ft. long and a mile high! What would the swr be?

Steve n4lq
-----Original Message-----
From: Able2fly at aol.com
To: tentec at contesting.com
Date: Mon, 23 Aug 2004 07:06:00 EDT
Subject: Re: [TenTec] grounding dipoles

>  
> In a message dated 8/23/2004 6:44:19 AM Eastern Daylight Time,  
> jsb at digistar.com writes:
> 
> I  experimented with this once (once is the operative word, about 15 
> years  ago) ) but didn't have the best success with it because the SWR 
> was  high.  Weather was bad and I was pressed for time so I didn't
> pursue  
> further.  Does this require a tuner or should the SWR be low?  I  would
> very much like to eliminate the extra runs of coax,  etc.
> 
> 
> 
> ====================================
> For minimum SWR, the dipoles of course need to be cut to the proper
> length  
> for resonance at your operating frequency. Formulas will only get you
> close,  
> then its "cut and try" time... Tuners generally aren't needed for
> resonant  
> coax fed dipoles, parallel connected or not...
>  
> Bill
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