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Re: [TowerTalk] Resonant boom

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Subject: Re: [TowerTalk] Resonant boom
From: "DF3KV" <df3kv@t-online.de>
Date: Sun, 24 Oct 2010 11:59:53 +0200
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Yes, that should work.
You could also detune the boom by connecting a capacitor across part of the
boom.
I built a new 40m FS yagi (12m boom) at 38m, about 50m apart is my
shorty-forty at 18m height. There is very little interaction between both
antennes when I turn them.
The large antenna is gamma matched on 80m to use it as a rotary dipol on
that band.
It works very well and SWR band with is 200kHz.
It does about 3-4db better then my full size vertical on DX.

http://www.pbase.com/df3kv/40m_fullsize_yagi

73
Peter, DJ7WW

-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Ron W8RJL
Sent: Sonntag, 24. Oktober 2010 06:23
To: Tower and HF antenna construction topics.
Subject: Re: [TowerTalk] Resonant boom

Why not linear load the boom. Use a conductive standoff at the end of the
boom, connect a wire to the top of the standoff and stretch the wire back
toward the mast area. Use insulated stand offs as needed along the boom
and as a tie off point. If that does not move the freq of resonance far
enough do same on other end. Linear loading works for elements it should 
work for a
boom. 73, Ron PVRC Tidewater.

Subject: Re: [TowerTalk] Resonant boom


>
> Hi, Stan.
>
> How about adding some "spikes" (like a capacity hat) to the end of the
> boom to add capacitive loading?
>
> 73,
> Dave   AB7E
>
>
>
>
> On 10/23/2010 6:04 PM, Stan Stockton wrote:
>> Anyone by chance have an easier to accomplish idea other than one I
>> remember being suggested to someone else with a similar problem -
>> fishing a wire through a hole near the center of the boom and letting
>> it hang out the end.  I can watch the SWR on my 40 meter antenna go
>> from 1.2/1 to 2.0/1 just by turning the rotatable 40m Yagi or the 20m
>> Yagi which is about 175 feet away and 65 feet lower.  Boom is 65 feet
>> and elements are insulated.
>>
>> Lesson learned on boom lengths...
>>
>> I would prefer to fix it with the least amount of work.  I can
>> probably do the wire thing on one side but not the other due to an
>> weight-balance obstruction.  Hate to have about 15 feet of wire
>> hanging out if the back of the boom.
>>
>> Thanks...Stan, K5GO
>>
>> Sent from Stan's IPhone
>>
>>
>> _______________________________________________
>>
>>
>>
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