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Re: [TowerTalk] Stack as vertical

Subject: Re: [TowerTalk] Stack as vertical
Date: Sat, 10 Oct 2009 09:05:35 EDT
List-post: <">>
Mike, a simple L network will match a huge range of impedances. If you can  
characterize the R +-j at the end of your gamma no doubt you will be able 
match  it with one of the four available L configurations.
Gerald K5GW
In a message dated 10/10/2009 6:17:35 A.M. Central Daylight Time, writes:

Hello  TTers,

I am planing a stack.  I would like to get double duty as a  160 M vertical 
as well.

I modeled the stack in EZNEC and I can get  resonant at about 1.9 MHz at 
the minimum height.  That is just a guess -  I won't really know till I build 
the stack. If I add height, of course, I can  lower the resonant frequency.

I can series feed or shunt feed at my  option.  I imagine series feed would 
require me to disconnect all the  rotor wires with relays or use 
common-mode chokes when I am in 160 M  mode.  For that reason, shunt feed seems 
best option.

The  first yagi in the stack will be at 30 feet.  That limits the height of 
 the Gamma rod or Delta wire to 30 feet also.

Will I be able to match  the tower with this limitation?  Especially since 
the actual resonance  might be lower than 1.8 MHz.  Would it be better to 
avoid having the  resonance in the band?

Mike W8GT


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