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[TowerTalk] Re: Filters

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Subject: [TowerTalk] Re: Filters
From: (Joe Subich, W8IK)
Date: Sat, 31 Jan 1998 15:52:06 -0500
At 09:11 AM 1/31/98 -0500, you wrote:

>If I understand correctly, to attenuate a 20 meter harmonic in the ten
>meter band, the 20 meter antenna line has a T-connector in it and off of
>that t-connector is a 1/2 wavewlength (at 20 meters) open stub........

Jim, if you want to attenuate the 20 meter harmonic in the 10 meter 
band, you use a SHORTED 20-meter quarter wave (aprox. 11' 8" of .66 vf 
line) connected to the t-connector.  On 20 meters that line is an 
OPEN CIRCUIT in parallel with the feedline but it is a SHORT CIRCUIT 
for the second harmonic energy (the 28.x MHz stuff).  Similarly, to 
attenuate the 2nd, and 4th harmonic energy from 40 meters one would 
use a piece of line aprox 23' 6" (.66 vf).  


   ... Joe Subich, W8IK  ex-AD8I

"Hindsight is an exact science."

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