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[TowerTalk] Re: Filters

To: <towertalk@contesting.com>
Subject: [TowerTalk] Re: Filters
From: k4oj@ij.net (k4oj)
Date: Sat, 31 Jan 1998 09:11:58 -0500
There still seems to be some confusion about the 1/4 wave versus 1/2 wave
stubs for harmonic suppression. The confusion seems to be if the length is
related to the band you are operating or the band you are trying to
suppress.


I think the problem for dummies like me is what you are referring to, is it
that the stub on the 20 meter antenna line is a 1/2 wave long at 20
meters............that is where the confusion is starting....or is it that
that length of line is attahced on the ten meter antenna's line.........and
is it still a half wavelength at 20 meters now or a 1/2 wavelength at 10
meters....... 

With the ARRL DX around the corner and a few of us interested in multi-op
and SO2R options this info is currently "in demand"


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........

Did I get it right?

(And I guess, the 40 meter feedline has a t-conn with a 1/2 wave 40 meter
open stub on it to minize 20 meter QRM..........)

DId I get it right?

73 - see you in the FQP

de

Jim White, K4OJ   
k4oj@ij.net
a proud member of THE Florida Contest Group
...visit our website @ 
http://www.4w.com/deemer/fcg.htm

What's an FQP?
Check out the new Florida QSO Party (its April 25 & 26, 1998)  @

http://home1.gte.net/wd4ahz/fcg/ssqp.htm

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