[TowerTalk] Stub tuning

[David Robbins]

The location of the stub may change the tuning due to some reactance
introduced when the stub is slightly off its tuned point, but the correct
length is measured from the T connector where it is inserted not including
any other cable between it and the amp or other equipment.  Stubs can be
T'ed in anywhere it is convenient along the feed line.

David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
 

> -----Original Message-----
> From: towertalk-bounces at contesting.com [mailto:towertalk-
> bounces at contesting.com] On Behalf Of Tom Osborne
> Sent: Monday, September 12, 2005 04:35
> To: Towertalk
> Subject: [TowerTalk] Stub tuning
> 
> HI TT'ians
> 
> I'm trying to get the stubs hooked up here.  I cut some and they are right
> where I want them to be, using the MFJ tuner option.
> 
> I cut the 20 meter one right at the meter and wanted to hook them up on
> the
> outside of my antenna switch.  Going from the rig, there is about a 3 foot
> cable to the MFJ tuner/swr bridge.  Going from there is about a 3 foot
> cable
> to the homebrew antenna switch.
> 
> Problem is, when I move the stub from the bridge to the output of the
> antenna switch, I would think it would be too long and would have to cut
> some off.  What is happening is that instead of the stub being on 14.100
> (where I want it), it moves up frequency to about 15.500 instead of going
> lower if frequency as they are now about 6' longer.  Can't figure what is
> going on.  There is no dip down below 14.100.  Any ideas?  73
> 
> Tom W7WHY
> 
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> 
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