[TowerTalk] Stub tuning

[Tom Osborne]

OK, Thanks Dave

I wasnn't sure about that.  I have W2VJN's book here, but it was kind of 
vague on that.  It said if you put the stubs right at the transmitter and 
bandswitch them, you have to compensate for the extra length through the 
switch and connector.  He also shows each stub on the output of the antenna 
switch, but doesn't say if you have to compensate for the length of line 
from the transmitter, through the antenna switch, to the stub.  So I can 
just cut them to length, using the MFJ and dummy load and then put them on 
the output of my antenna switch and be in fat city.  I noticed that when I 
put the stubs there, the SWR stayed the same and on a couple of them, even 
got a little better.  73
Tom W7WHY


----- Original Message ----- 
From: "David Robbins" <k1ttt at arrl.net>
To: "'Towertalk'" <towertalk at contesting.com>
Sent: Monday, September 12, 2005 3:26 AM
Subject: Re: [TowerTalk] Stub tuning


>
> 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
>>
>> _______________________________________________
>>
>> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless
>> Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with
>> any questions and ask for Sherman, W2FLA.
>>
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>
> _______________________________________________
>
> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
> Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>