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Re: [TowerTalk] shunt-fed tower capacitor match location

To: "Richard W. Harris" <Richard_Harris@byu.edu>,<towertalk@contesting.com>
Subject: Re: [TowerTalk] shunt-fed tower capacitor match location
From: ersmar@comcast.net
Date: Wed, 05 Oct 2005 13:41:53 +0000
List-post: <mailto:towertalk@contesting.com>
Richard:

     I have my matching cap (a single Gamma cap) in its plastic shoebox off to 
the side of the downcomer wire off the shunt wire cage.  IOW it's not directly 
below the pair of shunt-feed wires.  In Jeff K1ZM's book, he shows his matching 
cap off to the side of the wire cage as well.  I suppose macht nichts.  

     BTW - I believe the proper sequence of tuning is to tune the shunt cap for 
a 50 Ohm resistive component of the feed point impedance, then tune the series 
cap to reduce the +J component of the residual mismatch.

     Good luck.

73 de
Gene Smar  AD3F



> Hi,
> I have my shunt-fed tower for 160M about ready to tune.  I have an Omega 
> match 
> (two vacuum variable capacitors) inside a pelican case with stepper motors to 
> allow remote tuning.  I'm using insulated couplings to insure no electric 
> coupling between the caps and the stepper motors.  My shunt wire is a wire a 
> 10" 
> triangular cage of 13 gauge wire spaced about 2 feet from the 72 foot crankup 
> tower with the shunt-arm at the top of the tower.
>  
> My question is this:  My triangular shunt wire is spaced about 2 feet away 
> from 
> the tower.  Is there any problem with me putting the Pelican case with the 
> matching capacitor network next to the tower and run the feed line from the 
> box 
> horizontally 2 feet to connect with the triangular cage?  Or, do I need to 
> place 
> the Pelican case directly under the triangular cage.  Just a question I have 
> our 
> of ignorance and I haven't been able to find anything in print suggesting the 
> location of the matching network in relation to the tower and shunt wire.
>  
> Thanks much and 73,
> Richard - KJ7CU
> _______________________________________________
> 
> 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@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________

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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