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Re: [TowerTalk] Antenna matching values

To: "john@kk9a.com" <john@kk9a.com>
Subject: Re: [TowerTalk] Antenna matching values
From: Drax Felton <draxfelton@gmail.com>
Date: Tue, 22 Apr 2014 20:37:00 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I found the problem.  Torn cable into coax.   Must've snagged.   Thanks guys.   
Odd that damage only showed as a 2.0:1 mismatch!



Sent from my iPhone

> On Apr 22, 2014, at 8:08 AM, john@kk9a.com wrote:
> 
> What does this mean: "I tuned using the gamma matches on the antennas the
> best I could"  Did you have trouble obtaining a 1:1 match?  You can check
> and adjust the impedance of a single antenna though coax that is a
> multiple of 1/2 w.l. If the yagis are all good then there is something
> wrong with your phasing system or you have some serious interaction with
> something else on the tower. In the long run it will be much easier to
> correct the problem than cover it up.
> 
> John KK9A
> 
> To:     <towertalk@contesting.com>
> Subject: [TowerTalk] Antenna matching values
> From:     "Drax Felton" <draxfelton@gmail.com>
> Date:     Mon, 21 Apr 2014 23:44:02 -0400
> 
> 
> 
> I have a phased set of four 2 meter Yagi's that I tuned using the gamma
> matches on the antennas the best I could.
> 
> Now that the antennas are 90 feet in the air I have a slight SWR problem at
> the input of the array and cannot load my 1kW solid state amp to full power
> without it locking out.
> 
> 
> 
> I'd like to put a matching circuit at the input of the array on the tower
> end to avoid feed line losses.
> 
> 
> 
> I need to know what fixed values of impedance, capacitance, and inductance
> to put into two T match or other circuits to get nearer to a 1:1 SWR.
> 
> 
> 
> This is what my antenna analyzer says now:
> 
> 
> 
> When using horizontal polarization
> 
> 144.100 MHz   R=17  X=0  SWR 2.9
> 
> 
> 
> When using vertical polarization
> 
> 144.100 MHz  R=36   X=25  SWR 2.0
> 
> 
> 
> 
> 
> I know one of you is a good electrical engineer and can point me in the
> right direction.
> 
> _______________________________________________
> 
> 
> 
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