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Re: [TowerTalk] Re: Tuners and Matchers

To: "Mark Beckwith" <>, <>
Subject: Re: [TowerTalk] Re: Tuners and Matchers
From: "Jim Reid" <>
Date: Fri, 16 Jan 2004 08:36:22 -1000
List-post: <>
> >With a Pi network, there are many possible matching 
>> combinations at varying Q's, so if you run high
> >power, you can really stress your tuner without knowing.

Nearly always,  the "best" setting using the typical
T tuner is that either the input or output C is set
to the maximum capacitance, and the inductance
set to the least possible value.

If the impedance of the antenna is low,  the output 
side C should be set at full capacitance;  sometimes 
even needing to switch in added capacitance to 
achieve,  perhaps 400 pf or higher might be needed 
on the antenna side.  The more costly commercial tuners
on the market offer such added switch capacitance
for the antenna side of the T-network.

More often,  however,  it will be the rig side capacitor
which should be set to max. 

At the same time that one or the other C's is set to max
value,  the inductance setting should be as low as possible
for lowest loss in the tuner itself. 

Under these conditions,  the tuner efficiency will be
highest.  Not sure if this sort of highest efficiency 
setting is also the lowest Q or widest bandwidth
without needing re-tuning.  Might not be.

73,  Jim  KH7M


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