[TenTec] TT 238C will not tune

[Bob McGraw - K4TAX]

The question to be answered, is 0 maximum inductance or minimum inductance? 
If it is minimum inductance then the position of C would be on the input 
side of of 0 inductance or on the output side of 0 inductance.  There would 
be little to no apparent difference as a starting point.  Therefore one can 
not determine the best starting point for the Z siwtch position.  Now if the 
inductance is maximum value then it is very apparent where Z should be 
located, either on the input of L or the output of L.  I believe it general 
practice to start with maximum inductance for adjustment of any L network.

I do not change the BYPASS switch with any power applied.  My practice is to 
set the tuner values using my analyzer and then record the values based on 
frequency and band for future reference.  Bottom line, I do not tune with 
any power as it causes QRM on the band.

73
Bob, K4TAX




----- Original Message ----- 
From: "Marshall Stewart" <marsh at ka5m.net>
To: "'Discussion of Ten-Tec Equipment'" <tentec at contesting.com>
Sent: Saturday, July 27, 2013 9:49 AM
Subject: Re: [TenTec] TT 238C will not tune


>I have a new T-T 238C impedance matching network. A gear reduction system
> behind the front panel of the 238C is connected to a concentric skirt 
> turns
> counter numbered 0 - 30 in a 180 degree arc over the top of the inductor
> tuning knob. The operator's manual suggests that tuning start with the
> inductor set fully counterclockwise at 0. It is okay to adjust the 
> capacitor
> and inductor while transmitting with low power, 50W or less, but do not 
> turn
> the rotary impedance switch with power applied. The length of the
> transmission line, coax or Windowline, from the antenna feed point to the
> tuner can make the difference between a load that can be matched and one
> that is outside the range of the tuner.
>
> 73,
> Marsh, KA5M
>
>
>
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