Another thing people should look at is "Tuner Loss", not just tuner matching
capability.
There can be significant differences at certain extreme impedances.
Unfortunately nobody publishes any specs on that.
You have to measure it yourself, or wait for someone like ARRL to publish
test results - which they have.
In the last couple of years there have been two good tests by ARRL,
comparing matchbox losses.
Unfortunately each test only covers 5 or 6 matchboxes, and it seems like I'm
always interested in one that was not tested!
And since this is a Ten-Tec reflector, I'd like to remind people that at the
extremes, the Ten-Tec Model 238B was more efficient than the other "noble"
matchboxes it was compared to.
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Steve Hunt
Sent: Saturday, January 08, 2011 5:05 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] TT Eagle tuner spec: SWR v. impedance range?
It's tough to find a way to express a tuner's capability in some
succinct and meaningful way.
This was my attempt:
http://www.karinya.net/g3txq/temp/aat_chart.png
Each "cell" represents a particular load impedance going from 3.125 Ohms
to 3200 Ohms in binary steps, Resistive (X axis) and Reactive (Y axis)
If the cell is green, the tuner was able to find a match, and the number
in the cell shows the % power loss in the tuner. The darker the green,
the better.
If the cell is red it indicates that a power dissipation limit or a
capacitor voltage limit was exceeded
L+ indicates "no match - not enough inductance"
C- indicates "no match - too much minimum capacitance"
etc etc.
One chart needed per band.
The data was the output from the AAT programme on the Antenna Book CD.
73,
Steve G3TXQ
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