[Elecraft] high-power tuner

[Ron D'Eau Claire]

I was investigating tuner losses a few years ago and ran into many of these
same questions. 

A physicist buddy pointed out to me that the normal approach to measure loss
in something like a tuner is to put it in a well-insulated chamber and
measure the rise in temperature over time while transmitting. From there on
can calculate the energy required to cause the temperature rise which can be
used to calculate the number of watts of RF that never make it through the
box. 

73, Ron AC7AC

-----Original Message-----

There seems to have been no answer as to how to accurately measure the loss
in a tuner.  
Here is a solution but requires two tuners or at least one calibrated one
that could be used to measure others.
Take first tuner and tune it into the mismatch, say 600 ohms.  Use an
antenna analyzer.
Then remove the load, and connect another tuner to the output of the first
(back- to-back - antenna port on first to antenna port on second tuner.)
Then put a 50 ohm load on the second tuner where the transceiver would be
connected, and tune the second tuner to a match.  It will have the same
settings as the first tuner, complete symmetry.
Then measure the power in the 50 ohm load  to get the loss.

Since both tuners are matching the same load, and the system is symmetrical
the loss contribution by each tuner is half.  Repeat for other types of
loads, and now you have a calibrated tuner to use with any tuner you want to
test.

Rick  K2XT