The topic is a Murch Transmatch 2000. It is in 'better' condition with
no signs of internal arcing, etc.
The background: I am tuning a long wire, about 100 feet long. I tune
with either a 0 dbm generator, a directional coupler, and a scope or
with a network analyzer. Those both work well and they both show the
same tuning results, that is a min return on one will also be a min on
the other.
The issue is: When a small about of power, a watt or less is applied
things work well, the SWR is close to 1:1. However if more power is
applied the 'tune' point jumps a couple of hundred kc and the SWR jumps
accordingly. The tuner has 4 sliding contacts, one each on the two
variable caps and two on the variable induction. Those have been
cleaned. I am not sure where else to look.
This setup worked very well for several months. This behavior just
started a few weeks back. I am at a loss as to how to analyze what is
happening.
Thanks - Dan
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