Thanks Richard;

I can understand the need to calibrate and verify everything as you said.

One of the things that popped up was your comment on making certain that the
source matches the intended load Z. When I worked on receivers in the past
we used to use what is called "hard microvolts". This was done by putting
a 3dB pad in the line between the receiver and the signal generator. That
way the impedance of the generator was more likely to be 50 ohms even though
the generator was specified to be 50 ohms.

I always remember that it was hard microvolts because it was harder to make
specifications on the radio with the attenuator in place.

Thanks for all the pointers. It is amazing that some people don't
understand that the equipment may be up to snuff, but the procedures are
blowing the results out of the ballpark.

When we used network analyzers we always tried to make the device we were
developing so it could plug into the face of the analyzer. If that was not
possible we would use cables made by the factory for that analyzer, clean
all the contact surfaces thouroughly, make certain that connectors were
torqued properly for the series and then do a full calibration at the end
of the cables so the analyzer would be able to give us results as good as
possible.

Unfortunately I don't have access to that type of equipment anymore
otherwise I would be using that.

Thanks again for the information.

Al Butler
ka0ies