I received numerous responses regarding my proposed common mode noise test,
and here is a summary of the responses.
1) The majority of respondents supported my proposed test.
2) There was really only one respondent that I thought provided a thumbs down
to my proposed test by saying "first test is much less likely to produce
equivocal results", but a second respondent might have been hinting at this too.
3) One person said I could "determine the common mode current by simply
terminating the antenna end of the feed line in it's characteristic impedance
and then listen to the rig", and I thought I should mention in this summary
that this technique has long been considered an invalid test.
4) Guy (K2AV) felt small S-meter changes would be hard to detect when listening
to the noise, and he suggested the use of an AC voltmeter to measure the
receiver audio with the AGC off in order to detect small changes. I did some
preliminary testing with my high end AC voltmeter which also provides long term
averaging, and this method appears to be very beneficial in detecting small
changes (versus using the S-meter).
Thanks to everyone that responded.
73's
Don (wd8dsb)
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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