"chuck" wrote in message
link.net...
Thanks for the info, Frank.

Actually, the RSS125 on the site doesn't contain the procedure, but
RSS181, also available at that site, does.

FWIW, the procedure is basically what has been discussed, except that
the signal generator output to be recorded as the receiver's sensitivity
is that level which produces a 12 dB SINAD at 50% of rated audio output!
Probably a more realistic test than allowing the AF stage to operate at
a low-distortion level of something like 1% of rated output.

73,

Chuck
NT3G

Thanks Chuck, forgot all about RSS 181, even though I have type approval
tested countless SSB transceivers to that specification. Interesting that
it has not been updated since 1971. Note that he sensitivity is defined as
that input that will produce 12 dB SINAD or that input which will produce at
least 50% of the rated audio output. The fact is that most of the testing
that I did was measured at full audio output, just below the threshold of
audio clipping. I do not recall any unit where the receiver gain was a
factor in sensitivity. Also note they still refer to "A3j", and not J3E,
etc. All these old specifications are based on tube designs. With TDA2002
type audio chips, you could typically get 5W out at 1% distortion. It was
so easy to drop in an extra IF stage if you could not meet the 50% min audio
output at threshold sensitivity.

73,

Frank