[1000mp] Amps & IMD Low power

[Tom Rauch]

> Mike Tracy and I just talked about it and we can easily add a
> half-power IMD sweep to the IMD plots we put in the expanded reports,
> so he will start doing it on 80 and 20 meters.  I don't want to do the
> tests on all bands because those few minute-tests here and there can
> add up, but each of the expanded reports in the future should contain
> some half power tests.

What might be more useful is a time storage spectral display of 
bandwidth with speech Ed.

Two-tone tests (and especially noise notch tests) have limited value, 
since they do not show syllabic rate dynamic regulation shortfalls 
that really often are most problematic. 

A three-tone test would be better, but a time swept peak amplitude 
display would show real voice performance. It would be like the CW 
test, except you would use real speech and look at the stored peaks. 
Just like the FCC tests required for new FM equipment. 

A real speech bandwidth test would show us how most rigs get trashy 
when people use speech equalizers to boost the lows in a misguided 
effort and sound "hi-fi".

To be fair, we could digitally record a certain long phrase and 
everyone use that standard digi recording, or something from a 
commercially available CD recording. A picture of the transmitter 
bandwidth with speech would be MUCH more meaningful than a two-tone 
test, and might educate us as to how wide we really are.

The FCC now requires such a test for FM two-way transmitters and 
other devices. No reason we can't do the same to augment a two-tone 
test. After all, just like with CW we are really trying to measure 
bandwidth.

73, Tom W8JI
W8JI@contesting.com