[Amps] Checking for IMD

[Tom W8JI]

Hi Gary,

> My contention of using the other side band is that you are 
> always moving the
> receiver pass band the same amount every time you switch 
> side bands as
> opposed to tuning around. You can quickly switch back and 
> forth to compare
> levels of wanted and unwanted signals. It give you pretty 
> much the same
> information as you get by tuning but it is very repeatable 
> when checking
> various signals on the band. You can get a feel for what 
> the signal levels
> should be on the opposite side band with some practice.

Why worry about precise repeatability with a rough test?

We know now the test initially claimed to measure IM average 
power ratios measures something near peak power, misses some 
of the third order and much of the higher order products, 
and probably isn't useful on the air except under certain 
conditions.

Is this test explained correctly anyplace? Is it explained 
incorrectly anyplace where it should be corrected?

73 Tom