[Amps] Checking for IMD

[Tony King - W4ZT]

My use of the words "average IMD" was out of place and I apologize. 
Please do not let this cloud the discussion.

73, Tony W4ZT

Tom W8JI wrote:
> 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