[Amps] 12V IM3

[Gary Schafer]

When IM products are generated they are equally generated on both sides of
the carrier frequency. as Joe says, just flip over to the opposite side band
and you can immediately see what the level of the 3rd order products are.
They will be the same on the unwanted side as they are on the wanted side
but much easier to distinguish from the wanted signal.

73
Gary  K4FMX

> 
> If you want an easier way to tell ... just tune to the "opposite"
> sideband or look at the other side of the suppressed carrier on a
> panadapter/spectrum analyzer.  Overdrive/IMD causes the suppressed
> sideband to be regenerated.  That was one of the reasons analog (NTSC)
> TV transmitters required predistortion - to keep the signal in the
> channel.
> 
>  > ... The band will not get better until the signals get clean.
> 
> The signals will not get clean until ARRL Labs stops being a lap dog
> of the manufacturers.  They need to be very loud in condemning  rigs
> with IMD worse than -36dBc (-42dB PEP), the rigs with really terrible
> transmitted phase noise, rigs with "wide" (> 2.7 KHz) transmit audio
> response, those with user menus that allow CW rise time to be set in
> such a way as to guarantee terrible key clicks and those with FSK
> that is two to three times wider than necessary.
> 
> 73,
> 
>    ... Joe, W4TV
>