[1000mp] IP3 on Rob Sherwood's site

[Chuck Lewis]

It appears, from the superscript (b), that Rob used the preamp when
evaluating the Mk-V (and others). Is that everyone else's interpretation? If
so, it's a curious choice, because the Mk-V preamp adds little; my radio is
sufficiently sensitive even with the preamp off ("IPO"  illuminated) and
menu 9-1 reduced to 9 to accommodate the Inrad If mod. I have not found it
necessary to use the preamp even with 10 meter signals at the noise floor on
a quiet band. Perceived S/N (the 'practical' criterion, IMO) with the preamp
off is satisfactory. Surely the preamp affects IP3 adversely, right? The
question is how much a roofing filter would improve IP3 under the conditions
of a disabled preamp or additional attenuation. Even more basic is the issue
of why the test was conducted with the preamp on, if the preamp merely
provides the factory s-meter settings and a market-competitive sensitivity
specification. The same question could be asked for other radios whose data
reflects their preamp enabled.

I'm trying not to criticize here, just asking for some rationale other than
"That's the way the mfr. intended the device to be used". I'm looking for
someone to challenge the following premise:
    "Any overall system gain beyond that which is required to hear and copy
the desired signal is unnecessary and probably detrimental."

Anyone? Anyone?

Chuck, N4NM
(who uses his "Field" in the field, and not in the laboratory)