[1000mp] IP3 on Rob Sherwood's site

[Chuck Lewis]

Good question, Dale! I usually run tuned.

Chuck


----- Original Message ----- 
From: "D. J." <dalej2 at mac.com>
To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>
Sent: Wednesday, October 13, 2004 5:29 PM
Subject: Re: [1000mp] IP3 on Rob Sherwood's site


> Another question I would ask is if the preamp is used is it in tuned or
> flat (menu 8-4)?
>
> Dale, K9VUJ
>
>
> On Oct 13, 2004, at 16:12, Chuck Lewis wrote:
>
> > 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)
> >
> >
> >
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