[TenTec] IF gain pot

Duane Grotophorst n9dg@yahoo.com
Sat, 5 Oct 2002 16:12:57 -0700 (PDT)

Keep in mind that by tweaking the IF gain upward you
will most likely be degrading the overall dynamic
range of the Pegasus some. So I wouldn't just crank it
up Willie-nilly, if you do so - just be prepared for
the potential of some negative side effects.

I have noticed that the "from factory" setting is
always just slightly beyond the "knee" of where the
background noise just drops off. Which also appears to
be the same point where the AGC action of the DSP
circuitry is wide open (full gain). When you advanced
it for more background noise (higher IF gain) the
DSPís AGC is having to work whether there is a signal
present or not.

I have also found that advancing it ever so slightly I
can make the extremely low level spur (now very low
with firmware 1.19) all but disappear completely. I
believe this is due to the AGC action of the DSP
hardware/firmware kicking in. This is consistent with
my observation that those low-level spurs would always
immediately disappear as soon as there was any signal
(or band noise) in the passband.


--- Jim FitzSimons <cherry@getnet.net> wrote:
> There is a gain pot inside the Pegasus. Carl N4PY
> told me about it.
> The pot is on RF PC board. I set to maximum.
> Jim W7ANF
> ----- Original Message -----
> From: "Gary Hoffman" <ghoffman@spacetech.com>
> To: "Jim FitzSimons" <cherry@getnet.net>;
> <tentec@contesting.com>
> Sent: Saturday, October 05, 2002 12:47 PM
> Subject: Re: [TenTec] Have you Noticed
> > I also have a Pegasus.  While 10m isn't the band I
> usually use, I have
> tried
> > it on 10m of course.  I have no problem getting
> weak signals.  Like
> others,
> > I found that my computer was the main source of
> noise in all of my
> > receivers.  I have extensive grounding, shielding,
> and endless chokes in
> > place to correct this.  Once that was done, no
> problems.  I'd be thinking
> in
> > terms of something being broken, or external
> noise, as the more likely
> > source of all these extraneous noises.
> >
> > Also, Jim, how do you Turn Up the IF gain on a
> Pegasus ??
> >
> > Thanks.
> >
> > 73 de Gary, AA2IZ

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