If you want to see the effects of this AGC speed limitation
download Ten Tec's control program and run it on a decently
fast PC of 2GHz or so. Set the band to say 40M at night and
then bring up the sweep panel and then click on "Sweep". It
will indeed sweep quite fast but you will also see a series
of "saw teeth" on the display. The saw toothing effect is due
to the decay time of the AGC being too long. For several new
frequencies that sweep is tuning through the AGC will still
be dropping even though there is no longer a strong signal
there.
I've been long convinced that a *new* "mode" that is
specifically designed for sweeping could be done in firmware.
This mode would not do any demodulation of signals of any
kind. It would have essentially instant AGC decay, or no AGC
whatsoever. All that it would/should do is measure signal
strength and report it. If the DSP is only doing that then I
would think that it could be made to go much faster while
still providing a very nice sweeping action. Now I believe
that the only choice is to pick one of the exiting modes and
read its S-Meter value repeatedly.
Duane
N9DG
--- Steve N4LQ <n4lq@iglou.com> wrote:
> Thanks Carl. It makes sense. When the Jupiter does it's own
> scan, it's much faster. 2 questions:
>
> Does the agc not affect the Jupe in standalone mode
> scanning?
>
> Could a firmware change take care of this?
>
> Steve Ellington
> N4LQ@iglou.com
> ----- Original Message -----
> From: "Carl Moreschi" <n4py@earthlink.net>
> To: "Discussion of Ten-Tec Equipment"
> <tentec@contesting.com>
> Sent: Tuesday, February 22, 2005 9:34 PM
> Subject: Re: [TenTec] Pegasus/Jupe Band Scope Questn
>
>
> > Steve,
> >
> > I experimented with this a lot in developing the
> software. The limiting
> > factor is the speed of the AGC. If I run the sweep
> faster, the AGC does not
> > change quickly enough to give any decent resolution. The
> program has a
> > loop that goes ike this:
> >
> > 1) Set a frequency
> > 2) read S meter
> > 3) plot a point on the graph
> > 4) Go to step 1
> >
> > If you do this too fast, the returned S meter reading
> does not change
> > enough
> > from the previous reading for good resolution. I hope
> this explanation is
> > clear.
> >
> > 73,
> >
> > Carl Moreschi N4PY
> > Franklinton, NC
> > ----- Original Message -----
> > From: "Steve N4LQ" <n4lq@iglou.com>
> > To: <tentec@contesting.com>
> > Sent: Tuesday, February 22, 2005 9:21 PM
> > Subject: [TenTec] Pegasus/Jupe Band Scope Questn
> >
> >
> >> What limits the speed of the Peg/Jup's band scope? When
> I used the
> > Jupiter's bandscope it was fairly fast but when using it
> in Peg mode, it is
> > really s l o wwww.
> >> Is this the fault of the rig, firmware, comm port, pc
> processor, software
> > (N4PY) or what?
> >> I want the sucker to really fly but I want to see it on
> the computer, not
> > the Jupe's little green display. What would it take? Has
> anyone found
> > anything that makes a difference?
> >>
> >> Steve Ellington
> >> N4LQ@iglou.com
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