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RE: WiSP and 2.4gHz



Hello Gang, I have been through a few hectics hours as well using autotune.
I have tried WISP via
WISP DDE, Station, Nova, & SATPC32.

The major problem I have found is with the frequency stability of the
downconvert itself.

Find the LO of ur downconverter and use a program like Specbeta or
SpectraGram to measure the
audio freq of the carrier and i think u might (as least with my
downconverter) that it is not particular stable primarily based on
temperature. Also I notice that my Icom R8500 needs an hour before it is
stable enough to use the autotracking.

But I have noticed that WISP is the "most" inaccurate of all the programs I
have tried. I do not
know why. I believe the doppler routines are standard. It may be just me.

But check the downconverter first...rgs & 73s de lawrence

-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
Behalf Of Mark L. Hammond
Sent: Friday, May 11, 2001 4:01 PM
To: rdwelch@swbell.net; amsat-bb@AMSAT.Org
Subject: Re: [amsat-bb] WiSP and 2.4gHz


Hi Roy,

I've done it, and then used WispDDE to control my level converter to my
radio.

In principle, it works.  The problems I see are accuracy.  It's close, but
not quite close enough.  Seems that Wisp is at least partly (totally?) to
blame in how it calculates the doppler correction.  Other issues become
accuracy of the keps and the clock on the PC.  Even using the keps released
daily (or nearly so) for AO-40, and one of the "set your clocks to WWV via
the Internet programs", it's still off by as much as several kHz.

And as I recall, the error is not directly linear.  Meaning, it's off
frequency one way early in the pass, and can be off the other way late in
the pass.

(And that's with a TranSystem transverter I have put a thermistor in for
frequency stability, etc.)

I do use the WispDDE frequency displayed to tell me where to tune, but I
have to do it manually to actually find it.  I worked at this quite a bit
in an attempt to use Wisp/WispDDE for automated beacon capture.  So far,
not quite good enough.  One might use WispDDE in "SSB TNC mode" where it
sets the frequency at the start of the pass, and then use AO40Rcv to
correct for doppler there, but that assumes you get a good lock at the
start of the pass, and never lose a good signal from the bird.  I think
Alan NE1H does this exact thing.  With my trees however, that is NOT the
case....

Anyhow, these are one ham's experiences ;-)

73,

Mark N8MH

At 04:30 AM 5/11/2001 +0000, rdwelch@swbell.net wrote:
>Has anyone out there tried using WiSP with a 2.4gHz down converter, setup
>in WiSP as a transverter and done successful doppler correction on the
>2.4ghz beacon signal?  I know I will get this question and just want to
>research it a bit.
>
>--
>73, Roy
>
>Internet: w0sl@amsat.org
>Home Page: http://home.swbell.net/rdwelch
>----
>Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
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Mark L. Hammond  [N8MH]

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