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Re: 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
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Mark L. Hammond  [N8MH]

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