Message-ID: <008301c1e52b$e433a9b0$0700000a@parissn2>
From: "Stewart Nelson" <sn@scgroup.com>
To: rsgb_lf_group@blacksheep.org
References: <c6.9e10a30.29e94176@aol.com> <3CBB4AFD.30D47C43@virgin.net> <3CBBE887.F0D0D223@usa.net>
Subject: Re: LF: Phase meter for propagation experiment
Date: Tue, 16 Apr 2002 11:48:40 +0200
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The typical Doppler at end-of-life of a GEO satellite is about 40 meters
per second.  That translates to about .02 Hz at 136 kHz.  I don't know
what can be expected at midlife, perhaps an order of magnitude better,
but that's still too much error for a serious phase measurement.

73,

Stewart KK7KA

----- Original Message ----- 
From: "Alberto di Bene" <dibene@usa.net>
To: <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, April 16, 2002 11:01 AM
Subject: Re: LF: Phase meter for propagation experiment


> Stewart Bryant wrote:
> 
> > [...]
> > Thus the phase measurements must be made wrt an analogue
> > TV transmission.
> > [...]
> 
> What about analogue TV via Astra satellite ? There are dozens of
> analogue channels on this bird, and I am told some of them have
> very precise synch pulses.
> Would the relaying through satellite spoil their precision ? The satellites,
> while geostationary, are not exactly at a relative rest wrt the earth.
> They are wandering back and forth, with the small onboard jets correcting
> this movement. I don't have enough info on the rate of change of their
> speed to be able to evaluate the amount of the Doppler effect.
> 
> 73  Alberto  I2PHD
> 
> 
> 
>