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RE: AO-40: transponder off!!



I'll offer the following.

The squint angle calc in SatTrack is *way* off compared to something that
has a real geometry model for deep space satellites.  If you notice,
SatTrack uses the TLE mode for deep space objects (ao-40 counts as one).  It
will only use the LEO model for the LEO sats.

Because of this, there is an error of up to 20 degrees that I've seen
between SatTrack and Nova with the exact same alon/alat settings.

Alan

-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
Behalf Of Margaret Leber
Sent: Wednesday, May 30, 2001 7:10 PM
To: Douglas Braun & Nadia Papakonstantinou
Cc: amsat-bb@AMSAT.Org
Subject: Re: [amsat-bb] AO-40: transponder off!!


Douglas Braun & Nadia Papakonstantinou wrote:

> My version of SatTrack predicts squints as low as 22 degrees
> for this attitude.  Did I mess up my fix for AO-40 vs. AO-13
> attitude calculations?

On my SatTrack I've simply entered the attitude as given into the
software and assumed that the closer the squint is to 180 the more
favorable it is.

Right now I'm tracking the bird 13 degrees below my horizon at about az
80 degrees; the squint is reading as 157 degrees at MA 43, which I
interpret as an effective squint angle of (180-157)=23 degrees at my
location FN20hd=75W 40N.

Most of DE is north of 50N, of course.

73 de Maggie K3XS

--
-----/___.   _)   Margaret Stephanie Leber    / "The art of progress  /
----/(, /|  /| http://voicenet.com/~maggie   / consists of preserving/
---/   / | / |  _   _   _    `  _AOPA 925383/ order amid change and /
--/ ) /  |/  |_(_(_(_/_(_/__(__(/_  FN20hd / change amid order."   /
-/ (_/   '  K3XS  .-/ .-/    ARRL 39280   /___ --A.N.Whitehead ___/
/____ICQ 7161096_(_/_(_/__AMSAT 32844____/ <maggie@voicenet.com>


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