[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

RE: AO-40: transponder off!!



I would think that if a tracking program is able to correctly predict
the location of a satellite, figuring out the squint angle is a no-brainer.
No model required, just simple trigonometry.

So, are you saying that SatTrack's orbital calculation model is inaccurate?

SatTrack seems to work for me in the sense that when I point my
antenna where it says, I hear the satellite.  I have also
been playing with a Windows program called "WinOrbit", but
it seems to be way off in predicting AO40's position.

Actually, SatTRack's squint angles have not always correlated
that well with my reception quality, but I had assumed it
was due to poor or outdated attitude estimates.

Can you explain what you mean by "LEO model"?  I do not
understand your point about TLE vs. LEO.

Thanks,

Doug
NA1DB


At 08:32 PM 5/30/01 , Alan K. Adamson wrote:
>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>
>
>
>----
>Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>
>----
>Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org 

----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home