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Re: ao40 squint



The antennas on AO-40 are on the opposite side of the Z-axis from AO-10.  
Since WinOrbit is rather old (but still useful) the attitude assumes 
AO-10/13 type equipment.

So the attitude you are getting is 180 degrees off.

This can be worked around by modifying the ALON to (344 + 180) - 360 = 164 
degrees  (If in the future the ALON+180 is less than 360, don't subtract the 
360)
Leave ALAT at 1.

The expiration date has nothing to do with it-- put it at a suitable enough 
date in the future.

I just had to do that myself as I was getting equipment together for field 
day..  Wow, a properly tuned patch feed from W0LMD's site is fairly 
incredible compared to everything else I tried.  I'll have to write the BB 
with the minor modifications I did to make it tune better on the network 
analyzer.

Fred Spinner W0FMS

>From: James Cizek <jcizek@yuma.acns.ColoState.EDU>
>To: amsat-bb@AMSAT.Org
>Subject: [amsat-bb] ao40 squint
>Date: Mon, 16 Jun 2003 14:39:00 -0600 (MDT)
>
>   Hi all,
>
>   A quick question.  I am playing with WinOrbit right now
>   (usually use sattrack under linux) as a windows based
>   tracker that will run my Prarie digital board I use to
>   aim everything.  The program tracks the sats fine but the
>   squint calcs seem way off.  For todays ao40 pass I am using
>   ALAT of 1 and ALON of 344 in my AO40.ATT file (contents shown below)
>   and am getting a squint of 161 degrees at MA 30 increasing to 175 
>degrees
>   midway and reducing to 166 degrees at MA 130.
>   Am I missing something simple here?  The time is set right and accurate
>   (box is on NTP) and the qth is correct (to as good as GPS can do) also.
>   I read that the squint was supposed to be closer to 30 degrees and under
>   during this MA period (passbands on).  Is the program right or did I
>   misread something?
>
>   Contents of my ao40.att file in the winorb36/database/sat directory:
>
>; Remove the ";" from the following line if you have updated information
>[Attitude]
>Alon=344
>Alat=1
>Expiration=30503.1000000
>
>
>   Am I missing a minus sign on one of the numbers? Is the (way into the
>   future) expiration too far out?
>   Thanks for any suggestions!!

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