[amsat-bb] Re: AO40 Info none AVAILABLE???

["Stacey E. Mills" <w4sm@xxxxxxxxxx>]

>No fresh info on AO40 pass-band or ALON/ALAT changes.
>Are we been kept in the DARK hi,or are the command team
>on vacation???

Often, when I think I'm in the dark,  I realize that my eyes are closed.  :-)
Please read the available information.   Here is part of my post from 
2002-09-25, including the M-blk.

>Therefore, we have terminated
>the station keeping magnetorque and will begin drifting past the sun.  At
>approximately ALON =330 we can begin lowering ALAT.
>
>
>M  QST AMSAT OSCAR-40                              2002 Sept 25
>                          ALON/ALAT = 53/30
>         ** ALON will decrease 20 degs/week due to M.E. **
>       ** Passbands off in ~7 days as solar angles worsen. **
>
>           The AO-40 team would like your telemetry files!
>Please "zip" compress your daily telemetry files and e-mail to:
>                        ao40-archive@amsat.org

The drift is proceeding exactly as planned and based on this information 
(the 20 degs/week is very accurate),  you can calculate ALON for any time 
after  9/25, as long as we continue drifting.  There is no reason to update 
the "M" block on a daily basis.   When ALON approaches 330, as indicated, 
we will begin lowering ALAT and slowly moving ALON back towards 0.  I've 
outlined this in several prior postings. I'll also post information when we 
get there.

>Looks like the ME has brought the ALON back to fair figures.
>Heard AO40 Friday PM MA20 with S7 signals.
>Saturday, AO40 was at 62k Km's,beacon well rx'd at 5Deg ele..
>very useable signal...
>Yep you guessed it,NO TRANSPONDER...

The beacon has a relatively high output power and the helix has side lobes 
that give good signals at  some higher squints.  This does not mean that 
the receive antennas and  passband downlink would be adequate for routine 
use.  If you calculate the ALON and squint when MA = 20, as you mention 
above for example, you'll see that it is quite high and receive antenna 
function would not be good for passband use.

Also as noted in the M-blk, the solar angle is increasing and is about to 
approach 45 degs when we will lose sensor lock.  The passbands will be 
turned off within the next day or so until we pass through this phase and 
solar angles improve.   We should be able to turn them back on about 
October 15th, with modified MA on/off times to account for the different ALON.




-- 
  _______________________________________________________________________
  Stacey E. Mills, W4SM    WWW:    http://www.cstone.net/~w4sm/ham1.html
   Charlottesville, VA     PGP key: http://www.cstone.net/~w4sm/key
  _______________________________________________________________________

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