[amsat-bb] Re: AO-40 - Need help please

["Dave Bourne" <dave@xxxxxxxxxxxxxxxxxx>]

Hi Mike,

   It sounds like you are  going through the same learning curve that I just
went through (actually I'm still learning the ropes!) about AO-40. Here are
my answers to your questions:

1. Squint Angle - Your NOVA software will predict the "squint angle" based
on the keps and ALAT  and ALON values. You can get current ALON and ALAT
from the telemetry that you can receive from AO-40 or you can get
semi-current values from the Amsat DL homepage at
http://www.amsat-dl.org/journal/adlj-p3d.htm. A low value for squint angle
at your QTH is what you want to look for. They say a squint angle of less
than 30 is "useable" but I have found that I need a squint in the "teens" or
better for good SSB reception for AO-40. ALON and ALOT refer to the attitude
of the downlink antennas on the spacecraft with respect to
the earth. If the antennas aren't pointed your way you don't receive a good
downlink signal.

2. MA - MA stands "Mean Anomoly" - There is a "glossary" of terms that
describes what MA is at the Amsat DL web site. Your NOVA software will tell
you what the MA is at any point in time. Also the
telemetry will tell you what the MA is. The beacon is shut off during part
of the satellites orbit. The Amsat DL homepage will show the current
schedule.

I am using the AO40Rcv soundcard telemetry decoder program and it works
well. it is available for download at the Amsat DL site.

I am by no means an expert but I have managed to get my station up and
running and I have made a few contacts on AO-40. I am using a IC-910H
transceiver. Uplink is a linear 8 element yagi and downlink
is a Prime Star type dish with a homebrew helical feed and a Transystems
downconverter.

Dave Bourne WB8TMP
Corona, CA

"Michael P. Olbrisch" wrote:

  Howdy Y-all,

          Took a sick day today.  Fall cold I guess.  Too sick to
  spread it around work, but not sick enough to lay in bed.  So
  I am pulling cables and getting my AO-40 S-band system
  ready.

          Here is what I (soon I hope) need help on.  I am using
  NOVA 2.1o, Yaesu G-5400B, 26"x40" parabolic section dish,
  and AIDC 3733 converter.

  1.  I know what squint is, but I don't know how to predict it.
  Seems this might be important.

  2.  MA.  I know AO-40 is on at some MA, and off at some MA.
  That is the sum-total of what I know about MA.

  3.  I think I am going to need to learn about ALAT and ALON.
  Something to do with the way the satellite faces.  How do I
  predict it?

  4.  Somehow, I need to let NOVA know what all of this stuff is I
  think.  I know where to add ALAT and ALON, but the rest of it???
  and I seem to remember that some operators had to put this in
  some strange format to get it to work.  Anyone else using NOVA?

  5.  What other things do I not know that are waiting to bite me?

  I would appreciate any reference to web sites that would help
  get me on the road for this.  Otherwise, this could get real
  disappointing real fast.

  Thanks.  Y-all have a great day.

  Vy73,  Mike.   KD9KC    MARS: AAV6EV

  My E-mail address: mailto:kd9kc@elp.rr.com
  Ham Radio page: http://www.qsl.net/kd9kc/
  Gun page: http://home.elp.rr.com/elpasochl/
  Dog page: http://www.geocities.com/heartland/estates/4174

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