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Re: Now HERE is a stupid question...



Tim,

At 03:00 AM 12/26/1999 -0500, Timothy S. Zibrat wrote:
>When I align my antennas, do I use magnetic north or true north?  If the
>answer is true north, how do I find my "offset value" to add or subtract
>from magnetic north?  Is there any offset for elevation?
>
>The point being, (other than the obvious being able to point my antennas at
>the darn satellite) I want to automate my system eventually, and I was
>wondering what the satellite tracking programs use.

You have gotten a few answers to a good question.  If you have a prediction 
package running, there is a good way to determine true north, (which you 
should use,) by determining the exact time of sunrise and sunset for your 
location.

WINORBIT 3.5, available from http://www.amsat.org will show you these times.

Once you have both times, determine the minute that is exactly between 
these two times, and you will know the exact time of solar noon for your 
location.  A shadow from a perfectly vertical object will cast a shadow 
exactly north at this time.

I have used 3 sticks with flags on them to create a line on the ground at 
my location.  Push the first stick in the ground, and put the second in the 
ground in the shadow of the first, and repeat with the third.

There are many tracking packages available on the market.  Several are 
available from AMSAT.  I think your choice will be made based on what level 
of automation you desire.  Some will tune Doppler AND point the antennas, 
others will not.  Tell us a little more about your equipment, and what you 
hope to accomplish.

I use The Station software, which makes Doppler tuning of the FT847 a piece 
of cake.  I registered my copy with Martha at AMSAT.

Happy New Year!

Mike


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