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RE: Now HERE is a stupid question...





> -----Original Message-----
> From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
> Behalf Of Timothy S. Zibrat
> Sent: Sunday, December 26, 1999 8:01 AM
> To: AMSAT BBS
> Subject: [amsat-bb] Now HERE is a stupid question...
> 
> 
> Fellow Hams:
> 
> I'm about to install my first az/el satellite antenna system 
> (yeah!).  The stupid question is:
> 
> When I align my antennas, do I use magnetic north or true 
> north?  

True North.  Look at any Military map, on the bottom you will
find something called a Declination Diagram.  This indicates the
difference between True North, Grid North, and Magnetic North.
(This shoots the fellow who said ALL maps are True North in 
the foot.)  The map is set to Grid North, which is usually very
near True north.  True North is usually also Grid North for the
center map of a group of maps.  As you go from map sheet to
map sheet, the grid remains the same, but True North shifts
left or right very slightly.  The Declination Diagram also changes
with time, because of the instability of the rotation of the
earth, but it is a very gradual change.  Because of this, use
the newest map you can find.

I can only give you the exact data for El Paso, TX.  Grid
North is set to 0 deg.  True North is + 0.52 deg.  Magnetic
North is -12.5 deg.  Oh, I also have one map for Huntsville, AL.,
so if you live there, I can supply the data.

Bottom line, the fellow who said aim for the north star is
correct.  The error is in the order of 1/2 a degree.  That
should be close enough for you.  The slop in your rotor will
most likely be more than that.  BTW, can you tell that I
love maps?

Y-all have a great day.


Vy73,  Mike.   KD9KC    MARS: AAV6EV
kd9kc@elp.rr.com  -  kd9kc@amsat.org
Home page: http://www.qsl.net/kd9kc/

El Paso, where the sun spends the winter.
  

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