[Antennas] Finding True North (simplest method)

Sat, 23 Feb 2002 15:02:49 -0000

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Chris BONDE
> Sent: Saturday, February 23, 2002 5:18 AM
> To: [email protected]
> Cc: [email protected]
> Subject: RE: [Antennas] Finding True North (simplest method)
> 
> 
> Mike:
> I agree fully with you.  But then I would question  would not 
> other things come into play for satellite, the moving ones, 
> contacts?  I thought that if a person was going to the effort 
> of contacting a satellite they would set the dish with a GPS 
> satellite.

Once you have your system properly aligned, it will track the
moving satellites just fine.  If you don't have it aligned right,
your success you be determined by how close you get it.

There are any number of ways to fine-tune a system.  For me, I
tell it to track the sun, then I get up on the tower and adjust
the system for a clean  shadow on the ground.  If you have it 
mis-aligned you get a broad shadow, and when it is aligned you 
see just one shadow for all elements.  

XXX---XXX = misaligned horizontally

  X       X
  X-----X = misaligned vertically
  X       X

  X-----X = correctly aligned.

(hope this doesn't get mis-aligned in the mail.  <grin> )

But the coarse alignment is usually set to true or grid north.  
And I have found the easiest way to do this, no tools involved 
at all, (compass, GPS, etc) is to point it at the north star.
Most satellite operators know at least the degree, if not the
complete number, for their lat/lon.  You turn the rotors for
your latitude, and true-north longitude, then go out and slip
your antennae till they point at the north star.  Just sight
down the boom, you can get it amazingly close.

Of course, there are any number of ways to complicate doing
an alignment.  Engineers and techies love to play.  I am not
an engineer, I just wanted to get on the satellite.  To date, 
 I have 157 grids worked, 123 confirmed, 40 states worked 
and 39 confirmed,  11 countries worked and 6 confirmed.  
Most of them are on AO-40, S-band downlink.  So I guess 
this method works good enough.

The question of finding true-north....  (the original question)
well, like I said... with the north-star just 0.51 deg from true, 
how much closer do even us S-banders need it???

Mike.