[amsat-bb] Re: Adjusting true north for azimuth rotator.

Greg D. ko6th_greg at hotmail.com
Sat Sep 3 17:34:55 PDT 2011

> From: domenico.i8cvs at tin.it
> To: rhyolite at nettally.com; amsat-bb at amsat.org
> Date: Sun, 4 Sep 2011 01:24:18 +0200
> Subject: [amsat-bb] Re: Adjusting true north for azimuth rotator.
> ----- Original Message ----- 
> From: "Joe Leikhim" <rhyolite at nettally.com>
> To: <amsat-bb at amsat.org>
> Sent: Saturday, September 03, 2011 10:42 PM
> Subject: [amsat-bb] Adjusting true north for azimuth rotator.
> > I am planning to install my G5400 rotator inside a tower having a welded 
> > rotator shelf. The tower is not installed yet and will have one face 
> > against the side of my house which is positioned about 28 degrees 
> > northeast (Per Google Earth).
> > 
> > I assume when I drill the rotator shelf, I can adjust for the gross 28 
> > degree offset of the tower. However how important is it to do this at 
> > all? Does the rotator have to be installed exactly toward true north or 
> > can I make up the difference when clamping down the antenna mast 
> > assuming the antenna is oriented true north?  Note I will be using a 
> > Trakbox and need the ADC to center on true north.
> > 
> > Secondly does anyone know if the ruler function in Google Earth points 
> > true north? It seems pretty handy that a fire plug in front of a 
> > neighbors house is at about north point.
> > 
> > -- 
> > Joe Leikhim
> > 
> > Leikhim and Associates
> > Communications Consultants
> > Oviedo, Florida
> > 
> > www.Leikhim.com
> > 
> > JLeikhim at Leikhim.com
> > 
> > 407-982-0446
> Hi Joe ,
> Your rotator have to be installed exactly toward true north.
> First of all using the traching program rotate manually your
> azimuth rotator until its pointer schowes exacly the azimuth
> and elevation of the Sun at a selected time preferably near
> noon.
> Now quicly clamp down the antenna rotator to the mast
> until the antennas are aligned exacly toward the Sun.
> Now your Antenna system is calibrated as well toward the
> North.
> 73" de
> i8CVS Domenico

I don't think it matters at all which orientation the Azimuth rotor itself is mounted.  Bolt it onto the tower frame what ever way it wants to be, spin the motor around to zero degrees, and then mount the antenna to the shaft so that the antenna points North.  What I do then is what Domenico recommends - use the Sun to fine tune the alignment.  Most satellite tracking programs will tell you where the Sun is, or you can go on line to places like Heavens Above to find it.  Tell the rotor to go to that heading, then align the antenna so that the it points at the Sun.  I use the shadow so I don't have to look into the Sun itself.  Done.

Greg  KO6TH

> _______________________________________________
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

More information about the AMSAT-BB mailing list