# [amsat-bb] Re: How to calibrate the azimuth angle?

Bruce Bostwick lihan161051 at sbcglobal.net
Thu Dec 27 15:44:24 PST 2007

```A compass won't give you accurate azimuth unless you know for sure
that you're not near any large masses of metal, and even then, you
will need to know your local magnetic deviation.  I tried to use a
compass to align a satellite dish once, and it put me so far off on
the azimuth I never did find the satellite that way, even taking
magnetic deviation into account.  You might have better luck where you
are, but it's a lot of work to do it that way even if it does work.

A much easier solution is to look at your location in Google Earth and
find the orientation of a nearby road, and use that as your azimuth
reference.  That automatically gets you azimuth relative to true
north, which makes the job considerably simpler.  If you don't have
nearby roads that are straight enough to be useful, find a distant
visible landmark (like a radio tower) and determine what its azimuth
is from your location, then use it as a reference point and find your
desired azimuth from there.  (A long time ago, I worked out a formula
for determining the bearing to a distant landmark using only the
latitude and longitude of it and the observing location.  It's on
paper somewhere, unfortunately I don't know where and I'd have to redo
the math at this point.  But if you're interested, let me know.  It's
not too difficult to measure the orientation of the baseline between
the two using Google Earth though ..)

On Dec 26, 2007, at 11:08 PM, Chiu-Teng Tsai wrote:

> Dear all,
>
>  I am Chiu-Teng Tsai (BM6ERA) from Taiwan. Now we are building a
> mobile ground station. One of our problem is how to calibrate the
> azimuth angle. Use compass only, or any better solution? Thanks for
>
> Best regards,
>
> Chiu-Teng Tsai

"On this one we'd like to think of ourselves collectively as 'da men',
sir." -- Toby Ziegler

```