[amsat-bb] Re: How to calibrate the azimuth angle?
kc6uqh at cox.net
Thu Dec 27 22:12:56 PST 2007
Instatrack will give you the azmuth and elevation of the Sun vs time. Use
GPS for time and You now have an accurate calibration.
----- Original Message -----
From: "Jeff Mock" <jeff at mock.com>
To: <amsat-bb at amsat.org>
Sent: Thursday, December 27, 2007 5:15 PM
Subject: [amsat-bb] Re: How to calibrate the azimuth angle?
> Well, now that everyone has trashed compasses. Here's the compass that
> I really really like:
> Click on "precision instruments", it's the Suunto Tandem. It's a
> compass and clinometer in a nice machined aluminum package. It has
> optical sites for both instruments that really improves accuracy (if you
> ask me). It's really well made and it's from Finland... If nothing
> else, you can walk around measuring the height of trees.
> Bruce Bostwick wrote:
>> 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
>>> your help!
>>> Best regards,
>>> Chiu-Teng Tsai
>> "On this one we'd like to think of ourselves collectively as 'da men',
>> sir." -- Toby Ziegler
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