----- Original Message ----- From: "Tony Langdon" vk3jed@gmail.com To: "Chiu-Teng Tsai" n2693415@mail.ncku.edu.tw; amsat-bb@amsat.org Sent: Thursday, December 27, 2007 3:30 AM Subject: [amsat-bb] Re: How to calibrate the azimuth angle?
At 04:08 PM 12/27/2007, Chiu-Teng Tsai wrote:
Dear all,
I am Chiu-Teng Tsai (BM6ERA) from Taiwan. Now we are building amobile ground station. One of our problem is how to calibrate the azimuth angle. Use compass only, or any better solution? Thanks for your help!
Azimuth is given in degrees from true North. A compass is fine, if you know the magnetic declination (i.e. the difference between true North and magnetic North) for your location. That information should be readily available on the Internet.
73 de VK3JED http://vkradio.com
If the declination is less than half of your antenna's 3 dB beamwidth, you can probably ignore it and just point to magnetic north. With a dish, it becomes significant, however.
Another tried and true method is to track the sun, and adjust your antenna mounts and rotor mount to cast the smallest shadow ("X") of your antennas on the ground, or sight thru the antenna boom ("boresight") while tracking the moon (DON'T look at the sun!).
George, KA3HSW