At 04:11 PM 12/28/2007, Bruce Bostwick wrote:
Not meaning to trash compasses, just have had some less than satisfying experiences using them to align antennas on satellites due to the number of sources of measurement errors that have to be accounted for. I've used some very good compasses (my favorites are the ones from Morin that allow sighting across the compass to get a magnetic bearing of a landmark on the horizon :) but getting accurate true north out of even a good magnetic compass is a lot of work ..
Well, I rely on magnetic compasses not to get lost, and use maps that are most often aligned to grid North. I have managed accuracy far better than that to aim most antennas (maybe a high gain 10 GHz dish might have issues, but anything else I could get it near enough). Mind you, there were a LOT of other good suggestions here as well.
Like any tool, it comes down to practice in using it. Avoiding magnetic interference to compasses is akin to avoiding QRM when trying to work weak signals. :)
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