[TowerTalk] RE: Compass question

[Michael Tope]

Jim, et al:

>From the looks of it, the Garmin unit is nothing more
than standard GPS handheld with a built-in flux gate
compass (note that compass accuracy degrades
significantly in extreme northern and southern
latitudes suggesting a dependence on the earth's
magnetic field):

http://www.garmin.com/products/etrexsummit/spec.html

The advantage appears to be that unit automatically
performs the "true north" correction based upon the
GPS position data. Compass accuracy is specified to
depend upon calibration, so you probably have to
update the coordinates for the magnetic north pole
occasionally. Seems like a good idea (one less thing
to think about on the tower).

73 de Mike, W4EF....................




> The GPS receiver doesn't measure any bearings... it measures distance to
the
> satellites, and does "tri-lateration" not "tri-angulation"