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GPS Setup – Calibrating The Electronic Compass
By Blake Miller Recently I held a GPS navigation seminar at a Sportsman’s show in Central Oregon. At one point during the seminar one man described the inaccuracy of his GPS and asked what he could do about it. He was frustrated that on several occasions while returning to camp the GPS compass arrow (while in the “Find,” “Where to” mode) was providing unreliable information. He’d arrive in camp and the receiver would direct him in a new direction and distance. As he related his story, I noticed that several other attendees nodded in agreement that they too had the same problem. I asked the fellow if he had ever calibrated the electronic compass. “Yes, when I first got the GPS,” was his reply. When I explained that the electronic compass should be calibrated after EVERY battery change, the group’s response was one of surprise. That’s right, every time you replace those batteries, the electronic compass needs calibration. Over years of using different GPS receivers, I have found that those with electronic compasses really drain the charge quickly.
Most of the top of the line GPS receivers come with an electronic
compass. The electronic compass moves and operates seemingly like a
traditional magnetic compass. This is different than the original
compass page on older units like the Magellan 315, Garmin 12, Yellow
eTrek (the $100 model) and
early DeLorme. These units will provide compass information but you
must move forward in the direction of the destination to see the
display’s arrow shift. Here is an example of how to calibrate the electronic compass of the Garmin Map60CSx. First select “compass page.” You should see this screen.
I recommend verifying the GPS receiver’s direction information with a quality magnetic compass such as the Silva Ranger (515CL), Brunton 8010G, or the Suunto M3 before going further. Don’t forget to adjust the magnetic compass for declination. For more information on magnetic declination read my article at Magnetic Declination
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