I resisted the GPS technology for a long long time like this year. I used to use a Thomas Guide or similar map book and a cheap Cammenga compass that I mounted with double sided tape. I was the master of land navagation, map reading and finding places that others could not find, even wrong addresses. I could find a dimming glow-stick on a rainy moonless night with just a topographic map and compass/azimuth. But work provided us with GPS units and I was hooked, I had to buy one for my own car. The unfortunate thing about GPS is that you don't learn a new city or town the way you do with a map. GPS units are as cheap as $79 nowadays, so for me the days of shooting azimuths, compass-to-cheek and center-hold method are over. The other function I like is that it will locate any Chevron station close to me in case I need gas, I only fill with Chevron.

 

Got my "Analog GPS" at Pep Boys for ~$15. Brand name is Airguide (?). It has magnetic field compensation and can mount about anywhere (see Gallery). More than good enough for use when driving. If you're shooting azimuths, you shouldn't be driving, too! Note: When setting a car compass of any kind, make sure the engine is running! Electro-magnetic radiation, ya know.

 

I have a Whistler radar detector that has a built-in digital compass. It also happens to be a very good radar detector, LOL. My '05 MCS is brand new to me, so I haven't gotten around to mounting it yet. (First post here, BTW!) ...It has a calibration procedure, once a mounting location is found, and is very accurate (as checked against a Garmin), with no interference issues at all. I have never been able to find a mechanical compass--at any (reasonable) price--to work in any modern car. I guess the electrical systems cause too much shielding and EMF. The digital stick-on/ribbon/box cheapie compass, mentioned above, works fine...for about two weeks, until the button-battery dies (maybe less in the winter), and once mounted, is a PITA to replace.