Problems with a compass when the GPS dies.

[Guest Krepism]

I tell you guys, sometimes it does not pay to be so adventurous. I just got back from trying to find the "west of IPP" and "Topaz Solitude" in Utah. Did not find either of them. I perfer to use just my GPS and compass to find the cache, but this time it all most got me in trouble. We set out at 10:00 this morning, the gps said it was 110 miles from our house, we did not get to the general area untill 3:00. Partly due to great scenery, but I also went in the Wrong way. I added about 100 miles of very bad and remote miles to our trip. We got to within 2.3 miles when I noticed we were running low on fuel. We stopped to address the area when to GPS lost all signals and would not come back (who knows why). I thought no problem I will just use my compass, well it seems that because of a strange force nature (i think it was from all the metals in the ground), that my compass would not lock in. It would just stray back and forth. Knowing that I did not have enough fuel to go back the way I came, we used our best guess and a few topo maps to pick a direction. Anyway, with about 2 gallons of fuel left we finally made it to a gas station

(the only one within 50 miles or so)

 

To the Point: Does any one know why a compass would just stray back and forth? It would never stay still, it would swing almost 360 degrees in every direction. When I got home it worked just fine. My GPS came back on about half way back, so we were able to adjust accordingly, but thank goodness we were already heading the correct direction.( Thank you Boy Scouts)

[Guest ScottJ]

You might have been very close to a lode of iron ore, or something similarly ferromagnetic like lodestone.

 

Machinery (even cars) can sometimes have the same effect on some compasses.

 

Scott

[Guest Steve D]

Alien spacecraft and magneto-electric confusion rays ....

 

:-)

[Guest fryed]

I like the alien explanation better. It would also explain why the GPS lost track of the satellites. Did you happen to notice any lost time during this period? Maybe a small sore at the base of your neck? Or an 80ft antennae coming out of your butt? Just trying to help.

[Guest Krepism]

Now that you mention it, my butt is a little soar. Does anyone know if they make a compass that would not be affected by high level of iron? This was a heavy minnning area at one time. So I guess that could have been the reason.

[Guest BigFig]

Aircraft use a gyroscopic compass to get

around the magnetic problem. I've never heard of a "portable" gyroscopic compass though and you'd probably have to lug around a car battery to make it work.

 

If you had a sextant and it was close to

high noon ....

 

If you are in hilly terrain and have plotted the coordinates on the map, you could have probably navigated to it by terrain association - without a compass.

[Guest peter]

Reminds me of my first hike after buying a new Suunto compass. We stopped for a rest and I took out the compass for its first use and couldn't seem to get the map and compass oriented properly. I was getting a little annoyed with the thing, but then we left the rest stop and a few feet further there was a large pile of rubble and the entrance to an old iron mine.

Any magnetic compass will be affected by local magnetic fields, but of course the motion-based "compass" of a GPS is not affected and gyroscopic compasses are also immune. I wouldn't recommend a gyro for casual hiking use though.

[Guest daviskw]

Just an obvious question, were you using your hand held compass in the car? If so that was the problem, will not work. It sounded like you were in your account. If not then I agree with Steve Aliens!!

[Guest Krepism]

Yes, it was a hand held, but I got out of the Jeep and walked some 30 feet away. Just another reason to carry Topo Maps!

[Guest Mike_Teague]

gyro compasses are affected by precession.. even on an aircraft, they need to be manually reset in reference to a magnetic compass every half hour or so -- they drift if left alone... higher-tech type gyro systems update themselves automatically by using the magnetic field as well..

 

the reason aircraft use gyros are because they are stable and do not lag/lead in turns, dont bounce around in turbulence, etc. etc.