Desperado:
do you thing maybe the have a force field around the base so bad people can't use a GPS guided bomb

...Pulls out tin foil hat...

Heck I don't know, but I am very lucky I had someone with me who knew where we were going. Would have sucked to end up in an artillery impact zone by accident.

All of the deviations were either 300 meters or 1000 meters. Doesn't sound like much until you take the wrong road and wind up DOWNRANGE.

Removes tin hat....

Get good at map orienteering (map reading skills). Practice compass navigation. Those are invaluable skills.

Use GPS together with paper charts. It gives a much better understanding of how you move in relation to your environment. (And when the batteries die, you'll have a pretty good idea of where you are).

Make sure the datum of map and GPS are the same.

Use the waypoint functionality as you move along. Don't mark everything, but mark those spots which are handy to reach in a pinch (water, shelter) or constitutes important corners for your route (such as a bend to avoid nasty terrain).


If your map has UTM grid, choose MGRS coordinate for the GPS. It is the same grid as UTM, but you ignore the smaller numbers and the really big numbers are referenced to by alphabetic code which typically is written on the map. This code refers to the 100*100 kilometer square you'll find yourself in. So with a 100 meters accuracy, your only concern is to keep track of 3 digits (2 kilometer digits plus the 100 meter digit) in east and north direction, a total of 6 digits. A LOT more easy than all the digits of the full UTM system... 100 meters is plenty for outdoors navigation, and you won't be able to fix your position on the map any better than that in the field anyway.

The FAA routinely publishes areas where the signal is purposely degraded.

FL = Flight Level. Always add two zeros to altitudes, so FL400 = 40,000' MSL (mean sea level)

KEDW EDWARDS AFB

L0954/09 - NAV GPS IS UNRELIABLE (152100Z-2300Z, 162300Z-2359Z, 170001Z-0100Z, AND 171400Z-1600Z) AND MAY BE UNAVAILABLE W/IN A 344NM RADIUS OF N3556'52" W17734'35" NEAR BEATTY (BTY) VOR 218.3 RADIAL AT 65NM AT FL400 DECREASING IN AREA WITH DECREASE IN ALTITUDE TO 308NM RADIUS AT FL250, 228NM RADIUS AT 10000FT MSL AND 188NM RADIUS AT 4000FT AGL. THIS TEST IMPACT AREA ALSO EXTENDS INTO THE MEXICAN FIR. 15 SEP 21:00 2009 UNTIL 17 SEP 16:00 2009. CREATED: 14 SEP 16:16 2009

Good guess. But incorrect.

I lost the car BEFORE getting the GPS :-)

Returned to the road and wasn't real sure which way to turn. Did a little extra walking that day.

LOL! One of my brothers in northern Ontario used to paint his jeeps sunshine yellow (Tremclad), he said it was so he could find them when he was coming back out from fishing.

Another thing about all electronics is you should test them before leaving home. Especially if they were stored with the batteries in them. Corrosion is insidious.

I'd modify the statement to add INSPECT THE BATTERIES AND CONTACTS as well as testing. Any leakage must be dealt with quickly and further use should be done understanding that corrosion of contacts may cause problems.

Batteries don't leak as much as they used to but... all it takes is that one time when you really, really need the item to work...

Blake,

Tips for GPS users:

1. spare batteries.
2. Even so, carry a compass.
3. Understand how a GPS works so that you can use it. On mine, the compass only works while you are moving.

1. First learn navigation with map and compass.
2. Waypoints are free, use them.
3. Use the GPS sparingly, but carry spare batteries.

Use rechargeable batteries of the low self discharge (LSD) nimh (nikkel metal-hybride) type. Sanyo eneloop is the most recognized type and brand, but there are others.

Not only will they never leak - they also have much better performance than alkaline batteries (that WILL leak, sooner or later, no matter what the brand is). The low self discharge part means that they will loose charge when stored, but the rate is so slow that it's not an inconvenience - the battery will still be at 80% after 2 years. Here's a little to read on the matter: http://www.stefanv.com/electronics/sanyo_eneloop.html

Of course, the ultimate long storage battery is lithium primaries (1.6v), but they are so expensive you don't really want to use them. Makes excellent emergency backup, though.