[at-l] GPS questions

[wdlists at optonline.net (Walter Daniels)]

> >
> They'll all do that.  Just be forewarned that USGS maps 
> aren't the most 
> accurate things in the world, IMHO.
> 
They are good to about +-40 feet.

> Yes,  they all do altitude these days, but you need to have decent 
> reception to get altitude information from the sats 
> (basically, you need 
> one additional sat "locked on" to get the 3-D fix).
You need 4 satellites to get altitude information. How good it is depends on
how high in the sky they are. As I said before, consider 100ft good.

ight instead of (or in addition to) GPS.   
> 
> >cloudy weather? I don't need road maps and fishing info, but 
> do I need 
> >to buy
> >
> Cloudy weather is fine... any weather is fine.   A heavy tree canopy 
> will stop GPS signals though.
> 
I have almost never lost signal due to tree canopy even in heavy hemlock
groves. Where you lose signals is next to cliffs or in deep V shaped
valleys.

> 
> - I've never found a hiker-friendly GPS that is actually 
> useful enough 
> to leave powered on and have it record a track without fiddling with 
> it's orientation.  It seems like these little things are made 
> to be hand 
> held and not hung around your neck (which probably cuts your sky 
> coverage in half at least).    
> 
> 

That?s what external antennas are for. My pack has a slot at the top for a
drinking tube. I insert a long stick down behind the water bag with a metal
plate at the top that goes above my head. My antenna has a magnet in its
base so it just sticks on the plate. The GPS lives in a small pouch attached
to the sturnum strap until I want to look at it or record a waypoint. You
will want a GPS that beeps when it has problems like lost signal or low
battery when you aren't holding and looking at it constantly.

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