Some days my GPS is just pants.

[+Bland by name]

Today I did a circular walk around a reservoir (found 6 of 7 caches). Flat ground, no trees should be perfect but my GPS was bouncing around like crazy. It’s an Oregon 400t and usually performs well. Could the heavy, low cloud be causing grief, there has to be several tons of water between me and the satellites?

[+Lost in Space]

Could the heavy, low cloud be causing grief, there has to be several tons of water between me and the satellites?

 

Ever tried to watch Sky TV in a heavy downpour?

A home Sky dish is a high gain directional antenna pointed at a stationary object.

 

What chance does a tiny, non directional, antenna have in such occluded conditions?

[+Pharisee]

Today I did a circular walk around a reservoir (found 6 of 7 caches). Flat ground, no trees should be perfect but my GPS was bouncing around like crazy. It’s an Oregon 400t and usually performs well. Could the heavy, low cloud be causing grief, there has to be several tons of water between me and the satellites?

Does that model have an electronic compass?.... If it does, then turn it off unless you really need to know which way is North. I use a 60CSx and I've never noticed a degradation in signal when it's been cloudy. It performs well in pouring rain so I suspect the odd cloud isn't going to make much difference. Having the electronic compass turned on, however, renders it pretty much useless with the 'arrow' swinging about wildly.

[+Kryten]

Could the heavy, low cloud be causing grief, there has to be several tons of water between me and the satellites?

 

Ever tried to watch Sky TV in a heavy downpour?

A home Sky dish is a high gain directional antenna pointed at a stationary object.

 

What chance does a tiny, non directional, antenna have in such occluded conditions?

 

GPS operates in a frequency band deliberately chosen because it is almost entirely unaffected by atmospheric conditions. The most lilely explanations are, flat batteries, poor constellation (all satellites in the same part of the sky with big gaps elsewhere) or signal reflections from the reservoir surface.

Edited July 30, 2009 by McKryton

[+careygang]

When I have those sort of issues with my Vista HCx, I usually find a Compass Calibration sorts it out.

[+HazelS]

Yep - turn off the compass - you don't need it!!!

[GerritS]

Yep - turn off the compass - you don't need it!!!

 

Havel Have to disagree! I like the compass... Although never thought about it afftecting the GPS, will have to effect some trials, whislt caching of course

 

Also I do believe thick cloud cover does make a diffrence I notice it every time on my N95. Although the frequency may have been choosen to minumise the disruption, it still can cause problems.

[+The Blorenges]

The electronic compass works fine. My Etrex Vista has one as does MrsB's Colorado*. You do need to know how to use it though! It does need calibrating after you change the batteries and you do need to hold the unit horizontally and not vertically. You will get a warning message on the screen if you don't and the arrow will swing around. I did have some problems with the Colorado in Cornwall recently in a massive granite rock formation. I imagine a normal compass may have played up too.

If you are having problems with it take a couple of moments to re-calibrate it. Don't stand beside your car while you do it. It's a magnetic compass after all!

If you turn the compass off you are then using the GPS signal for direction and the compass then only works if you are moving. If you stop, so does the arrow!

The electronic compass does increase battery consumption but I've never noticed that being a significant problem.

 

* The earlier software on the Colorado did seem to have some problems with the compass and other things not working well.

 

Chris (MrB)

[+Bland by name]

I agree totally with the above, a GPS receiver has no way of knowing direction; it can only extrapolate it from previous movement.

 

I got the Oregon specifically as it has the compass. I don’t see how else you could use your GPS to point to a cache, waypoint or whatever. You do need to know how it works and how to use it to get best out of it.

 

I still think heavy clouds must make a difference – GPS does not work underwater the problem I had with jumping around was the position, not the bearing.

[+MacFlash]

I agree totally with the above, a GPS receiver has no way of knowing direction; it can only extrapolate it from previous movement.

 

I got the Oregon specifically as it has the compass. I don’t see how else you could use your GPS to point to a cache, waypoint or whatever. You do need to know how it works and how to use it to get best out of it.

 

I still think heavy clouds must make a difference – GPS does not work underwater the problem I had with jumping around was the position, not the bearing.

 

Let's see- I bought a Legend HCx and a 10 dollar liquid filled magnetic compass.- Never needs calibrating- works even when the GPS batteries are dead, which is a real advantage if you are lost.

 

Also cloud cover does not appreciably affect GPS- as they said above the frequency range was chosen just because of that- their are lots of other reasons why you could be having trouble including multipath off the lake.

Edited August 6, 2009 by MacFlash