[OSM-talk] fwd: Two thirds of mobile users want driving ANDwalking navigation

ce-test, qualified testing bv - Gert Gremmen g.gremmen at cetest.nl
Tue Feb 16 18:44:14 GMT 2010

No it ain't correct.
Satellite signals are blocked by conductive materials
such as metals, and to a limited extend by materials
containing humidity (= limited conductivity) such as leaves
and possibly concrete.
Due to their high frequency GPS signal tend to behave like light,
meaning that when there is metal in the line of sight between
GPS and satellite, there is decreased reception quality.
Most satellites can be seen (in west Europe and USA) in the southern
direction, and an uncovered horizon will give better signals.

Gert Gremmen

-----Oorspronkelijk bericht-----
Van: talk-bounces at openstreetmap.org
[mailto:talk-bounces at openstreetmap.org] Namens Dave F.
Verzonden: dinsdag 16 februari 2010 18:46
Aan: John Smith
CC: OpenStreetMap talk mailing list
Onderwerp: Re: [OSM-talk] fwd: Two thirds of mobile users want driving
ANDwalking navigation

John Smith wrote:
> On 17 February 2010 01:40, John F. Eldredge <john at jfeldredge.com>
>> Frequently you can't get a position fix at all, if the building has
much metal in its structure.  I can't get a position fix from inside my
house unless I am near a south-facing window, probably due to a
metallic-foil vapor barrier in the attic.
> It has little to do with the material it's made of, it's all about how
> much mass an object has, the more mass the more it will absorb RF.
Is this correct?

I assumed the reason I had trouble getting reception on board trains 
because of what their roofs were screened with. 
I can't believe they'd put much mass up there.

Dave F.

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