GPS: Magnetic mount effect on receiver

[Mudy_ovl]

I have an DeLorme Earthmate GPS receiver. This weekend I decided to place the receiver on my roof through my sunroof. I was able to improve my satellite reception a lot, especially through thick forest. My question is, what effect would a homemade magnetic mount have on the GPS receiver if any? I am just a lowly Mech Eng and do not have a lot of experience in the "unseen" sciences . Any input would be appreciated.
Thanks,
Chris D.

PS. I do plan to cover the receiver to make it pretty much water proof.

 

[dormobiledisco]

I've got a Holux mouse GPS, which is basically the same as the Earthmate, but a different manuf. and waterproof and magnetic. It seems to have five tiny, but powerful, disc-shaped magnets on the bottom, covered by a seemingly-metal sheet. It's also waterproof, though not sure how they did that.

I don't know if it's possible to do with the Earthmate...worth a try. If not, you can get the Holux ones on eBay for about $40-50, incl. shipping.

 

[p m]

Chris, magnetic mount should have no effect on GPS operation.
Your best bet is to use a remote-mounted antenna.

 

[D Chapman]

Chris, magnetic mount should have no effect on GPS operation.
Your best bet is to use a remote-mounted antenna.

Is that avaliable for DeLorme??

 

[Mudy_ovl]

Thanks for all the input. Looks like I'll be making a base this weekend.

Chris D.

 

[calebsg]

GPS systems locate at least 3 GPS satellites and then do some nasty geometry on them to determine position so magnetics should have no effect on the reading. What you need to aim for is the clearest view of the sky possible for the antenna which will give your GPS more to work with.

Caleb

 

[p m]

GPS systems locate at least 3 GPS satellites and then do some nasty geometry on them to determine position so magnetics should have no effect on the reading. Caleb

Actually, they need 4 for 3D navigation, but 3 may give a ballpark lat/lon reading. Nasty geometry is matrix pseudoinversion
Dan - I don't know anything about DeLorme units; many Garmin units like II to V+ series have BNC antenna connector. Any non-powered GPS antenna can be used; don't remember if Garmin has a provision for an antenna power. In any case, I've used several antennas from Synergy Systems
and they worked great. (It helps that the company's located 3 miles from where I work).

 

[davidz]

my external gps anntenna came with a magnet in it,
http://www.gpscity.com/cat-antennas.htm

 

[calebsg]

Actually, they need 4 for 3D navigation, but 3 may give a ballpark lat/lon reading. Nasty geometry is matrix pseudoinversion

Yeah, 3 for location, 4 for location + altitude IIRC.

Caleb

 

[parthog]

Dan - I don't know anything about DeLorme units; many Garmin units like II to V+ series have BNC antenna connector. Any non-powered GPS antenna can be used; don't remember if Garmin has a provision for an antenna power

I use a Garmin powered external antenna with my Garmin, it comes with two mounts, one of them magnetic.

Electrical noise and other antennas can affect reception, as can metal and even metallic paint, but the magnets do not.

- Jeff Miller

 

[Mudy_ovl]

Thanks again for the added info. The external mount magnetic base antennas look great, but my Earthmate plugs directly into and is powered by a USB port. I'd prefer not to buy a connector adapter or gps card just to use these external antennas. I will just make a bracket with a magnetic base and waterproof the antenna.

Chris