Cheap Easy improvement of GPS LOCK!... - Page 2

jpelzer · 07-20-2004, 08:12 PM

Quote: Originally Posted by jcdillin

I doubt it, it's more likely the ground plane effect, thats why xm or other sat radios have to be mounted at least 6 inches from your window to get a big enough ground plane to pick up the weak signal from space.

Ground plane effect is actually what I'm talking about. It is not an amplification, but actually a removal of interference (multipath interference, specifically). The signal level that a GPS displays is actually a signal-to-noise ratio, and by adding the ground plane, this ratio is improved.

That being said, your car is an excellent ground plane, even if you don't have your GPS on a piece of metal... There are two types of multipath that affect GPS: Multipath from the ground and multipath from above (buildings). There aren't antenna designs that help with the latter issue, but a ground plane helps with ground-reflections. Your car is a ground plane, even without the foil.

So I guess what I'm saying is that a ground plane can improve signal in handheld units (hiking for example) but is much less likely to cause noticable results with a car, since the car already is acting as a ground plane.

pip · 07-21-2004, 03:56 PM

Well, my car is mostly plastic (C5 Corvette), so I suspect a ground plane may help improve my lock then?

antimatter · 07-21-2004, 03:59 PM

Who else has done this.... does it work... Post!

judoGTI · 09-13-2004, 09:19 AM

*bump*

jpelzer · 09-13-2004, 09:43 AM

It works.

Some time after this discussion, I moved my gps to the skylight in the back of my car, so it was suspended in midair with no metal below it. I'd removed the magnet (magnets make me nervous with computers), and so it wasn't geting ANY signal lock.

I now have a 3" diameter piece of aluminum stuck below the receiver, and the lock is perfect. Aluminum foil would work just as well, just doesn't look as slick!

faichiu · 09-20-2004, 01:07 PM

I can't believe it. The refigirator magnet works for me!!! The GPS get lock quicker than before.

Quote: Originally Posted by daman10958

I was experimenting the other day on what I should do to mount My Earthmate because it was taking a while to get lock while in my car and I stumbled upon a solution that is both simple and cheap and really if you think about the physics makes some sense.

All I did is put a $2.00 refigirator magnet on the bottom of the GPS. it covered the bottom at about the size of the base and when I put it in the same spot that was getting (mediocre -> poor) signal reception it suddenly got a solid lock.

after I thought about it it is the same reason that they work better on the roof of your car. the reciver is designed to be on top of a ferrous ( including Iron) metal. Therefor the signals from above can come directly into the reciever or get bounced off of the base metal only to get caught on the trip back up.

Maybee this will just work for me but I thought I'd share my little sucess.

ppgt94 · 09-20-2004, 03:11 PM

I just took my BU-303 out from the front (on top of the dashboard, under windsheild). I moved it too the back and mounted to the metal trunk lid (BU-303 has built in magnet). I did get more satellites. I then moved it inside the car under the rear windsheild on the rear deck and got about just as good of a signal. I hate putting it in the rear of the car because I feel as if tracking is behind a few feet. I rather have it be ahead than behind.

nl4jy · 09-21-2004, 11:43 AM

hmmm... can I mount it upsidedown? Maybe I'll mount it under my bonnet.

Course how would I be able to receive a good reception if it's under the bonnet???

Maybe mounting it near the vents??? Then it's not upsidedown...

The more I type, the more this post doesn't make sense.

mutilator · 09-21-2004, 01:23 PM

my mates got gps under his pollen vent infront of window wipers, works fine.

tom.

carpcnoobie · 09-23-2004, 11:03 PM

Quote: Originally Posted by jpelzer

It works.

Some time after this discussion, I moved my gps to the skylight in the back of my car, so it was suspended in midair with no metal below it. I'd removed the magnet (magnets make me nervous with computers), and so it wasn't geting ANY signal lock.

I now have a 3" diameter piece of aluminum stuck below the receiver, and the lock is perfect. Aluminum foil would work just as well, just doesn't look as slick!

Do you have any pics of this? I'd like to see it. I'm still working on where to put my GPS. If I can improve my lock situation, that would help out a lot.

blicky_1 · 09-24-2004, 05:40 AM

Hi all,

I used to have my GPS mounted on top of the rear shelf and had lock problems with 3-4 sats at best (ebay GPS)

I now have it under the rear shelf on the metal (facing up) and get between 8-10 sats with instant lock!!

With my Merc you can get to the metal shelf by taking out the first aid kit and mounting it behind and the replacing the kit, no one would ever know its there!

Works for me!!

Regards
blicky_1

Motoko · 09-24-2004, 05:59 AM

So does it have a view of the sky?

blicky_1 · 09-24-2004, 09:09 AM

no it is under the shelf but the shelf has a clear view of the sky.

jcdillin · 09-24-2004, 09:20 AM

Quote: Originally Posted by hd54321

XM uses a combination of ground repeaters and satellites(sp?). Line of sight is more important than a ground plane.

-HD

Interesting. I dont have XM I have sirius, I dont know if sirius uses ground repeaters, I would think that would keep it from loosing signal under bridges but I could be wrong. I figured it was all sat based.

FAmonmouth · 09-28-2004, 03:38 PM

Quote: Originally Posted by jcdillin

Interesting. I dont have XM I have sirius, I dont know if sirius uses ground repeaters, I would think that would keep it from loosing signal under bridges but I could be wrong. I figured it was all sat based.

Sirius uses very few ground repeaters compared to XM. I will have to try the magenet thing when i get my truck back