Hmmm. Intersting. I will give this a try soon. Not that I have issues getting a lock but who knows.
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.
Very very interesting... Being that I have lock issues with a weak 3/4 satelite signal lock, this may be the magic trick.
Ima have to try this as well. Will let you know if it works
Check out my hopefully useful site...
It's still under design but it is functional
The reason gps works better on the roof of the car is simply that it is the highest point and gets the best line of sight to the sats. Refrigerator magnets are made of ceramic ferrite powder (just enough to make them magnetic) mixed with plastic, so there isn't really that much metal in them.Originally Posted by daman10958
But if it works for you, go for it.
I remember someone on this forum mentioned about GPS works better if you mount them on a ground plane. Well I tried it with my Delorme USB gps and it works like a charm. I used to glue my GPS to the rear window, but the signals are not that strong, and sometime it was difficult for the gps to lock. Several weeks ago I relocated my gps and mounted on top of the sunroof's sunshade. I used aluminum foils as the ground plane and run a ground cable from the gps casing to it. I got at least 5db increase in signal strenght. Now my gps lock within 20 second or less even while I am driving on a freeway.
Could it be that the orientation of the GPS was the problem, I assume that if you had it mounted on the rear window, it would be at an angle (not hrizontal), but with it on the roof, it can sit horizontal and the antenna can face up. Did you try it without the aluminum foil in the horizontal orientation?
Originally Posted by Supermike
yep, I tried it without the ground plane (aluminum foil) and the signals hovers around 35-37db on average. With the ground plane, the signals increased to 45-49db.
Wouldn't it be more likely that the foil is acting as shield to block interference coming from your engine/carputer/blah rather than as an amplifier? It sounds like it is helping you out, so that's pretty cool. Just thought I'd point out a more likely causal link.Originally Posted by 98_Prelude
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.