What can cause radio interference with GPS signals?

chilli_pepper · 04-24-2005, 01:11 PM

Ok guys,

Heres the senario...I have been using a BU-303 for a few months hooked up to a laptop and sitting on my dash with MapMonkey for long and new journeys. The signal was 90% locked with it sitting on my dash which i was pleased with.

So I have now installed the car PC with an Opus run leads upto the front for a Xenarc and a usb hub/extension. The Gps is mounted in exactly the same place as it always has been but now wont lock...or many/any signals for the majority of the time.

Shove it on the roof....instantly locks with 6-8 sats.

Its really ****ing me off as it was all working so my feeling is something that i have installed must be interfering with the reciever unit itself.

So what i am asking is what could there be that i have instaleld that interfers with the GPS signals in the car?

I have extensively tested the reciever and it is working great, it does the same thing connected to a dedicated port, the hub or an extension and i have tried changing the position within the car and it makes no difference!

Please help me

Bugbyte · 04-24-2005, 07:03 PM

RF interference from the PC or the power supply. I had an identical experience to yours. I picked out a nice spot on the rear shelf for the GPS, tested it with the laptop and it worked perfectly, always at least 7 sats and often more.

Installed the PC underneath the shelf. No lock. Didn't work. Had to move the GPS to the front of the car. Found out that when I swapped the screen to a Xenarc, it also interfered with the GPS signal!

Basically, anything in the 1.1 ghz band can potentially intefere with the GPS receiver.

chilli_pepper · 04-25-2005, 06:44 PM

Well

I have a Xenarc...and as the car is soooo small i cant really get the reciever anywhere more than 1.5 meters (if that more like 1 meter) away from any of it...and if its away from the pc+psu then its near the xenarc!

Nightmare!

What are my options? could i wrap the pc and powersupply in foil or something like that?

How have u sloved your problem if you pc is in the back and screen in the front?

Cheers

trillion · 04-25-2005, 10:32 PM

Im having a similar problem in another thread, using a Xenarc and a Garmin GPS mouse split from the same 12v plug; not that that should matter :/

http://www.mp3car.com/vbulletin/gps/48137-garmin-gps18pc-causing-mouse-pointer-act-strange.html

Bugbyte · 04-26-2005, 02:03 AM

Haven't really solved it. The GPS is about a foot away from the Xenarc. It gets intermittent reception. Never loses the lock for a real long time so I just put up with it.

My PC doesn't have a case. It would probably help if I put it inside a metal casing.

phord · 04-26-2005, 02:12 PM

No case on my PC. I mounted my Earthmate GPSr inside the dash behind my Lilliput and I always got an excellent lock.

Then I got a USB GPS mouse because StreetAtlas sucks in a car... and it wouldn't lock unless I held it just right against the glass. Sometimes it worked ok, but usually it showed pretty weak signals. If I put it on top of the car it immediately gets 100% signals from all sats.

So I punted. I pulled the USB wire through the firewall of the car and put the receiver (magentic mount, doncha know

) on the hood by the windshield.

chilli_pepper · 04-28-2005, 04:03 AM

My PC is in a wooden box, and under the rear seat the Opus is next to it.

Is there anyway i can screen them? Would wrapping in foil be a waste of time?

0l33l · 04-28-2005, 04:12 AM

Tint can interfere with radio signals.

ShawJohn · 04-28-2005, 05:38 AM

As boris said, I found my tinted windscreen contained a metallic film which blocked over half of the GPS signal. But my sunroof didn't so I placed the receiver on top of the sunroof blind under the glass, only thing was, when the roof openned you had to grab the receiver and stick it out on the roof before it got swallowed into the roof cavity

The GPS receivers also work better with a small piece of sheet metal under them. Mine sits on a 6"square piece of 1mm thick mild steel plate and regularly picks up 8-10sats.

HTH

chilli_pepper · 05-01-2005, 07:17 AM

Decided to waterproof it and throw it on the windscreen scuttle!

Works now

Thanks

KyleYankan · 05-01-2005, 11:07 AM

A possible solution - use metal shielding. Your GPS may work on the roof because the car's roof is blocking the RFI (radio frequency interference). Try some experiments with tin foil and see if you can block the RFI inside your car.

Kalt · 05-01-2005, 02:09 PM

I had the same problem with my bu-303 and lilliput. I had the gps behind the lilliput and i never go a good lock. I was able to solve the problem by trying out different monitor refresh rates, now i see at least 8sats and sometimes i get 12 out of 12.

Goddy · 05-02-2005, 07:18 AM

I think i know what it is, i have/had the same. You installed a new pc, so perhaps you have set your screen to 85Hz. Try to lower it to 75 or even 60hz. Your think your LCD is interfering. You will see you will have an instant lock when you turn off your lcd.

I have had the same when i installed another laptop.