Why do some cars block GPS signals?

kaiowas · 28 Aug 2009 at 12:53

Jez said:
the only cars i have experienced no GPS have been a Bentley Flying Spur and both the old and new gen Mercedes S-class.

Isn't the chauffeur supposed to know where he's going without the aid of satnav?

iaind · 28 Aug 2009 at 12:55

Jez said:
If this spreads to cars not equipped with GPS this is going to become a bit of a problem.

Weirdly, cell phone reception seems absolutely fine in everything

Different frequencies so different effect. The renaults definitely have a gap in the coating, its pretty visible - it just restricts where you can mount the sat nav.

I doubt it will become too widespread that quickly, I imagine built in satnav will become more widespread first

Django x2 · 28 Aug 2009 at 12:56

Are any of these vehicles running tints and or shaded glass? I'm surprised at the M5 (assuming you mean E60) why would you need to use GPS.

It's a big issue in the tinting world where the tints use a metalic coating and wreak havoc with the cars systems.

iaind · 28 Aug 2009 at 13:01

Lucero said:
Are any of these vehicles running tints and or shaded glass? I'm surprised at the M5 (assuming you mean E60) why would you need to use GPS.

It's a big issue in the tinting world where the tints use a metalic coating and wreak havoc with the cars systems.

Its not a tint, its a heat reflective coating

NVP · 28 Aug 2009 at 13:06

iaind said:
Its not a tint, its a heat reflective coating

I'm sure if the tints contain metallic in its coating then it could cause the same effect.

jamoor · 28 Aug 2009 at 13:10

My clio seems to do this, I think itsthe front screen.

PeterNem · 28 Aug 2009 at 13:11

Lucero said:
Are any of these vehicles running tints and or shaded glass? I'm surprised at the M5 (assuming you mean E60) why would you need to use GPS.

He's referring to my E39 M5 with has the optional "358 Climate Comfort windscreen" and "761 Sun protection glass".

The GPS doesn't work in my car, but does work in Olly's car which just has "761 Sun protection glass" (OEM tinted rear windows) so it must be the windscreen's UV coating.

Finglonga · 28 Aug 2009 at 13:12

nuvpal said:
It is to do with the heating elements in the windscreens I think...

No effect, always had Fords with heated screens and GPS and phones work properly. Plus I am sure Ford are the only ones with elements inside the screen.

As said its the UV coating that blocks it and acts like a Faraday cage so signals can't pass through it. Renault were the first to use the coating and others have followed.

kaiowas · 28 Aug 2009 at 13:19

jamoor said:
My clio seems to do this, I think itsthe front screen.

I've recently got some prescription Oakleys with polarised lenses in them and the lenses have made these coatings really obvious, have noticed them on loads of Renaults coming the other way whilst driving with them on.

BigDannyO · 28 Aug 2009 at 13:23

My GPS works in both my Mondeo (with heated screen) and the wife's Clio (with UV reflective glass). So I've no idea!

Freefaller · 28 Aug 2009 at 14:07

Jez said:
Oh do go away

*pooof*

Dangerous Dave · 28 Aug 2009 at 14:19

It is the UV coating however generally they have a open spot to allow GPS signals through on my Golf for example the area is around the rear view mirror. It should mention the spot in the manual.

It was a pain when I retro fitted the satnav, I ended up hiding the GPS aerial in the boot area as I wasn't going to fit the external factory shark fin as it is an advert to the car thieves you have satnav.

AmDaMan · 28 Aug 2009 at 15:00

I have the UV coating on my clio and it works anywhere on the dash, it doesn't need to be under the UV gap on the windscreen.

What GPS are you using?

Dangerous Dave · 28 Aug 2009 at 15:06

AmDaMan said:
I have the UV coating on my clio and it works anywhere on the dash, it doesn't need to be under the UV gap on the windscreen.

What GPS are you using?

I think it depends on the device GPS in phones won't work in the front of my car but fine in other cars, Racelogic/SatNav does work but can take longer to lock onto all the satellites compared to the aerial being in the boot.

MikeHunt79 · 28 Aug 2009 at 15:11

I don't think a UV coating would do it... But anything metal in the windscreen such as a heating element would block GPS.

Google "faraday cage"

kaiowas · 28 Aug 2009 at 15:12

Dangerous Dave said:
I think it depends on the device GPS in phones won't work in the front of my car but fine in other cars, Racelogic/SatNav does work but can take longer to lock onto all the satellites compared to the aerial being in the boot.

Warning - Off topic!

What racelogic stuff you got and what do you think of it? Thinking of getting a PerformanceBox for the sprint car as and when funds allow.

/OT

NVP · 28 Aug 2009 at 15:13

MikeHunt79 said:
I don't think a UV coating would do it... But anything metal in the windscreen such as a heating element would block GPS.

Google "faraday cage"

The UV coatings apparently contain a metalic compond in them thus resulting in the same effect.

MikeHunt79 · 28 Aug 2009 at 15:16

nuvpal said:
The UV coatings apparently contain a metalic compond in them thus resulting in the same effect.

Thanks, didn't know that, you learn a new thing everyday!

CookieRocks · 28 Aug 2009 at 16:01

My satnav works in my 172, but takes an age to get a signal

iaind · 28 Aug 2009 at 16:29

MikeHunt79 said:
I don't think a UV coating would do it... But anything metal in the windscreen such as a heating element would block GPS.

Google "faraday cage"

Heating element causes my satnav no problem at all - the wires are too thin I think