TomTom 940 Athermic Windscreen - Official Reply

jbsolutios · Occasional Visitor Joined: Jan 11, 2008 Posts: 29

I contacted TomTom as I have a TT 940 and a Ford S-Max with athermic windscreen. TT does not work at all (have to take it outside to get a fix then it drops even when driving along the M1).

This is what TT suggested: -

I can confirm that we do not have an external antenna for the Go 940. We will not be launching this accessory in the future as the Go 940 does not have the required connecting port on it.

We can however direct you to something called a 'GPS repeater'. Although we do not sell this accessory ourselves we do know that it will boost the GPS signal in your car even with a heated windscreen. If you type 'GPS repeater' into a search engine ( e.g google) then it will provide you with lots of retailers who offer this accessory. There is usually a part that attached to the outside of the car and that picks up the GPS signal. You have a second part inside your car, the signal is bounced from outside to the inside of your car.

Does anyone have any experience with these please and / or any recommendations?

Many thanks

mikealder · Posted: Sat Nov 21, 2009 7:10 pm Post subject:

They are only telling half a story here, the x40/ x50 docking connector does have pins allocated for an external GPS aerial but neither TomTom or CarComm make a mount that can use this connectivity.

As for the GPS Repeater more often called a GPS Re-Rad they were banned in the UK due to OFCOM regs a few years ago, it should be possible to purchase one from E-Bay though even though using such a device means you are breaking the law in this country - The comical part is the very low power levels coupled with your windscreen would make detection of the Re-Rad impossible as you are a moving target in a car. The rules around banning the Re-Rad are plain stupid and unenforceable IMHO, your choice if you want to try and get a Re-Rad, but you need to be aware that use of such a device in the UK is illegal. If you want to go shopping on E-Bay look for retailers outside the UK Wink

- Mike

jbsolutios · Occasional Visitor Joined: Jan 11, 2008 Posts: 29

Hi Mike

Thanks for such a prompt reply!

Do you happen to know if anyone has successfully connected an external aerial to the x40/x50 series please?

At the moment, my TT940 is pretty useless and I do an awful lot of miles, so would like to find a solution.

I looked on eBay but could not find anything.

How would you suggest I move forwards please? Any help would be greatly appreciated.

Many thanks

JB

richard345 · Posted: Sat Nov 21, 2009 7:25 pm Post subject:

A Google search for 'GPS RE RADIATING ANTENNA' gave this amongst others http://www.parkingsensoronline.co.uk/radiating-antenna-c-68.html

Expansys have removed their offering from sale in the UK, so be aware of the legal issues, probably difficult to enforce, though.

Hope it helps.
_________________
Ric - TomTom 520 DEAD - Passed to the great traffic jam in the sky. Now using Maps & Waze on Samsung Galaxy S4 + CamerAlert of course!

mikealder · Posted: Sat Nov 21, 2009 7:31 pm Post subject:

I don't know it anyone has ever connected anything to the pins that are provisioned for external GPS aerial I just know they are present on the device.

Have a look at This I found it by entering "GPS Repeater" in to the e-bay search, there will be more such items listed, but if you have a look at this item it will give you a clue as to what you are looking for then search further to get a cheaper price - Mike

AndyVaughan · Posted: Sat Nov 21, 2009 7:32 pm Post subject:

I spot a gap in the market - time to get the soldering iron out Mike Laughing Out Loud

jbsolutios · Occasional Visitor Joined: Jan 11, 2008 Posts: 29

Hi Richard & Mike

Many thanks for this and sorry that I didn't dig deep enough before replying.

Do you happen to have a pinout for the 940 please?

Many thanks

JB

jbsolutios · Occasional Visitor Joined: Jan 11, 2008 Posts: 29

I second that Andy - I would buy one for sure!

Is it just me, or are TomTom really fouling up on this one?

Their high-end devices seem to be limited to cars which do not have heated and / or athermic windscreens.

Regards

JB

mikealder · Posted: Sat Nov 21, 2009 8:01 pm Post subject:

JB lets put this in to context, yours is the first post I have seen on this forum that an x40 device is unable to work when under an athermic windscreen, considering these units have been available for over a year or so if the problem were common place I am sure we would have heard of it more often by now?

I appreciate the above doesn't help you but there could be a couple of issues here:

1/ Your x40 might not be working correctly, try a trip to Halfords and let them try fitting a unit in your car to prove the GPS reception is OK under the false pretence that you might purchase a unit. Make sure the device isn't switched on until its in the car with the doors shut. If you live anywhere near me I will pop around to try my units in your car, at least this way you can establish whether its your TomTom that has sub-optimal reception. A comparison test such as this is the only way you will know whether your device isn't performing correctly.

2/ Your car is fitted with a Friday afternoon windscreen that has a much thicker Athermic coating on it than intended (highly unlikely).

I won't be getting the soldering iron out for this one due to the fact the market place isn't viable, a single issue in 12+ months simply points to either 1 or 2 above - Mike

AndyVaughan · Posted: Sat Nov 21, 2009 8:17 pm Post subject:

True Mike, gone are the days when external antenna where required to get a decent satellite lock.

You are quite right - it could be a 'Friday Afternoon' TT that has problems getting a satellite lock - a comparison is the only way of being sure.

Darren · Posted: Sat Nov 21, 2009 9:00 pm Post subject:

I'm more surprised to hear the 940 does not work behind an athermic windscreen. Rather than discuss work-arounds I'd be looking at why it is affected when many other devices using GPS chipsets of an identical type are not?

I suspect you may have a duff unit. Current chipsets are more than capable of functioning behind athermic screens and even quick clear heated ones.

As yours isn't I'd be looking to get it swapped. TT don't offer an external antenna simply because one isn't needed and I've yet to come across a car where that wasn't true.
_________________
Darren Griffin

Graeme2812 · Posted: Sat Nov 21, 2009 11:34 pm Post subject:

Perhaps this sounds a tad obvious but have you tried different locations on your windscreen, particularly the outer corners of the screen?
_________________
Graeme Bennett
Go 540 LIVE
App. 9.510.1234792.1 (2039,04/04/2013)
United Kingdom & ROI v945.6174

jbsolutios · Occasional Visitor Joined: Jan 11, 2008 Posts: 29

Thanks everyone for this.

I shall get Halfords to install a new unit and test it, to ascertain whether the unit is faulty or not.

I have seen a number of people complaining about the TT940 with a Ford Mondeo when they have this type of windscreen.

I have tried the TT940 in the different corners. It is slightly better when installed on the quarterlight next to the windscreen, but nowhere near as good as it was on my VW.

Regards

JB

psyskiesman · Posted: Sun Nov 22, 2009 1:26 pm Post subject:

I have a 740 and, whichever way you view it, I am either lucky or unlucky enough to be driving all day in any model Ford, Volvo, VW or Honda, and have had no problems whatsoever in getting a signal inside the car.

jbsolutios · Occasional Visitor Joined: Jan 11, 2008 Posts: 29

Just spoke to Halfords and they only have the 950 in stock now, not the 940.

Is this a worthwhile upgrade please?

Many thanks

JB

	PocketGPS
	Web