k band is KILLED by dads car's windshield

[Mackid343]

i took my dads car the other day and mounted my v995 in it. i was doing some errands around town for him and i realized that the detector was really quiet. i saw quite a bit of x band but since i have it on city lox i didnt get any audio alerts for those.

all the usual k band sites seemed to go undetected unless at a very close range. i even saw a cop pull out of a neighborhood and come toward me on the other side of the road with his k band on and i got about a 3 or 4 alert where i should have been getting full like i do in my car.

i also got farther rear detection on all the k falses than i did front (i had the windows and sunroof open so i'd assume the windows wernt killing detection from the rear).

i know he has some special coating that came on his windshield when he bought the car so i'm assuming that this is whats causing it. just found it to be really weird...

oh, and i put it back in my car and k band is great, so i know its not falling out of tune.

[RacerX]

that's interesting.
what kind of car?

i remember some V1 users here talking about how it seemed they got better rear reception than front. they thought maybe it was a defective unit.

maybe it's certain windshields that have some type of metallic coating affecting that range (k band).

[kpatz]

Yeah, what kind of car is it?

Some cars have metallic tint (or could have had aftermarket metallic tint added). Also some cars have the "instaclear" feature to defog the windshield, and this can block radar as well.

[Mackid343]

its a cadillac catera 2001. they explained this special coating when he bought the car, i think it was to reflect heat or something so the car wouldn't get as hot in the summer when parked outside...not sure tho. it definately kills k band for sure, didn't encounter any ka but x band seemed fine...

[allyoops]

There's a type of laminated windscreen glass which is becoming more widespread in Europe and it's called "Athermic" or heat reflective Glass.

To the best of my knowledge, it's has a very fine metallic layer sandwiched in the middle of the glass. It's supposed to reflect the heat of the sun better than normal glass. This Metallic content is enough to stop radar signals passing through. It also restricts GPS signals from passing through as well.

You can normally tell it's an "Athermic" windscreen by standing about 50 feet away from the front and it appears to have a "petrol" blue haze over the glass. If you're driving along you can definitely spot cars with it as it looks completely different to a normal windscreen.

I do not know which American cars use this glass. In Europe, it was first introduced on French cars made after 2001 - and is slowly spreading to other makes and models.

To the best of my knowledge, the list of European cars affected is as follows:-

Renault (all models post 2001)

Citroen (all models post 2001)

Peugeot (all models post 2001)

Vauxhall (Vauxhall Zafira)

Audi A8 (bronze coloured tint glass)

Some new high-end Mercedes

Bentley Continental GT

BMW X5

I've heard reports that Ford Focus models made after 2005 may havce this glass as well but this is not confirmed.

Normal InstaClear (in UK Ford calls it "QuickClear") windscreens can have a big impact on detectors at lower end of the market but if should be of a marginal effect on the better products.

It's normally only used on the front windscreen and the other glass is normal so that's why you were getting better radar reception through the rear (clear) window. It's also why you need to buy an external GPS Antenna for some cars or run an antenna to the rear parcel shelf.
The only exception is the Bentley Continental GT which has every bit of glass Athermic (apart from a 2 inch strip at the top of the rear window.)

If your car has an A-thermic windscreen you really need to use a remote head detector which bypasses the whole windscreen issue.

The funny thing is, try asking a car dealer if their models have A-thermic glass and they probably won't even have heard of it.

Hope this helps

A

[allyoops]

Forgot to say the reason you start to get the K Band Alert until short range. Athermic glass doesn't cut out the signals completely, it just reduces the amount that gets through. You could also be picking up the radar through your side windows as you get really close.

A

[Mackid343]

thats exactly how it looks when you stand about 50 feet away and how they explained it to work. thanks!

[allyoops]

glad to help.
A

[Mackid343]

i'll definately be making sure i dont buy any future cars with this if i can help it . or if i do, i'll just get a remote system

[allyoops]

just as an aside, the metallic layer doesn't do that much good at keeping out the sun, but I bet it's going to be really useful for future in-car heads-up displays.

A