Question handheld GPS in cabin

[Master Red Cylinder]

For the first time in years I took my trusty Garmin GPS III along inside the jet I fly. Sadly, it would not receive any satelites, only barely holding it against a side window, but none at all under the front windows. I´ve turned it on when flying as a passenger and have had no problems before...holding it beside the cabin window...
What do cockpit windows have that prevent these GPS signals to go thru??? Anyone know?
MRC

[mrmagooo]

Heating elements in the A and B screen can prevent signals

[spannersatcx]

Which is similar to why you can have the same problems in cars with heated front windscreens.

[As I See It]

Heated screens as has been stated block the signal, this is as a result of the Faraday cage effect.

[A2QFI]

GPS

I did get my Garmin E Trex to work OK in a GNER train some time ago but the windows are way bigger than any in a aircraft cockpit or passenger cabin. I have a car with a metallised windscreen, to prevent heat build up, and I need an xtn aerial to get my GPS to work in that

[Master Red Cylinder]

Makes sense ! Thanks for replies
MRC