Heated rear screen, radio and tinting!

Hello all,

I have just had my CLS 320 rear window and passenger side windows tinted on Sunday. I have now noticed that the radio signal goes, as soon as I put the rear heated screen on and is fine once its turned off?

Also the top 1/4 section of the rear screen doesnt get warm like the lower section?

Any help or advice would be appreciated please:D

Thanks,

Chris.