The 433Mhz band
The 433Mhz band is licensed as low power frequency band.
http://en.wikipedia.org/wiki/LPD433
It is also common to use 868Mhz for wireless sensor (LTE interference is now a problem in that frequency). I don't know about car keys.
The 433Mhz band is licensed as low power frequency band.
http://en.wikipedia.org/wiki/LPD433
It is also common to use 868Mhz for wireless sensor (LTE interference is now a problem in that frequency). I don't know about car keys.