With regard to your reply to the problem with the keyless entry system on the Toyota RAV4. This problem is because the car manufactures install these keyless systems which have key fobs that have virtually no RF screening whatsoever. They can be swamped by other local radio transmissions across a very wide frequency range.

I am a licensed amateur radio operator and operate VHF/UHF radio equipment from my car that is very narrow band that has to comply with stringent regulations regarding bandwidth. Most keyless entry systems on vehicles operate around 433mHz and they are so poor that they can blocked with a nearby radio transmission, anywhere from 430 to 440mHz. I used to wait in my car whilst my wife is in the supermarket, and I would talk to other local radio amateurs on my UHF transmitter. Whilst I was transmitting the majority of people within a 100-metre radius could not lock or unlock their cars using the key fob.

All radio transmitting equipment used in the UK and Europe is regulated and is very stable in its transmission. Perhaps car manufacturers ought to get their act together and provide some decent keyless systems, preferably infrared. Taxi radio installations do not operate on 433mHz.