Many customers ask how they can listen to the emergency services now most of the UK has switched to digital. The bottom line is you can't. They are using a system called TETRA which is encrypted and uses multiple mobile phone frequencies.
 A common inquiry is what happens if marine or aircraft go digital. This is not anything to worry about as all aircraft and shipping around the world would have to install new radio's. There are advantages to aircraft using AM transmissions. If two aircraft transmit simultaneously the controlers hear an awful noise which tells them that two stations are trying to contact them.