Police scanners are used to tune in to the radio frequencies that the police communicate on. Historically, they were standalone devices, but technology has evolved now, and police scanner apps are available for most modern smartphones, enabling anyone to just download and install a tool to turn their phone into a receiver for the police radio communications.
Listening in on crime fighters with your police scanner can be fun, but not all states consider it to be an acceptable thing to do. In some states, simply listening to the police radio is illegal. You will need to check the law in your specific state to make sure that what you’re doing is OK.
The confusing thing is that it is legal to own a police radio scanner in almost every state. It is not always legal to take those scanners out of your home, however. So, if you turn your phone into a police radio using a scanner app then you could be breaking the law.
In Kentucky, New York, Florida, Minnesota, and Indiana it is illegal to use a mobile police scanner if you do not have a license from the FCC or from your local law enforcement. The law is complex, however, and there are some exceptions. If you really want to use a police radio then it’s a good idea to talk to a lawyer to make sure that what you want to do is operating within the bounds of the law.
In Michigan, New Jersey, California, Vermont, West Virginia, Oklahoma and Virginia it is OK to use a mobile scanner, but using them to facilitate a crime is illegal. Some other states simply have not issued a formal ruling on police radios at all.
Of course, the law may change. When the radios were invented, lawmakers were probably not expecting that the day would come when anyone could turn a handheld computer and communication device into a police radio and listen in to every move of law enforcement. It could be that the next move for the police will be to encrypt their communications, or it could be that they will move to ban those apps. Whatever you decide, think carefully before using a police scanner and make sure you know what you are getting into before you run one while in your car, because that will be viewed less kindly than using it at home.