I recently saw a couple of questions about police scanners posted to the wonderful Q&A site crimescenewriter. The questions there were some I’ve seen often enough that I thought I’d also share and respond to them here as well.
 

The inquisitive author asked if scanners were legal to possess by private citizens, including retired police officers who reside in California.
 

Answer – Yes, the possession and use of a scanner is legal in California. However, it is a misdemeanor to use one during the commission of a crime, such as to use the messages received to aid in the escape of custody, etc.
 

In some states it is illegal to install or use a scanner inside a motor vehicle. For example (click the links below to read the statues).
 

Florida
› Indiana
› Kentucky
› New York
› MinnesotaOther states also have laws regarding scanner use during the commission of a crime, such as this one from the Code of Virginia.

§ 18.2-462.1. Use of police radio during commission of crime.

Any person who has in his possession or who uses a device capable of receiving a police radio signal, message, or transmission, while in the commission of a felony, is guilty of a Class 1 misdemeanor. A prosecution for or conviction of the crime of use or possession of a police radio is not a bar to conviction for any other crime committed while possessing or using the police radio.In New Jersey it is illegal for felons convicted of certain crimes to possess a scanner, even inside their own homes.§ 11-1-11. Felons prohibited from possession of radio scanners.

No person: (1) who has been convicted of a felony violation of chapter 28 of title 21 involving the illegal manufacture, sale or delivery or possession with intent to manufacture, sell, or deliver a controlled substance classified in Schedule I or II; or (2) who has been convicted of a felony in violation of chapter 8 of this title involving the burglary or breaking and entering of a dwelling house or apartment, whether the house or apartment is occupied or not, any business place, or public building, with the intent to commit larceny; shall carry, transport, or have in his or her possession, or under his or her control outside of his or her own home, any operational police radio, police scanner, or any other device capable of monitoring police broadcasts. Every person violating the provisions of this section shall, upon conviction, be punished by imprisonment for not more than five (5) years, or a fine of not more than five thousand dollars ($5,000), or both.

And, Michigan:

750.508 Equipping vehicle with radio able to receive signals on frequencies assigned for police or certain other purposes; violation; penalties; radar detectors not applicable.

Sec. 508. (1) A person who has been convicted of 1 or more felonies during the preceding 5 years shall not carry or have in his or her possession a radio receiving set that will receive signals sent on a frequency assigned by the federal communications commission of the United States for police or other law enforcement, fire fighting, emergency medical, federal, state, or local corrections, or homeland security purposes. This subsection does not apply to a person who is licensed as an amateur radio operator by the federal communications commission. A person who violates this subsection is guilty of a misdemeanor punishable by imprisonment for not more than 1 year or a fine of not more than $1,000.00, or both.

(2) A person shall not carry or have in his or her possession in the commission or attempted commission of a crime a radio receiving set that will receive signals sent on a frequency assigned by the federal communications commission of the United States for police or other law enforcement, fire fighting, emergency medical, federal, state, or local corrections, or homeland security purposes.

As you can clearly see, it’s best to check local laws before purchasing a scanner for your home.

Another of the questions related to the terminology used when speaking of a scanner—do I call it a “police scanner” or simply a “scanner?”
 

Answer – Today, most scanners are capable of receiving radio traffic from a variety of sources, such as police, fire, EMS, marine, air, and even weather. Therefore, the use of “scanner” is a better fit. Still, many people still refer to the electronic devices as “police scanners.”
 

When I worked as a police investigator, and during my time as a sheriff’s deputy, our in-car radios weren’t set up to receive radio traffic from EMS, fire, and nearby law enforcement agencies outside of our jurisdictional territory. Therefore, many of us, including me, installed scanners inside our vehicles which allowed us to monitor the activities of other departments.

 
It’s not that we were nosy, though. Instead, we’d sometimes, for example, hear an officer’s call for help, and if we were close enough to assist we could do so, and would. Also, by listening to nearby agencies we’d often hear of pursuits heading in our direction, fleeing felons, descriptions of stolen cars and wanted persons, locations of fires, car crashes, explosions, and other valuable information.
 

By the way, there are apps for phones that offer similar service. Most are free. Not all locations are available within the online versions, though. Therefore, if the goal is to monitor broadcasts in your area, a scanner might be the best option.
 

The final question about scanners was about what a listener would hear regarding a missing person broadcast.
 

Answer – As always when dealing with law enforcement, it depends. These days, such as in Virginia, the state where I worked as a law enforcement officer, scanner listeners may not hear much at all. This is due to the use of in-car mobile computer terminals (MCTs) which is basically a silent dispatch system and car-to-car exchanges of information, all without the use of a radio. However, when officers are away from their cars they still rely on portable radio communication (walkie-talkies).
 

Police radio transmissions, while fascinating to hear, can be dangerous for the officers on the street. This is so because not only are you able to hear what the officers are doing and possibly where they’re located, well, the bad guys could also be listening, and they do. Therefore, they could easily flee, hide, and even use those radio transmissions to ambush police officers.
 

To combat the problem of criminals listening to police radio calls, many departments encrypt their transmissions which basically winds up sounding like conversations among space aliens who’re speaking with a mouth full of marbles while underwater.
 

We’d always used encrypted channels for tactical reasons during special operations, but the general day-to-day channels were open for all to hear. Since 911, many agencies abandoned the use of 10-codes, opting for plain speak (“Okay” in stead of “10-4.”). This transformed police radio “speak” into simple, everyday conversations. Everyone could then understand what was being said.
 

FYI – Virginia State Police 10-codes are exempt from the Commonweath’s Freedom of Information Act (FOIA). They are not public. And, when they are used they differ from many local departments. For example, the 10-code for a “fight in progress” call in Bumble Stump County’s sheriff’s office may mean “abandoned vehicle” to the state police (the two examples are totally ficticious).
 

Anyway, see how a simple question—Is it legal for a retired California police officer to have a scanner in his car—can evolve into a rambling blog article.
 

In summary, yes, it’s legal to possess and use a scanner … except when it’s not.