07Scanners, encryption and what you're allowed to hear

The short version: In the US, owning a scanner and listening to unencrypted public safety radio is generally legal under federal law, but sharing or profiting from what you hear can violate the Communications Act, scanners that can receive cell phone calls are banned, and a few states restrict scanners in vehicles. The UK is stricter: using a receiver with intent to learn the contents of a message not meant for you is an offense. Meanwhile, many US police departments, including Boston's since August 2025, have encrypted their radios, and the arguments for and against that move are still being made in statehouses and newsrooms.

Is it legal to own a police scanner in the US?

What you see: A handheld or desktop scanner for sale at an electronics shop, or a scanner app on a neighbor's phone playing dispatch audio.

A scanner is a receiver that steps through many frequencies, or follows a trunked system's control channel, to find active transmissions. (A software-defined radio on a computer can do the same job; see hobby radio.) Federally, the key rule is Section 705 of the Communications Act (47 U.S.C. 605). According to the FCC's consumer guide, Section 705 "generally does not prohibit the mere interception of radio communications," and monitoring scanner traffic such as emergency reports is not a violation¹⁰².

The other federal law in play is the Wiretap Act. It permits interception of radio communications that are "readily accessible to the general public" (18 U.S.C. 2511(2)(g)(ii))¹⁰³. Unencrypted public safety radio falls on the permitted side of that line; encrypted traffic does not, as covered below.

Federal permission is not the whole picture. Some states add their own rules, mostly about scanners in vehicles, and the FCC notes that intercepting cellular, cordless or landline calls may violate other federal law (18 U.S.C. 2510-2520) with severe criminal penalties¹⁰².

Can I post or use what I hear on a scanner?

What you see: A neighborhood social media page relaying "what's on the scanner," or a tow truck arriving at a crash suspiciously fast.

Listening and divulging are treated differently. The FCC's guide says "a violation of Section 705 would occur if you divulge or publish what you hear" or use it for your own benefit¹⁰². Its example is a tow-truck operator who hears about an accident on police radio and dispatches a truck to get the business¹⁰².

The divulgence ban does not apply to broadcasts meant for general public use, to distress traffic from ships, aircraft, vehicles or persons, or to amateur and CB transmissions¹⁰².

The legal ground is less settled than that guide's wording suggests. RTDNA, the journalism association, points to a 2011 FCC guide noting that the Supreme Court's 2001 decision in Bartnicki v. Vopper "questions the ability of the government to regulate the disclosure of legally-obtained radio communications"¹⁰³. So the FCC's text states a divulgence ban, and the FCC itself has acknowledged that a Supreme Court ruling casts doubt on how far it can be enforced against people who obtained the audio lawfully. This guide does not try to resolve it.

Why can't a scanner pick up cell phone calls?

What you see: Scanner packaging or specs with a gap in the frequency range, or a note that cellular bands are "blocked."

That gap is required. Section 302(d) of the Communications Act bars the FCC from authorizing scanners that can receive cellular frequencies, that can be readily altered to do so, or that can decode digital cellular signals to analog¹⁰². Under 47 CFR 15.121, such receivers could not be manufactured or imported for US use after April 26, 1994, and 47 CFR 2.803 bars selling unauthorized scanners¹⁰².

Separately from the equipment rules, intercepting phone calls can bring criminal penalties under 18 U.S.C. 2510-2520¹⁰².

Can I have a scanner in my car?

What you see: A scanner on a dashboard, or a state law that says scanners in cars require a license or permit.

Federal law does not address this; some states do. The list below comes from a scanner retailer's state guide, a secondary commercial source, and the statutes themselves should be checked before relying on it¹⁰⁴.

Massachusetts does not appear on that list of in-vehicle restrictions¹⁰⁴.

Read on the states' own code sites (Indiana via Justia) as of October 2026, the statutes differ more than the table suggests:

• Florida, s. 843.16 (2026 Statutes): a first-degree misdemeanor to install or transport, in a motor vehicle or business, a receiver tuned to police, fire rescue or state agency frequencies. Exemptions include FCC amateur licensees, full-time news organizations, alarm monitoring contractors and some public safety workers.¹⁰⁵
• Indiana, IC 35-44.1-2-7: a general possession offense rather than a vehicle rule. Knowingly possessing a "police radio" - defined to cover radios used in vehicles or carried by a person, but not radios designed only for home use - is a Class B misdemeanor. Exemptions include amateur licensees who do not transmit on police frequencies, news gatherers, home or business use and written police permission; using a police radio or a police scanner app in a crime or to evade police is a separate offense.¹⁰⁶
• Kentucky, KRS 432.570: bars possessing or installing a radio that can send or receive police messages, including in vehicles, but exempts, among others, receive-only radios at home, licensed tow operators, reporters and amateur licensees. A violation is a misdemeanor with a $50 to $500 fine, up to 12 months in jail, or both.¹⁰⁷
• Minnesota, s. 299C.37 (2025 Statutes): bars equipping, using or possessing in a vehicle a receiver for a "police emergency frequency" without a permit from the superintendent of the Bureau of Criminal Apprehension. Peace officers and most FCC amateur licensees are exempt; a first offense is a misdemeanor.¹⁰⁸
• New York, VTL s. 397: bars equipping or knowingly using a vehicle with a receiver that picks up police frequencies without a local permit. It exempts licensed amateurs using amateur frequencies; the penalty is a fine up to $1,000, up to six months in jail, or both.¹⁰⁹
• Michigan, MCL 750.508: not a vehicle rule. It bars anyone convicted of a felony in the past five years from possessing a receiver for police, fire, EMS, corrections or homeland security frequencies, and bars possessing one while committing a crime.¹¹⁰

Why did my scanner go quiet, and do I need a digital one?

What you see: A scanner that used to carry local police now hissing or silent, or a listing that says "P25 Phase 2" or "encrypted."

There are three common reasons, and they need different answers:

Encryption is a feature of the P25 standard, which "supports secure communication through the use of encryption, key management, and equipment authentication"⁸⁴. Encrypted traffic is not "readily accessible to the general public" under the Wiretap Act, whose definitions exclude radio that is "scrambled or encrypted"¹¹¹, and RTDNA notes that no law requires agencies to keep their feeds publicly available¹⁰³. This guide does not cover ways around encryption.

Some agencies that encrypt offer a delayed online feed instead; Boston's is described below. For P25 basics, see the public safety section; for how dispatch works end to end, see https://works.cold.fyi/911/.

Why are police departments encrypting their radios?

What you see: A local news story about the police scanner "going dark," or a department notice about a new radio system.

By December 2023, according to New York Times reporting republished by Boston.com, Denver, San Francisco, San Diego County, Baltimore, Chicago, New York and Sioux Falls had encrypted some or all of their signals; Minneapolis planned to in 2024 and Indianapolis was considering it¹¹².

The case for encryption, as police and dispatchers put it. Minneapolis Police Chief Brian O'Hara cited a suspect search relayed live on social media, a viral false abduction report, and victims' personal information going out over the air¹¹². The same reporting describes strong support for encryption in the dispatch community, quoting Mike Hubbs¹¹². In Colorado, Greenwood Village city manager John Jackson argued that criminals monitor police traffic and that victim and witness details should not be released instantly¹¹³.

The case against, as journalists and civic groups put it. Greg Nojeim of the Center for Democracy and Technology said immediate emergency information has value to society and that privacy can be protected without cutting off access¹¹². The Rev. Charles Harrison in Indianapolis said encryption would increase distrust of police¹¹². Denver-area TV and newspaper reporters cited shootings where police were slow to warn the public, or did not warn it at all¹¹³.

Compromises in use. Las Vegas, which encrypted in 2018, gave some journalists access; Chicago kept a Broadcastify feed on a 30-minute delay; San Diego County publishes a call log without precise addresses or names¹¹².

What did Colorado decide?

What you see: References to a Colorado "media access policy" for police radio.

Colorado had one of the longest-running fights. Bills to limit encryption failed in 2018, 2019 and 2020; the last, HB 20-1282, died 6-5 in the House Transportation and Local Government Committee on March 4, 2020¹¹³. Aurora police had encrypted around 2016 and Denver police in 2019¹¹⁴.

In 2021 the rule arrived by another route, added to HB 21-1250, a police accountability bill¹¹⁴. The current statute, C.R.S. 24-6-502, says an agency that encrypts all of its radio traffic must adopt a communications access policy, developed with Colorado media, giving the media access to primary dispatch channels or talkgroups through commercially available scanners or radios or other feasible technology¹¹⁵. The policy may cover credential checks, limits on use and equipment costs¹¹⁵.

Putting it into practice was slow. As of August 2022, COLab reported that Denver-area news outlets still had no access agreements, and Denver cited an auditor's clause in its contract¹¹⁴.

What happened in California?

What you see: Bay Area departments announcing encryption in 2021, while the Highway Patrol stayed audible.

California's push came from data protection rather than officer safety. A state Department of Justice bulletin, 20-09-CJIS, dated October 12, 2020, told agencies to protect criminal justice information and personally identifiable information drawn from CLETS, the state's law enforcement data system; the options were to stop sharing that information on open channels, or to encrypt all communications¹¹⁶.

Agencies chose differently. The CHP did not encrypt, citing older radios, and since October 2020 limits personal information per transmission and sends details to in-car computers¹¹⁷. Palo Alto encrypted on January 5, 2021, and Mountain View and Los Altos followed in early 2021; in July 2021 the DOJ told Palo Alto it could not go back to broadcasting personal information unencrypted¹¹⁷. Fremont kept its primary channel open and moved sensitive channels to AES 256-bit encryption on October 15, 2025, through the East Bay Regional Communications System Authority¹¹⁶.

In Boston: why can't I hear the police on my scanner?

What you see: Boston Police dispatch missing from a scanner or a live scanner app since August 2025.

Boston Police switched from analog radio to a "digital encrypted radio system" on August 9, 2025, and analog scanners no longer receive it⁹⁰. The department gave its reasons as replacing old equipment, improving coverage, reducing static, and preventing monitoring and interference by "bad actors"⁹⁰.

BPD offers a free public feed at radio.rapidsos.com/boston, which the department says is "delayed slightly"⁹⁰; a police spokesperson told the Boston Globe the delay is about 5 minutes in most cases¹¹⁸. Justin Silverman of the New England First Amendment Coalition told the Boston Globe that most police radio traffic is routine and only sensitive traffic needs encryption¹¹⁸.

Boston's switch covers the Boston Police Department. Many neighboring towns share the regional BAPERN network described in the public safety section, and BPD's notice does not say whether their traffic, or Boston Fire and EMS, is affected; a current scanner listing for those agencies is the place to check.⁹⁰

Elsewhere in the world

What you see: A scanner sold in the UK with a leaflet warning about what you may listen to.

United Kingdom. Section 48(1) of the Wireless Telegraphy Act 2006 makes it an offense, "without lawful authority" (wording substituted by the Investigatory Powers Act 2016, in force from June 27, 2018), to use wireless telegraphy apparatus "with intent to obtain information as to the contents, sender or addressee of a message" of which you are not an intended recipient, or to disclose such information¹¹⁹. The penalty on summary conviction is a fine up to level 5¹¹⁹¹²⁰.

The test turns on whether you are an intended recipient, so the US idea that anything unencrypted is fair to hear does not carry over. Broadcast radio, aimed at everyone, is a different case from a dispatcher talking to a patrol car. UK police radio runs on Airwave, the national TETRA network described in the public safety section. The government's July 2026 ESN business case discusses the security risks of Airwave's "air interface encryption algorithm," which confirms the radio link is encrypted.¹⁰⁰ Wikipedia describes the move from open analog to the encrypted digital TETRA system as making it "practically impossible" for civilians to listen to UK police radio.¹²¹

Report an error in this section