Why did my local police scanner go silent?

The agency most likely encrypted its radio system. Encrypted traffic cannot be received by any scanner or app, so the feed goes quiet or carries only unencrypted channels such as fire and EMS.

Can a scanner app decrypt police radio?

No. Encryption is applied at the radio itself using keys held by the agency. No consumer scanner, app, or software can decrypt it, and attempting to do so is a federal offence.

Are fire and EMS channels also encrypted?

Usually not. Fire and EMS dispatch is encrypted far less often than law enforcement, because those services coordinate with mutual-aid partners and hospitals that need open access.

Why Are Police Channels Encrypted? What Changed and What You Can Still Hear

Updated July 27, 2026 · 6 min read

If a feed you followed for years went quiet, encryption is almost certainly why. This is the single biggest change in scanning over the past decade, and it is worth understanding what drove it.

What encryption actually does

On an unencrypted system, a transmission leaves the radio as a signal any compatible receiver can decode. Encryption scrambles the audio before it is transmitted, using a key loaded into each authorised radio. Without the key, a receiver picks up the transmission and produces noise or silence.

This is not a setting a scanner can work around. The audio never exists in listenable form outside the agency's own radios. No app decrypts it, no firmware update enables it, and attempting to break it is a federal offence under the Electronic Communications Privacy Act.

Why agencies made the switch

The move to digital made it nearly free. Agencies replacing ageing analogue systems with P25 digital ones found encryption built into the standard. Turning it on became a configuration decision rather than a purchase.

Officer safety. The argument agencies make most often: suspects with scanner apps can track responding units in real time. Documented cases exist, though how common this is remains contested.

Privacy law. This one has more force than it first appears. Dispatch traffic routinely carries names, home addresses, dates of birth, medical conditions, and criminal history lookups. Several states passed laws restricting broadcast of criminal justice information, and agencies concluded that open radio was inconsistent with them. In some states, encryption was effectively mandated by a state police policy that local agencies had to follow to keep access to shared databases.

Tactical operations. Almost universally accepted, even by transparency advocates: surveillance, warrant service, and active-shooter response are encrypted nearly everywhere, and few argue they should not be.

The transparency argument

The counterargument is not merely that scanning is a hobby. Open radio has historically served:

Journalists, who use dispatch traffic to learn about incidents in real time — often the only way a local newsroom hears about an event at all.
Accountability researchers, for whom archived radio is a contemporaneous record of what officers said as an incident unfolded, independent of any later report.
Neighbours and residents, who use it to understand what is happening nearby during a fire, a chemical spill, or a search.

Several cities have adopted compromises: encrypting tactical and records channels while leaving primary dispatch in the clear, or providing delayed access to journalists under credentialing agreements. Denver, Chicago, and others have gone through public fights over exactly this balance, with different outcomes.

What you can still hear

Encryption is far from total, and its pattern is fairly consistent:

Fire dispatch — usually still open. Fire services coordinate with mutual-aid departments, and encryption breaks that.
EMS — usually open, for the same reason plus hospital coordination.
Public works, transit, utilities — almost always open.
State police and highway patrol — mixed; many still broadcast primary channels.
Smaller and rural agencies — often still open, because they have not yet replaced analogue equipment.
Aviation, marine, rail, and amateur radio — entirely unaffected.

In many metropolitan areas, the practical result is that you can still follow an incident through fire and EMS traffic even when law enforcement has gone dark. A structure fire, a multi-vehicle accident, or a hazmat response is often better covered by fire dispatch anyway.

How to find what is still open near you

Feed directories list what is actually streaming, which is the fastest way to see the current state of your area. If law enforcement is gone, look for:

The county fire or EMS dispatch feed
A regional or mutual-aid channel covering several jurisdictions
The state police district covering your county
Neighbouring counties, which may not have converted

Is the trend reversible?

In a few places, yes. Public pressure and press-freedom litigation have produced partial rollbacks and negotiated access. But the underlying driver — digital systems where encryption is a checkbox, combined with privacy statutes — is not going away. The realistic expectation is a patchwork that varies enormously by state and by agency.

For what the traffic means once you find an open channel, see police radio codes explained. For the legal side of listening, see is it legal to listen to a police scanner.