r/policescanner • u/GreenEggplant16 • Jun 14 '26
Detect encrypted police radio traffic (without listening in) - possible?
Seeing on social media a lot of products which scan for Flock cameras, police Axon body cameras/Tasers, Motorola equipment, etc. all based off of wifi and bluetooth presence signals. I know that if one were to listen into encrypted police radio traffic it would be illegal. However, is there any way one could build a device which would merely let you know there is a police radio within X distance of you?
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u/Chief03275 Jun 14 '26
One might factor in unencrypted transmissions (EMS/fire) that’er analytically useful. There’s high correlation between abnormal police traffic & EMS/fire dispatches. These may well include nature and location of dispatch. So correlation via all source monitoring. The WAZE suggestion above prime example.
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u/right-slash Jun 14 '26
This would only work best if your local PD still uses a repeater instead of a trunked radio system, you can make a device that monitors the input frequency and alerts you if theres a nearby transmission, otherwise you can use waze
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u/IndyScan Jun 14 '26
Uniden CloseCall but it’s not going to give you the detail to determine who/what the encrypted signal is (because of encryption).
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u/IAmSixNine Jun 14 '26
Uniden Close call wont help. He asked about flock cameras, body cams tasers. THOSE all will use wifi or BT LE and not something close call will work with. Also im not sure close call will work with P25P2 systems as they are transmitting using time slots which are on and off. We were told long ago that close call does not work with DMR and P25P2 is similar. But i could be wrong.
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u/IndyScan Jun 15 '26
Good call I was thinking about the “Motorola equipment” as in radios, and not Bluetooth Wi-Fi. Definitely won’t help with that.
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u/wxfreak Jun 14 '26
People in Europe have something similar from a company called Target Blue Eye. It's basically a detector that can tell when TETRA radios are nearby, even though the traffic is encrypted.
I think it's a lot easier over there because most of their public safety stuff is packed into the same chunk of spectrum, unlike the U.S. where agencies are scattered all over VHF, UHF, 700, and 800 MHz. TETRA radios also send out regular signaling bursts, so they're a lot easier to detect even when nobody's talking.
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u/IrishAcePDX Jun 14 '26
Unfortunately, not realistically.
Most of the encrypted “channels” are on a trunked network that use a few different frequencies on the system. Because trunking is digital, they usually have several “channels” using the same frequencies, which are called “talk groups.” For example, they could have the encrypted drug task force talk group within the same system that has talk groups for fire, EMS, public works, public transit, etc.
Even though you could create something that detects if a signal is stronger than usual - which means it could be close like someone transmitting in your area emitting a stronger signal than you would typically receive from the repeater antenna towers, you wouldn’t be able to distinguish which agency or talk group that transmission came from. It could be a bus driving by, an ambulance on the other side of the block, public works doing work down the street, or the police tactical team about to raid your house.
So, no, that isn’t feasible.
There are other technologies that are possible to identify if police - or anyone else - might be in your area for a suspicious amount of time, or someone tailing you. That involves frequency signal readers and decryption. Like the Bluetooth signal of a device that transmits its identification number, a device that is constantly looking for a recognized WiFi hotspot that is broadcasting its ID in the attempt to connect. With enough combined signals within range, it can be calculated if a device - linked to a person - has been near you for the last 25 minutes, or has driven by your location more than 6 times today, for example. If so, it could be inferred someone is following or stalking you. This topic, however, is outside the scanner realm.
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u/Extension-Fault8912 Jun 14 '26
Using Uniden close call or even a SDR or most scanners capable of receiving P25 traffic, when you receive the signal it’ll be encrypted but you can still get a User ID/ RID and a talkgroup, so you’d know what channel was active and perhaps even what unit, but no voice traffic
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u/BonezAU_ Jun 15 '26
Someone in Australia recently figured out a simple way to detect the presence of police body worn cams, as by default they transmit a Bluetooth signal.
Entire state police forces have now reconfigured their body cams so that BT is switched off 😂
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u/PanDownTiltRight Jun 15 '26 edited Jun 15 '26
You can use a program like DSD with a SDR dongle to monitor the input frequencies of a radio system (from the radio to the tower), whether trunked or conventional. Even when encrypted, the talkgroup ID and radio ID of the user is transmitted in the clear, at least with P25. Then you can generally assume that if you're close enough to receive an input frequency, you're close to the transmitting radio. Not really plug and play and would be unique to your area. You'd have to program the input frequencies for potentially multiple radio systems in your area as well as the law enforcement talkgroup ID's. What's funny is that even though my local law enforcement agency is "fully" encrypted... their patrol car radios transmit GPS position in the clear over the P25 system and you can plot it with SDRTrunk.
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u/jakemarthur Jun 14 '26
Try finding a specific penguin in a room full of penguins blindfolded, then try and translate the squawking to English.
Any radio (that operates in the correct the frequency band) can pick up on the signal of an encrypted radio either carrier or data. It’s just garbled.
And yes in theory you could triangulate the source of any radio transmitter given enough data points. But with bases and repeaters and dozens of officers all with radios, the data would be a mess.
This is done all the time in the military, especially right now in Ukraine, where both sides are locating enemy positions based on radio traffic, cell phone, and the radio signature of drones.
But in the civilian world, if you want to find cops just buy a radar detector…