Police Scanners

The common police scanner is an essential intelligence-gathering tool for journalists, activists, forward observers, neighborhood watch groups, spies, and more. With it, you can listen in on many of the conversations that law enforcement officers have with each other on their radios - from officers out on patrol, to the dispatch teams manning the radios at the precinct.

The term “police scanner” is actually somewhat of a misnomer, as all of the devices described on this page can listen to more than just police frequencies, including fire/EMS, aircraft bands, marine radio, weather radio, civilian walkie-talkie channels, amateur radio, and much much more.

Scanners are (usually) only capable of receiving audio. If you want to transmit, you will need a two-way walkie talkie or amateur radio.

Thanks to modern technology, in many places you can remotely listen to what this man is saying.

Before you decide to go out and acquire your own scanner, it is absolutely imperative that you understand the different types of scanners on the market. Not all scanners can listen to the same frequencies. You will have to research ahead of time what frequencies & modes your local emergency services use, in order to find a compatible radio.

Police scanners will generally fall into one of four categories:

The most common type of scanner on the market is your basic analog scanner, which picks up plain old analog radio signals and spits them out for you to hear. Analog signals are the original form of radio communications that people have been using for decades, and not much about them has changed.

Since the 1990's there has been a shift away from plain analog communications. One technology employed by police departments is trunking, in which conversations jump across a pool of frequencies. This enables more efficient use of the increasingly crowded Frequency spectrum. For eavesdroppers, this means you will need a trunk-tracking scanner to “follow” the conversation as it moves from frequency to frequency.

Many emergency services have also recently made the jump to digital communications, in which analog voice is digitally encoded, broadcast out over the radio in that format, then de-encoded by a capable receiver back to analog so you can hear it over your speaker/headphones. This has enabled even more efficient use of the spectrum, as well as a host of other convenience features for large organizations. However, if your scanner is not capable of making sense of these digital signals, it will just sound like unintelligible noise. This brings us to the next category of scanners….

If you are looking for maximum compatibility out-of-the-box with minimal configuration, you will need to pony up the cash for a trunk-tracking digital scanner. While they are a substantial investment up-front (especially if you have to purchase, yes purchase, a firmware update for your model), nothing beats having one of these mounted to your vehicle or tactical bag, pre-programmed and ready to go.

Some popular digital scanners with trunk-tracking capabilities include:

• Uniden BCD325P2
• Uniden BCD436HP
• Uniden BCD536HP
• Uniden BCD996P2
• Uniden SDS100
• Uniden SDS200
• Whistler TRS-1
• Whistler TRX-2
• Whistler WS1098

Software-defined radio (or SDR) is a simple type of radio tuner, which relies on piggybacked software to tell the radio what to do, instead of built-in firmware and hardware components. Many modern consumer radios are now glorified SDR's, as they are far cheaper to manufacture than your typical digital scanner. This is also extremely useful for hobbyists and other people with too much time on their hands, who can spend forever working on the perfect custom radio setup by tweaking some applications on their computer.

The easiest way to get started with SDR, is with RTL-SDR, which is built off of the notoriously cheap and widely available Realtek RTL2832U. For under fifty dollars, you can get an RTL-SDR starter kit from RTL-SDR Blog or Nooelec, which works with any standard PC and even many phones, as long as you have the right software to make it work. With RTL-SDR you can only receive (no transmit) which is fine if you are using it as a scanner, though some high-end SDR models let you transmit as well.

Note: If you choose to go the RTL-SDR route, do so through Nooelec or RTL-SDR Blog. Because anyone can order a crate of these RTL2832U chips and haphazardly slap them in a case, there are many RTL-SDR knockoffs which are infamously unreliable. DO NOT try to cheap out on these already inexpensive chips by going to Aliexpress or eBay, as YOU WILL REGRET IT.

The first drawback with RTL-SDR (and other similar SDR setups) is that you are basically on your own when it comes to the implementation. There are a bunch of open-source software applications that will do the heavy lifting for you, but you have to set them up yourself, and not all of them are available on every operating system. There are all sorts of guides and write-ups out there, but other than that, expect minimal documentation and lots of conflicting advice. Furthermore, expect to have to learn a lot of nitty-gritty details on how the radio spectrum even works, if you want to make sense of this software yourself. Also, trunk-tracking with these requires the use of two RTL-SDR's running simultaneously, each with their own antennas. After that, you will find out that regular broadcast AM/FM signals and background noise will overpower your radio and “intrude” on other frequencies, necessitating the use of a bunch of extra in-line filters and low noise amplifiers if you even want to hear anything of value. Then there's the matter of cable management, as instead of a single device you now have a bunch of tiny dongles and filters and external antennas all daisy-chained to your computer or phone, which is not practical on the field at all, and especially not while driving. And don't forget spare batteries, as plugging your computer into an outlet or your car's cigarette lighter can introduce even more radio interference.

For these reasons, many people will just give up and buy one of the digital scanners mentioned in the above section. But, if you persevere, and make it work, then the knowledge, skills & capabilities you will acquire as a result will make you a radio-god among Anons.

Some of you may now be wondering: “But Anon, I have no money to buy any of this fancy hardware that you talk about! Is there any way I can still eavesdrop on law enforcement and emergency services?”

Lucky for you, there sure is! There is a plethora of websites and apps out there, where scanner owners across the world have hooked their radios up to the internet, so that others may tune in. This means you can listen to conversations in Washington all the way from Timbuktu.

Some of these apps include:

• Broadcastify
• OpenMHZ
• Scanner Radio
• 5-0 Radio

The trade-off with these apps is that, since the scanners streaming to these websites are tuned to specific frequencies by their owners, you cannot just tune to a random part of the dial. Whatever stations are on the list at the time, are the ones that you get.

Furthermore, if you're reliant on a cell phone signal for mobile data, police can track you with a stingray, or cut the towers entirely. Neither of these are things you want to deal with on the field, so you will definitely want to upgrade to one of the physical radio options above if you plan on doing radio recon on a regular basis.

Police are well aware that people are listening to them with these devices all the time, and they are known to take advantage of this for counter-intelligence during major protests and stings. It is not uncommon for police to throw out decoy plans over the radio, in order to disrupt protests and break up crowds.

This was especially evident during the 2020 Capitol Hill Protests in Seattle, where cops would frequently drop false-movements of SWAT teams over the radio. This would spook radio recon teams, who would pass the bogus “intel” to their fellow protesters on the front lines. In turn, the protesters would take the bait and move to their fallback positions, where the police were secretly waiting to have them kettled.

Watch out that you are not fooled by these types of charades!

Some police departments really do not like the general public listening to their conversations, and so they encrypt their transmissions. In some cities they will only encrypt some channels, and leave others open. In other cities, they encrypt everything. In either case, when it comes to encrypted frequencies, you will only hear a bunch of noise if you try to tune in. Short of having a person inside the police department to steal one of their radios (which WILL be remotely disabled once someone notices it is missing, and then YOU WILL be hunted down) there is no way around this. Even if you don't steal a radio, it might still be illegal in your locality to try and bypass this encryption through any other means.

For an list of agencies known to use encrypted communications, check out this list at the RadioReference Wiki.