Last edited: October 8th, 2020
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For the purposes of this article, Staten Island will mostly be ignored.
NYPD has an enormous and complicated radio system that is used as the backbone of operations within the city. Though information is increasingly shared via the Domain Awareness System through laptops in vehicles and apps on officer phones, the radio remains the primary way for communication to take place in day to day operations.
Before we begin discussing the technical nature of this coverage, we need to understand the geographic and bureaucratic layout of the city and how it relates to the way NYPD operates their radio spectrum.
NYPD has divided their radio coverage of the city into four tiers: citywide, patrol boroughs, precincts (typically merged as two or three precincts known as radio zones), and local channels such as Tac.
Citywide coverage is divided into 4+1 bands labeled Citywide 1-4 . The +1 is an additional encrypted frequency they keep for CW 4 that is hardly, if ever, used. The typical use for these channels varies quite a bit even throughout a day and covers everything from protests, to traffic, training exercises, to water rescues. During the George Floyd protests, the city started using CW-1 is their predominant “disorder control” channel with CW-2 standing in as additional overflow for Brooklyn when Manhattan was too busy and filling the airwaves of CW-1. Protest coverage has been heard on all four channels so it’s not a bad idea to scan through them all for information.
There are additional citywide channels for specific departments and groups. Special Operations Division (SOD) for example covers special detective assignments (and many calls for “EDP’s” or “Emotionally Disturbed Persons” - cop talk for people who aren’t cooperating). Traffic is another channel and does what it sounds like. There are also channels for Detective units, organized crime control (including one encrypted channel), VIP (also with an encrypted channel), command (encrypted), internal affairs (encrypted), aviation, and fleet services.
NYPD in their on the ground operations divides the city not into the five boroughs, but 8 patrol boroughs which are a more fine-grained division of the city (for example, Brooklyn becomes North and South Brooklyn). Interestingly, these are not mirrored in their radio divisions which keeps a single patrol boro channel for each of the five boroughs. Discussion on these freqs are usually scarce and focused on non-critical command operations and updates.
Radio zones are what NYPD calls their precinct level coverage. Due to a lack of available spectrum and a strategic choice for joint operations, most radio zones are actually two precincts geographically next to each other using a single band (for example Brooklyn 84/88 or Queens 105/113). There are a few single precinct radio zones due to their isolation (Queens 109 for example) and a few three precinct zones (Manhattan 25/28/32) but these are not the norm. As of writing, here are 33 radio zones (if we ignore Staten Island).
The sections listed above (Citywide channels, PBBX, and Radio Zones) are all broadcast throughout the city with the powerful repeater network NYPD has built of hundreds of antennas throughout the city. We’ll elaborate on this in a bit, but it’s important to note as it makes some of the channels effectively citywide with a good antenna and favorable positioning.
There is a subset of channels typically referred to as Tactical that are local only and do not utilize the repeater network. These are used for on the ground organizing and instructions similar to low power family or commercial walkie talkies. These cover patrols, narcotics, SOD, interop with FDNY, special security, Strategic Response Group (riot police), etc. and are completely localized. This means you must be within ~500ft (higher in some areas, lower in others) of the transmitting radio to pick up the signal. Again, these calls are not broadcast over the citywide repeater network or sent to dispatch.
Every officer in NYPD is issued a radio (we’ll discuss the tech more in a bit) and these comms are integral part of operations in the city. It’s worth explaining a little about how these are utilized in day to day work.
Dispatch will utilize radio zones to issue orders to units on the ground. For an example of what this sounds like, if you were tuned to MN 1/5/7 (476.56250MHz) and hear dispatch advise “we have reports of a shoplifter at the CVS Nassau and Fulton, request units to check it out” and a unit will reply “4782 heading to CVS” or something similar. You’ll also hear units make requests to dispatch for more information, to advise on things they say, or occasionally for backup (say a “10-13” call). This is the vast majority of radio chatter.
On citywide channels you’re more likely to find commanders communicating with each other and dispatch with occasional updates from units on the ground. Say during a protest, dispatch might request an update on the tail end of a bike group. A unit on the ground will radio in what street they’re currently passing as they follow the protesters. Commanders will request an update on headcount from aviation who will give an estimate. SRG will be called and told to barricade an entrance to a bridge or expressway. With that said, the use and style of CW’s can change dramatically depending on what’s happening in the city and even the dispatcher currently running the channel. These are loose and flexible airwaves for whatever NYPD needs at the moment.
NYPD has over 50,000 individual radios of a variety models (APX7000 used by SRG, CTB, Transit; APX6000, Vertex VX537, VX800, VXP824, VXP924, etc.). Recently, they’ve been moving to standardize under the Motorola APX 900/Vertex P949 which supports the analog channels currently in use as well as digital P25 decoding and of course encryption (which we’ll discuss later).
Radios for patrol units are interesting here in New York City because they’re extremely low power, typically 1.5-2W for broadcasting - about the same as family walkie talkie packs you might find at a big electronics retailer. Most other police departments use much more powerful units but the nature and geography of the city limits this ability for a number of reasons. First, NYPD operates on foot far more than any other police department in the United States. Other cities have the luxury of patrol cars which give officers a place to store extra batteries, charge their portable units, and utilize a more powerful car radio and accompanying antenna. NYPD on the other hand has to have a small portable radio that can be worn on the hip that lasts 9+ hours across an entire shift. This means they were forced to sacrifice transmitting power to reduce bulk and make sure the battery lasts that long.
For those who have used cheap walkie talkies (Family Radio Service or FRS as it’s known in the radio world), you have probably seen the packages advertise 22+ mile range and then been sorely disappointed when you can’t hear someone more than a block or two away in the city. Well 22 miles may be possible with two people standing on the top of mountains 22 miles away and nothing in between them with good transmitting weather, but giant concrete and steel buildings forming the canyons that is NYC means these signals are reflected, scattered, and spread so the range is dramatically reduced. It may surprise you to learn that these devices are transmitting at essentially the same power as NYPD radios in almost the same frequency range (465ish MHz for FRS and 475ish MHz for NYPD - incidentally freqs that would be used for UHF HDTV in other cities, NYPD gets special treatment from the FCC).
So how is NYPD able to communicate effectively with these low power units in a city with such dense radio blocking geography? The trick is hundreds and hundreds of antennas stationed all around the city wired into a massive receiving and transmitting network. This system is comprised of repeaters (these rebroadcast signals for more reach), voting receivers (these receive transmissions from the weak portable radios), radio sites (where dispatchers receive the transmissions and reply), and emergency control stations with full double redundant wireless backup in case the wired backhaul network goes down.
To understand how this works, let’s walk through a simple transmission. First, if you’ve looked at radio reference for NYPD, you probably assume that say 476.76250 MHz is the frequency used for Precincts 84 and 88 (NYPD BK 84/88 or radio zone 25) transmissions. Turns out that’s only half the story.
The NYPD system uses something called talk-in, talk-out where each transmission is done over two separate frequencies. The way this works is if a patrol officer in 84/88 is making a call to dispatch, their radio will broadcast on 479.76250 Mhz. This signal is then heard by dozens of “voting receivers” installed all over that precinct (most have at least 20-30 of these within the precinct borders). A voting receiver is more sophisticated than a regular antenna and part of what makes NYPD’s system so unique. Our example transmission will likely be heard by several antennas, but we want to make sure the best quality is transmitted back to dispatch. All of these receivers are wired to a central device called a comparator (NYPD uses a Motorola GRV 8000 they had specially designed for the city) which compares the signal strength of all the receivers and sends only the best quality to dispatch (this is where the “voting” term comes from).
Dispatch will hear the signal and then reply on their radio on the talk out frequency 476.76250 MHz which is then sent to the repeater base stations positioned around the precinct. These broadcasts picked up by portables in the field that are tuned to that station and the entire loop is complete.
This talk-in, talk-out system allows NYPD to mix mobile units and dispatch base stations allowing officers to interrupt and talk over dispatch if an emergency occurs (most systems around the country prevent this with dispatch always having priority). As a side note this frequently results in hilarious open carrier messages from forgetful and negligent officers.
Radio zones are set up to only be repeated within their precincts, but citywide and special channels like SOD are carried across the city via the vast network of repeaters ensuring everyone can hear broadcasts even in buildings or below ground in subway stations.
How big is this system? Suffice to say it’s certainly the largest in the United States. I’m not sure what the exact current figures are (you could probably discover this in FCC docs [use FRN 0003462421] if you wanted to dig), but the numbers I’ve heard are from 200-1,400 voting receivers, ~160 base station repeaters, 300 radio sites, 130 emergency control stations, and two separate wireless backup locations.
There are other interesting features such as the use of PL tones (Private-Line, the Motorola version of Continuous Tone-Coded Squelch System or CTCSS) which are low frequency or otherwise generally inaudible tones added to voice transmissions that if they’re not present will tell a repeater or handheld not to transmit that signal. This is the same way NYPD can “blacklist” unauthorized radio transmissions. Of course, if someone knew the publicly available tones and codes coupled with proper talk-in/talk-out freqs, this ability to filter would be moot with even a cheap radio.
In fact, this very behavior has been a problem in the past with one individual receiving a proposed $400,000 fine for operating a radio on NYPD licensed frequencies.
Speaking of these frequencies, NYPD is currently operating in a grey area having not switched to narrowband FM in 2013 as they were required to do by the FCC. The FCC granted the organization a special waiver to delay the transition (citing NYPD’s complaint that it would cost over $88 million and introduce officer safety concerns). To make matters worse, NYPD utilizes T-Band frequencies which are dedicated to TV in many areas and coming up for auction soon (470-512MHz by Feb 2021 under federal mandate). There are attempts to stop the sale by NYC, Boston, LA, and Philadelphia (among others)which all utilize some spectrum within the band for “public safety,” but as of writing little progress has been made leaving the future of the spectrum in question.
No conversation about police radio would be complete without discussing encryption (The Big E as it’s known in the scanner community). I’m going to make this very simple:
NYPD currently utilizes encrypted radio communications on a limited basis. These channels include SWAT and other crisis response specialized groups, CW-4 (sometimes), VIP Escort/Detective/Intel Division, Organized Crime, Internal Affairs, and Command
NYPD has made no firm commitment to moving fully towards encryption, however some individuals have spoken up saying that is the intention and the changes in new radio models will eventually give them the ability to. There is no known timeline, but some have said (pre covid) that end of 2020 is the earliest and sometime during 2021 is likely. Others say this timeline is unrealistic due to testing and officer safety concerns.
We have obtained the following memo from 2018/19 that indicates encryption is eventually the plan.
Encrypted radio systems can utilize a variety of different schemes and protocols, but NYPD (if and when they switch) will be utilizing P25 digital system with AES 256 encryption and potentially rolling encryption codes. You’re not going to crack this, this is the same scheme used by most secure technology like the web, banks, military, etc.
P25, as mentioned, is digital unlike the current analog system. This means NYPD will be able to make more efficient use of the spectrum they utilize (maybe finally actually being narrowband like they’re supposed to), could have higher quality calls (but also will be worse in many scenarios), identify exactly what radios/individuals are transmitting, and if they choose to enable encryption (P25 can function without it) prevent people from listening in.
However, this all comes with many drawbacks. Digital systems either work or they don’t unlike analog systems which gradually fade out and slowly lose contact. If an officer is currently in an area with bad reception, they’ll know it by the garbled transmissions they receive which informs them they need to move outside/above ground/etc. to safely transmit a clear message. With a digital transmission, if it can’t be fully received it won’t be received at all meaning officers won’t know if they’re transmitting and not being heard or not hearing commands from dispatch. This has huge potential safety impacts especially in scenarios such as September 11 where system disruptions or poor transmission quality could mean officers don’t receive vital information that could save their lives. Further, if an officer is calling for help in an area with poor reception dispatch may not hear leaving the officer helpless.
Encryption compounds some of these problems as it prevents easy interoperability work (say I’m NYPD and want to talk to FDNY to organize evacuation or clearing a fire, etc.) that can and has resulted in injuries and deaths in other places around the country prompting some to disable encryption completely from general operations.
For journalists, politicians, civilian review boards, police accountability activists, and other concerned citizens, department wide encryption means a police organization that is already constantly overreaching their authority, violating the rights of individuals, and generally menacing the city is even more opaque. Encryption and other obfuscation of the operations of governmental organizations allegedly acting on behalf of public service is the death of liberty and can and has actively resulted in the death and harm of innocent individuals (and certainly will contribute millions more to the annual lawsuits NYC has to pay out on behalf of the abusive NYPD). Some departments around the country have compromised by releasing time delayed radio streams (typically 30 to 60 minutes) so there is at least a public record available without “being accessible for criminals to use strategically.”
Finally, encryption introduces an interesting flaw where these digital signals can be more easily jammed by bad actors (very illegal). There are talks and resources on this information available online and devices were made for tens of dollars that were able to render digital police radios completely useless or selectively jam encrypted signals getting officers to disable the feature completely. These devices can be very small and placed strategically with a little technical knowledge and introduce further risks to officers if departments purse digital encryption.
To put it short, encryption is bad for officer safety when you actually explore the technology and bad for the public who must deal with a more secretive and abusive police. As the comms which require secrecy are already encrypted, there is no need to encrypt the entire system except for the drive of police to reduce their public accountability at the potential cost of officer lives (a sacrifice we shouldn’t be surprised they’re willing to make).
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