How to build Signals Intelligence capabilities for the ACE

Readers had a lot of great feedback about the last article on police scanners. (That article is here.)

Today, I’ll write a bit more about Signals Intelligence (SIGINT), but first here’s some of the last article’s feedback, summarized:

  • D.C. Metro police asked Broadcastify not to air D.C.-area police transmissions during the 2017 Inauguration. (If you count on online/app scanner feeds, you may be out of luck during an emergency.)
  • LOTS of emails were about encryption. The Home Patrol II — or any other police scanner for that matter — won’t decrypt anything. (It will, however, decode digital voice transmissions.) More law enforcement agencies are moving to encrypted communications, either for tactical channels or for their entire communications systems. (Additionally, some police departments are moving away from radio dispatch and towards computer-aided dispatch, a software system that displays dispatch information on computers inside police vehicles.) A radio scanner is a great tool, but understand that there are some limits to its use. I still highly recommend having a police scanner, in general, even if you only have Fire, EMS, and other non-police channels.
  • “A Home Patrol II with a discone at 30ft above ground pulls it ALL in.”
  • Some readers want to learn more about using a ADS-B receiver to monitor the air space above them. (“Situational awareness involves three dimensions.”) I’ll answer that one in a future Forward Observer Dispatch blog post.

Bradley has a few questions along the lines of SIGINT:

“How do I integrate my scanners and other receivers into a system? What frequencies should I monitor? Should I setup my laptop with an SDR? Should I join AmRRON?”

All great questions.

Let me answer the last one first: YES. The American Redoubt Radio Operators Network (AmRRON) is my go-to resource for all things radio communications. John Jacob is extremely knowledgeable about this stuff, and he’s an excellent resource on the radio/comms/signals side.

Now for all the other questions: If you can staff a SIGINT section in your ACE/intelligence section — even just two people — then you’re more capable than 90 percent of your peers.

Depending on the operational tempo during an emergency, you may want to let the police scanner run in the background so everyone can listen to what’s breaking, or put one person with headphones in the corner to write down SALUTE reports as they come across the scanner.

Next, you can check out to see what other frequencies are in use in your area. If there are lots of other transmissions aside from Police, Fire, and EMS, then I would seriously consider running a second scanner aside from your police scanner. You can use the frequencies listed on Radio Reference to program your second scanner for the non-emergency channels, which could still be transmitting useful information during the emergency.

If you wanted to set up a Software-Defined Radio (SDR) alongside the scanners — if you have the staff to do it — then you could run the Automated Dependent Surveillance – Broadcast (ADS-B) receiver to monitor your airspace. This really goes back to your collection requirements. Is monitoring flights above you necessary? If not, then direct your time and resources to other pursuits. Running an SDR to record what’s coming over the police scanner is another option. This is a huge rabbit hole that we’ll have to cover in another post.

The truth is that even a rudimentary SIGINT capability — a police scanner and a receiver to monitor non-emergency channels — is going to give you an advantage over your non-intelligence-trained peers.

One caveat on Analysis & Control Element (ACE) operations, in general: the greater the emergency, the more likely you’ll be overwhelmed. Analysis is always the bottle neck. We can set up an automated OSINT collection system, receive emails, phone calls and text messages from human sources, and have our SIGINT section up and running, but unless you have the time and brainpower to put it all together and produce the intelligence, you’re going to be wasting resources.

I highly recommend that you prioritize: get in touch with local friends, monitor local open source feeds and the police scanner, battle track the security situation, record information of intelligence value, and ensure that you’re communicating these things to drive informed decision-making. If you can do all these things, then we can start branching out to other collection methods and sources of information.

Don’t suffer from collection overload. There’s only one thing worse than missing collectible information, and that’s collecting it but not being able to analyze and use it. (That’s exactly NSA’s problem: they’re collecting x terabytes per second, but until an analyst sees it, it’s basically worthless.)

I hope that answers at least some of what you wanted to know.


If you want to take the next steps in intelligence training, there are over two dozen hours of intelligence, security, and defense videos and webinars available at the Schoolhouse. If you know that you need to develop these skills, I’ve made this super easy for you: join, learn, and then do.


Always Out Front,
Samuel Culper



Samuel Culper is a former military intelligence NCO and contract Intelligence analyst. He spent three years in Iraq and Afghanistan and is now the intelligence and warfare researcher at Forward Observer.

1 Comment

  1. There are quite a few impairments to the use of ADS-B data for ground-based situational awareness (as opposed to the intended use, which is collision avoidance in the air). Without on-line access to the FAA database, even targets with tail numbers won’t have much meaning. Additionally, aircraft operators are permitted to enter non-tail-number codes for SAR ops, for example, and airliners can enter their flight code (airline flight number) in place of the aircraft registration number. Aircraft flying below 10,000 ft. MSL and outside of airspace that does not require a Mode C transponder, are not required to transmit ADS-B Out data. Finally, operators can squawk an anonymous code (hide the registration number). This comment is written by an owner of multiple aircraft that are Mode ES and ADS-B equipped, not by an air traffic controller or ADS-B engineer, so I might not know what other options exist, and additional comments or corrections would be appreciated.

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