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How to Listen to Military ATC Communications

Buckley Air Force Base

Overview

I had already been familiar with ATC listening and ADS-B interception for a little while, but I decided to share this write-up with you.

To put it simply, I will show you how to use the ATC listening features of my software, TYPHOON, and how to deepen your research using .asx and .pls listening files provided by the open-source platform LiveATC.

ATC Map

Using TYPHOON

First, I will use TYPHOON to identify various ICAO codes with the following color code:

Blue: Normal
Orange: Military
Red: No listening available

By clicking, you can obtain various details about the airport, such as its name, IATA and ICAO codes, city, type, location, METAR weather, as well as the available listening channels and their corresponding frequencies.

KBKF Data

Using the map overlay options in TYPHOON, it is also possible to get precise information about the location. (Real-time satellite view coming soon ^^)

KBKF

LiveATC Streams

Normally, when you click on one of the channels for listening, you will be automatically redirected to a LiveATC link for live listening through a web app.

However, there are several files .asx, .pls available that allow direct connection to the ATC feed provided by LiveATC, and that's what I'd like to focus on.

ATC

If we look inside the .asx and .pls files, we find interesting information, such as a URL with an .mp3 file.

Cat KBKF

Recording with ffmpeg

It is then possible to directly record the transmitted ATC stream using ffmpeg, a tool for processing audio and video streams.

To do this, use the following command:

ffmpeg -i http://d.liveatc.net/kbkf1_atis.mp3 capture_kbkf_atis.wav

We can clearly see that it correctly identifies the stream as ATC and also provides the precise name of the channel ATIS (Automatic Terminal Information Service) we are listening to.

You can also use this command for more accurate capture using the provided information, such as the 8000 Hz sample rate:

ffmpeg -i http://d.liveatc.net/kbkf1_atis.mp3 -ar 8000 -ac 1 -acodec pcm_s16le spectral_capture_kbkf_atis.wav
Listen KBKF

To stop the recording, press CTRL+C.

Once your .wav file is correctly saved, you can open it and listen to the captured ATC stream.

Listen KBKF 2 Listen

Spectrum Analysis

What's particularly interesting is that we can reverse-engineer the captured stream by displaying the spectrum at each frame of the .wav file.