AntennaHeadAn aviation-band scanner for your local airport
Find your airport’s frequencies, save them as Favorites, group them in a Category, and let AntennaHead scan them. You can try the pages involved in the live UI demo.
Overview
Aircraft and air traffic control talk on AM voice channels between 118 and 137 MHz, a range an RTL-SDR radio receives well. In this project you’ll look up the frequencies for the airport nearest you, save each one as a Favorite, collect them in a Category, and let AntennaHead scan the whole set and stop whenever someone is talking. Listening is receive-only, and you can do it from any device on your network.
You’ll need: AntennaHead running with an RTL-SDR Blog V3 and an antenna. The telescopic whip that comes with the radio works for aircraft or towers within a few miles; for a longer range, use an outdoor antenna made for the airband. You’ll hear the strongest signals, usually the tower and the approach and departure controllers, first.
Step 1: Find your airport’s frequencies
Look up an airport near you and write down the frequency for each service it uses. Good free sources:
RadioReference.com
Search by state, county and airport. Airport pages list tower, ground, clearance delivery, approach, departure and ATIS, along with the type of modulation. Some details are free; others need a paid account.
AirNav.com
Enter an airport’s identifier (for example KLIT) to see its communications frequencies, with no account required.
What you’ll typically find
ATIS (a looping weather recording), Clearance Delivery, Ground, Tower, and Approach/Departure. Larger airports often have several approach and departure frequencies, one for each direction or altitude.
Airband voice is AM, not FM. The frequencies are in MHz, such as 118.700.
Step 2: Save each frequency as a Favorite
Use the Airband Tuner to enter a frequency, and save it so you can return to it with one tap.
1. Open the Airband Tuner
Go to Radio → Tuner and tap Airband, which is set up for AM and the 108–400 MHz range.
2. Enter the frequency
Type a Station Name such as “Tower”, then tap the digits of the Frequency. Use + and − to nudge it.
3. Try it
Tap Listen to confirm you can hear it. If it’s a busy frequency, you’ll hear a transmission within a few minutes.
4. Add it as a Favorite
Choose a category in Add to category if you’ve already made one, then tap Add New Favorite Frequency. Repeat for each frequency on your list.
Name each Favorite with the airport and the service, for example “KLIT Tower” or “KLIT Approach”, because those names appear in the scanner and on Now Playing.
Step 3: Group them into a Category
A Category is a named collection of Favorites, and it’s what the scanner steps through.
Create the Category
Go to Radio → Categories and tap Add New Category. Name it for the airport, such as “KLIT Airport”.
Add your Favorites
Put the Favorites for Clearance Delivery, Ground, Tower, Approach, Departure and so on into it, using the Add to category menu when you save a Favorite in the tuner, or on a Favorite’s Edit page.
Turn on scanning
Open Category Settings and set Enable Category Scanning to Enabled. Set Modulation to AM, since the settings here apply to every frequency in the Category. Then tap Save Changes.
Keep one Category per airport, or per job. You could make a second one for a different airport, or an “Emergency and guard” Category for 121.500.
Step 4: Scan, and set the squelch with Now Playing
Squelch is the volume gate that keeps the audio silent until a signal is strong enough. If it’s too low, you’ll hear hiss and the scanner will stop on noise. If it’s too high, you’ll miss weaker transmissions. The Now Playing page shows you the numbers to set it by.
1. Start the scan
Open your Category and tap Scan All Frequencies. AntennaHead steps through the Favorites and stops on one when a signal crosses the squelch level.
2. Open Now Playing
Now Playing shows the current frequency, the signal level and the squelch level, updating as the scanner moves. In scan mode the squelch is the one under Category Scanner Settings.
3. Read the quiet level
Watch the signal level between transmissions. That’s the noise floor of your antenna and location.
4. Read the talking level
When someone transmits, the signal level jumps up. Note the lowest value that you still want to hear.
5. Set the squelch between
In Category Settings, set Squelch Level to a value just above the noise floor and below the transmissions. Tap Save Changes, then scan again and check Now Playing.
6. Adjust the delay
Squelch Delay sets how long the scanner holds on a frequency after the signal drops. Raise it so a controller’s reply isn’t cut off, lower it so the scan moves on faster.
Not every squelch value suits every frequency. A distant tower may need a lower setting than the one next door. If the scanner keeps stopping on noise, raise the squelch a little at a time; if you’re missing calls, lower it. To tune one Favorite by itself, use its own Squelch Level under Edit.
Tips
Read it as you listen
Turn on Live Captions in the scanner clip to see the radio chatter as text.
Listen on any device
The scanner’s audio streams to your iPhone, Apple Watch or Apple TV, so you can leave the Mac and RTL-SDR radio at home and carry the stream with you.
Record the good stuff
Use the Recordings screen to capture the stream to a file and play it back later.