You’ve probably been there. You get your RTL-SDR, you’re hyped to track some planes, and you open up SDRangel. Then, you see the interface. It looks like a flight deck from the 1970s—buttons everywhere, sliders that don’t seem to do anything, and a waterfall that stays stubbornly blank. It's frustrating. Honestly, SDRangel is a beast of a program, but it's not exactly "plug and play" if you don't know which knobs to turn.
Basically, if your sdrangel adsb feed settings aren't dialed in, you aren't seeing a thing. You might get the software running, but without the right sample rates and thresholds, those 1090 MHz signals are just getting lost in the noise.
Getting the Hardware Foundation Right
Before we even touch the ADS-B demodulator plugin, we have to talk about the source. You can't decode a signal the software isn't actually "seeing" properly.
First, the center frequency. Planes talk on 1090 MHz. In SDRangel, you’ll want to set your device center frequency to exactly 1,090,000 kHz.
Now, here is a pro tip that most people miss: The "DC spike." Most SDRs, like the RTL-SDR v3 or v4 and the SDRplay series, have a tiny bit of noise right at the center of the spectrum. If you tune exactly to 1090 MHz, that spike might sit right on top of your data. Some experts recommend tuning your device to 1,090,400 kHz and then using the Delta-f setting in the ADS-B demodulator to shift it by -400,000 Hz. This moves the actual decoding away from the center spike. It’s a cleaner way to work.
Sample Rates: The Magic Numbers
Sample rate is where everyone trips up. ADS-B signals have a chip rate of 2 Mchip/s. This means you need a baseband sample rate of at least 2 MSa/s.
If you're using a standard RTL-SDR, try setting your sample rate to 2.4 MSa/s. I’ve seen people try to crank it up to 8 or 10 MSa/s, but honestly, your CPU will probably start crying, and you’ll drop frames. Stick to 2.4 or maybe 3.2 if your hardware is beefy.
💡 You might also like: What Does Diffusion Do: Why This Invisible Force Is Changing Everything From Biology To AI
For the Channel Sample Rate (SR) inside the ADS-B demodulator window, try to match it to your baseband. Usually, a value of 2 or 4 MSa/s gives the most reliable decodes. If these numbers don't match, SDRangel has to do extra math (interpolation or decimation) to make them play nice, which just eats up more of your laptop's battery.
Tuning the ADS-B Demodulator Plugin
Once the radio is humming, you need to open the ADS-B Demodulator (it’s the one with the little plane icon). This is where the actual "sdrangel adsb feed settings" live.
There are three settings here that dictate whether you see a 747 or just static:
- Correlation Threshold: Think of this as the "how sure are you?" setting. It's the dB level the signal must reach to be considered a real 1090ES preamble. Start with a value of 7. If you’re in a quiet area with a great antenna, you can drop it to 5 to catch distant planes. If you go too low, you’ll get "ghost" planes that don't exist.
- Mode S Preamble Chip Errors (PCE): This allows for some "slop" in the signal. A value of 1 or 2 is usually fine.
- S Button: This is the "Mode S" toggle. You definitely want this checked. It enables the demodulation of ELS (Elementary Surveillance) and EHS (Enhanced Surveillance) frames. Basically, it’s the difference between seeing a dot on a map and seeing the plane's altitude, heading, and speed.
The Gain Problem
"Max it out!" That’s what most people say about gain. They're usually wrong.
If you live near an airport, maxing out the gain will saturate the receiver. The signal becomes a big, distorted mess. If you're using an RTL-SDR, try a gain of around 40 to 45 dB first. If you’re using an SDRplay device, turning on the IF AGC (Automatic Gain Control) is often the smartest move.
You’ll know the gain is right when the "Level Meter" in the plugin stays in the green but kicks up sharply when a signal hits. If it's constantly red, you're deafening the software.
Connecting to the Outside World
SDRangel is great because it’s a "one-stop shop," but sometimes you want to feed that data to other places like Virtual Radar Server (VRS) or FlightAware.
To do this, you need to look at the data output. SDRangel can act as a server. You can download the aircraft database (there’s a button right in the plugin for this) which adds registration and owner details to your local list.
💡 You might also like: Why auctiontwin.shop video header bidding is changing the way publishers monetize
But for external feeds, you’re looking at the Feature Plugins. You can add a "Local Network" or "UDP" output to push those decoded frames to a different port on your computer. Most external software expects data on port 30003 (BaseStation format) or 30005 (Beast format).
The QNH and Altitude Mystery
Have you ever noticed the altitudes look... wrong?
Planes report pressure altitude. This is based on a standard pressure of 1013.25 hPa. If the local weather is different, the "real" altitude will be off.
In the SDRangel ADS-B settings, you’ll see a QNH field. You can manually enter your local air pressure in Hectopascals (hPa) or millibars. If you leave it unchecked, the software tries to guess based on planes flying below the "transition altitude." It’s a neat trick that makes your 3D map way more accurate.
Troubleshooting the "No Planes" Bug
If you’ve done all this and still see nothing, check these three things. Seriously, it's almost always one of these:
📖 Related: Life in the space station: What it actually feels like for astronauts
- The Antenna: Are you using the little whip antenna that came in the box? If it's indoors, you’re basically trying to listen to a whisper through a brick wall. Put it near a window or, better yet, get a dedicated 1090 MHz antenna outside.
- My Position: Go to Preferences > My Position. If SDRangel doesn't know where you are, it can't calculate the distance to the aircraft or show them correctly on the map.
- The Play Button: It sounds stupid, but you have to hit the "Start" button on both the main device and the specific ADS-B channel. If the little green light isn't on for both, nothing is happening.
Tracking planes with SDRangel is incredibly rewarding once the setup is finished. You aren't just looking at a website; you are the one pulling that data out of the air. It’s your radio, your antenna, and your settings doing the work.
Next Steps for Your Setup
- Download the Aircraft Database: Click the "Download" button in the ADS-B plugin settings to instantly turn ICAO hex codes into real airline names and logos.
- Check your SR: Ensure your Channel Sample Rate is exactly 2MSa/s or 4MSa/s to keep the CPU load manageable while maintaining high decode rates.
- Adjust QNH: Look up your local METAR for the nearest airport and input the current pressure to calibrate your altitude readings.