What Can You Do With an RTL-SDR? 12 Beginner Projects
What can you do with an RTL-SDR? 12 projects by level, from aircraft (ADS-B) and ships to Meteor-M satellites and the hydrogen line, with the kit needed.
With an RTL-SDR, a USB radio receiver that costs around €60, you can track the aircraft and ships around you, receive images from weather satellites, read your own wireless sensors and even detect hydrogen in our galaxy. Here are 12 projects in four levels. Each one tells you what to add, in antennas or software, to move on to the next.
If your dongle isn't set up yet, start with our RTL-SDR beginner setup guide: drivers, software and a first FM signal.
Every project here is about receiving transmissions meant for the public, or your own. An RTL-SDR cannot transmit.
Level 1: FM, aircraft (ADS-B), ships (AIS)
These work with the dongle and a simple antenna, often on the first evening.
1. FM broadcast and RDS data
This is the starting project. In SDR++, select WFM mode and tune between 87.5 and 108 MHz. RDS (Radio Data System) carries the station name and the current track title. SDR++ can display it, depending on the version and modules installed. Above all, this project teaches you to set the gain and read a waterfall.
Kit: the dongle and its antenna.
2. Digital radio (DAB+)
DAB+ is digital terrestrial radio. It broadcasts in Band III, roughly 174 to 230 MHz, and covers much of the UK and a growing share of Europe. The open-source welle.io decodes it with an RTL-SDR on Windows, Linux and macOS. You see the multiplexes, the station list and the signal quality.
Kit: the dongle, and a dipole with elements of about 40 cm.
3. Live aircraft tracking (ADS-B)
Airliners continuously broadcast their identity, position, altitude and speed on 1090 MHz; this is ADS-B. With the open-source readsb decoder and the tar1090 web interface, you get your own live traffic map, fed by your own antenna. A Raspberry Pi can run it around the clock.
Kit: the dongle and a 1090 MHz antenna (≈ 6.9 cm elements as a dipole), ideally by a window or outdoors.
It is the most rewarding first project, and it has its own full guide: track aircraft with an RTL-SDR.
4. Ships (AIS)
AIS (Automatic Identification System) is the maritime version of ADS-B. Ships broadcast their name, position and heading on 161.975 and 162.025 MHz. AIS-catcher decodes both channels with an RTL-SDR and draws a map. It is worth trying near the coast, and also near large rivers and canals used by commercial traffic.
Kit: the dongle, a dipole with elements of about 46 cm, and a high spot with a view of the water.
5. Mapping the spectrum (rtl_power)
rtl_power, which ships with the driver, sweeps a wide frequency range and logs the received power. Turn the output into a heatmap and you can see FM, digital TV, mobile networks and sensor bands. Leave it running overnight and it shows what transmits at which time of day.
rtl_power -f 80M:1000M:100k -g 30 -i 10 -e 1h scan.csv
The heatmap.py script, included in the Debian rtl-sdr package (in its examples folder), turns the CSV file into an image.
Kit: the dongle and a wideband or telescopic antenna.
Level 2: weather satellites (Meteor-M), radiosondes
6. Meteor-M weather satellite images (LRPT)
For years, the flagship RTL-SDR project was receiving the US NOAA-15, 18 and 19 satellites in APT mode. That is no longer possible. According to rtl-sdr.com, NOAA-18 was decommissioned in June 2025, then NOAA-15 and NOAA-19 in August 2025, and their transmitters are off. Many online tutorials have not been updated. If a guide tells you to receive NOAA APT on 137.1 or 137.9 MHz, it is out of date.
The Russian Meteor-M N2-3 (launched 2023) and Meteor-M N2-4 (launched 2024) satellites remain the accessible target for hobbyists. They transmit LRPT, a digital mode, around 137 MHz: 137.1 or 137.9 MHz depending on the satellite and the period. The open-source SatDump handles recording, demodulation and image processing on Windows, Linux and macOS.
A few tips:
- Check the status before you start. Frequencies and satellite health change over time. Look at the forums and the SatDump community channels before each session.
- Plan for a pass. A satellite crosses the sky in 10 to 15 minutes. SatDump, Gpredict or a prediction website give you the pass times.
- Get the antenna right. A V-dipole works well. Use two elements of about 54 cm, opened to 120°, lying flat and pointing north-south, outdoors, with the clearest possible view of the sky. QFH or turnstile antennas perform better but take longer to build.
Kit: the dongle, an outdoor 137 MHz antenna, and often decent coax. A low-noise amplifier (LNA) helps if the cable run is long.
7. Weather balloon radiosondes
Every day, national weather services across Europe launch weather balloons from dozens of stations. Their radiosondes transmit position, altitude and measurements between 400 and 406 MHz. radiosonde_auto_rx finds and decodes them automatically with an RTL-SDR on Linux or a Raspberry Pi, and can share positions with the community tracker SondeHub. Some hobbyists then go and recover the sonde where it lands. If you do, respect private property and any instructions printed on the sonde.
Kit: the dongle, a 400 MHz vertical antenna (≈ 18 cm), and a Raspberry Pi for a permanent station.
8. The International Space Station (ISS)
The ISS carries an amateur radio APRS digipeater on 145.825 MHz. During events announced by the ARISS programme, it also sends SSTV (slow-scan television) images on 145.800 MHz. You can decode them with SSTV software fed with audio from SDR++. It is a perfect way to test a 2 m antenna.
Kit: the dongle, a dipole with elements of about 50 cm, SSTV software and a pass schedule.
Level 3: 433 MHz sensors in your home (rtl_433)
9. Decoding your own sensors with rtl_433
Weather stations, freezer thermometers, tyre-pressure sensors and meters: many devices transmit in the clear on 433.92 MHz or 868 MHz. rtl_433 recognises several hundred models and prints their readings.
sudo apt install rtl-433 # Debian, Ubuntu
brew install rtl_433 # macOS
rtl_433 # listens on 433.92 MHz by default
rtl_433 -f 868.3M # 868 MHz band
Once you have found your own station, rtl_433 can publish its readings over MQTT (-F mqtt://...) to a home-automation system such as Home Assistant. You will also see your neighbours' sensors go by. Only keep and use your own: what leaves someone else's home is not yours.
Kit: the dongle and a dipole with elements of about 17 cm (433 MHz) or 8.6 cm (868 MHz).
10. Understanding your own remote control's signal
Your wireless doorbell or smart-plug remote probably transmits OOK, an on-off modulation. Universal Radio Hacker (URH) records the signal with an RTL-SDR, demodulates it and shows you the bits. It is an excellent introduction to fixed codes versus rolling codes, and to why modern gates and cars use the latter.
Stick to your own devices. The dongle cannot retransmit anyway, and analysing someone else's remote is not a game.
Kit: the dongle, the 433 MHz antenna, and a remote you own.
Level 4: radio astronomy (the hydrogen line)
11. Hearing meteors with the GRAVES radar
The French military GRAVES radar, whose transmitter is near Dijon in eastern France, continuously beams a signal into the sky on 143.050 MHz. When a meteor burns up, its ionised trail briefly reflects that signal back to the ground. Set SDR++ to USB (upper sideband) slightly below 143.050 MHz, for example 143.049 MHz. Each meteor then gives an audible "ping" and a streak in the waterfall. During showers such as the Perseids in August or the Geminids in December, you can count dozens per hour. Hobbyists across much of western Europe use it.
Kit: the dongle, a 2 m antenna (dipole or Yagi) pointed towards east-central France, and patience.
12. The hydrogen line at 1420 MHz
Neutral hydrogen in the Milky Way emits at 1420.405 MHz. An RTL-SDR can detect it if you add three things:
- a directional antenna, such as a cardboard horn lined with foil or a small dish;
- a low-noise amplifier;
- a filter centred on 1420 MHz.
Average for a long time with rtl_power or a Python script, then compare the galactic plane with an "empty" patch of sky. Repeat the measurement and you can even see the Doppler shift caused by the galaxy's rotation.
This is the most demanding project on the list. It takes some building, careful measurement and a stable TCXO.
Kit: the TCXO dongle, a 1420 MHz LNA and filter, a directional antenna, and a computer to record.
Extra kit for each project
| Project | Frequency | Antenna | Useful extra | Software |
|---|---|---|---|---|
| FM, RDS | 87.5–108 MHz | Telescopic | None | SDR++ |
| DAB+ | ≈ 174–230 MHz | Dipole ≈ 40 cm/element | None | welle.io |
| ADS-B | 1090 MHz | 1090 dipole or vertical | 1090 MHz filter, Raspberry Pi | readsb, tar1090 |
| AIS | 162 MHz | Dipole ≈ 46 cm/element | High location | AIS-catcher |
| Spectrum | Wideband | Telescopic | None | rtl_power |
| Meteor-M | ≈ 137 MHz | V-dipole, QFH | LNA, good coax | SatDump |
| Radiosondes | 400–406 MHz | Vertical ≈ 18 cm | Raspberry Pi | radiosonde_auto_rx |
| ISS | 145.8 MHz | 2 m dipole | Pass schedule | SDR++, SSTV software |
| Sensors | 433 / 868 MHz | Short dipole | None | rtl_433 |
| Remote control | 433 MHz | Short dipole | None | URH |
| GRAVES meteors | 143.050 MHz | 2 m dipole or Yagi | None | SDR++ |
| Hydrogen | 1420 MHz | Horn or dish | LNA + filter | rtl_power, scripts |
A telescopic dipole like the one in our SDR antenna kit covers projects 1 to 11 on its own: you only adjust the element length. For ADS-B and satellites, a fixed outdoor antenna is what makes the biggest difference next.
What you must not listen to
Receiving is not transmitting, and French law is broadly permissive about listening to transmissions meant for the public: broadcast radio, radio amateurs, ADS-B, AIS, weather satellites. Private communications are a different matter. Cordless phones, pagers, emergency-service radio and private networks are covered by the secrecy of correspondence. Article 226-15 of the French Penal Code punishes intercepting, using or disclosing them in bad faith. Other countries have their own rules; in the UK, for example, the Wireless Telegraphy Act 2006 restricts making use of messages you are not authorised to receive.
The practical rule: if a transmission is obviously not meant for the public, don't look for it, don't record it and don't share it. We go through the French texts in is SDR listening legal in France?. This is general information, not legal advice.
Getting started
A TCXO RTL-SDR and a telescopic dipole cover the first ten projects on this list. Our RTL-SDR receiver (≈ 24 MHz – 1.7 GHz, receive-only, around €60) will be back soon: join the waitlist to be notified. If you are shopping for someone just starting out, our gifts for beginner hackers follow the same idea: learn with real hardware, legally.