The Stratux open-source ADS-B receiver and the hundred-dollar build that changed how general aviation pilots see weather and traffic

Stratux is an open-source, DIY ADS-B In receiver built on a Raspberry Pi that delivers FAA weather radar, METARs, TFRs, and traffic data to your iPad or tablet for roughly $100 in parts. It feeds the same free government broadcast data as commercial receivers like the Stratus, Sentry, or GDL 50—units that cost $500 to $1,000. The project has reshaped the portable ADS-B market since its launch in 2015 and remains one of general aviation’s most compelling examples of open-source engineering.

How Does ADS-B Weather and Traffic Actually Reach Your Cockpit?

The FAA operates a nationwide network of ground stations as part of the Automatic Dependent Surveillance-Broadcast (ADS-B) system. These stations receive position reports from aircraft equipped with ADS-B Out transponders and uplink a product called FIS-B (Flight Information Services-Broadcast). FIS-B carries NEXRAD radar imagery, METARs, TAFs, winds aloft, PIREPs, NOTAMs, and TFRs, all broadcast on the 978 MHz UAT (Universal Access Transceiver) frequency.

The critical fact most pilots overlook: that data is free. The FAA broadcasts it continuously, nationwide, to anyone with a receiver tuned to 978 MHz. No subscription. No monthly fee. You just need hardware that can listen and decode.

What Hardware Do You Need to Build a Stratux?

The complete build requires a handful of commodity electronics components:

• Raspberry Pi (most builders use a Pi 3B+ or Pi 4)
• Two RTL-SDR dongles — small USB software-defined radio receivers originally designed for European digital television. One tuned to 978 MHz for UAT/FIS-B weather, one tuned to 1090 MHz for Mode S/ADS-B Extended Squitter traffic.
• WAAS-capable GPS receiver — typically a VK-162 USB module or a GlobalSat unit
• A case — 3D-printed or a simple plastic project box
• Micro SD card flashed with the Stratux disk image
• Power source — USB battery pack or cigarette lighter adapter

Total cost runs approximately $100, depending on component sourcing.

How Does the Stratux Software Work?

The Stratux project was started around 2015 by developer Christopher Young and grew into a community-driven open-source effort hosted on GitHub. The codebase handles signal demodulation, message parsing, GPS position processing, and GDL 90 protocol output.

GDL 90 is Garmin’s standard protocol for feeding ADS-B data to electronic flight bags. Because Stratux speaks GDL 90 natively, it is recognized by ForeFlight, Garmin Pilot, iFly, FlyQ, and most other EFB apps as if it were a commercial receiver. You connect your iPad to the Stratux Wi-Fi network, open your app, and weather and traffic appear.

How Does Stratux Compare to Commercial Receivers?

On weather, the data is identical. Stratux delivers the same NEXRAD radar mosaic as a Stratus or Sentry. Same source, same latency. FIS-B radar imagery updates roughly every five minutes for regional composites and every fifteen minutes for the national picture. That latency is a property of the FAA broadcast, not the receiver. A $1,000 Sentry Plus gets the same five-minute-old radar as a $100 Stratux. METARs, TAFs, winds aloft, and TFRs arrive at the same cadence because they all originate from the same FIS-B uplink.

Traffic is more nuanced. With two SDR dongles, Stratux receives both UAT (978 MHz) and Extended Squitter (1090 MHz) traffic. It displays ADS-B Out–equipped aircraft on both frequencies and shows TIS-B (Traffic Information Services-Broadcast) targets where available.

An important limitation applies equally to Stratux and commercial portables: TIS-B is only generated in response to an ADS-B Out signal. If your aircraft lacks ADS-B Out, the ground station does not generate TIS-B traffic for your receiver. You will still see aircraft broadcasting ADS-B Out directly, but your traffic picture will have gaps. This is a system-level constraint, not a Stratux shortcoming.

What Features Do Commercial Receivers Offer That Stratux Does Not?

Commercial units justify their price premium with several additions:

• Integrated AHRS (Attitude and Heading Reference System): The Sentry Plus includes a built-in AHRS that provides synthetic backup attitude indication on your iPad. Stratux supports AHRS through add-on boards (BMP280 or MPU9250 IMUs), but these require calibration, are sensitive to placement, and carry no certification or formal testing.
• Carbon monoxide detection: The Stratus 3 added a CO sensor. Stratux does not detect CO.
• Pressure altitude encoding: The Sentry Plus includes a barometric altitude encoder for improved traffic accuracy. Stratux uses GPS altitude, which is less precise for traffic deconfliction.
• Thermal management and build quality: Commercial receivers are designed, tested, and packaged for cockpit environments. A Raspberry Pi on a glareshield in direct July sunlight in Texas can thermal throttle. Builders manage this with heatsinks, fans, or aluminum cases, but they are their own quality assurance.

Is Stratux FAA-Approved?

No. Stratux is not certified, not TSO’d, and carries no FAA approval. It cannot meet any regulatory requirement. It provides advisory information only—the same legal status as a commercial portable receiver like the Stratus or Sentry. For VFR situational awareness, this is perfectly acceptable. You are supplementing your decision-making with data you would not otherwise have, which is a net safety gain regardless of what the receiver cost.

Should You Build One?

Build a Stratux if you enjoy tinkering, want to understand exactly how ADS-B data flows from ground station to moving map, and are comfortable being your own tech support. You will learn more about the ADS-B system by building a receiver than by buying one.

Buy a commercial receiver if you want zero-maintenance reliability on every flight. The engineering, thermal management, and support behind products like the Sentry or Stratus are worth the premium for pilots who prioritize plug-and-play simplicity.

Stick with commercial products if you fly professionally or for hire, for the liability protection alone.

Why Stratux Matters Beyond the Price Tag

Stratux is more than a budget gadget. It is an existence proof that changed the market:

• It demonstrated that ADS-B receive hardware is commodity electronics.
• It proved that volunteer-written open-source software can implement complex aviation protocols reliably.
• It applied competitive pressure across the portable ADS-B market. When Stratux gained traction in 2015–2016, the cheapest commercial option exceeded $500. Today the Garmin GDL 50 sells for around $400. Commercial manufacturers had to justify their premiums with genuinely better features rather than the absence of alternatives.

The GitHub repository has received contributions from dozens of developers. Community members have adapted the platform for different GPS receivers, SDR chipsets, the compact Raspberry Pi Zero form factor, dual-band antennas, and even integrated cellular modems for pre-takeoff ground-based weather.

Combined with the FAA’s MOSAIC rulemaking efforts and growing acceptance of ASTM standards for light sport avionics, affordable uncertified products like Stratux are pushing the industry toward a future where capable avionics do not carry inflated price tags.

Key Takeaways

• Stratux is a $100 open-source ADS-B In receiver built on a Raspberry Pi that delivers the same free FAA weather and traffic data as commercial units costing $500–$1,000.
• Weather data is identical across all receivers—the NEXRAD imagery, METARs, and TFRs all come from the same FIS-B broadcast with the same update latency.
• Traffic coverage depends on your aircraft’s ADS-B Out equipage, not your receiver brand—a limitation of the FAA system, not of Stratux.
• Commercial receivers add AHRS, CO detection, pressure altitude, and superior build quality—features that matter for certain pilots and missions.
• Stratux reshaped the portable ADS-B market by proving the technology is commodity hardware, driving down prices industry-wide.