Open flight tracking exists because tens of thousands of volunteers share what their antenna hears. Here is how those individual bubbles of sky become a global picture, and where the model still falls short.
ADS-B transmits on 1090 MHz, and at that frequency propagation is essentially line of sight. The practical consequence is that range is governed by geometry rather than by transmitter power: the higher the antenna and the clearer its view of the horizon, the further it hears. A rooftop antenna with an unobstructed outlook will comfortably outperform a more expensive one sitting behind a building.
Because the Earth curves away, even an excellent site loses aircraft beyond roughly 200 to 300 nautical miles, and low-flying aircraft disappear much sooner. There is no antenna that solves this. The only fix is more antennas, in more places, which is precisely what the volunteer networks are.
| Layer | Role |
|---|---|
| Feeders | Individual volunteers, typically running a Raspberry Pi with an RTL-SDR dongle and a 1090 MHz antenna. Each decodes locally and forwards what it hears. Building one costs roughly $40. See the receiver setup guide. |
| Aggregator networks | adsb.fi, adsb.lol, airplanes.live, OpenSky and others combine many feeders into open regional and global streams, handling deduplication, storage and public APIs. |
| Satellite ADS-B | Space-based receivers pick up broadcasts over oceans and remote regions where no ground receiver can exist, filling the largest structural gap in the terrestrial picture. |
| Consumers | Platforms such as AeroScope read the aggregated feeds and add analysis. See data sources for exactly which feeds are used. |
Not every transponder broadcasts a GPS position. Older Mode S aircraft reply with identity and altitude but no coordinates. Networks with several receivers hearing the same reply can still locate them using multilateration, which compares the tiny differences in arrival time at four or more stations to solve for position.
Multilateration is a genuine collaborative-network capability rather than a property of any single receiver, and it illustrates the wider point: density does not just extend coverage, it unlocks methods that are impossible alone.
Coverage is thinnest wherever few people are feeding. If you are in an under-covered region, a single receiver measurably improves the global picture. The practical steps are documented in the receiver build guide: flash a Raspberry Pi, install a decoder such as readsb, mount the antenna as high and as unobstructed as you can, then feed one or more aggregator networks.
AeroScope does not run its own feeder network and does not ask you to feed it directly. Feed the open aggregators, and your coverage benefits every platform that consumes them, this one included.