Satellite Tracker FAQ

Orbital elements are published by the US Space Force (18th Space Defense Squadron) and distributed by CelesTrak. Names and amateur radio frequencies come from the SatNOGS DB. The positions themselves are computed here with the SGP4 model, so the live view does not depend on any third-party map or tracking service.

With fresh elements the error is typically a few kilometres for low orbits, small enough to point an antenna or predict a pass to within a few seconds. The error grows as the elements age, faster for low satellites that feel atmospheric drag. The catalog shows the age of the elements of every satellite.

The positions are recalculated every minute on the server. Orbital elements are refreshed a few times a day, which is how often their source publishes new ones. In the browser the satellites move continuously.

Only active satellites with recent orbital elements are shown. Debris, decayed objects, and satellites whose operators do not publish elements are not included, and a satellite is hidden when its elements are more than 30 days old because the position would no longer be reliable.

Listening to amateur transmissions is generally allowed, but rules differ from country to country. Transmitting through an amateur satellite requires an amateur radio licence. See working amateur radio satellites.

A dual-band (2 m / 70 cm) handheld or mobile radio and a small directional antenna such as a handheld Yagi or a three-element beam is enough for the FM voice satellites. You have to correct for Doppler shift, which the table on the amateur satellites page does for you while the satellite is above your horizon.

The satellite moves at about 7 km/s, so the frequency you receive is higher while it approaches and lower while it recedes. On 70 cm the change can reach roughly ±10 kHz during a pass, on 2 m about a third of that. See the guide.

No. Your location is kept only in your browser and all pass and Doppler calculations run on your device. The server never receives it, unless you call the API yourself with coordinates.

Not yet. It shows when a satellite is above your horizon, which is what matters for radio. Visual visibility also needs the satellite to be lit by the Sun while you are in darkness.