Updated
G7RDX is an amateur radio station in the north west of England, building live tools and writing build notes at the operating position.
Every pass of the working AMSAT satellites over your Maidenhead locator for the next 7 days, computed in your browser with SGP4 from fresh Celestrak elements: rise time, direction, maximum elevation, sky track and Doppler-corrected uplink and downlink.
Your station:
| Satellite | Rises AOS | Max el | Length | Rises → sets | Downlink · uplink | Calendar |
|---|---|---|---|---|---|---|
| Loading orbital data… | ||||||
What it does
Shows every pass of 19 working amateur satellites over your station for the next 7 days: rise and set times, maximum elevation, sky track, and Doppler-corrected uplink and downlink for FM, linear and digital birds.
Data and refresh
Orbital elements come from the CelesTrak amateur group, refreshed every 24 hours and cached on this server. Frequencies come from the AMSAT status pages. Your locator never leaves the browser: SGP4 runs on your device.
How to read it
Pick a satellite card to see all its passes grouped by day. A pass above 30° is easy, above 45° is a gift. Open a pass for the polar plot: north at the top, the satellite rises at AOS and sets at LOS.
Who it is for
Anyone with a handheld and a small yagi can work SO-50 or the ISS repeater. Linear birds such as RS-44 need an all-mode radio. Start on a high FM pass, listen first, then call.
Frequently asked questions
Which satellite should I try first?
SO-50 is the usual answer for a first FM contact, because it is reliable, well known and worked by a large and patient community. For a first SSB contact through a linear transponder, RS-44 is the easiest: its passband is wide, its signal is strong, and passes are long because it sits in a high orbit.
What do AOS and LOS mean?
AOS is acquisition of signal, the moment the satellite rises above your horizon. LOS is loss of signal, when it sets again.
Why does maximum elevation matter so much?
Maximum elevation is how high the satellite climbs in your sky at its closest point, and it is the single best predictor of whether a pass is worth working. Below about 10 degrees the signal has to cut through a long slant path and whatever is on your horizon, and passes are short.
Why does SO-50 need a 74.4 Hz tone?
SO-50 keeps its transmitter off until someone arms it. Sending a 74.4 Hz subaudible tone for about two seconds starts a ten minute timer, after which the repeater is usable with the normal 67.0 Hz tone.
Can I work a satellite with a handheld radio?
For FM satellites, yes. A dual band handheld that can transmit on one band while receiving on the other, together with a small directional antenna, is a complete satellite station.
What is a TLE and why does it expire?
A two line element set is a compact description of an orbit at one instant, using the mean elements that the SGP4 model expects. It is not a fixed truth: atmospheric drag, solar activity and small manoeuvres all move a satellite away from the prediction.
Is my location sent to the server?
No. Your locator is stored in your own browser and the pass calculations run on your device.
What is full duplex and do I need it?
Full duplex means hearing the downlink at the same time as you transmit on the uplink. It is not required, but it changes the experience completely: you can hear your own signal coming back through the satellite, which tells you immediately whether you are on frequency and getting in.