Satellite Console
BETAYour horizon
Click a slice of the outer ring to raise your horizon there: 0°, 10°, 20°, 30°. Houses, trees, a hill. Passes are scored on what clears it, and the briefing says when the satellite first comes out from behind it.
Point the antenna
Elevation
Pass briefing
Passes
Click a column heading to sort by it. Click it again to reverse the order.
Passes are computed in your browser with SGP4 on amateur satellite elements . Radio control talks CI-V to an Icom IC-9700 over USB from Chrome or Edge, and is in daily use on the station’s own 9700.
What it does
Follows 18 working amateur satellites from your station: which one is up right now, which come next, and every pass for the next 7 days with AOS, LOS, maximum elevation and path across your sky. Uplink and downlink are corrected for Doppler second by second, and an IC-9700 on a USB cable can be tuned by the page itself.
Data and refresh
Orbital elements come from the CelesTrak amateur group, fetched once a day and cached on this server; the header says how old the current set is. Frequencies and modes come from the AMSAT status pages. Your locator never leaves the browser: SGP4 runs on your device and the passes are recomputed there.
How to read it
The four cards on the left are the satellite up now and the next three to rise. The map shows the one being followed, with its orbit and footprint; anything else above your horizon is drawn in green. The slider under the map runs the whole picture up to two hours ahead. On the right: the elevation curve of the pass, the track across your sky with azimuth and elevation, and the live frequencies.
Radio control
Press Connect IC-9700 in Chrome or Edge on the computer wired to the radio. The page puts the radio in satellite mode, downlink on MAIN and uplink on SUB, sets the mode and tone, and retunes both twice a second. On a linear bird turn the radio’s own dial to move through the transponder and the uplink follows. It never keys the transmitter, and Copy log under Radio connection shows every CI-V exchange.
What it cannot tell you
The predictions are only as good as the elements behind them, and elements age: a day or two old is fine, a week old and the times start to slide by a minute or more. It cannot tell you whether the satellite is actually working either, because transponders get switched off, put into eclipse mode, or fail without the orbit changing at all. Your horizon it only knows if you draw it: the Sky tab lets you raise it where houses and trees get in the way.
Using it in practice
Click Max elevation in the pass table and ignore anything under about 20 degrees until you have worked a few. Click a row for the satellite sheet: its sky track, its elevation curve and every pass of the week. Add the pass to your calendar so the reminder finds you, and be listening a minute before AOS, because the first thing you hear is usually somebody already in the middle of a call.
Frequently asked questions
Whose passes am I looking at?
Yours, once you type your locator into the box at the top and press Set. Until then the page shows passes for IO91, which is the station’s own square in the south of England. The locator is remembered by your browser, so you only do it once.
Is my location sent anywhere?
No. Your locator is kept in your own browser and the orbital arithmetic runs on your device. The server only ever hands out the orbital elements, which are the same for everybody. Nothing about where you are leaves the machine you are reading this on.
Where do the orbits come from and how old are they?
From CelesTrak, fetched on a schedule and cached on the site rather than downloaded by your browser. The small line in the header says how old the current set is. A day or two old is fine for FM work; once elements are a week old the predicted times start to drift by seconds and then minutes.
Which column tells me whether a pass is worth working?
Max elevation, before anything else. It is how high the satellite climbs in your sky at its best moment, and it decides whether you are working through a short clean path or a long slanting one full of houses and trees. Click any heading in the table to sort by it, and click again to reverse the order. Below about ten degrees, expect a brief and difficult pass.
What does the slider under the map do?
It moves the whole picture forward by up to two hours, orbits and footprints included, so you can see where a satellite will be when it rises rather than where it is now. The cards, the plots and the frequencies follow it. While it is away from now the radio is left alone; Back to now returns everything to live.
Which radios does it control?
The Icom IC-9700 over its USB cable, through the CI-V protocol. It needs Chrome or Edge, because those are the browsers that can open a serial port, and the page must be the one wired to the radio. On the radio set CI-V USB Port to Unlink from REMOTE and the USB baud rate to 115200. There is a demo radio under Radio connection to try the feature with nothing plugged in.
What is in the Downlink and uplink column?
The published frequency pair, or passband, for that satellite. The live values are in the frequencies card on the right: they include the Doppler shift, which on a 70cm downlink runs to several kilohertz between AOS and LOS. Click a row to open the satellite sheet with its sky track and elevation curve.
What does the Add to calendar button give me?
A standard .ics file for that pass, so it lands in whatever calendar you already use, with both frequencies in the notes and a reminder ten minutes before AOS.
Why is a satellite I use not in the list?
The list is a working set of amateur satellites with active transponders rather than the whole orbital catalogue, so anything without a usable amateur payload is left out. GreenCube, IO-117, was removed after it fell silent in September 2024. If one you use is missing, or one in the list has gone quiet for good, tell me and I will change it.