Amateur radio satellites
Small radios in orbit that relay your signal. Here is what is up, where the data comes from, when they fly over, and what a real pass is like.
1 · What is up
15 satellites you can actually use
FM repeaters, linear transponders, a digipeater in MEO, one geostationary. Frequencies, modes, status.
2 · When
Pass predictor
Live TLEs, your location, next 24 h. Sky track, Doppler, duration.
3 · Where the data lives
9 datasets and schemas
TLE layout, CelesTrak, SatNOGS, AMSAT status, N2YO, tracker files.
4 · Reality
What to expect
Gear tiers, Doppler, crowded repeaters, how many passes per day, a first-pass checklist.
How it works. A satellite in low Earth orbit (LEO) crosses your sky in 5–20 minutes, a few times a day. While it is above your horizon it relays whatever it hears on its uplink to its downlink. Your signal goes up on one band and comes back down on another.
Mode letters. Bands are named by letter: A = 10 m, V = 2 m, U = 70 cm, L = 23 cm, S = 13 cm, X = 3 cm. “V/U” means uplink on 2 m, downlink on 70 cm.
Two families. FM repeaters: one conversation at a time, any dual-band HT. Linear transponders: a slice of spectrum, many SSB/CW conversations at once, needs an all-mode full-duplex setup.