Dozens of amateur satellites carry transponders or FM repeaters. A dual-band handheld and a small handheld Yagi are enough to work an FM satellite — this is one of the cheapest impressive things in the hobby.
The two families
- FM satellites ("easy sats", e.g. SO-50, AO-91) — single channel, one contact at a time, busy.
- Linear transponder satellites (e.g. RS-44, AO-7) — SSB/CW, many simultaneous contacts,
Work them with a handheld.
quieter and more forgiving. Need an SSB-capable radio.
What you must handle
- Tracking. Satellites are overhead for 8–15 minutes. Apps and desktop software predict passes
- Doppler shift. The frequency moves several kHz through a pass — high at acquisition, low at
- Polarisation and pointing. A hand-held Yagi and a slow turn of the wrist beat any fixed
- Full duplex, ideally. Hearing your own downlink tells you instantly whether you are getting in.
from your grid square.
loss of signal. Tune the higher band; software can do it automatically.
vertical.
Exchange
Call sign and grid square. Passes are short, so contacts are brief by necessity.
The International Space Station
The ISS carries an amateur station. It runs a cross-band FM repeater much of the time, crew members occasionally make contacts, and ARISS schedules contacts between astronauts and school groups — an outstanding club and classroom project. See youth and schools.