145.800 MHz International Space Station (ISS ARISS Downlink)
145.800 MHz FM is the official worldwide amateur radio voice downlink aboard the International Space Station (ARISS program). When astronauts talk to schools or ham operators, their voices beam down on this VHF channel.
145.800 MHz ISS FM
2 Meters Space & Satellite (VHF) • VHF (Very High Frequency) • FM Mode
- Modulation Standard
- Frequency Modulation (Standard 25 kHz FM voice)
- Channel Grid / Bandwidth
- Amateur Satellite Band Downlink Channel
- Transmitter Power (Typical)
- Kenwood TM-D710GA Transceiver (5 Watts to 25 Watts)
- Polarization
- Circular / Elliptical due to station rotation
- Signal Propagation Mode
- Direct space-to-ground vacuum line-of-sight
- Typical Broadcast Range
- Line-of-sight footprint radius of ~2,200 km from orbital ground track
Scheduled educational contacts between ISS astronauts and schools, random astronaut CQ calls during leisure hours, cross-band FM voice repeater operations, and Slow-Scan TV (SSTV) image transmissions.
- Because the ISS travels at 7.6 km/s, expect noticeable Doppler frequency shift: starts around 145.803 MHz on acquisition, shifts to 145.800 MHz at closest approach, and drops to 145.797 MHz at loss of signal.
- A handheld walkie-talkie or SDR receiver with a simple whip antenna can clearly pick up the ISS when overhead!
Frequently Asked Questions about 145.800 MHz
Which astronauts operate the ISS ham radio?
Many astronauts and cosmonauts hold amateur radio licenses, including NASA, ESA, JAXA, and Roscosmos crew members.
What is SSTV on 145.800 MHz?
During commemorative anniversaries, the ISS crew transmits analog pictures using Slow Scan Television (Robot 36 mode) that anyone can decode into high-resolution space photos.
Related Radio Frequencies
121.500 MHz VHF Guard
121.500 MHz is the internationally reserved aeronautical emergency frequency (Guard). Monitored 24/7 by civilian air traffic control towers, military interceptors, and commercial airliners worldwide.
156.800 MHz Marine Ch 16
Channel 16 (156.800 MHz FM) is the universal international maritime distress, safety, and calling frequency. Monitored continuously by all sea-going vessels and global Coast Guard agencies.
162.550 MHz NOAA Weather
NOAA Weather Radio All Hazards (NWR) on 162.550 MHz is a nationwide network of radio stations broadcasting continuous weather information directly from the nearest National Weather Service office.