The International Space Station currently uses Kenwood TM-D710GA VHF/UHF transceivers as its main ham radios, operated under call signs like NA1SS (US segment) and RS0ISS (Russian segment).

Quick Scoop: What ham radio is on the ISS?

The ISS ham station is part of the ARISS (Amateur Radio on the International Space Station) program, which equips the station with gear so astronauts can talk with hams and student groups on Earth.

The actual radios on board

  • Kenwood TM-D710GA in the Columbus (European) module, primary ARISS station.
  • Kenwood TM-D710GA in the Zvezda service module, secondary station.
  • These rigs form ARISS’s “Interoperable Radio System (IORS),” the next‑gen radio system on the ISS.

They’re standard dual‑band FM ham radios (like a high‑end mobile rig you’d put in a car), adapted for spaceflight use.

Call signs used from the ISS

The same hardware can use different call signs depending on who’s operating and where:

  • NA1SS – primary US station call sign.
  • RS0ISS – primary Russian station call sign.
  • DP0ISS, OR4ISS, IR0ISS – European call signs used at various times.
  • Packet/APRS aliases such as RS0ISS‑11 / RS0ISS‑1 for digipeater modes.

So if you hear “NA1SS” or “RS0ISS” on VHF/UHF, you’re listening to the Kenwood rig on the ISS.

What modes and frequencies they use

The same radios support several operating modes for hams on the ground:

  • FM voice contacts with schools and events, usually downlink on 145.800 MHz.
  • Cross‑band FM voice repeater (V/U), typically 145.990 MHz uplink and 437.800 MHz downlink.
  • APRS/packet digipeater on 145.825 MHz (VHF) and sometimes 437.550 MHz (UHF).

A separate HamTV payload in Columbus can send video on 2395.00 MHz, though that’s a different system from the Kenwood voice rigs.

Mini “story” to picture it

Imagine an astronaut floating in the Columbus module, holding a hand mic plugged into a familiar‑looking Kenwood mobile rig mounted to the rack.

When a school back on Earth keys up on the scheduled uplink frequency, that same everyday‑style ham radio receives their signal, and the astronaut replies using NA1SS, making a QSO that feels almost like a local repeater chat—except the “repeater” is orbiting 400 km above the Earth.

TL;DR

  • Radio model: Kenwood TM‑D710GA dual‑band FM transceivers.
  • Main call signs: NA1SS, RS0ISS (plus DP0ISS, OR4ISS, IR0ISS).
  • Typical use: ARISS school contacts, FM voice repeater, APRS/packet digipeater, and occasional HamTV video.

Information gathered from public forums or data available on the internet and portrayed here.