ISS radio

The ISS has a radio, and you can hear it from home

The International Space Station has carried amateur radio stations since 2000. They are run by ARISS (Amateur Radio on the International Space Station), a programme of the amateur radio societies and the space agencies. Many astronauts hold a licence and use it to talk to schools around the world; when no contacts are scheduled, the radio is usually left on as a repeater so that radio amateurs can talk to each other through the station.

You don't need a licence or expensive gear to listen: a receiver of about 30 € and knowing when the station is above your horizon are enough. Unlike spotting it with the naked eye, radio doesn't need darkness: any pass will do, and there are several every day.

ISS radio frequencies

The station's call signs are NA1SS (United States), RS0ISS (Russia) and DP0ISS, OR4ISS and IR0ISS (Europe). These are the details ARISS published on 25 September 2026. The radios are sometimes switched off for spacewalks, manoeuvres or vehicle arrivals: before you go out to listen, check the current status of the stations.

What you hear in each mode

• School contacts. ARISS arranges between 60 and 100 a year: for about ten minutes, students put their questions to an astronaut by radio. If the pass also covers you, you will hear the astronaut's answers on 145.800 MHz even if the school is in another country. Dates and times are published in the ARISS contact schedule, and many are streamed live online.
• Voice repeater. Radio amateurs from half a continent calling and greeting each other in a hurry: they give their call sign and location and hand over, because the pass lasts less than ten minutes.
• APRS. Short bursts of data that sound like beeps. With a decoder app you will see the messages and positions that radio amateurs send and the ISS relays.
• SSTV. During announced events, the station sends images by radio, with pauses of about two minutes between them. With an SSTV decoder app on your phone, held near the receiver's speaker, the picture appears line by line. ARISS gives an electronic certificate to anyone who uploads a received image to its SSTV gallery.

What you need to listen

• An FM receiver for the 2 m and 70 cm bands. A dual-band (VHF/UHF) amateur handheld or a scanner will do. The simplest ones cost about 30 €.
• Or a USB SDR. An RTL-SDR receiver (about 30-40 €) plugged into a computer, or an Android phone, with a program such as SDR++, SDR# or SDR Touch. One advantage: you see the signal on screen, so following the Doppler shift is easy.
• A better antenna than the stock one. The stock antenna is enough on high passes. A dual-band handheld Yagi, or a home-made quarter-wave antenna, makes the difference on low passes.
• Knowing when it passes. That's what the calculator on this page is for: it tells you when, where it appears and which frequency to use.

Step by step: your first radio pass

1. Pick a high window. In the list above, look for one with a maximum height of 30° or more: the higher it is, the stronger and longer the signal.
2. Tune in. Set the receiver to narrow FM (NFM) on 437.800 MHz for the repeater, or 145.800 MHz if there is a school contact. Turn the squelch down to the minimum.
3. Correct for the Doppler effect. The station moves at about 7.7 km/s. As it rises, the signal arrives higher than nominal: about 10 kHz higher on 437.800 MHz and about 3.5 kHz higher on 145.800 MHz. At the highest point it matches the nominal frequency and, as it moves away, it drops below. On 145.800 MHz almost every FM receiver copes without touching anything; on 437.800 MHz it is worth stepping down 5 kHz at a time. While the ISS is above your horizon, the calculator above gives you the corrected frequency second by second.
4. Point and follow. Aim the antenna where it appears and follow it across the sky. In the first and last few degrees the signal is lost behind buildings and hills; if it fades mid-pass, rotate the antenna on its axis.
5. Record the audio. Even if you can't follow everything live, you can listen calmly later, or decode it if it was APRS or SSTV.

Listening to the ISS without a radio

If you don't have a receiver, the SatNOGS network brings together volunteer ground stations that record satellite passes and publish the audio and spectrum of each observation: look up the ISS by its NORAD number, 25544. And the ARISS schedule shows which school contacts are streamed live on YouTube.

Quick questions

Do I need a licence to listen to the ISS?

Not in most countries: listening to the amateur radio bands is free. You need a licence to transmit.

Why do I only hear noise?

Most often the station's radio is off or in another mode (check the status on ARISS), the pass is too low, or you are not correcting for Doppler on 437.800 MHz. Try a pass above 30° with the corrected frequency from the calculator.

Can I talk to the astronauts?

Only with an amateur radio licence, and even then it's hard: the long contacts are the ones scheduled with schools. Now and then an astronaut makes short contacts with radio amateurs on 145.800 MHz.

How often is the ISS within reach of my radio?

Several times a day. The station is about 400 km up and, when it rises above your horizon, it covers a circle more than 2,000 km in radius. The list above gives you the exact windows from your location.