ISS Ham Radio: How to Contact the Space Station With ARISS

Few experiences in amateur radio compare with hearing an astronaut answer on a handheld radio from 400 kilometres above your head. ISS ham radio makes that possible. The International Space Station carries amateur radio equipment, and a worldwide programme called ARISS keeps it on the air for school contacts, casual conversations with licensed amateurs, packet radio and occasional slow-scan television events. With a modest 2 metre station, you can listen on your first pass and, with patience, make a contact of your own.

This guide explains what ARISS is, what radios are aboard, which frequencies are used for each mode, what equipment you need, how to find passes, how to operate when a crew member is on the air, and how to get a QSL card for your contact. Details change as equipment and schedules change, so check the official ARISS pages before you operate.

What ARISS Is

Amateur Radio on the International Space Station, or ARISS, is a programme that facilitates radio communication between licensed amateurs and crew members aboard the station using the amateur satellite service. According to the overview of ARISS, it was established in 1996 and evolved from the Shuttle Amateur Radio Experiment, and the first amateur radio contacts from the ISS were made on 12 November 2000 during Expedition 1.

The programme’s main goal is educational: to inspire students to pursue science, technology, engineering and mathematics through amateur radio contacts with the crew. The ARISS website explains that it is run by volunteers from national amateur radio organisations and the AMSAT organisations of several countries, together with space agency partners. Scheduled contacts with schools are arranged either as direct contacts or as telebridge contacts, depending on the equipment and volunteers available and the orbit of the station over the contact location.

Alongside the scheduled contacts, ARISS notes that astronauts can make unscheduled contacts with radio amateurs around the world on a one-to-one basis during their personal time. That is the opportunity most amateurs are chasing.

What Radios Are on the Station

ARISS lists two Kenwood transceivers on the station. A Kenwood D710GA is installed in the Columbus module and a second Kenwood radio, a D710E, in the Zvezda service module. They cover 2 metres and 70 centimetres, and the Columbus radio is restricted to a maximum of 25 watts in ISS operation. That power is enough for nearly horizon-to-horizon reception with simple handheld radios or scanners.

The call signs in use on the station are:

• NA1SS for the United States segment.
• RS0ISS for the Russian segment.
• DP0ISS, OR4ISS and IR0ISS for the European operations.

Other call signs may come into use as the station and crew change. The ARISS status page lists which radios are active and in which mode at any given time. It also warns that the radios are sometimes turned off to support vehicle, spacewalk and payload activities, so always check it first.

Frequencies and Modes

Most ARISS operation is split-frequency. The downlink is the frequency you listen on, and the uplink is the frequency you transmit on. The table lists the frequencies published by ARISS for contacts with the station. The ISS cannot always use every one of them at the same time, and the status page shows what is active.

Two voice uplink frequencies exist because of band plan differences between IARU regions. The crew switches between them, and the radio does not scan. A crew member who begins a contact over the United States can work stations there until the station reaches the Atlantic, then switch to the other uplink to work Europe and Africa. Please do not transmit on the ISS downlink frequency, because that is the frequency the station uses to transmit.

The Station You Need

ARISS describes a typical ground station for contacting the ISS as a 2 metre FM transceiver with 25 to 100 watts of output power. It adds that a circularly polarised crossed Yagi antenna that can be pointed in azimuth and elevation is desirable, but that successful contacts have also been made with vertical and ground plane antennas. For listening only, a handheld radio or even a scanner with a simple antenna is enough.

A practical progression for a newcomer looks like this:

1. Listen first. A handheld with a simple antenna is enough to hear the downlink during a pass. Doing this a few times teaches you how the signals behave and when passes occur.
2. Add a better antenna. A vertical or ground plane gives a decent start, and a small handheld Yagi improves your signal, especially at lower elevations. Our guide to 2 metre antenna options compares the common designs.
3. Use a transceiver with enough power. A mobile or base radio with a few tens of watts gives a more reliable uplink than a handheld.
4. Learn split operation. Program the downlink and uplink frequencies into memory channels so that you can switch quickly during a short pass.

Finding Passes

The ISS passes overhead several times a day, but only some passes are well placed for your location, and each pass lasts only a few minutes. A pass prediction program tells you when the station will rise and set, how high it will climb, and in which direction to point your antenna. ARISS points to the online tools on the AMSAT tools page, where you can select the ISS and enter your location. Many logging and mapping programs and phone apps also provide predictions.

Remember that signals are affected by the Doppler shift, because the station is moving quickly. ARISS publishes Doppler correction tables for the frequencies it uses, and many satellite programs adjust your radio automatically. If you are new to satellites in general, our introduction to getting started with amateur radio satellites explains how passes, elevation and Doppler work.

When Crew Members Are on the Air

The work schedules of the crew decide when they can operate. ARISS says that the usual waking period is 0730 to 1930 UTC, and the most common times to find a crew member operating casually are about an hour after waking and before sleeping, when they have personal time. The crew is usually free for much of the weekend. Astronauts have contacted thousands of amateurs worldwide.

When the crossband repeater is on, the station receives on the uplink frequency and retransmits what it hears on the downlink, so any station that can hear the downlink can listen in. The Columbus radio is the one most often used in this way. When a crew member is making voice contacts, the ARISS contact page indicates that the voice operation uses the 145.80 MHz downlink with the regional uplink frequency, so listen first and work out which mode is in use before you transmit.

A few operating habits help:

• Listen before you transmit. Make sure you can hear the station and that someone else is not already in contact.
• Keep your transmission short. Give your call sign clearly using standard phonetics. Our article on the ham radio phonetic alphabet explains how to make a call sign easy to copy.
• Do not call continuously. Many stations are trying to work the same pass. Send your call, then listen.
• Respect the schedule. If a school contact is scheduled, leave the frequencies clear.
• Accept that success takes tries. Many passes produce no contact at all. Persistence is part of the experience.

Packet, APRS and SSTV

Voice is not the only way to use the station. ARISS describes a packet digipeater on the station, using the call sign NA1SS and responding to the alias ARISS, and the status page describes APRS activity on 437.825 MHz from the service module. Packet operation lets stations exchange short digital messages and position reports through the station, which can be a good alternative when you have no antenna that can be pointed and no one is speaking on the voice channel.

SSTV events are scheduled periodically during the year. During one, the station transmits images that you can decode with a computer or a phone app, and the published downlink is 437.550 MHz in Robot36 mode. The images are a very visible reward: a successful decode shows a picture that was transmitted from the station. ARISS announces events in advance, so follow its upcoming events page and social media.

School Contacts and How You Can Help

The scheduled contacts are the heart of the programme. During a contact, students ask questions of a crew member over a few minutes of direct radio contact. A team of amateur volunteers operates the ground station. Because these contacts are arranged and scheduled, you can often listen to them from your own station when the station is in range, because the voice downlink carries the crew’s answers.

If you belong to a club or a school, you can also apply to host a contact. ARISS has a page with the requirements. Hosting a contact takes careful planning, but the educational reward is large.

Confirming Your Contact: QSL Cards

ARISS offers QSL cards to confirm contacts with the station. The process uses a postal request. You send a QSL report that includes the date, the time in UTC, the frequency and the mode (voice, packet or SSTV), together with a self-addressed stamped envelope or at least two International Reply Coupons, to the QSL manager for your region. Email addresses on the page are for inquiries only, because applications must be made by mail. ARISS notes that waiting for a card requires patience. For an overview of other ways to confirm contacts, see our guide to LoTW, eQSL and paper QSL cards.

Common Problems and Fixes

• Hearing nothing. Check the status page. The radios are sometimes switched off, and a voice downlink is silent when no one is operating.
• Signal drifts off frequency. This is Doppler shift. Retune during the pass or use software that corrects it.
• Weak uplink. Use more power, a better antenna or a pass with higher elevation.
• Pointing difficulties. Practise tracking on the first part of the pass while listening, and use a pass prediction display.
• Transmitting on the wrong frequency. Double-check the split frequencies for your ITU region before you key the radio.

The Bottom Line

ISS ham radio is easier to try than most people expect. The ARISS programme keeps amateur radio equipment on the station for school contacts, casual voice contacts, packet and SSTV. A 2 metre FM station with a simple antenna is enough to start listening, and a few tens of watts and a pointable antenna help when you want to transmit. Check the current status and the published frequencies for your ITU region, plan around the crew’s free time, keep your calls short, and apply for a QSL card when you succeed. Even if you never make a contact, hearing an astronaut speak directly to a school over your own radio is an experience that stays with you.

Frequently Asked Questions

What frequency do I listen on for the ISS?

ARISS lists 145.80 MHz as the worldwide voice downlink. The crossband repeater downlink is 437.80 MHz, and packet and APRS use 145.825 and 437.825 MHz. Always check the current status page, because the active mode changes.

Do I need a license to talk to the ISS?

Yes. Transmitting to the station needs an amateur radio license, since the contacts are made on amateur frequencies. Listening usually requires no license, but check the rules in your own country.

Can I use a handheld radio?

A handheld with a simple antenna is enough for listening, and the station’s power allows reception from almost horizon to horizon. For transmitting, more power and a better antenna improve your chances.

When are astronauts usually on the air?

ARISS says the usual waking period is 0730 to 1930 UTC, with casual contacts most common about an hour after waking and before sleeping, and during much of the weekend.

Why are there two uplink frequencies for voice?

Band plans differ between IARU regions. 144.49 MHz is used for ITU Regions 2 and 3 and 145.20 MHz for Region 1, and the crew switches between them as the station passes over different regions.

How do I get an ISS QSL card?

Send a QSL report by mail with the date, time in UTC, frequency and mode, plus a self-addressed stamped envelope or at least two International Reply Coupons, to the ARISS QSL manager for your region.