Ham radio is not just a hobby – it’s a technical and communication challenge that enables amateurs to connect with people around the world. Thanks to advancements in technology, communication is no longer limited to Earth-based partners. It’s now possible to make contact with the International Space Station (ISS), which orbits the Earth. This possibility is both exciting and motivating for hobbyists and tech enthusiasts alike. It’s worth knowing that you can listen in with a simple handheld transceiver and rubber duck antenna if the ISS passes overhead at a sufficient altitude (with appropriate apogee). Moving your radio to follow the ISS’s trajectory can improve reception.
Historical overview
The ISS ham radio program operates under the ARISS (Amateur Radio on the International Space Station) initiative. ARISS began in 2000 when the first amateur radio equipment was installed on the Station. Since then, many hams around the world, including several from Hungary, have successfully contacted the crew. Technology has significantly evolved since those early days, and today reception is possible even with basic gear such as handheld transceivers, half-wave dipoles, or rooftop antennas.
What equipment do you need?
To make contact with the ISS, you primarily need a VHF/UHF amateur radio with at least 5 watts of power. Recommended equipment includes:
- Dual-band radio (e.g., Yaesu FT-60R, Icom IC-2730A)
- Yagi or other directional antenna (Arrow II, Elk log-periodic)
- Antenna rotator (not essential, but helpful)
- Computer or smartphone for tracking (e.g., Heavens Above, ISS Tracker, GPredict)
It’s important to note that listening is possible even with a simple handheld transceiver if the ISS is visible at the right apogee. Rooftop antennas can also be effective, although their narrow radiation angle often picks up signals when the ISS is farthest away, resulting in weak signals. Many users also successfully receive ISS signals using a half-wave dipole.
How to contact the ISS
- Licensing: You must have a valid amateur radio license (in Hungary, typically with a HA/NG callsign).
- Listening: The easiest way to begin is by monitoring ISS transmissions. The station often broadcasts during school contacts or via APRS mode. Listening can be done with a handheld radio and rubber duck antenna, especially if you move the radio to follow the ISS’s path.
- Attempting a QSO: The ISS commonly operates on 145.800 MHz in FM mode. Use clear, short transmissions for calling (e.g., “NA1SS this is HA5XYZ calling on 2 meters”).
- Using APRS: Sometimes, the ISS acts as an APRS digipeater, allowing for digital mode messaging.
When can you catch the ISS?
The ISS orbits the Earth every 90 minutes and passes over a given location 4–6 times daily. Of these, 1–2 passes are typically high enough for communication. You can plan the best times using tracking apps. Even if you only want to listen, having precise tracking data is valuable because signal reception depends heavily on elevation. You can achieve reception with simple equipment, like a handheld radio or half-wave dipole.
Tips for a successful contact
- The communication window is usually 8–10 minutes long
- Use directional antennas to improve signal strength
- Try digital modes if voice contact isn’t successful
- Remember the Doppler shift and adjust your frequency accordingly
- Even a rubber duck antenna on a handheld radio can be effective for listening
- Half-wave dipole antennas often yield good results
- For rooftop antennas, ensure they can receive near zenith, not just near the horizon
Frequently asked questions
- Do I need a license to call the ISS? Yes, a valid amateur radio license is required.
- Can I talk to the astronauts? Yes, if they are using the radio at that time.
- How difficult is it? It’s a challenge but achievable with well-prepared equipment. Even basic gear like a handheld or dipole can work for reception.
Future trends
The ARISS program continues to evolve, introducing new equipment and digital modes. Educational outreach is expanding, enabling more schools to connect with the ISS. As commercial space stations emerge, the future of amateur radio in space looks promising. Reception options will improve, and increasingly accessible equipment, such as handhelds, will make listening easier.
Making contact with the International Space Station is one of the most thrilling aspects of amateur radio. It demands technical knowledge, patience, creativity, and persistence. If you succeed, it will be a once-in-a-lifetime experience. Remember, you can start by simply listening in with a rubber duck antenna on a handheld radio.