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Talking with ISS on VHF

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MIXW is a popular software application used in the amateur radio community for digital modes, particularly for operating in various digital communication protocols such as PSK31, RTTY, and others. It…Continue readingMixW

Working VHF with the International Space Station (ISS) can be an exciting experience for amateur radio operators. The ISS is equipped with amateur radio equipment, and it often operates on VHF frequencies, allowing operators on the ground to make contacts with astronauts aboard the station. Here are some key points to consider when attempting to communicate with the ISS:

1. Equipment Needed:

  • VHF Radio: A VHF transceiver capable of operating on the 2-meter band (144-148 MHz) is essential. Many handheld radios (HTs) and mobile transceivers can be used.
  • Antenna: A good quality antenna is important for making contacts. A simple vertical antenna or a Yagi antenna can improve your chances of success.
  • Tracking Software: Software or apps that track the ISS’s orbit can help you determine when it will be overhead. Programs like “Gpredict” or websites like “Heavens-Above” can provide real-time tracking information.

2. Frequency:

  • The primary frequency used for amateur radio operations on the ISS is 145.800 MHz (FM). This is the frequency for voice communications, and it is often used for school contacts and general operations.

3. Operating Procedure:

  • Listen First: Before transmitting, listen to the frequency to see if the ISS is active. You may hear other operators making contacts or the ISS crew responding to calls.
  • Timing: The ISS orbits the Earth approximately every 90 minutes, so you will need to time your operation to when it is overhead. The station moves quickly, so be prepared to act fast.
  • Calling CQ: If the frequency is clear, you can call CQ ISS or simply transmit your call sign. Keep your transmissions brief, as the crew may be busy with other contacts.
  • Use Simplex: The ISS typically operates in simplex mode, meaning that both the station on the ground and the ISS use the same frequency for communication.

4. Propagation:

  • VHF signals can be affected by line-of-sight conditions, so you will need to be within the coverage area of the ISS. The station is usually visible to a radius of several hundred kilometers, depending on the elevation of the pass.

5. Best Practices:

  • Be Patient: The ISS crew may not be able to respond to every call due to the volume of operators trying to make contact. Be patient and ready to try again during subsequent passes.
  • Keep It Short: When you do make contact, keep your conversation brief. The crew has limited time to communicate with ground stations.
  • Follow Protocol: Be respectful of other operators and follow good operating practices. Avoid monopolizing the frequency.

6. Special Events:

  • The ISS sometimes participates in special events, such as school contacts or public outreach programs. These events may have specific schedules and procedures, so it’s worth checking for announcements from organizations like AMSAT or ARISS (Amateur Radio on the International Space Station).

7. Logging Contacts:

  • Keep a log of your contacts, noting the time, frequency, call signs, and any other relevant information. This can help you track your activity and improve your skills.

8. Community Engagement:

  • Engage with the amateur radio community to share experiences and learn from others who have successfully contacted the ISS. Online forums, social media groups, and local clubs can provide valuable insights and support.

Working VHF with the ISS can be a rewarding experience, allowing you to connect with astronauts in space and participate in a unique aspect of amateur radio. Enjoy the adventure!