Re-post from ANS-060:
Amateur Radio on the International Space Station (ARISS) reports that the packet radio in the Zvezda Service Module has been configured for temporary APRS operation on 437.825 MHz. The system is expected to remain active for testing through March 2, 2026, giving stations worldwide an opportunity to receive packet transmissions and attempt limited digipeating through the orbiting station.
Operators wishing to access the ISS digipeater are advised to include ARISS or APRSAT in the PATH field of their transmissions. The Service Module station is operating under the call sign RSØISS using FM packet at 1200 bps. ARISS recommends transmit power of 5 watts or less, preferably with a directional antenna, to improve uplink reliability and help minimize interference.
The current activation follows a prolonged outage of the Service Module amateur radio system that began during ARISS SSTV Series 30 in November 2025. Images were received early in the event, but subsequent passes produced no SSTV transmissions, and the event was ultimately scrubbed. The Service Module radio used for APRS and SSTV was then taken out of service while teams investigated the problem.
Subsequent ARISS updates reported that the primary Kenwood D710GA radio was replaced with an onboard spare D710E while teams continued troubleshooting and preparing reset procedures. Status reports in the following months continued to show the Service Module radio offline while restoration efforts were planned and carried out.
The newly announced APRS configuration suggests the system is now being evaluated through on-orbit testing following these repair activities. Temporary activations such as this allow radio amateurs worldwide to help confirm reception, observe system behavior, and provide useful reports while the station’s amateur radio capability is assessed.
ARISS encourages operators to monitor official status channels for schedule updates and to share reception reports as testing continues. Additional information on ISS amateur radio operations and current station status is available at https://www.ariss.org.
[ANS thanks Amateur Radio on the International Space Station (ARISS) for the above information]