The cross-band FM voice repeater aboard the International Space Station has not officially been activated for general amateur use, although some stations have reported successful contacts. The system is being used in an effort to detect telemetry from three recently deployed CubeSats.
Russian ISS crew members last week released three satellites carrying Amateur Radio payloads — TOMSK TPU-120 (RS04S), with FM voice announcements on 437.025 MHz; Tanusha-SWSU-1 (RS-6S) with FM voice announcements and AX.25 9,600 bps packet on 437.050 MHz, and Tanusha-SWSU-2 (RS-7S) with FM voice announcements and on AX.25 9,600 bps packet on 437.050 MHz.
They set up the ISS repeater as a cross-band relay between 437.050 MHz and 145.800 MHz at the last minute, because they were concerned about getting telemetry from their satellites, which might be spinning more than expected. They are hoping that the nearby receiver on ISS might be able to capture and retransmit telemetry not being received up on the ground.
ARISS has advised that using the voice repeater for general contacts can interfere with this mission. ARISS Ham Project Coordinator Kenneth Ransom, N5VHO, noted that the FM cross band repeater has been a capability of the onboard Kenwood D-700 transceiver since it was first flown to the ISS in 2004.
“It has been utilized very little during that time, due to concerns by the Russians that the unit might overheat,” he said.
When the ARISS voice repeater is active and authorized for general amateur voice contacts, the uplink is 437.800 MHz, and the downlink is 145.800 MHz. — Thanks to ARISS and AMSAT News Service