SB SPACE @ ARL $ARLS005 ARLS005 SAREX frequency changes ZCZC AS84 QST de W1AW Space Bulletin 005 ARLS005 >From ARRL Headquarters Newington, CT April 5, 1995 To all radio amateurs SB SPACE ARL ARLS005 ARLS005 SAREX frequency changes Space Shuttle flight STS-71, to be launched in June, is the first to feature a docking between the Shuttle and the Russian Mir space station. Special Shuttle Amateur Radio EXperiment (SAREX) voice frequencies will be used. The special frequencies are: Downlink: 145.84 MHz worldwide; and Uplinks: 144.45 and 144.47 MHz worldwide . SAREX and Mir Amateur Radio stations normally share the same downlink frequency, which would cause interference on the STS-71 mission. Because of this and lessons learned from using particular frequencies during previous SAREX missions, the SAREX Working Group has made these changes for STS-71. The new frequencies were chosen after much deliberation to minimize interference between SAREX, Mir, and terrestrial stations. Most SAREX operations are split frequency, with a downlink (astronauts transmitting to Earth stations) and an uplink (Earth stations transmitting to astronauts). Listen to the downlink and transmit only when the shuttle is in range and astronauts are on the air. Mir operations are simplex and remain on 145.55 MHz. Before transmitting, listen to the SAREX uplink to avoid interfering with others, and listen for the astronauts' instructions about frequencies they're using. They won't favor a specific uplink, and your ability to work them will be ''the luck of the draw.'' If these special SAREX frequencies prove acceptable, they will be used for future docking missions. If you have comments, send them to AMSAT's Frank Bauer, KA3HDO, at his Callbook address, or to the ARRL Educational Activities Department. Please note that there is a strong chance that STS-70 will fly before STS-71; if so, STS-70 will use the regular SAREX frequencies. NNNN /EX