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Hams Report ARISSat-1’s Linear Transponder Is Working


After its eventful deployment yesterday, ARISSsat-1 is definitely working. Hams from all over the world have reported hearing the voice, CW and SSTV transmissions. Despite concerns that the UHF antenna was either missing or damaged, the linear transponder is working and some people are already making contacts with it. The August 3 deployment was delayed nearly four hours after cosmonauts Sergei Volkov, RU3DIS, and Alexander Samokutyaev, expressed concerns that only one antenna -- the VHF antenna -- was visible.

“I was able to hear myself with as little as 1 W on the 0425 UTC pass,” AMSAT Vice President for Operations Drew Glasbrenner, KO4MA, wrote on the AMSAT e-mail reflector. “Antennas are a M2 CP42 on RHCP up, and a 10 element horizontal Yagi down. ARISSat-1 sounded very good, and cycled on and off with the telemetry. I also managed to grab two frames of telemetry right after AOS.” Glasbrenner posted a video of his transponder test.

Calling it a “very good first day,” ARISSat-1/KEDR Project Manager Gould Smith, WA4SXM, said that hams are submitting SSTV images to ARISS SSTV Gallery, and BPSK-1000 telemetry and experiment data is coming into the telemetry server. “ARISSat-1/KEDR continues to work well with good reports coming in from around the world,” he said. “The satellite is warmer than we expected, so we will continue to monitor this.”

The 435 MHz/145 MHz linear transponder operates in Mode U/v (70 cm up, 2 meters down). It is a 16 kHz wide inverting passband, and the convention is to transmit LSB on the 435 MHz uplink and receive USB on the 145 MHz downlink.



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