Radio Amateurs

HAM radio information for contacting Aalto-1 satellite (OH2A1S)

• The satellite will be launched on June 23. 2017 (TBC) with Indian PSLV rocker on a sun-synchronous orbit (TBC)
• Launch time 03:59 GMT
• Initial orbit Two-Line Elements (TLE) (TBC)

  • AALTO_1
    1 19022U42775U 19022A17036L 1717417183.1820569455378403 0.0000000000000858 00000-0 0000043040-04 0 9993
    2 1902242775 97.44784493 233243.94522000 00129040013862 234200.94498305 358159.41902366 15.1988835419929546 061376

     

UHF Telecommand uplink / Telemetry downlink / CW beacon

• Frequency: 437.220 MHz
• Bandwidth: 13 kHz
• Max TX power: 1.2 W (dBm 30.8)
• Modulation: GFSK, deviation 3 kHz
• 6 second long beacon every 180 s CW beacon followed by an AX.25 data message
  • Information contained in CW beacon:
    • Callsign: AALTO1
  • Information contained in AX.25 (G3RUH compatible, 9600 bauds) beacon
    • Callsign: From OH2A1S to OH2AGS
    • UI-frame containing following fields TBD
• Telemetry/Telecommand exchange over Aalto Ground Station (OH2AGS) using TI CC1125 packet protocol
  • Preamble and sync word: 0x35 0x2E  0x35 0x2E
  • Data and symbol rate: 9600 bits/s
  • Variable length packets
  • Protocol specification: TBD

S-Band Science Data Downlink

• The S-band radio is operated only by request of ground operations team
• Frequency: 2402.000 MHz (S-Band)
• Bandwidth: 1.6 MHz
• Polarization: RHCP
• Max TX power: 1.29 W (31.1 dBm)
• Modulation: GMSK, deviation TBD
• Data downlink over Aalto Ground Station (OH2AGS) using TI CC1125 packet protocol
  • Preamble and sync word: 0xD3 0x91 0xD3 0x91
  • Symbol rate: 500k symbols/s
  • Fixed 256 bytes long packets
  • Data is transmitted in long bursts with 50% dutycycle
  • Optional convolutional code (c=1/2, k=3)