Radio Amateurs

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

  • The satellite will be launched in May on June 23. 2017 (TBC) with Indian PSLV rocker on a sun-synchronous orbit (TBC)Initial orbit
  • Launch time 03:59 GMT
  • Orbit Two-Line Elements (TLE) will be provided on this website as soon as possible after the launch

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
  • 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)


Radio frequencies
  • UHF: 437.220 MHz
  • S-Band: 2402.000 MHz
Aalto Ground Station (OH2AGS)

Located at Aalto University in Otaniemi, Espoo, Finlands

Maarintie 8, 60.18718° N, 24.81760° E

QTH locator: KP20JE