Mode CubeSat telemetry

CubeSat telemetry: frames from amateur satellites, named and dumped.

Group	Satellite & navigation
Default frequency	145.825 MHz
Default sample rate	2 Msps
In the mode list	Satellites, 2 m / 70 cm

Step-by-step: Tutorial-CubeSat-telemetry

What CubeSat telemetry is

Many small amateur satellites broadcast telemetry as AX.25, GOMspace or CCSDS packets on 2 m and 70 cm. Their downlinks are open to anyone with a radio.

Frequencies and settings

Amateur satellites on 2 m / 70 cm (145.8 - 146 and 435 - 438 MHz): AX.25 at 1200 baud AFSK and 9600 / 4800 baud G3RUH, GOMspace AX100 Mode 5 (ASM + Golay + Reed-Solomon, GMSK 9600 / 4800) and Mode 6 (Reed-Solomon in HDLC), CCSDS Reed-Solomon (255,223) frames, all at once.

Setting	Value
Start frequency	145.825 MHz
Tuning range of the mode table	130 to 1000 MHz
Sample rate asked	2 Msps
Lowest working rate	1 Msps
Channel width	30 kHz

OnAir takes any frequency you type; the numbers above are the mode's starting point and the range its table describes. In the app the shortcut label is Satellites, 2 m / 70 cm.

What OnAir shows

A frame log with callsigns or CSP addresses, hex and ASCII dumps, Reed-Solomon corrections, satellite names from an editable table (NORAD number, frequency, framing, callsign), KISS out to SatNOGS-style tools through the data feeds; the pass planner starts it at AOS with Doppler correction. The AX100 convolutional code and AO-40 FEC are not decoded.

The mode's own tab has these screens: Frames, Satellites. The other tabs (Overview, Receiver, Scan, History) are described on the Main window page.

Tips and caveats

• Checked with generated signals and impairments; recordings of real signals welcome.
• Which radio: Usually yes for narrowband signals: an RTL-SDR tunes roughly 24 MHz to 1.7 GHz at up to about 2.4 Msps. Wide signals such as TV channels need a faster radio, and OnAir says next to the source what the selected radio can do.
• Try it without a radio: most modes include a built-in synthetic test signal, so you can open the screen and try the controls first.
• Receiving and the law: Receiving satellite downlinks is generally legal. Encrypted or spread content is not decoded, and voice codecs that are patented are not shipped with OnAir. See Legal.

Related pages

• All modes, Satellite & navigation
• Supported radios, Troubleshooting, FAQ
• More in Satellite & navigation: GNSS, Inmarsat-C, Inmarsat Aero, Iridium, Meteor-M LRPT, GOES HRIT, Elektro-L, Orbcomm, QO-100, Globalstar