COMS Meeting Notes 13.03.07

Space Research Centre, 17:30-19:00

LED BY: Andy Thomas, Jon Heath (two experienced ham-radio operators) & Daniel Brandt (Uni. of Leicester)

CUBESAT TEAM:
Comms team: Joanne Askew, Neil Gray, Ryan Laird.
Also present: David Acreman, Lucy Benson, Dylan Bishop, Glen Cornhill, David Gray, and Robert Royles.

Contact: Andy Thomas – email: ku.oc.oohay|liamsamohtydna#ku.oc.oohay|liamsamohtydna
When e-mail put in Leicester/ Cubesat in title.

LEO – about 400km, general gravitational Doppler shift (not relativistic), 18,000mph.

Doppler shift – worse high frequency (Maybe use about 145MHz, 436MHz*)
• 436MHz best sort of frequency
Downlink 2.4Ghz – technical problems using higher frequency.

Burst of Morse code data – keeping beacon on may cause problems due to power restraints. Command on/off, program when to come on/off – e.g. after 6 orbits send data down.

Typical LEO – 84% passage of 30˚ above the horizon or less. No problems with water, leaves at the frequency using.
Japanese Cubesat – send down on command, CW beacon – Morse code
Quakesat – (research)

Packet radio – use equipment at National Space Centre!!!
Licensing who needs? – easy to obtain, not a problem. International arrangement of frequency allocation - amateur radio band.

Look into National Lottery funding.

Link budgets

Antenna – “tape” measure deployment may be useful!? (Look into more)

Amsat convention every year – Surrey University

Comms system
Tranceiver (transmitter, receiver) – use NSC
Modulator (frequency modulates wave form, can use morse code, bandwidth 5kHz, freq. channels 12.5kHz wide.)
TNC (modem, TX) Bell 202 codes, audio freq shift keying AFSK.
Command receiver – on board data handling

Other
Oscar 1 – satellite, constraints, American airforce launch (Look into more)

Hi resolution pics -> 9K6? 38K5?

Cubesat could be good tool for teaching at schools as could easily set up equipment to receiver equipment, portable.

Useful websites:
Andy Thomas' Website (Team Leader)
Celestrak
Cubesat
Amsat (Cubesat section, LH column => archives, posts, debate useful!)

NEXT MEETING AFTER EASTER!!!
TUESDAY 15 MAY 5.30PM SRC

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