Reply to post: Having read the paper...

Boffins' satcomms rig uses earthly LEDs to talk to orbiting PV panels

Brewster's Angle Grinder Silver badge
Terminator

Having read the paper...

The LEDs are only used for the downlink. (A 140W laser is used for the uplink.) They transmit using 1000 lumens worth of LEDs with a peak power of 140W and use lenses to focus the beam. It is reckoned it will emit a 19.9 dBW signal -- that's visual magnitude of 1, so naked eye visible under ideal conditions.

Those fins are a conventional aluminium heat sink. But the LEDs only transmit for 2min/orbit and then they let the heat dissipate. Radiation benefits from surface area every bit as much as convection, so perhaps.

The signal is received using a commercial 30cm telescope. Accounting for losses that's a -107.3 dBW signal giving a speed of 8.85E4 bit/s or 700 photons per bit. But they plan to use "deep learning" on both ends to develop a modulation scheme -- they haven't done so,.

They don't say much about the uplink to solar panels, referring to other work. But it uses a laser mounted on the receiving telescope.

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon