Server Sky Uplink

Most server sky customers will have small earth antennas, perhaps one square meter, emitting perhaps 100 mW of 70 GHz power. Through 10 dB of atmospheric and Lambertian attenuation, that is 10 mW transmitted in a 25 μsteradian beam (WAG), or 400 W/steradian. At 1E7 meters distance, that is 4 pW/m2. If one thinsat has a collecting area of 200 cm2, that is 8e-14 W. Assuming 120 meV per bit, 1E-19 J/bit, one thinsat can receive 4 Mbps. That might fit in a single 5 MHz wide frequency channel.

This does not offer much angular selectivity. How can multiple thinsats combine receive signals coherently for better source selection and more bandwidth for one earth antenna?

MoreLater , this seems too good for one thinsat. OTOH, 70 GHz does imply a very narrow beam!

Uplink (last edited 2014-08-07 05:35:17 by KeithLofstrom)