An interesting question for the short term is what can we do with 1 watt of RF from a LEO satellite. RS-10 and RS-12 were interesting as they required only omnidirectional antennas but they had a lot of power available as they were attached to much larger satellites. AO-16 was a small satellite but was capable of only 1200 bps data using uncoded BPSK and simple vertical antennas.
Given the type of hardware developed for Suitsat-2, we should be able to do a lot more. Using modern error-correcting codes 4800 bps is possible using omnidirectional antenas and with modern codecs that can carry 4 voice channels or 3 voice channels plus 40 PSK31-like channels. With 10 dBi of gain at the ground station the data rate and number of voice channels could be quadrupled. The downlink could also be split between 2 voice channels for use with omnidirectional antennas and 8 voice channels for high-gain antennas.
73,
John KD6OZH
I have extracted from it the most important following part:
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i8CVS Domenico
Extracted from G3RUH article "THE EARTH MOVES"
An example, 1 watt transmitted from a 20 dbi gain dish on the Moon, received on a 1.2m dish at Earth with a system noise temperature of 100K results in a signal to noise ratio in 2.4 kHz bandwidth of 10.5 db. (Note that frequency matters not). This would support one rather noisy SSB voice signal. Alternatively it would carry an error-free 2400 bps binary PSK data transmission without coding, 9600 bps with modest coding [2].