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: 73" de 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]. _______________________________________________ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
