In article <d9a0b8$ec7$2@gnus01.u.washington.edu>,
Max Power <mikehack@u.washington.edu> wrote:

I really do believe that as time goes on it will be necessary to use 
software and SETI like intercept technology to intercept and decode Voyager 
31 and 32 (craft launch numbers) data.

SETI is trying to detect the existence of signals, where the signals
are assumed not to be detectably present in most directions and on
most frequencies.  Deep space probe communication is about communicating
with something whose position, frequency and signal characteristics are
very well known.  They are very different problems.

The hardware Viterbi decoders can only sustain signal interception for so 
long, as signal interception is more or less at the limits of current 
hardware receiver design.

Viterbi decoding is an algorithm (its about error correcting
codes), so a move from custom hardware to software wouldn't make any
difference to the performance.  Receiver limitations apply to SETI
applications just as much as deep space network ones.  (In fact,
S@H has a signal that has been degraded compared with signal from
the receiver.)

The actual receivers used will be very similar to those used for microwave
SETI, as are the antennas.  If you really mean distributed processing, 
rather than SETI, the problem doesn't match well as the amount of processing
required isn't that high.

The real solutions to Voyager detection are, to some extent lower noise
receivers, but the total noise is now within about a factor of
three of the sky noise, and not all of the excess over the sky noise
is actually from the receiver, and larger antennas.

A more real example of recovering very weak signals was the missing channel
on Huygens.  As I understand it, the design aim was to have the lander
data relayed by the Cassini craft, but one of the channels used wasn't
turned on.  However, a number of ground based radio telescopes managed to
combine their signals to do a direct detection and demodulation of the
Huygens signal.