There was a thread about how RF signals may look like ... this is an actual RF image of Voyager 1 spacecraft taken in February 2013 by the NRAO VLBA radio telescopes.
the space probe's main transmitter radiates just 22 watts, about the same amount of power as a typical ham radio ... But compared to many natural objects probed by radio telescopes, Voyager 1's signal is actually quite bright.The dish antenna on Voyager has approximately 42dBi gain. NASA uses a massive 70m dish on earth (»
deepspace.jpl.nasa.gov/d ··· 70m.html) to get approx -210dBm RSSI after 18.5 billion kilometers! It takes Voyager's RF signal more than 17 hours and 22 minutes to reach earth at light speed.
The RX LNA is super cooled to reduce noise floor below that level and currently 600-1000 bit/s two way data tranfser is possible.
Soon Voyager will not be able to receive commands from earth because it uses older 1970s RX LNA with much higher noise floor. But it will still send data towards earth ... until fuel and battery runs out.
SETI folks can also detect Voyager 1 signal: »
setiquest.org/forum/topi ··· -1-redux