QUESTION:
How big in diameter would a single antenna have to be to provide the same
performance as the arrayed configurations of multiple antennas that will be
used to communicate with Cassini?

ANSWER from FAQ on June 3, 1999:
Case A: Canberra site alone (DSS-43,42,34) - 90 meters (295 feet)
Case B: Canberra (Case A) with Parkes Radio Telescope - 100 meters (328
feet)
Case C: Case B with Goldstone DSS-14 - 125 meters (410 feet)