Who voiced the P.A. announcements on M*A*S*H during its entire television run?

This site says it was three different people:

There's Sal Viscuso, from "Soap" fame (was shown in one or two MASH episodes (check the ever-so-handy Episode Guide), though he wasn't playing his P.A. announcer character), Todd Susman, from ah, "Operation Noselift" fame, and Jimmy Lydon was the missing *third* voice. Viscuso and Susman were the most commonly known ones.

http://www.bestcareanywhere.net/announcements.htm

Who owns the faceless voice that does all the P.A. announcements? It usually isn't Radar or Klinger.
A: The voice is that of Sal Viscuso, who you may remember from the 70's sitcom, "Soap". Sal was shown in one or two MASH episodes (check the ever-so-handy Episode Guide), though he wasn't playing his P.A. announcer character.

http://stason.org/TULARC/tv/mash/17-Misc-Q-A-s-MASH.html