(HUAC) the House Un-American Activities Committee began the investigation of 7 radio commentators on November 6, 1945. This list includes: Bertolt Brecht, Norman Cousins, Carey McWilliams, Dorothy Healey, and W. E. B. DuBois... most of them worked for Pacifica.
Starting in the year 1946, HUAC issued general reports on subversive activities, based on its research and hearings. Their first report contained a very partisan section on the radio broadcasts of “certain unnamed liberal commentators.” The committee found the radio commentators to be pro-communist based on their comments regarding the State Department, presidential appointees, foreign governments, and General Douglas MacArthur. [Yes, the far right has really been trying to convince America that liberals are communists for that long.]
Three ex-FBI agents in 1950 published a booklet titled Red Channels: The Report of Communist Influence in Radio and Television. This tome listed people, organizations and publications purported to have ties to communism. Among those people cited for their ties to communist organizations the following peopel in radio: Rod Holmgren, Lisa Sergio, William S. Gailmor, William Shirer, Johannes Steel, J. Raymond Walshand even Orson Welles!
By the time the book was published, all six commentators listed in its pages had been forced off the air. More here: http://www.moderntimes.com/palace/huac.htm
This crap went on for more than a decade with the FCC withholding the license renewals of KPFA, KPFB, and KPFK pending its investigation into "their communist affiliations." but after McCarthy Sputtered and crashed like the paranoiac alcoholic that he was, the whole movement loast steam. He had been reckless and like a gambler on a winning streak he had not planned for failure. He imploded and drank himself to death. The radio men he ran out of the buisness mostly met sad ends as well, but some found new work writing under psudonyms.
At the end HUAC offered lines of poetry by Sir Walter Scott in defense of their witch-hunt in their final report. I think they misread him myself. Poem Here: http://www.writing.upenn.edu/~afilreis/50s/scott-quote.html
great documentary here: http://radfilms.com/huac.html