About 100 people marched, held signs and sang union songs Thursday to protest layoffs at Berkeley-based radio station KPFA, the liberal bastion on the FM dial. Facing a drop of about $500,000 a year in listener donations and other funding for each of the past three years, KPFA's parent organization, Pacifica Foundation, plans to cut the equivalent of seven full-time jobs from a paid staff whose full- and part-time hours add up to about 30 full-time positions, said Tracy Rosenberg, a KPFA and Pacifica board member. Rosenberg said the station's budget this year is about $3.6 million, but the station...