Grabowski, the operator of Cassie's Cafe in Roxbury, said on Ackershoek's Facebook page today that he died at 2 a.m. She said a memorial service for him will be scheduled for a date after the upcoming holidays.
Friends said Ackershoek and Grabowski were on vacation in South Carolina this week when he was hospitalized as the result of the heart attack.
Ackershoek was known for playing popular rock songs from the 1960's through 1980's on his evening show at the non-profit station staffed by volunteers. He called his show, "This Is The Rock."
By noon today, his Facebook page was festooned with tributes posted by his friends and fans of his show.
Grabowski wrote on her post: "I thank everyone again for all of your good vibes. Hopefully, he is gone to Rock and Roll Heaven and is hanging with those good people."
WIOX station manager Joe Piasek said staffers at the radio station were stunned and devastated by Ackershoek's death.
"Bob was one of the kindest and most thoughtful individuals you could ever meet," Piasek said. "His displays of passion went beyond the extreme."
Artie Martello, the office manager and a disc jockey at WIOX, said: "Bob was a great person who gave so much of himself to WIOX. He was a real curmudgeon. I loved the guy. He was a great friend."
Piasek said Ackershoek had managed a stereo shop in New Jersey before moving to the Roxbury area. He was one of the first volunteers at the station, and became known as "the Fill-in Czar," for offering his assistance when a show needed to be covered, he noted.
Ackershoek not only had a wide knowledge of the history of popular music but he also had tremendous respect for recording artists, Piasek said. "He was a real audiophile."