In the late 1970s I worked at several rock and MOR stations in S.
Florida. I remember watching the first episodes of WKRP in Cincinnati
in 1978 and thinking, "This show really nails it. Whoever did this has
been around radio stations and knows what they are talking about." One
of the first running gags they introduced in the show was station
manager Art Carlson's fear of his mother. Whenever she was about to
make an appearance, Carlson would run out of his office and shout
"Mother's coming! Look busy! Get to work!" and so on.

In 1980 I joined the rock station WGVL-FM in Gainesville, Fla. I was in
the lobby meeting the other people in the station for the first time. A
fat guy wearing a blue shirt and slacks ran out of an office and
announced, "Mother's coming! Clean the place up! Look busy!" Then he
turned around without saying anything to me and slammed the door shut.
I turned to the others and said, "Hey, do you know what that reminds me
of?" Everyone laughed and said, "WKRP." It turned out that Hugh Wilson,
the creator of the show, was a journalism student at the Univ. of
Florida in Gainesville and worked at the station a few years earlier.
He lifted some of the characters and events from his time at WGVL.

In the show, Carlson's nickname was "Big Guy." In real life, the
station manager's name was Irv Uram, and his nickname was "Big Blue."
The manager's mother was the station owner, and apparently really was
an intimidating individual; people at the station tried to avoid her. I
remember that she used to stay up after midnight listening to my show,
then complained to the GM about my song selection. Wilson's genius was
in taking situations that weren't really that funny in real life, and
rewriting them with humor.

In the few articles that I've read about the sources for WKRP, Wilson
never credits WGVL. It makes me wonder if he was worried about being
sued by the real-life people the show was based on.

http://www.answers.com/topic/hugh-wilson-2