I think this article was poorly worded. If you look up the definition of "short-spaced" it means to reduce the power or increase directivity to protect another station on the same channel at less than normal distance.
The article says:
"On that day, the station activated a new 1,000-foot (305 m) transmitter tower in Orange City. The tower was located farther north than the other major Orlando stations' transmitters because of Federal Communications Commission (FCC) rules at the time that required a station's transmitter to be located within 15 miles (24 km) of its city of license. The station's signal was short-spaced to prevent interference with non-commercial educational station WTHS-TV (channel 2, now PBS member station WPBT) in Miami."
I think it should say:
"On that day, the station activated a new 1,000-foot (305 m) transmitter tower in Orange City. The tower was located farther north than the other major Orlando stations' transmitters to prevent interference with non-commercial educational station WTHS-TV (channel 2, now PBS member station WPBT) in Miami. The tower had previously been located closer to Orlando because Federal Communications Commission (FCC) rules at the time that required a station's transmitter to be located within 15 miles (24 km) of its city of license. The shorter distance to Miami had required the signal to be short-spaced."
see:
https://en.wikipedia.org/wiki/City_of_license