The station signed on the frequency of 1250 kHz in 1925, as WGBI. It was owned by Frank S. Megargee. In 1927, the station moved to 1300 kHz,[3] which it time shared with Scranton's other radio station, WQAN (now WEJL). The two stations, which were time sharing a single frequency, moved to 880 kHz in 1931,[4] and then again to 910 kHz by 1941[5] (the later move, forced by a nationwide frequency reassignment, took place in 1941). WGBI remained at 910 kHz when WQAN moved on to its own broadcast tower and new frequency of 630 kHz in 1948. This meant that WGBI had full-time use of the 910 kHz frequency, where it remains to this day. WGBI was a CBS radionetwork affiliate by the 1940s.[6]
The Megargee family's company, Scranton Broadcasters, put an FM station on the air (now WGGY) and Northeastern Pennsylvania's second television station (now WYOU). The Megargees held on to the radio stations well into the 1990s. By the turn of the century, WGBI had been sold to Entercom (now Audacy) and become a repeater of WILK, existing mainly to improve its signal in Scranton. While WILK's daytime signal easily covers most of Scranton, the northern portion of the city only gets a grade B signal. At night, WILK must power down to 1,000 watts, leaving most of Scranton with only a grade B signal.
In 2007, the station moved its transmitter to the tower location atop the Times Building at 149 Penn Avenue in downtown Scranton[8] also being used by WEJL's transmitter. The full-time switch over to the new transmitter facility and tower location happened on August 2, 2007.[8] This tower sharing arrangement repeats an arrangement the stations shared over 60 years ago in their early history. The efficiency of the new transmitter tower location also caused WBZU to slightly reduce its power to keep within Federal Communications Commission rules on signal strength and coverage.
On February 26, 2020, the WAAF call letters were transferred to WBZU from 107.3 FM in Boston, which had held the call sign since 1968. When Entercom announced they would sell WAAF to the Educational Media Foundation, the call letters were "parked" in Scranton, preventing a rival Boston station from using the call sign and trading on its 52-year legacy in Boston (including 50 years as a rock station).
