The station signed on the air at 3:00 p.m. Eastern Time on September 23, 1968, as one of the ten charter stations of the KET network. All of the network's satellites were strategically located to serve as much of the state as possible. WKZT-TV was the default KET satellite serving the Louisville metropolitan area until the creation of WKMJ-TVin September 1970, nearly two years later. WKMJ-TV aired KET's statewide schedule until 1997, when the network acquired WKPC-TV and used WKMJ to start its second programming service, KET2.
Digital television
The station's digital television companion signal, WKZT-DT, along with the digital companions of thirteen other KET stations signed on the air in May 2002.
Analog-to-digital conversion
On April 16, 2009, WKZT-TV shut down its analog signal, over UHFchannel 23 as part of the mandatory analog-to-digital television transition of 2009. The deadline was moved from February 17 to June 12 of that year as part of the DTV Delay Act, but all KET stations completed the transition on April 16. The station's digital signal remained on its pre-transition UHF channel 43. Through the use of PSIP, digital television receivers display the station's virtual channel as its former UHF analog channel 23.
WKZT currently holds a construction permit to reallocate its digital signal to its former analog allocation of UHF channel 23. This is part of the network's participation in the 2016–17 FCC Spectrum incentive auction. The station's current digital frequency, on UHF channel 43, is one of the upper-mid UHF band channels to be removed from broadcasting use for use by wireless services.
Availability
Over-the-air coverage
WKZT-TV mainly serves the south-central portion of the Louisville market, from Louisville's southern suburbs to Campbellsville, as well as Hart and northeastern Edmonson counties in the northern portion of the small Bowling Green market. WKZT's signal can also reach central and southern portions of Harrison County, Indiana. As with most other KET stations, its over-the-air signal covers some of the same areas as those of some of KET's other stations. In the case of WKZT, the signal is overlapped with the network's two Louisville stations, along with WKGB-TV/Bowling Green, and WKSO-TV/Somerset. WKZT can easily penetrate the Campbellsville and Lebanon, Kentucky area where WKSO can also reach, while WKGB can be picked up in Leitchfield and the Nolin Lake vicinity along with WKZT.
