However, until mid-November 2009, the PSIP identifier continued to identify the main channel 6.1 as KWQC-DT. This finally changed before Thanksgiving Day in late November and the PSIP now identifies the main channel on 6.1 as the station's legal callsign, KWQC-TV. KWQC-TV shut down its analog signal, over VHF channel 6, at 11:59 p.m. on June 12, 2009, the official date when full-power television stations in the United States transitioned from analog to digital broadcasts under federal mandate. The station shut off its pre-transition digital signal on channel 56 just after midnight on June 11–12. the station returned to the air on channel 36 around 1:00 a.m. on Friday June 12. Through the use of PSIP, digital television receivers display the station's virtual channel as its former VHF analog channel 6. Most of the station's programming on the broadcast day of June 12, 2009, was actually broadcast both on analog channel 6 and the new digital channel 36, until 11:59 p.m. when KWQC used analog channel 6 to provide a Nightlight service to those remaining analog-only television viewers without a digital TV set or digital converter box for the two weeks following the digital transition. KWQC's audio signal transmitted on a frequency of 87.76 MHz (+10 kHz shift) and was picked up on the lower end of the dial on most FM radios in most of the Quad Cities until 11:59 p.m. on June 12, 2009. As of 11:59 p.m. on June 12, 2009, the station's main programming is no longer heard on 87.75 MHz on FM radios. After June 12, KWQC continued using its analog channel 6 for Nightlighting for the next two weeks strictly for the purpose of informing the public about the need to switch over to digital. This included the details on purchasing and installation of DTV converter boxes and television sets, as well as how digital TV works. This service is known as "Nightlighting." The national PSAs, produced by the National Association of Broadcasters, as well as a locally produced version by the station itself, was a joint effort between KWQC and the other broadcasters in the Quad Cities, including WHBF-TV, WQAD-TV, WQPT-TV, and KLJB, to inform the remaining unprepared TV viewers about the need to take action to continue receiving over- the-air television broadcasting.