Just past 10:00 AM CDT today, August 21st, WGEM-TV in Quincy, Illinois shut off transmissions on VHF channel 10.
(Signal graph times are EDT.)
At about 12:30 AM CDT, it appears WGEM-TV’s signal on UHF channel 19 was activated, as evidenced by my loss of reception of KPTN-LD at that time (and a huge jump in signal strength on channel 19 at the exact same time on another logger located near Quincy in Payson, IL).
These results suggest that reception of either KPTN-LD or WGEM-TV will be difficult at my location going forward, unless conditions are such that either signal rises significantly above the noise threshold.