Andy comments further

It just occurred to me another simple test. At the outlet that
measures 111 volts, does it still measure 111 when there is
no load on the outlet ?
Measure the no load voltage, then measure the loaded voltage
with your TV set or otherwise..... There should be no appreciable
difference with loads under, say, 10 amps ( TV will be around 1
amp)....

This is a clue as to where the drop is occurring...

Andy in Eureka, Texas