There are well confirmed reports (including off screen photos) of BBC 405 line TV being received in the US on occasion. Including before WW2. Channel B1 (45MHz vision, 41.5MHz sound) can go a long way if the propagation condtions are right.
https://en.wikipedia.org/wiki/405-li...evision_system
"It soon became apparent that television reception was also possible well outside the original intended service area. In February 1938, engineers at the RCA Research Station, Riverhead, Long Island, New York, in the USA, were able to receive the BBC signal 5,000 km (3,100 mi) away, due to the signal being "bounced" back to earth from the ionosphere. A few minutes of programming were recorded on 16mm movie film. This is now considered to be the only surviving example of pre-war, live British television.[2] The images recorded included two of the original three BBC announcers, Jasmine Bligh and (in a brief shot) Elizabeth Cowell, an excerpt from an unknown period costume drama, and the BBC's station identification transmitted at the beginning and end of the day's programmes. "