[Sandy G]

IIRC, late in '41 they went to the 525 line system we still use today-before that, it was something like 441 lines, & I think they'd had that since only '39 or so. TV was really "experimental" til after the war. And I think they were really "pushing the envelope" w/prewar TV, the 525 line system was at the limits of what was feasable then.