Radar was surprisingly advanced by the end of WW2, the Brits and Americans had ground scanning radar by the end of WW2 (H2S and the later H2X) all done without

Radar was surprisingly advanced by the end of WW2, the Brits and Americans had ground scanning radar by the end of WW2 (H2S and the later H2X) all done without transistors or computers as we'd recognise them :).