In Poland, since the beginning of television broadcasting, i.e. after 1952, the definition of an image is 625 lines. Earlier experimental emissions were on 441 lines, but that was in the 1940s. Only single receivers were built to this standard:
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The audio-video frequency separation was 6.5 MHz. This meant that even if someone watched Western stations with favorable propagation conditions, there was no sound (their distance was 5.5 MHz). Amateur radio newspapers showed how to make changes so that they could be viewed with sound.