There are actually existing copies of 405-line TV programmes on tape, because domestic VCRs would quite happily record it. Each "stripe" of a head rotation is a

There are actually existing copies of 405-line TV programmes on tape, because domestic VCRs would quite happily record it. Each "stripe" of a head rotation is a complete field, and as long as they're coming every 1/50th of a second it doesn't really care what if any line sync pulses you want to feed it. I don't remember us having 405-line TV because by the time they built out transmitters that far north in the early 70s there was no point, but I remember going round to a neighbour's house down south with my dad in the late 70s when they asked him to repair their TV. I remember the objectionably loud 10kHz line whistle which my elderly neighbours just couldn't hear :-)