Old NTSC tricks: 240p?

[tony duell]

>
> At one time there were at least four B&W video transmission standards in Europe (we had a tube TV with a 
> 4-position selection knob to support them).  625/50 regular, 625/50 inverted in some way (?) used by the Dutch 
> speaking Belgian stations, 819/50 for France, and a different 819/50 for French speaking Belgian stations.

Not part of the _video_ signal, but part of the overall signal : IIRC continental Europe (mostly?) put the sound
carrier 5.5 MHz way from the video carrier, but the UK had a 6MHz offset. 

-tony