[old_tv_nut]

I'd also note that the filter design theory available at the time was based on approximate methods that had worked well for the telephone industry, but didn't have any of the sophisticated controlled trade-offs between amplitude and phase distortion that came some years later. So, a video filter design would start with a first guess and then have to be tweaked.

It is quite possible that the color coder filters developed by RCA had good sideband cutoff in the Q channel but it wasn't realized that this needed to be spec'd in addtion to the rolloff shoulder.