On 02/12/2011 06:31 AM, m II wrote:
This is an accumulation of seven years worth of work on this pest.
Nobody disagrees with me.

NTSC redefined it slightly off 60Hz so that power supply ripple
will move on the screen (two slightly black bands that scroll
up/down your screen

That's usually another TV signal. The speed at which the black bar moves
is the difference between the two stations' oscillators. All obsolete now.