Sigh. The ceramic resonators were used as a chroma trap. Quartz
crystals were used for the color reference. As far as 'Never The Same
Color', network programing was carried across the US on buried coaxial
cables or by microwave relays. Unlike tiny European countries, we
couldn't broadcast from a singe site. Because of this, they were video
amplifiers and equalizers spaced at regular intervals. Because it was
mostly tube, and there were thousands of them in each network they
required constant maintenance. When the network switched to a different
feed from a different studio, there was a phase difference. temperature
changes on the coax caused it's properties to change, as well. That was
why VIR and VITS were developed. It allowed for automatic equalization
to compensate for temperature changes, or when a signal had to be
rerouted. There were a lot of redundant paths, to allow for equipment
failures, or live remote feeds in the days before STL equipment. The
flexibility of the system was proven when Bell Telephone technicians
tied every TV station in the country together in a couple hours, to
allow full, live coverage of the assignation of President Kennedy. I
was at school when it was announced over the PA system. Less than an
hour later, all the students were in the auditorium watching the news
coverage live. By using some spare equipment and knowing the system
inside out, they were able to adapt it to a use it wasn't designed for,
with no permanent changes.

This is basically backwards. The US had high quality, phase-linear
transmission systems. Europe did not. The problem with NTSC was sloppy
studio standards.