Richard Fry wrote:

Before calling this reality absurd, consider that a television station
transmits a video signal in/on an RF channel. The demodulated video
waveform in the TV receiver will be identical to the baseband video
signal applied to the TV tx -- including its DC components (subject to
any distortions along the transmission path).

If it wasn't ~ identical, a TV set could never "fade to black" when the
original image did, and low-luminance colors such as blue, red, brown
etc would be impossible to reproduce with their original chromaticity.

RF (ex-RCA Field Engineer, and installer of
hundreds of TV color studio and film cameras)

You perhaps never installed a receiver. Without its DC restorer circuit,
the problems you mention do indeed exist. In a black-and-white set, a
large white area will cause everything else to go black, to maintain a
zero average. But the DC information is transmitted as a level
difference between the sync tip and the "porches". At the receiver (as I
mentioned in another post), this voltage *difference* is turned into a
DC value. No DC is transmitted.

Surely a little bit of thought will establish why direct transmission of
DC isn't possible beyond the range of a static field.

Roy Lewallen, W7EL

"Roy Lewallen" wrote

But the DC information is transmitted as a level difference
between the sync tip and the "porches". At the receiver (as I mentioned in
another post), this voltage *difference* is turned into a DC value. No DC
is transmitted.
_________________

As I wrote in my slightly earlier post to you on this, the actual video
waveform is DC coupled through an analog TV transmitter. Please refer to
that post for more on this topic.

RF