When did B/W broadcasts stop?
 

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1966 for prime time, 1967 for daytime (soaps). By 1968 all of the network shows AND commercials were broadcast in color.

Hope this helps!

At the time all three networks were colorcasting, many ABC affiliates still had BW equipment. As I understand, some of those ABC stations could not colorcast until the early 70's.

I've seen bw film news footage (network) from the early 70s showing that not the entire newscast was in color. Certainly some stations did not have color cameras way up in the 70s & in some cases 80s. In a small market, or at a small public broadcaster or independent even in a big city, there probably wouldn't have been enough original programming eminating from that station to pay for color equipment. Forwarding the network programs in color would be a different matter. But I think the networks are what is important here.

Since even today someone can broadcast a BW picture or show over a color signal, maybe some more questions to ask would be:
"what was the last major network affiliate to completely eliminate broadasting of a non-color-encoded signal?"
"what was the last low-budget local (non-major-network) channel, uhf or vhf, to broadcast a black and white only signal?
"what was the last major network television show that was produced in black and white?"

The thing about the news not being completely in color could just be a factor of when they had gotten rid of all their old black and white film cameras and switched to color film....then switched to color videotape.

Yup! I didn't see color from our local ABC and PBS stations until the late 60's!

Y'know, it occurs to me that nowadays, TV stations probably transmit a color signal constantly even when broadcasting old B&W shows. If so, would there even be a point to having a "color killer" circuit on a modern TV, except to supress color "snow" on unused channels..?

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The problem is not colored snow, but the unnecessary cross color (flickering colors) that occur on high-contrast fine black and white details (worse in non-comb-filter sets).

By the way, in the early color days, some stations put a color burst inside the left edge of the picture on B&W programs, and another burst just inside the right edge (the normal burst was not present, so the color was killed). By turning the horizontal hold on a color set, you could pull the H phasing over to where the left side burst went through the burst gate, opening up the color killer. Then if all was well, the right-side burst would appear as a vertical yellow-green stripe in the picture. On any reasonably wideband B&W set, you could see the subcarrier dot pattern in these stripes.

I know here in Pittsburgh, we had/have a PBS station on Channel 16 that started broadcasting in the early 1960's in black and white and continued to do so well up past 1985, maybe even close to 1990. Somewhere between those dates, I can't remember if their tower blew down or maybe the transmitter died but they were off the air for a while and came back in color. I remember watching "Dr. Who" in black and white, the picture quality from the station reminds me a little of the old 405 line British standard.

Light years from here
 

Of course those early black & white pictures never really stopped. And are still being transmitted, and perhaps, received. Somewhere out there............................................. ............................




-Steve

In U.S.A. you had b/w televsion in the '80's?

I used to read "Twilight Zone" magazine, & there was a story about the transmissions from the '50s that kept going...and going...and going. Bunch of "Foriegn Investors" showed up & wanted some more episodes of a '50s program...-Sandy G.

Am sure we've all heard of the stories of I Love Lucy having been transmitted into deep space.....but I wonder if there's a point in which the signal disperses. Whether due to distance or some form of interference. Any care to postulate?

Anthony

Humm... Waytoowise or someone can fill me in on this, but electromagnetic radiation follows the square law: if you double the distance from the transmitter, the signal strength is not one-half, but one-quarter. Therefore, when you get far enough away, do you get down to the last photon? or maybe just keep dispersing the wavefront to the edge of the universe? :scratch2: One thing for sure, the 6BQ7A cascode RF amp in Steve D's CT-100 would have long since lost the signal!

Hey Pete,

I'm not so sure those old 50's color programs aren't still inside my CT-100 somewhere.
I remember the movie "Contact", where an Earth bound SETI scientist received tv images from the 1936 Berlin Olympics being returned to us from a distant galaxy. Fascinating stuff.


-Steve

OK, I couldn't resist:

photon energy = hf = 0.4136e-14 electron volts x f

supposing 500 MHz (about channel 19), hf = about 2e-12 ev

putting that into joules (so we can work in joules/second or watts):
photon energy = 3.3e-31 joules.
Then assuming 500 kW effective radiated power, to a receiver in the beam this looks like 5e5 joules/second or 1.5e36 photons/second into a full sphere.

Distance to nearest star, proxima centauri = 3.8e16 meters, so the sphere at that radius has an area of 1.8e34 meters.

To reconstruct the signal we need about 12 million samples per second, and each sample needs about 900 photons to get a 30:1 signal to noise ratio. (This assumes a photon-counting detector, and ignores thermal noise - a big assumption, but let's go with it.)
That means we need a total of 10.8e9 photons per second, so we need a dish of area
(1.8e34)(10.8e9/1.5e36)=130e6 square meters, or about 6.4 kilometers radius.

If we only want to detect the carrier with a 1 Hz bandwidth, we could get by with a one or two meter dish (really would use a more conventional UHF antenna).

This says that the signal does not get very far in galactic terms as a watchable program. It also says something about why space probes use digital signaling and error-correcting codes, so they do not have to reach the high signal to noise ratio needed for analog transmission.

Awww, shit ! Killjoy ! It's a LOT more fun to think somewhere out there some little green whatzit is laughing his asses-all 3 of 'em- off at "Milton Berle" or "I Love Lucy"...<grin>-Sandy G.

I personally don't know when American B&W broadcasts stopped but I guess main networks like CBS and ABC would of went full colour by 1967-69 period. I read that NBC was in full colour for all programs by 1966 being the first all colour station, well it's obvious for NBC to be first to drop B&W broadcasts as it was first really give NTSC colour technology a fair go unlike the other networks :thmbsp: !

In Australia, us being the LAST developed country to get colour television :dammit: , between the beginning of colour broadcasts on 19th October 1974 to the opening day of colour 1st March 1975 B&W broadcasts gradually reduced and on 1st March 1975 (the opening day of colour) all networks went full colour for all TV shows except for older repeats! Though some commercials were still done in B&W right into 1976 a mate told me.

Cheers
Troy

for the most part after nbc crowned itself the full color network in 1966 everyone else followed suit even cbs

Actually, doesn't NTSC still transmit the full B&W signal anyway? :) Color's just something added to the mix - you could say B&W broadcasting never stopped :)

Turn on the weather report, then turn the color control to zero, and note that there is no longer any great concern for distinguishing between chart colors on a B&W set, although they usually avoid using equal-luminance colors for titles/backgrounds. So, some of the practices of black-and-white broadcasts, like checking contrast on-camera, have disappeared.