EARLY TELEVISION COLOR TRANSMISSION QUESTION

[Al Timiter]

I asked this on the Classic TV board but perhaps it belongs here:

Maybe someone can answer this for me: In Columbia SC in the mid-60's, the ABC affiliate was broadcasting shows in color from the network but the color was "washed out" looking. Sorry, I'm not a techie and that's the only way I can describe it. Whereas, the local NBC Affiliate had glorious color, you had to manually turn the color knob as high as it would go on the ABC station to see the "color" and it still looked weak. The signal strength of the station itself was o-k but the color looked faded. Anybody know what kind of bizarre-o system they were using for this to happen? It was just the darndest thing. The ABC affiliate later upgraded and the problem was solved but this has always intrigued me.

 

[spunker88]

Well in analog color is transmitted separately from the black and white picture, just like stereo on FM. Remember back in the days on analog TV when a weak signal would fall back to a b&w picture just like a weak FM stereo signal falls back to mono. I imagine something was wrong with their color transmission only. I dont know a whole lot about how its broadcasted, but I imagine color was added in to existing broadcasting setups.

 

[Schroedingers Cat]

I do remember the times mentioned. Many stations could not originate their own programming in color, and only network shows were in color. I think that there may have been problems also with intercity relay links either incapable of transmitting color, or losing a lot of the saturation in the process. Also, many stations pulled in networks via off air antenna installations from adjacent markets, and may have lost saturation that way also.

I do remember this specifically with stations in outstate Michigan. Much programming originated in Detroit, then Flint Saginaw Bay City, then Cadillac Traverse City and from Chicago, then South Bend, then to Kalmazoo Grand Rapids, then Cadillac Traverse City.

 

[frankberry]

Washed-out color means that there was a high frequency response problem with their video equipment.
Old black and white transmission equipment needed modifications to improve the response in the 3 to 4 MHz range.
Even with the mods, some of the equipment didn't perform very well.

 

[w9wi]

I asked this on the Classic TV board but perhaps it belongs here:

Maybe someone can answer this for me: In Columbia SC in the mid-60's, the ABC affiliate was broadcasting shows in color from the network but the color was "washed out" looking. Sorry, I'm not a techie and that's the only way I can describe it. Whereas, the local NBC Affiliate had glorious color, you had to manually turn the color knob as high as it would go on the ABC station to see the "color" and it still looked weak. The signal strength of the station itself was o-k but the color looked faded. Anybody know what kind of bizarre-o system they were using for this to happen? It was just the darndest thing. The ABC affiliate later upgraded and the problem was solved but this has always intrigued me.

The frequency response of one or more parts of the station's transmission path wasn't very good. This could happen in the microwave equipment for receiving the network signal; in equipment distributing signals around the studio; in the studio-transmitter link; or in the transmitter itself. If any of this stuff was rolling off the high-frequency components of the video, the color would lose saturation.

(it is also plausible it was happening *at your antenna* - that multipath reflections were causing your TV to see less high-frequency material than the station was transmitting. Or, that an error in fine-tuning settings was rolling it off in the TV set. Though IIRC the ABC and NBC affiliates there were UHF and it would have been necessary to "re-fine-tune" when switching between them. And that part of South Carolina isn't that hilly, I wouldn't think terrain-based multipath would be an issue.)

When I was working with the CBS station in Madison, Wis. in the 1980s, our original 1956 transmitter was still in place & operating as a backup. There was a manual for a "Color Supplement' -- apparently the original transmitter design didn't support color, but you could order an upgrade.

I might guess the station in question had a transmitter that didn't really support color. There's nothing in a black-and-white transmitter that would really strip off the color information, but it might well roll off the color signals resulting in the "weak' color you cite.

 

[nmoore6676]

If I recall correctly ABC color shows at the beginning were less "colorful" than NBC. One reason is that they did not have live color equipment in their studios so their first shows were on film. If they were using a lesser grade of film the colors would look washed out. I can remember even on the retro cable channels some shows not looking very brilliant. I believe that the first live show in color on ABC may have been Lawrence Welk. I also think that the Walt Disney series was their first filmed offering in color and those should have been good quality but compared to NBC may have appeared less brilliant.

That was because NBC was owned at the time by RCA which was a major manufacturer of TV sets and they had a vested interest in making them look as good as they could. In fact many of the early NBC color productions had garishly colored sets and on their daytime game shows hosts like Gene Rayburn wore outlandishly colored clown suits.

 

[Gatekeeper007]

I remember when I was little we went to Columbia to visit some friends who had just bought their first color TV. This was in early 1962 as best as I remember and that uncle James was not happy since he could not get the color right on his new Magavox TV on channel 25. He wasn't sure if it was the TV or the UHF converter box he had bought that was the problem but I do remember him talking about the colors being washed out as he also called it. We could not receive channel 25 or 19 here in the Elloree/Santee area 50 miles from Columbia until the early 1980's as their signals were too weak to get any thing until channel 25 put a new transmitter in the early 80's, their signal was snowy but watchable the first ABC network for many people in this area as channel 2 out of Charleston was ABC and wasn't watchable most of the time. In early 2000 channel 25 new transmitter brought them in like thunder until digital TV came along. Also seems like I remember channel 25 having a CC in their call letters instead of WOLO when we would visit in Columbia.

 

[Al Timiter]

Hey everybody, thanks for the technical explanations, even though some of it was over my head a bit. And Gatekeeper, your post confirms that it wasn't just my set. Yes, WOLO was WCCA in the early 60's. It signed on as WCOS-TV in 1953 and went dark in 1956. Came back on circa 1961, as WCCA then later became WOLO; I think that was when Sy Bahakel bought it.

Thanks again, everyone.

 

[Tom Wells]

Two more question come to my mind.

1. I grew up near the AT&T concrete-tower microwave link from the east into Chicago.
We were impressed that it was carrying nationwide television feeds on microwave links.
One is beside a drive-in movie theatre we still go to. How good was this microwave link as far as bandwidth
and resolution? The signal must have made many hops and suffered degradation.


2. You were expected to fiddle a lot with color, our new 1973 Zenith had quite a booklet describing how to adjust
color for each channel, and written as though they expected you to be adjusting it a lot.....
By this time it was just color level ( chrominance) and tint ( phase angle relative to the 3.58 osc chroma).

But in the early RCA's at least, there was HUE, then instead of shifting red/green and TINT does, If I recall, it made a shift between blue and green/yellow. Was this somehow reversing phase or injection of the color burst,
or assuring its phase ran "in the correct direction"? I don't remember this ever being addressed in Gillespie's TV lectures in 1980,
and I don't recall it in the textbook, which I still have here somewhere.
Anyone here remember exactly what HUE varied or acted upon in the chroma phase angle?

 

[frankberry]

Hue and Tint are the same. The controls merely rotate the phase of the 3.58 color subcarrier. The color monitors at the TV station have the same adjustment. Professionally, it's called "phase" rather than Hue or Tint. In one direction, it will skew the reds towards blue. In the other direction, it will skew the reds towards green.
All other colors are skewed equally.

 

[Tom Wells]

On these particular sets, hue and tint were two different knobs, and both had to be adjusted.
I remember one day in the early 60's when I was sick and kept out of school we went to my grandma's house, I was put in Uncle Richard's bedroom with a brand new 23" RCA color with remote control.
I had to see what the knobs did, and hue and tint made different changes.

 

[frankberry]

Interesting.
The Hue control may have been added to improve the reproduction of flesh tones.
Some of the early sets didn't track the colors as accurately as the newer sets because the color circuitry wasn't very linear.
I remember (in the early 70's) when RCA produced a series of sets that had "automatic flesh tone correction".
It produced good flesh tones at the expense of every other color.
Perhaps the RCA Hue control was an early adaptation of the "flesh tone correction" system.
The Hue control probably affected the linearity of the red and green colors.

Anyone else have further information about this?
What did RCA call this circuitry?

 

[Tom Wells]

I have one of this approx vintage over yonder in the basement but I don't think those controls are up front and the sides are
"not accessible" as we say, due to other treasures also stacked about. I will have a look.

This RCA is awaiting some antique color TV junkie to give it a real home one day.
I'm out of time on projects, but I will continue to store it. It allegedly "works".

I am however certain about this memory of tint AND hue.
I'm a little less certain about it being an RCA, but pretty sure.

 

[frankberry]

It took awhile to jog my memory but here goes ..........
I remember an Admiral color set (from many, MANY years ago) that had an adjustment similar to what you're describing.
It controlled the balance of the CRT background colors and shifted them from blue to brown (yellow).
When you turned the chroma down, you could see what the control was doing ... skewing the entire screen color.
Careful adjustment could improve an otherwise bad color reproduction.

 

[ncradioeng]

NTSC - Never Twice the Same Color. The "color" control adjusted the gain of the color subcarrier (from B&W to full saturation) and the "tint (or hue)" control adjusted the phase. The other controls that affected color were in the back of the set - three drive controls for red, green and blue guns and three screen (bias) controls for each. This in addition to the convergence controls nightmare of the three-gun picture tube. There were some smart people at RCA that made this work within the confines of the the existing television channel AND be backward compatible with B&W sets.

 

[frankberry]

I received the following information from a fellow Television Engineer:

-------------------------------------

Hi Frank,

Motorola produced the first rectangular Color CRT in 1963 and to
enhance sales, added a third color adjustment.

I remember watching a friend's Motorola 23 inch rectangular color set
around 1964 that had the three knobs to control color.

It had the standard saturation and tint knobs, but it also had a 3rd
knob that was called 'color balance'.

The Owner's booklet explained that the viewer should turn the saturation
control all the way CCW to NO color, then turn the balance control to
set the "color temperature" of the screen to his liking.

All the way to the left produced a 'sepia' ~5000K colored screen, in the
center of it's range the picture was probably 6500K to 7500K [normal
looking B&W] and turning it to the right raised the color temperature to
probably 9000K to 12000K, a very cold looking blue-ish white picture.

I am pretty sure this control was changing the screen bias voltages
through a resistor matrix to accomplish such a wide range of color balance.

While it allowed the typical viewer more of a sense of control over the
color, to me it was a bit confusing not knowing exactly what the station
was transmitting.

I'm forwarding the RCA bit to a friend who probably has one of every RCA
color set ever made--all working! He will know if RCA ever incorporated
a third color control into their sets.

 

[littlejohn]

To answer Tom Wells' earlier question. Mother Bell, vie AT&TLong Lines division told the networks they could deliver a television signal coast to coast over 4MHz with a phase sift not exceeding 5 degrees across that bandwidth. This made NTSC transmission possible, and a somewhat cheaper receiver than the system used most other places, where the phase of each succesive line is reversed, so that phase errors in chrominance cancelled each other from line to line. I was told Long Lines usually >did< make the trip within 10 degres of shift pretty much all the time. Satellite transmission improved this greatly since it is one - hop. Digital cured it. Setting up an analog envelope delay compensator - which I did for the military Back When - was an interesting exercise. Ma Bell did it on video channels regularly... and it prety much worked.
"Brought to you in Living Color, pioneered and developed by RCA"