I found that I have uploaded it in the past on dropbox: https://www.dropbox.com/s/jste6bfxspjh9dv/RCA-BC-138-com.pdf?dl=0

I'm confused. When I click on that link, it goes to my dropbox, not to the pdf file.

But now? :)

There are a number of vintage publications from RCA and other manufacturers on
www.americanradiohistory.com all downloadable as a pdf.

But now? :)

Working now - thanks

The ad for the TR-70 brags about how even yellows are good, and calls yellow "the noisiest color around."

I wonder why that was? Was it because the FM carrier was deviated toward the high end on yellow and starting to approach the end of the heads' frequency response?

I notice they also show the live production of Kraft food commercials in Canada. The live Kraft commercials in the U.S. always had the best color of anything on TV.

There are a number of vintage publications from RCA and other manufacturers on
www.americanradiohistory.com all downloadable as a pdf.

It dosen't works :(

It works for me.

It dosen't works :(

It works for me too.

Perhaps your country is blocked from the site. :scratch2:. You could try accessing it from a VPN that makes your computer appear to be connected to the internet in the USA to all sites you access.

The ad for the TR-70 brags about how even yellows are good, and calls yellow "the noisiest color around."

I wonder why that was? Was it because the FM carrier was deviated toward the high end on yellow and starting to approach the end of the heads' frequency response?

Got a reply from Jay Ballard:
"RCA was referring to overdeviation experienced in Low Band color. Yellow with its comparitively high luminance was a challenge that was largely solved with High band, INTRODUCED in the VR 2000 by Ampex. It used a 10 MHz peak carrier that eliminated so called "bearding" (no RF). The same FM parameters were adopted for Type C"

While working at an ABC affiliate, we got a program from SCETV that played on Saturday morning called Job Man Caravan. It appeared to be low band when I set it up.
About 10 minutes into the show, it switched to hi-band (done while recorded).
You can imagine the surprise when the video went to $#!T. I had never seen a tape do that before. It took me a minute to figure out what had happened. Switching to HB solved the problem.

Did the editors for RCA's magazine's get a bonus for every time they mentioned color TV?

The ad for the TR-70 brags about how even yellows are good, and calls yellow "the noisiest color around."

I wonder why that was? Was it because the FM carrier was deviated toward the high end on yellow and starting to approach the end of the heads' frequency response?

I think that is exactly it: the FM deviation extreme for video tape recording composite video was yellow. If the heads were worn, yellow would show the speckly drop out most noticeably in yellow first.

I recall however for 1970's studio cameras using plumbicon tubes, the noisiest color was blue. I think this was because blue is low luma and at the low (expanded) end of the gamma curve.

I recall however for 1970's studio cameras using plumbicon tubes, the noisiest color was blue. I think this was because blue is low luma and at the low (expanded) end of the gamma curve.

The calculation of which saturated color will be noisiest is not simple. It depends on which color contributes most to luminance, among other things. On this basis, you might expect blue to be least noisy looking, but the problem was that the blue channel signal level was much lower than green or red under studio incandescent lighting. Because of this, the channel gains were set to give equal output on a white object under studio lighting with a clear filter in the optical path, and then an orange filter was rotated into place when doing outdoor pickups, where the signal level could be higher in all three channels.

I believe most up-to-date solid-state pickup cameras dispense with the filter change and use only electrical gain adjustments to get white balance. Blue is still the weakest channel under incandescent lighting, but gets a boost under daylight. This is certainly the case with DSLRs used for video, as well as stills.

The color splitting prisms in the Plumbicon cameras were designed in conjunction with the Plumbicon tube spectral responses and the assumption of incandescent light to give the lowest possible noise along with good color rendition, but it still resulted in the blue channel being much weaker than red or green.

By the way, the camera noise balance is not the same as the relative noise of different colors due to RF noise added to the composite signal during transmission/reception. That involves the CRT gamma (which affects the amount of luminance that is actually "carried by" or produced by the chrominance signal in saturated colors), and the R-Y and B-Y scaling factors in the composite signal. The result in NTSC or PAL is that, measured with a scope, the B-Y is noisier than the R-Y, but once the signals are applied to a CRT, saturated reds look noisier than saturated blues.

Thanks for sharing that RCA Broadcast Gear 1968 magazine, there was an excellent article on the experimental 1967 ATV0 colour broadcast of the Pakenham horse races down here in Australia including a rare colour photo of the camera at the races which I have never before! I have a personal interest in the history of experimental colour television in Australia before we officially went full colour in March 1975!