#16
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Speaking of UHF, I got in an auction, one of the RF modulators used at one of the UHF stations in the area. Among a weird coaxial baseband video input, it also has the emergency broadcast inputs too. And when I got it, it was still set on the frequency that the station aired, it was never messed with.
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#17
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My parents bought a GE 25" console with VIR new in '77. Lasted until '83. Been looking for a VIR equipped set for many years and never found one.
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"Restoring a tube TV is like going to war. A color one is like a land war in Asia." |
#18
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His is a 19" GE...I don't know if he would sell it, but I could check.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#19
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So I'm guessing VIR has nothing to do with the auto color button on my TV?
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#20
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That's what I thought, only really seen it on the GE 19" with that red VIR light on controls panel. What a pity as VIR was a brilliant innovation
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Audiokarma |
#21
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Quote:
Brilliant of General Electric to have a wider burst in active line - and at a luminance level of a typical flesh tone! So, to me, the "problems" would have been easily avoidable with good broadcasting practice: For example source material with VIR needed to be first reclaibrated thru a professional VIR processor that also regenerated burst & VIR (with exact phase similitude) to the gated line 19 sample). Was there such an instrument? Last edited by NewVista; 09-28-2016 at 11:59 PM. |
#22
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I remember quad videotapes (2 inch) coming in that had a sticker saying "Protected by VIRS- adjust proc amp to pass."
In reality burst and sync got "regenerated" 2 times. After leaving the switcher it went to a proc amp where it would get black and white clip and agc. (I thought the best AGC amp was the RCA TA19. You could always tell a station that had one of these on the air.) Sync and burst would also be regenerated. Then it went to the virs inserter where it sync and burst would be regenerated again. NOW, all of this is ahead of a pre-corrector that was required to compensate for non-linearities in the modulation process of the transmitter. It had to look flat on the air. AND don't forget the low pass filter. Video was band limited to 4.2 MHZ to avoid components bleeding over into the sound at 4.5 MHz.
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Last edited by kf4rca; 09-29-2016 at 07:55 AM. |
#23
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Quote:
To eliminate any guesswork, just have color bars on another vert interval line! |
#24
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They DO run a line of color bars. But one of the biggest problems of NTSC is that it was compromised from the beginning. It had to fit in the same space as the existing B&W system.
As a result the bandwidth of the chrominance was limited. The I components were limited to 1.5 MHz and Q is limited to .5 Mhz. Not much detail in the color. AND its not even symmetrical. How screwey is that??? NOW, in Japan they had an analog HD system called the MUSE which I've heard took a 12 MHz channel. So when color (and HD) came along ,they should have allowed MORE bandwidth than what the old B&W system started out with. SO, even today we are stuck with the constraints of an old system.
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#25
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I've seen them sometimes at top of underscanned picture.
So alternatively, this is as good as VIR insomuch as there should be no guesswork for the tech before adding new VIR before transmission, as all he has to do is line up the color bars in the vectorscope avoiding subjectivity. And since, by 1975, NTSC still had 40 more years (counting cable), LSI chips could have been produced for consumer TVs to either derive reference from V.I. colorbars or VIR and making this the default mode of the receivers - keeping consumers' fingers away from contrast and tint - if not also saturation - knobs! |
Audiokarma |
#26
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Cool early 80's GE projection with vir on ebay.
http://www.ebay.com/itm/Vintage-Anti...sAAOSwHoFXu0Kd |
#27
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That set has 'VIR II' - wonder what improvements were made by then (1982)?
Magazine article on VIR Last edited by NewVista; 10-01-2016 at 09:46 AM. Reason: fixed link |
#28
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Had a Mot WARDS 19" with the VIR back in late 70s we paid $444 for brand new.. Great set till the fly shorted. Neighbor had a similar WARD set they tossed with a dead Vertical circuit. Swapped they Flys and it was up and runnin till i sold it years later and the vertical died 2 yrs after and it was tossed..
SR |
#29
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Not sure what VIR2 is. Never heard of that.
Even before the HD switchover, stations were going digital in NTSC days. I remember spots and syndicated programs coming in as a file from a digital satellite. The files were fed directly to the playout server (a raid 5 computer). And then to air. Sometimes the programs had low video or high chroma. Since it never went to analog at the station there was no way to adjust it. This was eventually corrected as stations raised hell with the syndicators. Turns out the spots and programs had been uplinked by a secretary who had no knowledge of video parameters.
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#30
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Did it make much difference when you ran it with VIR switched 'on'?
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Audiokarma |
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