UHF TV in England...

[Colly0410]

ARC Tech-109...After spending some time in Miami watching 60 Hz tv pictures the first thing I noticed when watching 50 Hz TV back in England was the flicker. Nowadays we have scores of channels on terrestrial digital antenna TV & I still can't find much to watch, my favourite channel is PBS America, & PBS channel 2 was my favourite channel when I was in Miami...

[Alex KL-1]

Originally Posted by Colly0410

ARC Tech-109...After spending some time in Miami watching 60 Hz tv pictures the first thing I noticed when watching 50 Hz TV back in England was the flicker. Nowadays we have scores of channels on terrestrial digital antenna TV & I still can't find much to watch, my favourite channel is PBS America, & PBS channel 2 was my favourite channel when I was in Miami...

When I goes to where I live now (2011), in the triple border with Brazil, Argentina and Paraguay, the TV stations are transmitting in analog mode yet. The Argentinian ones and some Paraguayan are 50Hz, because in these countries the power lines are 50Hz. In Brazil is 60Hz as in the USA (hence the PAL-M). I instantly noticed the flicker from 50Hz stations. 60Hz (in 480i) also produces some flicker but is less annoying.

CRT monitors capable of higher V scan ratios and hence resolution, you can apply 75, 85, 100 or even 120Hz (I have one that supports it but only at 1024x768, and supports 1600x1200 at 85Hz) and then not notice any flicker.

[ppppenguin]

Flicker is worse when the screen occupies a greater fraction of your vision. This is simply because peripheral vision is more sensitive to movement (and hence flicker) than central vision. 60Hz may look OK when watching TV from a reasonable distance but it's horrible when close up to a computer monitor.

For interlaced pictures there is an additional 25Hz or 30Hz flicker which is hard to describe but very obvious on 625 or 525.

When I was a kid, the 50Hz large area flicker and 25Hz interlace flicker didn't bother me at all. That's how it was and most of us in Europe were used to it. In my late 20s (c1985) I got a job where I was investigating flicker on displays so I had to train myself to see it. Ordinary TV looked flickery then. We had an experimental rig that could show pictures with various scan rates and 2:1 or 1:1 interlace. 50Hz without interlace was pleasant. 100Hz interlaced wasn't too bad but 100Hz without interlace was lovely. It was also at the limit of the kit we were using so picture quality suffered in other ways. When I left that job I gradually became less sensitive to flicker again.

At the Broadcast Engineering Museum we have built an all-CRT gallery (control room in US parlance) so many of the monitors are inevitably in peripheral vision. They flicker horribly.

[Alex KL-1]

Very interesting your experience with it.

Funny... in the past, tech people worried about quality of movement/displacement of objects on display and choose/set 2ms or near it for CRT phosphours formula persistence. Times flies, and S/H (sample and hold) displays such as LCD and all variants (CCFL-backed, LED-backed etc) come in. The market flooded with these marvels but it seems only I are worrying about the horrible motion rendering of it (but all people loved the absence of flicker). No manufacturer are at least concerned with it at least in the beginning. Then: https://blurbusters.com/blur-busters...mple-and-hold/ I discovered that I'm not alone: the nature of these displays really havocs the manner that we perceive motion (blur), and then makers have spent some years in pursuit of things for mitigation it (such as flickering the back light). I prefer flicker. Less processing power needed for same motion perception (1000Hz capable video board? $$$$$). But is a headache for eg. typing a text for the Videokarma... this is the field where LCD reigns supreme due to S/H mode of working (and the individual addressable pixels).

Just in case, I don't believe we see with a 1000Hz frame rate biologically speaking, but I imagine that the motion/scan rate interacting with our own "scan" (variable for the peripheral vision, as you said), so the 1000Hz is for nulling any interaction. Proof of it is the difficult to see ficker on an 120Hz CRT. Besides other motion issues as explained in the link.

LATE EDIT: I'm maintaining some CRT monitors and the test UFO is very clear against regular LCD displays. Amazing to see. No blur in the UFO! Is possible to see it with full detail at scrolling, even at 60Hz frame rate. The CRT holds up. Only OLED with flickering can truly enters into this territory.

EDIT 2: I have a LG OLED TV that strobes the entire display once. Is horrible. Is usable only with 120Hz sources. Is different than a CRT monitor, due to the manner that CRT flickers (following the scan, not entire display once), even close watching the CRT monitor and hence seeing with some peripheral vision. Is good to save some dinosaurs to see the "real" new tech and what are really capable.

Naturally, for very slow movements, the S/H displays will not show artifacts.

Conclusion is the big size of newer TV's imposes automatically the nned of consider the peripheral vision and a eye-friendly reduction of blur.

[kf4rca]

I remember when I started in TV we had a Saturday afternoon program about 2 guys fishing in a little boat on a river. I remember thinking why would anybody watch this crap. The answer is there was nothing else any better to watch.
Being off the air for only 10 secs is good. After we installed our back-up generator at the transmitter site, we were thrilled it only took about 7 secs. for automatic switchover. It was exciting working for a corporate engineer whose philosophy was "we were going to stay on the air no matter what just short of a direct nuclear strike."

[ARC Tech-109]

That would have been the best 10 seconds for UK television. The what I remember was during the early 90's and it didn't take me long to find the power button.

[ARC Tech-109]

The What I do know is what I saw of PAL really wasn't any better than NTSC on a 19" CRT and the program itself was nothing to write home about... I know I must consider this comes from a place where they drive on the wrong side of the road, take tea at all hours of the day and drink warm beer.