(OK, 49yo. But still - I _think_ I saw it when originally broadcast!)
Just been watching The Birth of Television (<https://www.bbc.co.uk/iplayer/episode/m002q94w/the-birth-of-television>), which apparently was first broadcast 1976-11-1 21-25. My first thought
was that it was amazing quality for nearly 50yo 576i material; then I
noticed some twinklies - quite a few of them at fixed points on the
screen. Very noticeable when the picture is almost black, as it is not
far in (simulated living/viewing-room scenes).
Presumably due to head/tape damage; someone can probably tell what sort
of machine it has been archived on from the pattern.
They seem to disappear about 1'27 in (and I don't think recur).
Still enjoyed seeing it again. (And the one on JLB that preceded it [on
BBC4 this, well Tuesday, evening].)
Maybe the twinklies (I can see them too) are something that some media studies Herbert has added
(OK, 49yo. But still - I _think_ I saw it when originally broadcast!)
Just been watching The Birth of Television (<https://www.bbc.co.uk/iplayer/episode/m002q94w/the-birth-of-television>), which apparently was first broadcast 1976-11-1 21-25. My first thought
was that it was amazing quality for nearly 50yo 576i material; then I
noticed some twinklies - quite a few of them at fixed points on the
screen. Very noticeable when the picture is almost black, as it is not
far in (simulated living/viewing-room scenes).
Presumably due to head/tape damage; someone can probably tell what sort
of machine it has been archived on from the pattern.
They are Quadruplex VT 'Stab Dots'. Basically, interruptions in the off
tape RF at the head switch points. Remember Quadruplex used four heads across the field (the clue is in the name) .
Am I really the only remaining member of this Usenet group, to know that !?
Mark Carver wrote:
They are Quadruplex VT 'Stab Dots'. Basically, interruptions in the
off tape RF at the head switch points. Remember Quadruplex used four
heads across the field (the clue is in the name) .
Am I really the only remaining member of this Usenet group, to know
that !?
<https://www.youtube.com/shorts/a_m1Iqs3W3s>
On 21/01/2026 00:33, J. P. Gilliver wrote:I don't think so - they seemed to only be there for the first 87
(OK, 49yo. But still - I _think_ I saw it when originally broadcast!)I've recorded them to watch when I get a Round Tuit. All we need now is
Just been watching The Birth of Television
(<https://www.bbc.co.uk/iplayer/episode/m002q94w/the-birth-of-television>), []
Jack Rosenthal's excellent play "Fools on the Hill" about the early days
of TV. (*)
Maybe the twinklies (I can see them too) are something that some media > studies Herbert has added to show that this is "from the archive" ;-) At
least it wasn't fake film dirt on something that's come from video
camera and videotape. I've seen that before now. The biggest giveaway is that it's a pattern that repeats - you see the same hair mark every n seconds, regular as clockwork ;-)
(*) I liked the seat-of-the-pants stuff::-) (You wouldn't think TV announcer would be a hazardous profession!)
[a TV performer in a long ballgown has just come out of the studio]
Helen McKay: My hem - it's all wet. Is there water on the floor?
Jasmine Bligh: There had better not be. There's ten thousand volts of electricity running through...
Stage Manager: Oh hell! Excuse the language, ladies. It's the cyanide
again. No! Don't touch it! The cameraman's spilled his ruddy fixing
fluid again. Extinguishers! As fast as you can!
[two men spray the performer's dress with water]
On 21/01/2026 00:33, J. P. Gilliver wrote:I knew there'd be someone here who knew! You're probably not the _only_.
(OK, 49yo. But still - I _think_ I saw it when originally broadcast!)They are Quadruplex VT 'Stab Dots'. Basically, interruptions in the off
Just been watching The Birth of Television
(<https://www.bbc.co.uk/iplayer/episode/m002q94w/the-birth-of-television>), []
tape RF at the head switch points. Remember Quadruplex used four heads > across the field (the clue is in the name) .
Am I really the only remaining member of this Usenet group, to know that !?
I was a little surprised Quadruplex was still in use in 1976.
They stop, not at a scene change; do you think someone noticed and
tweaked something?
I was a little surprised Quadruplex was still in use in 1976.
It was the only broadcast quality tape format in 1976, the 1 inch tape C
and B formats emerged (in the market place at least) in the late 70s.
However, UK broadcasters carried on with 'Quad' well into the 80s, >particularly for material and programmes that hadn't been transferred to
1 inch. Which was a lot
On 21/01/2026 00:33, J. P. Gilliver wrote:
(OK, 49yo. But still - I _think_ I saw it when originally broadcast!)
Just been watching The Birth of Television
(<https://www.bbc.co.uk/iplayer/episode/m002q94w/the-birth-of-
television>),
which apparently was first broadcast 1976-11-1 21-25. My first thought
was that it was amazing quality for nearly 50yo 576i material; then I
noticed some twinklies - quite a few of them at fixed points on the
screen. Very noticeable when the picture is almost black, as it is not
far in (simulated living/viewing-room scenes).
Presumably due to head/tape damage; someone can probably tell what sort
of machine it has been archived on from the pattern.
They are Quadruplex VT 'Stab Dots'. Basically, interruptions in the off
tape RF at the head switch points. Remember Quadruplex used four heads across the field (the clue is in the name) .
Am I really the only remaining member of this Usenet group, to know that !?
However, UK broadcasters carried on with 'Quad' well into the 80s, particularly for material and programmes that hadn't been transferred toI believe it was used in sports broadcasting long after 1" helical
1 inch. Which was a lot
I read somewhere that the total playing time of all the 2" and 1"
existing tape material is greater than the total head life of all the
tape heads in existence, and nobody's making new ones.
And even if they were, there's a dwindling number of people who would
know how to replace them and line up the machines.
Which means that a lot of stored videotape material will never be
played again, and if we want to make decisions about what's worth transcribing this will depend on recordings being accurately
documented and described because we would otherwise have to play them
to find out.
On 21/01/2026 13:23, Mark Carver wrote:
However, UK broadcasters carried on with 'Quad' well into the 80s,I believe it was used in sports broadcasting long after 1" helical
particularly for material and programmes that hadn't been transferred
to 1 inch. Which was a lot
formats had taken over in all other areas, because Quad tape can be cut- and-splice edited without needing to be selectively dubbed, which makes
it a *lot* quicker to compile a highlights-of-the-match tape.
I read somewhere that all cut-and-splice tapes were marked very
prominently "Not to be bulk-erased" because doing so would erase the electronic "sprocket holes" on the control track so there would be a
risk of the spinning heads colliding with a splice point and clogging
the head with oxide, whereas the existing control pulses would sync the heads so the splice was always between head-passes. And if you started
the tape at the beginning and recorded something over the top, the VTR
would still use the existing control pulses and not record new ones in different places.
On 21/01/2026 11:16, Mark Carver wrote:
On 21/01/2026 00:33, J. P. Gilliver wrote:
(OK, 49yo. But still - I _think_ I saw it when originally broadcast!)
Just been watching The Birth of Television
(<https://www.bbc.co.uk/iplayer/episode/m002q94w/the-birth-of-
television>),
which apparently was first broadcast 1976-11-1 21-25. My first thought
was that it was amazing quality for nearly 50yo 576i material; then I
noticed some twinklies - quite a few of them at fixed points on the
screen. Very noticeable when the picture is almost black, as it is not
far in (simulated living/viewing-room scenes).
Presumably due to head/tape damage; someone can probably tell what sort
of machine it has been archived on from the pattern.
They are Quadruplex VT 'Stab Dots'. Basically, interruptions in the
off tape RF at the head switch points. Remember Quadruplex used four
heads across the field (the clue is in the name) .
Am I really the only remaining member of this Usenet group, to know
that !?
So did head-switching of Quad occur *within* a line, rather than in the line-flyback period between lines? Or is it a delayed effect which is manifested n microseconds after head switching?
On 21/01/2026 14:58, NY wrote:[]
On 21/01/2026 11:16, Mark Carver wrote:
On 21/01/2026 00:33, J. P. Gilliver wrote:
(OK, 49yo. But still - I _think_ I saw it when originally broadcast!)
Just been watching The Birth of Television
(<https://www.bbc.co.uk/iplayer/episode/m002q94w/the-birth-of-
television>),
They are Quadruplex VT 'Stab Dots'. Basically, interruptions in the
off tape RF at the head switch points. Remember Quadruplex used four
heads across the field (the clue is in the name) .
So did head-switching of Quad occur *within* a line, rather than in the
line-flyback period between lines? Or is it a delayed effect which is
manifested n microseconds after head switching?
I think Quad (and the other helical scan VT formats) were largely line
rate agnostic, so I don't think the head switch was necessarily during horizontal blanking ?
On saturated, flat field chroma, notably a big area of uniform coloured background, you would sometimes see 'head banding' where one or more
heads was not equalised properly (or the signal had not been uniformly recorded by all four heads)
On 21/01/2026 15:08, NY wrote:
I read somewhere that all cut-and-splice tapes were marked very
prominently "Not to be bulk-erased" because doing so would erase the
electronic "sprocket holes" on the control track so there would be a
risk of the spinning heads colliding with a splice point and clogging
the head with oxide, whereas the existing control pulses would sync
the heads so the splice was always between head-passes. And if you
started the tape at the beginning and recorded something over the top,
the VTR would still use the existing control pulses and not record new
ones in different places.
I don't think so. A mechanical splice in a tape was the equivalent of hitting the heads with a hammer when they rode over it, control track or not. Playing physically edited tapes would shorten the head life. It was
(as ever) a cost/benefit thing, and was accepted that the operational advantages of physical editing was worth the cost of replacing the heads.
On 21/01/2026 14:58, NY wrote:
So did head-switching of Quad occur *within* a line, rather than in
the line-flyback period between lines? Or is it a delayed effect which
is manifested n microseconds after head switching?
I think Quad (and the other helical scan VT formats) were largely line
rate agnostic, so I don't think the head switch was necessarily during horizontal blanking ?
On saturated, flat field chroma, notably a big area of uniform coloured background, you would sometimes see 'head banding' where one or more
heads was not equalised properly (or the signal had not been uniformly recorded by all four heads)
I think Quad (and the other helical scan VT formats) were largely line
rate agnostic, so I don't think the head switch was necessarily during >horizontal blanking ?
On 21/01/2026 16:24, Mark Carver wrote:
On 21/01/2026 15:08, NY wrote:
I read somewhere that all cut-and-splice tapes were marked very
prominently "Not to be bulk-erased" because doing so would erase the
electronic "sprocket holes" on the control track so there would be a
risk of the spinning heads colliding with a splice point and clogging
the head with oxide, whereas the existing control pulses would sync
the heads so the splice was always between head-passes. And if you
started the tape at the beginning and recorded something over the
top, the VTR would still use the existing control pulses and not
record new ones in different places.
I don't think so. A mechanical splice in a tape was the equivalent of
hitting the heads with a hammer when they rode over it, control track
or not. Playing physically edited tapes would shorten the head life.
It was (as ever) a cost/benefit thing, and was accepted that the
operational advantages of physical editing was worth the cost of
replacing the heads.
Seems I've been wrong all these years. I thought that because a splice
must occur at a well-defined gap between the frames, it is *defined* to
be a safe zone, between one pass of the heads and the next.
I'm trying to remember where I read that spliced tapes must never be
bulk erased because it destroys the control track "electronic sprocket holes" and therefore risks moving a splice to a random point where a
head will almost certainly collide with it. But you're saying that a collision occurs even with the pulses on the control track undisturbed.
Each head would thus contribute a horizontal band of a whole number of
lines, either fifteen or sixteen in a sequence that averaged out at
15.625 lines for the 625 line system and (I think) 15.750 for the 525
line system. I can't remember what the numbers were for 405, as I
joined after they'd stopped using it so it wasn't invluded in any of
my training courses.
I've heard it said that VHS can record either 405 or 625 line withoutIt certainly could. I remember - many decades ago - an exhibition in the Science Museum where they had some _really_ old 405 sets (including e.
any modification or change in drum speed - always assuming that you can find a source of 405 line and a TV to play it back on. I imagine there > was a small window of time when 405 was still being broadcast and VHS
had become available, though whether there were any VHF tuners to
produce a baseband signal is another matter.
And later VHS machines can play back 525/30 VHS tapes: I brought backYes. You missed the presence of an (external) height control!
some tapes from my sister who was living in the US at the time and I
could heard the hum of the drum change pitch and "hunt" a bit until it > locked-on... and a loud clonk from relay in my CRT TV as it switched to
525/30. Playback was B&W, I think, which suggests that NTSC signals were recorded differently to PAL rather than the colour being recorded in an identical format for both formats; also the TV displayed the picture as
a letterbox rather than stretching the picture to the same height even > though there were fewer lines - but that was a TV rather than VCR issue.
I discovered something by accident about VHS: if you turn the tape
upside down, the picture is upside down. Somehow the VCR manages to sync even though the sync pulses are now occurring at the other end of the
line. I discovered this when a tape got mangled and I spliced the
remaining good tape and though "what happens if I turn the tape over?" -
as you do... ;-)
I discovered something by accident about VHS: if you turn the tape
upside down, the picture is upside down. Somehow the VCR manages to sync
even though the sync pulses are now occurring at the other end of the
line. I discovered this when a tape got mangled and I spliced the
remaining good tape and though "what happens if I turn the tape over?" -
as you do... ;-)
I had the same thought when I had my Philips reel-to-reel machines, so
tried it: deafening buzz from the audio as it was getting the sync
pulses instead, and jumpy picture - but yes, upside down. (On that
format I'm pretty sure the sync. pulses and the audio were on opposite
sides of the helical part ... oh, you're talking about the _line_ sync. pulses; I can't see those being a problem, just differing front and back porch durations. Or do you mean the colour worked too? I wouldn't have expected _that_, the bursts being as you said at the wrong end.)
On 22/01/2026 19:47, J. P. Gilliver wrote:
I discovered something by accident about VHS: if you turn the tape
upside down, the picture is upside down. Somehow the VCR manages to sync >>> even though the sync pulses are now occurring at the other end of the
line. I discovered this when a tape got mangled and I spliced the
remaining good tape and though "what happens if I turn the tape over?" - >>> as you do... ;-)
I had the same thought when I had my Philips reel-to-reel machines, so
tried it: deafening buzz from the audio as it was getting the sync
pulses instead, and jumpy picture - but yes, upside down. (On that
format I'm pretty sure the sync. pulses and the audio were on opposite
sides of the helical part ... oh, you're talking about the _line_ sync.
pulses; I can't see those being a problem, just differing front and back
porch durations. Or do you mean the colour worked too? I wouldn't have
expected _that_, the bursts being as you said at the wrong end.)
I think the colour decoder did its best to try and produce colour from *somewhere* but it decoded noise and had random colours out of nowhere!
I'm not sure how VHS stored colour but I know it was completely separate from the luminance, whereas broadcast formats mostly store the original
PAL waveform with colour burst, alternating phase of B-Y, etc.
So it is possible that colour could have been recovered more easily from
VHS that was played line-backwards than it could have been done from broadcast helical formats where the colour burst was in completely the
wrong place to be fed through to kick the 4.43 MHz oscillator into phase.
I wonder... if you had very sensitive heads, could you play the tape
from the opposite (non-oxide) side? My head hurts trying to work out how
it would affect the geometry of the picture... if at all. Don't think
I'll bother trying it.
Yes, the control tracks were picked up as a horrendous 25 Hz buzz. I'm surprised the VCR could follow the tracks with only an audio track to
serve as track markers. I wonder what would happen if you played the
tape normally but blanked off the control head. Because if the tracking still worked, you wonder what purpose the control track had. Of course
VHS machines started out as really clunky devices with mechanical
counters, and which needed to stop the tape and thread/unthread the tape when changing between REW/FF and Play (tedious!!!!) (*). By the end,
they were able to play at 1/2 or 1/3 original speed with not much loss
of quality, with counters that used real HH:MM:SS, able to switch
between REW/FF, fast shuttle play and normal speed play in an instant,
and could record CD-quality sound (when fed from NICAM), recording subtitles, and could give pretty good still-frame pictures.
Paradoxically, still-frame was better quality (in colour and with less
noise and jitter) on EP (1/3 speed) than on LP (1/2 speed).
(*) My first experience with a VHS machine was when I was a prefect in
the 6th form in 1980 and my duties (along with a couple of like-minded friends) were in the school's audio-visual room, which knocked spots off having to break up playground fights or keep order in the dinner queue!
It meant we could play with someone else's expensive toys. And that was
with top-loading Ferguson VCRs which had to thread/unthread the tape
when you went from FF to Play, so it made it tedious to find the correct place on the tape, with a five-second delay at every change from one
mode to the other. We had to train the teachers how to use the VCRs, and what not to do (eg don't leave the tape on still-frame for too long otherwise you cause tape wear). I have very fond memories of
demonstrating to a young female teacher only a couple of years older
than me, and telling how to put your fingers on each side of the
cassette cradle and press down very gently and evenly on both sides with your fingertips to stop the cradle jamming. She smiled in a way that no teacher ever should to a sixth-former and said, in best Kenneth Williams voice, "Oooooooooh, Matronnnnnnnnnn" as she looked at me with a shocked expression. We both collapsed in a fit of the giggles. I genuinely
hadn't realised that what I was saying might have sounded a bit suggestive.
I'm not sure how VHS stored colour but I know it was completely separate from the luminance, whereas broadcast formats mostly store the original
PAL waveform with colour burst, alternating phase of B-Y, etc.
Is videotape ever used in TV production these days?
Or is everything recorded digitally?
Is computer-type tape used for archiving digital recordings,
or are hard drives (or optical discs similar to DVDs) used
as the archive medium?
I was meaning DVD-type recording (burning 1s and 0s in a metallic layeror are hard drives (or optical discs similar to DVDs) used
as the archive medium?
What are "optical discs similar to DVDs"?
I wonder... if you had very sensitive heads, could you play the tapeI think it's be reading across tracks: \\\\ instead of ////, and thus probably not get anything usable at all.
from the opposite (non-oxide) side? My head hurts trying to work out how
it would affect the geometry of the picture... if at all. Don't think
I'll bother trying it.
Did EP reach the UK? I always thought it was a US-only thing.
demonstrating to a young female teacher only a couple of years older
than me, and telling how to put your fingers on each side of the
cassette cradle and press down very gently and evenly on both sides with
your fingertips to stop the cradle jamming. She smiled in a way that no
teacher ever should to a sixth-former and said, in best Kenneth Williams
voice, "Oooooooooh, Matronnnnnnnnnn" as she looked at me with a shocked
expression. We both collapsed in a fit of the giggles. I genuinely
hadn't realised that what I was saying might have sounded a bit
suggestive.
:-) [Ah, happy days.]
"J. P. Gilliver" <G6JPG@255soft.uk> wrote in message news:10kuk1t$30k2f$5@dont-email.me...
Did EP reach the UK? I always thought it was a US-only thing.
It certainly did. I have two (*) late-model Panasonic VCRs which do EP (1/3 SP speed) and so give a maximum recording time of 15 hours on an E300 (5-hour) cassette. Useful for recording lots of things while I was away on holiday.
expression. We both collapsed in a fit of the giggles. I genuinely
hadn't realised that what I was saying might have sounded a bit
suggestive.
:-) [Ah, happy days.]
Very happy days. I wonder if she realised that she made a certain 6th former have some very happy dreams ;-)
I took the VCR to a local TV-repair shop who also reproduced the fault and pronounced Dead on Arrival and offered me two choices: pay a nominal cost and keep the VCR, or let the shop keep the VCR for spares and pay nothing.
I'm glad I chose the first because lo-and-behold, a few weeks later when I tried it, it; worked perfectly and has done ever since. However in the meantime I'd gone out and bought another similar model. I used both VCRs (I now had the ability to record overlapping programmes) for another five years or so until I started using Windows Media Centre (Win XP) and a DVB tuner, and then migrated to Raspberry Pi and dual DVB-T2 and one DVB-S2 tuners. I last used one of the VCRs (not sure whether it was the "broken" one or its replacement) a few years ago to copy some old tapes to MPEG and hence to DVD.
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