https://www.youtube.com/watch?v=dCOcmGyqnLU - 2:51 in.
Banded into about four horizontal, fairly static bars. And then briefly
at the end of the bad patch - about 3:05 - a large number of bars.
The show is 1978, so I presume well after 2" formats were in general
use; of course, who knows what it's been stored on subsequently. Audio
solid throughout.
Not being in the profession, I can't really guess - other than that I
can't think of any mechanism whereby this distortion could have come
from a domestic machine. (Though from the bandwidth, I think it's been
stored on one at the final level - though one in excellent condition.)
On 25/01/2024 18:08, J. P. Gilliver wrote:[]
https://www.youtube.com/watch?v=dCOcmGyqnLU - 2:51 in.
Banded into about four horizontal, fairly static bars. And then briefly
at the end of the bad patch - about 3:05 - a large number of bars.
Quad tape was in regular use until the mid 1980s, and the four bars are
a common fault. Somebody will likely be along shortly to explain how it >happened here.
The recording has also been through a domestic system, probably VHS,
which has left the trademark noise bar from a poorly aligned machine or
dirt on the head drum at the bottom of the picture. That may also be
where the total breakdown of the picture into noise bars came from, >indicating that the edge of the tape may have been damaged, causing
loss of sync.
Just before or after the noise, there were multiple picture bars - 10 to
13 I would say.
In message <l1h7ilFeuknU1@mid.individual.net> at Fri, 26 Jan 2024
08:07:50, John Williamson <johnwilliamson@btinternet.com> writes
On 25/01/2024 21:10, J. P. Gilliver wrote:I can understand the four-banding - AIUI, there are four head passes to
ss of sync.
Just before or after the noise, there were multiple picture bars - 10 to >>> 13 I would say.
As the sync pulses degrade, the rest of the circuitry tries to keep
things running, then gives up until the pulses come back. You can see
the start of the breakup as the colour problems get worse, and the
image starts breaking up inside each bar. My guess would be damage to
the edge of the quad tape due to poor storage or a problem with a
previous playback.
a field? - but the 15- or 16-banding (I've been back to count)? Is that
that, as things fall apart, the heads pass across adjacent tracks? 16
(or even 4 each main band, though the 16 look even and not grouped into
4) seems quite a lot of mistracking.
On 25/01/2024 21:10, J. P. Gilliver wrote:
ss of sync.
Just before or after the noise, there were multiple picture bars - 10 to
13 I would say.
As the sync pulses degrade, the rest of the circuitry tries to keep
things running, then gives up until the pulses come back. You can see
the start of the breakup as the colour problems get worse, and the
image starts breaking up inside each bar. My guess would be damage to
the edge of the quad tape due to poor storage or a problem with a
previous playback.
On 26/01/2024 09:39, J. P. Gilliver wrote:
In message <l1h7ilFeuknU1@mid.individual.net> at Fri, 26 Jan 2024
08:07:50, John Williamson <johnwilliamson@btinternet.com> writes
On 25/01/2024 21:10, J. P. Gilliver wrote:I can understand the four-banding - AIUI, there are four head passes to
ss of sync.
Just before or after the noise, there were multiple picture bars - 10 to >>>> 13 I would say.
As the sync pulses degrade, the rest of the circuitry tries to keep
things running, then gives up until the pulses come back. You can see
the start of the breakup as the colour problems get worse, and the
image starts breaking up inside each bar. My guess would be damage to
the edge of the quad tape due to poor storage or a problem with a
previous playback.
a field? - but the 15- or 16-banding (I've been back to count)? Is that
that, as things fall apart, the heads pass across adjacent tracks? 16
(or even 4 each main band, though the 16 look even and not grouped into
4) seems quite a lot of mistracking.
Quad head video is very intolerant of incorrect tape speed, so even
slight corruption of the sync pulses will cause all sorts of problems.
This is why it can not be used for things like still frames and slow
motion. The tape speed was either 7.5 or 5 inches per second,and the
tape is 2 inches wide, so the slope of each track is pronounced enough
for a head to cross many tracks if the tape speed if not correct.
Wow, that's quite fast! I can see that it will indeed cross many tracks,
if it gets to a poor speed (or stops).
On 26/01/2024 10:59, J. P. Gilliver wrote:
Wow, that's quite fast! I can see that it will indeed cross many tracks,
if it gets to a poor speed (or stops).
I've just seen the typo. Early machines ran at 15 ips, later ones at 7.5.
On 26/01/2024 09:39, J. P. Gilliver wrote:
In message <l1h7ilFeuknU1@mid.individual.net> at Fri, 26 Jan 2024
08:07:50, John Williamson <johnwilliamson@btinternet.com> writes
On 25/01/2024 21:10, J. P. Gilliver wrote:I can understand the four-banding - AIUI, there are four head passes to
ss of sync.
Just before or after the noise, there were multiple picture bars - 10 to >>> 13 I would say.
As the sync pulses degrade, the rest of the circuitry tries to keep
things running, then gives up until the pulses come back. You can see
the start of the breakup as the colour problems get worse, and the
image starts breaking up inside each bar. My guess would be damage to
the edge of the quad tape due to poor storage or a problem with a
previous playback.
a field? - but the 15- or 16-banding (I've been back to count)? Is that that, as things fall apart, the heads pass across adjacent tracks? 16
(or even 4 each main band, though the 16 look even and not grouped into
4) seems quite a lot of mistracking.
Quad head video is very intolerant of incorrect tape speed, so even
slight corruption of the sync pulses will cause all sorts of problems.
This is why it can not be used for things like still frames and slow
motion.
The tape speed was either 7.5 or 5 inches per second,and the
tape is 2 inches wide, so the slope of each track is pronounced enough
for a head to cross many tracks if the tape speed if not correct.
In message <l1hi0vFgv3vU1@mid.individual.net> at Fri, 26 Jan 2024
11:06:07, John Williamson <johnwilliamson@btinternet.com> writes
I've just seen the typo. Early machines ran at 15 ips, later ones at 7.5.(I was wondering why only a 3:2 ratio.) Wow, that's even faster -
somebody was being _very_ conservative!
And/or, perhaps - did they do linear audio tracks and that influenced
the speed choice? (Presumably before they'd thought of audio subcarrier
- or at least chosen frequencies that weren't visible.)
In article <l1hed2Fg967U1@mid.individual.net>,
John Williamson <johnwilliamson@btinternet.com> wrote:
Quad head video is very intolerant of incorrect tape speed, so even
slight corruption of the sync pulses will cause all sorts of problems.
This is why it can not be used for things like still frames and slow
motion.
Not quite true. BBC Designs Dept developed a slow motion facility for quad machines. It was used in the 1966 World Cup coverage.
In article <l1hed2Fg967U1@mid.individual.net>,[]
John Williamson <johnwilliamson@btinternet.com> wrote:
[]Quad head video is very intolerant of incorrect tape speed, so even
slight corruption of the sync pulses will cause all sorts of problems.
This is why it can not be used for things like still frames and slow
motion.
Not quite true. BBC Designs Dept developed a slow motion facility for quad >machines. It was used in the 1966 World Cup coverage.
On 26/01/2024 11:31, J. P. Gilliver wrote:
In message <l1hi0vFgv3vU1@mid.individual.net> at Fri, 26 Jan 2024No, the limit was how small they could make the heads when the standard
11:06:07, John Williamson <johnwilliamson@btinternet.com> writes
I've just seen the typo. Early machines ran at 15 ips, later ones at 7.5. >>>(I was wondering why only a 3:2 ratio.) Wow, that's even faster -
somebody was being _very_ conservative!
was drawn up. In 1956 when the format was invented, they were actually >pushing the limits, and as a result,the earlier machines were horribly >unreliable, and needed setting up for every tape individually. By 1978,
the format was pretty reliable.
And/or, perhaps - did they do linear audio tracks and that influenced
the speed choice? (Presumably before they'd thought of audio subcarrier
- or at least chosen frequencies that weren't visible.)
Both audio and sync were on linear tracks. The electronics of the time
could not handle anything more complicated. Even the later hi-fi audio
in the video area on VHS and Betamax used separate audio and video
heads, with different azimuth angles so the audio head didn't respond
to the audio and vice versa.
On 26/01/2024 12:00, charles wrote:
In article <l1hed2Fg967U1@mid.individual.net>,
John Williamson <johnwilliamson@btinternet.com> wrote:
Quad head video is very intolerant of incorrect tape speed, so even
slight corruption of the sync pulses will cause all sorts of problems.
This is why it can not be used for things like still frames and slow
motion.
Not quite true. BBC Designs Dept developed a slow motion facility for
quad machines. It was used in the 1966 World Cup coverage.
<Grin> In the days when the BBC employed real engineers...
On Fri Jan 26 13:37:38 2024 "J. P. Gilliver" wrote:
In message <5b28be12a5charles@candehope.me.uk> at Fri, 26 Jan 2024
12:00:06, charles <charles@candehope.me.uk> writes
In article <l1hed2Fg967U1@mid.individual.net>,[]
John Williamson <johnwilliamson@btinternet.com> wrote:
Quad head video is very intolerant of incorrect tape speed, so even
slight corruption of the sync pulses will cause all sorts of problems. >>>> This is why it can not be used for things like still frames and slow
motion.
Not quite true. BBC Designs Dept developed a slow motion facility for quad >>> machines. It was used in the 1966 World Cup coverage
I thought the "instant replay" - used for sporting events, football
goals mainly - used a spinning magnetic disc (capable of storing, I
don't know, a second or less)?
Ampex HS-100, 36 seconds PAL, 30 seconds NTSC
The old VCR double decker tapes used to fold the bottom of the tape at
times, though I never saw it on Scotch tapes, most of the other non back coated ones did it, and whether it was top or bottom both had tracking or audio, the performance was marred in all sorts of unusual ways I found.
On Fri Jan 26 13:37:38 2024 "J. P. Gilliver" wrote:
In message <5b28be12a5charles@candehope.me.uk> at Fri, 26 Jan 2024
12:00:06, charles <charles@candehope.me.uk> writes
In article <l1hed2Fg967U1@mid.individual.net>,[]
John Williamson <johnwilliamson@btinternet.com> wrote:
Quad head video is very intolerant of incorrect tape speed, so even
slight corruption of the sync pulses will cause all sorts of problems. >>>> This is why it can not be used for things like still frames and slow
motion.
Not quite true. BBC Designs Dept developed a slow motion facility for quad >>> machines. It was used in the 1966 World Cup coverage
I thought the "instant replay" - used for sporting events, football
goals mainly - used a spinning magnetic disc (capable of storing, I
don't know, a second or less)?
Ampex HS-100, 36 seconds PAL, 30 seconds NTSC
On 26/01/2024 14:37, Bill Posters wrote:
On Fri Jan 26 13:37:38 2024 "J. P. Gilliver"Â wrote:
I thought the "instant replay" - used for sporting events, football
goals mainly - used a spinning magnetic disc (capable of storing, I
don't know, a second or less)?
Ampex HS-100, 36 seconds PAL, 30 seconds NTSC
Yep, only ever I gather three in the UK, the Beeb had one, LWT had
another, and the third was owned by a facilites house in Soho ?
On 27/01/2024 12:48, Mark Carver wrote:
On 26/01/2024 14:37, Bill Posters wrote:
On Fri Jan 26 13:37:38 2024 "J. P. Gilliver"Â wrote:
I thought the "instant replay" - used for sporting events, football
goals mainly - used a spinning magnetic disc (capable of storing, I
don't know, a second or less)?
Ampex HS-100, 36 seconds PAL, 30 seconds NTSC
Yep, only ever I gather three in the UK, the Beeb had one, LWT had
another, and the third was owned by a facilites house in Soho ?
As few as that? I imagined that they were an integral part of any
scanner van that was used for sports where action replays were needed.
Or are you saying that there were many other models of slo-mo, and that
it is specifically the Ampex HS-100 of which there were only three
instances in the UK?
The HS100s usually stayed at home ! They were not the sort of devices to
have on board a truck. There's an article in one of the IBA Yearbooks,
where ITV were covering an international football match in Glasgow. The
HS100 remained 400 miles away at LWT, and a video link established back
and forth to it from the football ground.
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