On Friday, 23 June 2017 00:49:11 UTC+1, Steve Walker wrote:
I think it was only in the '80s that they changed the tone received by
an operator from a payphone - until then they could not tell them from
private phones and people had learned that you could make free reverse
charges calls *to* phoneboxes.

This was because the 1980s GPO/BT owned all the payphones and knew which lines were coinbox lines. It was possible to make reverse charge calls to a payphone because the operator could ask the person at the payphone to insert money to pay for the call (and on the old Button A/B boxes listen to the separate 'dings' for sixpences and shillings).

When private payphones were introduced they were connected to ordinary lines so the operators had to have some means of knowing a payphone was connected, hence the 'cuckoo' tone.

Owain

On 23/06/17 08:59, Martin Brown wrote:
On 23/06/2017 00:45, Steve Walker wrote:
On 22/06/2017 18:56, Max Demian wrote:
On 22/06/2017 09:46, Chris Green wrote:
Graeme wrote:
In message ,
writes

And being told to put the radio on at 5 to 1 for the 1 o'clock news -
it needed time to 'warm up'.

10 to 1, otherwise you'd miss the shipping forecast :-)

Many of our 'radios' (internet, etc.) take just as long to start up.
Give me a 'tranny' any day.

Mains valve radios were up and running in 20 seconds.

A lot of modern equipment takes a lot longer than that. Apart from
(obvious) computers, TVs and mobile phones have quite restricted
functionality, or are very slow to respond, until a lot of background
tasks have finished running.

Why do modern, but non-smart TVs take so long to start up? You'd have
thought they'd be up and running in seconds, but they take ages. What
is there to do other than switch on the back-light, clear the memory
sync the data stream from the last used input (or start from the next
frame when using UHF to ditribute around the house) and start
displaying it?

At a guess you have to wait for it to go through hardware self test and
boot the realtime OS. It is only a few tens of seconds on most TVs.

Whereas this desktop using very ordinary components is asking for my
password in under 7 seconds and is ready to use in 15.

Its ******** really. It shouldn't take that long to boot a TV.


My internet radio is considerably slower and handles much less data.



--
"It is an established fact to 97% confidence limits that left wing
conspirators see right wing conspiracies everywhere"

On 22/06/2017 20:22, DerbyBorn wrote:
"Jim GM4DHJ ..." wrote in
news

"DerbyBorn" wrote in message
2.236...
Remember trying to improve an old TV by adjusting the Convergenece
Controls.
I recall, my old Murphy had about 20 potentiometers and other
ajustements.

magic eye valve radio....Mmmmmmmmmmm

The CRT was amazing how it became so good and could be mass produced.
Reminds me ot that old Cadbury Smash advert - Aliens laughing as it was
explained that electrons would fire through some magnetic coils and through
holes in a mask to hit little dots of phospor to make them glow.

The truly amazing one was the Sinclair flat screen CRT TV - FTV1

http://www.thevalvepage.com/tv/sinclair/ftv1/ftv1.htm

A friend of mine had one. It was impressive if a bit on the small side.

Another won an earlier MTV1 on the very first Krypton Factor Show.

--
Regards,
Martin Brown

"Martin Brown" wrote in message
news
On 22/06/2017 20:22, DerbyBorn wrote:
"Jim GM4DHJ ..." wrote in
news

"DerbyBorn" wrote in message
2.236...
Remember trying to improve an old TV by adjusting the Convergenece
Controls.
I recall, my old Murphy had about 20 potentiometers and other
ajustements.

magic eye valve radio....Mmmmmmmmmmm

The CRT was amazing how it became so good and could be mass produced.
Reminds me ot that old Cadbury Smash advert - Aliens laughing as it was
explained that electrons would fire through some magnetic coils and
through
holes in a mask to hit little dots of phospor to make them glow.

The truly amazing one was the Sinclair flat screen CRT TV - FTV1

http://www.thevalvepage.com/tv/sinclair/ftv1/ftv1.htm

A friend of mine had one. It was impressive if a bit on the small side.


it was so good I just sold one on ebay for a fiver ......tee hee

"The Natural Philosopher" wrote in message
news
Whereas this desktop using very ordinary components is asking for my
password in under 7 seconds and is ready to use in 15.

Your PC boots from total power-off (ie not resuming from hibernation or
sleep) to password and desktop in 15 seconds? I'm impressed. My two PCs
(both Win 7) take about 5 mins from power-off state, and that's after
checking for unwanted startup processes (msconfig) etc and after running
CCLEANER. What OS do you use? And is that with spinning HDD or solid-state?

I tend to leave my desktop PC on 24/7 because I use it as a PVR and for
logging info from my weather station, so I only reboot it about one every
couple of weeks (eg after MS updates). I tend to leave my laptop on as well
(even if I put it to sleep when I'm not using it) because its battery no
longer holds any charge so it needs to be booted from cold each time. Of
course booting from sleep only works as long as the laptop is plugged into
its power supply. For some reason, hibernate (boot from memory image on disk
rather than from battery-backed RAM) is greyed out on my laptop.

In message , at 09:13:53 on Fri, 23 Jun
2017, The Natural Philosopher remarked:

At a guess you have to wait for it to go through hardware self test
and boot the realtime OS. It is only a few tens of seconds on most TVs.

Whereas this desktop using very ordinary components is asking for my
password in under 7 seconds and is ready to use in 15.

Its ******** really. It shouldn't take that long to boot a TV.

Have you considered buying a TV with more then five quids worth of
computer inside?
--
Roland Perry

In message , at 09:24:43 on Fri, 23 Jun
2017, Martin Brown remarked:

The truly amazing one was the Sinclair flat screen CRT TV - FTV1

http://www.thevalvepage.com/tv/sinclair/ftv1/ftv1.htm

A friend of mine had one. It was impressive if a bit on the small side.

Then there was the Sony Watchman B&W, which I had, and worked well for
the ten or fifteen minutes the batteries lasted.
--
Roland Perry

"Roland Perry" wrote in message
...
In message , at 09:24:43 on Fri, 23 Jun
2017, Martin Brown remarked:

The truly amazing one was the Sinclair flat screen CRT TV - FTV1

http://www.thevalvepage.com/tv/sinclair/ftv1/ftv1.htm

A friend of mine had one. It was impressive if a bit on the small side.

Then there was the Sony Watchman B&W, which I had, and worked well for the
ten or fifteen minutes the batteries lasted.

which was way better than running the sinclair off polaroid batteries ......

On 23/06/17 09:47, NY wrote:
"The Natural Philosopher" wrote in message
news
Whereas this desktop using very ordinary components is asking for my
password in under 7 seconds and is ready to use in 15.

Your PC boots from total power-off (ie not resuming from hibernation or
sleep) to password and desktop in 15 seconds?

yup.

I'm impressed. My two PCs
(both Win 7) take about 5 mins from power-off state, and that's after
checking for unwanted startup processes (msconfig) etc and after running
CCLEANER. What OS do you use? And is that with spinning HDD or solid-state?


Linux Mint/SSD

about 3 secs is BIOS followed by the splash screen to see if I want to
boot linux. If i hut yes then its about another 4 secs to the login
screen, and after that another 7-8 loading up the desktop and so on.




--
€œit should be clear by now to everyone that activist environmentalism
(or environmental activism) is becoming a general ideology about humans,
about their freedom, about the relationship between the individual and
the state, and about the manipulation of people under the guise of a
'noble' idea. It is not an honest pursuit of 'sustainable development,'
a matter of elementary environmental protection, or a search for
rational mechanisms designed to achieve a healthy environment. Yet
things do occur that make you shake your head and remind yourself that
you live neither in Joseph Stalins Communist era, nor in the Orwellian
utopia of 1984.€�

Vaclav Klaus

In article
,
says...

When STD coin box phones came in, they took threepenny bits, sixpences
and shillings. They soon blocked up the threepenny slot, so doubling the
cost of short local calls.

Soon?????

I lived in Grays in Essex. In 1955, the manual Tilbury
exchange (which was actually located in Grays!) was being
replaced by a new automatic exchange (and Grays got its own
exchange for the first time).

There was an exhibition in the main Post Office
demonstrating the new STD system we were to have, with
phones that you could use to dial up various test numbers in
various places in Britain.

Thus, I think, we were probably about the first exchange to
have the new STD phone boxes. They continued to accept
threepenny bits until around 1964/5, so around 10 years.

--

Terry

In article b1d536d4-b8e9-431f-a989-
,
says...

Showing images extracted from a length of rust-coated
plastic tape dragged past a spinning magnetised metal disc
tilted at an angle.

If the metal disc was magnetised, the plastic tape would
carry the images for long!

--

Terry

On Thu, 22 Jun 2017 17:30:12 +0100, "NY" wrote:

I remember in the early 1970s my friend's parents had a Hitachi colour TV
and it had a tint control (we had fun tweaking it just before his granddad
wanted to watch the snooker!). I understand that Hitachi didn't pay the
royalty to use a genuine PAL decoder and converted PAL to NTSC and then used
an NTSC decoder (or something like that).


The Sony 18 inch from that era also had something similar but they called it a
hue control. It also had a shedload of wirewrapping between boards rather than
using connectors.

On a Bush 26 inch from the mid 70's you removed the back and a panel could be
swung up which had all the setting up adjustments in sequence complete with
instructions.
--

In article -
september.org, lid says...

In article b1d536d4-b8e9-431f-a989-
,
says...

Showing images extracted from a length of rust-coated
plastic tape dragged past a spinning magnetised metal disc
tilted at an angle.

If the metal disc was magnetised, the plastic tape would
carry the images for long!

OOPS! ... would NOT carry ...!

--

Terry

"The Other Mike" wrote in message
news
On Thu, 22 Jun 2017 17:30:12 +0100, "NY" wrote:

I remember in the early 1970s my friend's parents had a Hitachi colour TV
and it had a tint control (we had fun tweaking it just before his granddad
wanted to watch the snooker!). I understand that Hitachi didn't pay the
royalty to use a genuine PAL decoder and converted PAL to NTSC and then
used
an NTSC decoder (or something like that).


The Sony 18 inch from that era also had something similar but they called
it a
hue control. It also had a shedload of wirewrapping between boards rather
than
using connectors.

Ah, maybe the Hitachi also called it a hue control, which amounts to the
same adjustment. I don't remember my friend's parents' TV suffering from
what I now know are called Hannover Bars compared with our (fully
PAL-compliant) TV, which I'd expect if they didn't use the PAL delay line.

On a Bush 26 inch from the mid 70's you removed the back and a panel could
be
swung up which had all the setting up adjustments in sequence complete
with
instructions.

That may be the one I was thinking of when I described that panel with
knurled knobs and/or pots that you turned with a screwdriver - Granada may
have rented the Bush to customers.

I remember that in the early 80s, my parents stopped renting from Granada
and bought their first TV (a Bang & Olufsen) and the sound quality was a lot
worse: probably because the audio bandwidth of the sound decoder was wider
but the amplifier wasn't similarly improved so sibilance was a problem (as
it is to this day with female newsreaders' voices on Radio 4 in FM - the
Charlotte Green effect!). The shop where they bought it said they'd had
quite a lot of complaints and came out to tweak things - not sure whether
they improved the amplifier bandwidth or filtered out the higher audio
frequencies from the IF decoder.

When I got my first VCR, which had SCART and phono outputs, I connected the
sound to my hifi and realised what I'd been missing by listening through a
tiny speaker and poor amplifier in my TV. When I got a later VCR with NICAM,
the difference was even more noticeable. I don't think I ever used the TV
speaker after that - I always used headphones and my hifi from then on.

On 23/06/2017 09:47, NY wrote:
"The Natural Philosopher" wrote in message
news
Whereas this desktop using very ordinary components is asking for my
password in under 7 seconds and is ready to use in 15.

Your PC boots from total power-off (ie not resuming from hibernation or
sleep) to password and desktop in 15 seconds? I'm impressed. My two PCs
(both Win 7) take about 5 mins from power-off state, and that's after
checking for unwanted startup processes (msconfig) etc and after running
CCLEANER. What OS do you use? And is that with spinning HDD or solid-state?

I tend to leave my desktop PC on 24/7 because I use it as a PVR and for
logging info from my weather station, so I only reboot it about one
every couple of weeks (eg after MS updates). I tend to leave my laptop
on as well (even if I put it to sleep when I'm not using it) because its
battery no longer holds any charge so it needs to be booted from cold
each time. Of course booting from sleep only works as long as the laptop
is plugged into its power supply. For some reason, hibernate (boot from
memory image on disk rather than from battery-backed RAM) is greyed out
on my laptop.

On XP you used to have to enable hibernate so it could allocate enough
space on the HDD for the memory image.

More recent Windows versions talk about "Hybrid sleep" disabling Hibernate.

--
Max Demian

On 23/06/2017 00:47, Steve Walker wrote:
On 22/06/2017 17:17, pamela wrote:
On 08:26 22 Jun 2017, wrote:

On Thursday, 22 June 2017 08:17:08 UTC+1, DerbyBorn wrote:
Remember trying to improve an old TV by adjusting the
Convergenece Controls.
I recall, my old Murphy had about 20 potentiometers and other
ajustements.

Probably lots of them conveniently close to tingly high voltage
bits.

I remember when all the 2ps we'd saved for the telephone became
useless as the telephone got changed to 5ps and 10ps. (This was
of course the telephone box down the road -- we didn't have one
in the house.)

That's posively modern. Before 2ps were used in public
telephones it was 'Press Button A'.

And if you were to pay a visit to Crich tram museum, you could use the
only working Button A/Button B payphone still in operation to make a call.

What do you put into it? 4d?

--
Max Demian

On 23/06/2017 11:52, Terry Casey wrote:
In article
,
says...

When STD coin box phones came in, they took threepenny bits, sixpences
and shillings. They soon blocked up the threepenny slot, so doubling the
cost of short local calls.

Soon?????

I lived in Grays in Essex. In 1955, the manual Tilbury
exchange (which was actually located in Grays!) was being
replaced by a new automatic exchange (and Grays got its own
exchange for the first time).

There was an exhibition in the main Post Office
demonstrating the new STD system we were to have, with
phones that you could use to dial up various test numbers in
various places in Britain.

Thus, I think, we were probably about the first exchange to
have the new STD phone boxes. They continued to accept
threepenny bits until around 1964/5, so around 10 years.

I mean the ones where you put the coin in when connected as opposed to
the old button A/B type.

--
Max Demian

On 23/06/2017 12:31, The Other Mike wrote:
On Thu, 22 Jun 2017 17:30:12 +0100, "NY" wrote:

I remember in the early 1970s my friend's parents had a Hitachi colour TV
and it had a tint control (we had fun tweaking it just before his granddad
wanted to watch the snooker!). I understand that Hitachi didn't pay the
royalty to use a genuine PAL decoder and converted PAL to NTSC and then used
an NTSC decoder (or something like that).

The Sony 18 inch from that era also had something similar but they called it a
hue control. It also had a shedload of wirewrapping between boards rather than
using connectors.

My 1978 Sony 18" had a "Picture" slider control that adjusted the
brightness, contrast and colour contrast together. Useful to adjust to
suit different room lighting. Behind a panel at the front there were
additional colour contrast and either brightness or contrast buttons.
And a tone control (treble cut).

There were also controls at the back - I think you had to insert a
screwdriver through holes - one was "Height" which I had to adjust to
show the whole picture from my BBC Micro.

--
Max Demian

"Max Demian" wrote in message
o.uk...
There were also controls at the back - I think you had to insert a
screwdriver through holes - one was "Height" which I had to adjust to show
the whole picture from my BBC Micro.

Yes, the PAL (either colour or plain 625/25 monochrome) outputs from a lot
of computers were a bit borderline-compliant. I had a Wren CP/M computer in
the early 80s and that had 625/25 RGB output, rather than the more normal
US-standard 640x480 in 525/30 format. The waveform was evidently a bit
borderline (if you connected one of the three colours to a TV's composite
video input) because the TV picture would roll briefly and suffered a bit of
tearing near the bottom of the picture. The waveform looked OK on an
oscilloscope: it had line sync etc included with each colour, as well as
having a separate sync pin, but evidently the timing was slightly out.

I made a PAL converter using a 4.43 MHz crystal and an RGB-to-PAL IC, and
this produced better results as regards sync - no rolling or tearing - so
maybe the presence of the PAL colour burst and clamping of sync, black and
white levels improved things. But although TVs could display the signal
fine, VHS VCRs couldn't lock and the head servo and tape-transport motor
made some alarming noises as they had a jolly good try!

The Sinclair ZX80 produced a good (though monochrome) signal from its RF
modulator: that would display and record fine.

In article , NY
wrote:
"Max Demian" wrote in message
o.uk...
There were also controls at the back - I think you had to insert a
screwdriver through holes - one was "Height" which I had to adjust to
show the whole picture from my BBC Micro.

Yes, the PAL (either colour or plain 625/25 monochrome) outputs from a
lot of computers were a bit borderline-compliant. I had a Wren CP/M
computer in the early 80s and that had 625/25 RGB output, rather than
the more normal US-standard 640x480 in 525/30 format. The waveform was
evidently a bit borderline (if you connected one of the three colours to
a TV's composite video input) because the TV picture would roll briefly
and suffered a bit of tearing near the bottom of the picture. The
waveform looked OK on an oscilloscope: it had line sync etc included
with each colour, as well as having a separate sync pin, but evidently
the timing was slightly out.

Sorry, but if the computer produced 3 component colours it wasn't producing
PAL. That is a composite system.

--
from KT24 in Surrey, England

In article ,
The Other Mike wrote:
On a Bush 26 inch from the mid 70's you removed the back and a panel
could be swung up which had all the setting up adjustments in sequence
complete with instructions.

My first colour set, a Philips, had the convergence pots on a panel above
the channel selector on the front. Well away from the nasty voltages round
a tube.

--
*Save the whale - I'll have it for my supper*

Dave Plowman London SW
To e-mail, change noise into sound.

On 23/06/2017 10:10, The Natural Philosopher wrote:
On 23/06/17 09:47, NY wrote:
"The Natural Philosopher" wrote in message
news
Whereas this desktop using very ordinary components is asking for my
password in under 7 seconds and is ready to use in 15.

Your PC boots from total power-off (ie not resuming from hibernation
or sleep) to password and desktop in 15 seconds?

yup.

My laptop takes 18 seconds for win10.
Not bad when some of the stuff is still on spinning rust.
Its not a top of the line one and its running in power saving mode all
the time so its probably quicker if I run at full power.


I'm impressed. My two PCs
(both Win 7) take about 5 mins from power-off state, and that's after
checking for unwanted startup processes (msconfig) etc and after
running CCLEANER. What OS do you use? And is that with spinning HDD or
solid-state?


Linux Mint/SSD

about 3 secs is BIOS followed by the splash screen to see if I want to
boot linux. If i hut yes then its about another 4 secs to the login
screen, and after that another 7-8 loading up the desktop and so on.

I think mine is in the BIOS for a bit longer than that, about 7 seconds.

You have to do a restart and power down once the BIOS is there to stop
the win10 quick start to get a true time from power to boot as above.
Just letting it "shutdown" brings it up in about 3 seconds.

On 23/06/2017 13:54, Max Demian wrote:

On XP you used to have to enable hibernate so it could allocate enough
space on the HDD for the memory image.

More recent Windows versions talk about "Hybrid sleep" disabling Hibernate.


Hybrid sleep is hibernation except it stay suspended for a while so it
doesn't need to reload from disk if you use it again after a short time.
Its safer than suspend as if the battery goes flat nothing is lost.

On Fri, 23 Jun 2017 12:52:56 +0100, "NY" wrote:

"The Other Mike" wrote in message
news
On Thu, 22 Jun 2017 17:30:12 +0100, "NY" wrote:

I remember in the early 1970s my friend's parents had a Hitachi colour TV
and it had a tint control (we had fun tweaking it just before his granddad
wanted to watch the snooker!). I understand that Hitachi didn't pay the
royalty to use a genuine PAL decoder and converted PAL to NTSC and then
used
an NTSC decoder (or something like that).


The Sony 18 inch from that era also had something similar but they called
it a
hue control. It also had a shedload of wirewrapping between boards rather
than
using connectors.

Ah, maybe the Hitachi also called it a hue control, which amounts to the
same adjustment. I don't remember my friend's parents' TV suffering from
what I now know are called Hannover Bars compared with our (fully
PAL-compliant) TV, which I'd expect if they didn't use the PAL delay line.

Think this was the Sony, a KV1810

https://www.vintage-radio.net/forum/...7&d=1172410608


On a Bush 26 inch from the mid 70's you removed the back and a panel could
be
swung up which had all the setting up adjustments in sequence complete
with
instructions.

The Bush was very similar to this (I recognise the tuner and the AFC switch) I
seem to recall they did both 22 inch and 26 inch models

http://www.oldtechnology.net/images/bushctv1122.jpg


That may be the one I was thinking of when I described that panel with
knurled knobs and/or pots that you turned with a screwdriver - Granada may
have rented the Bush to customers.

I remember that in the early 80s, my parents stopped renting from Granada
and bought their first TV (a Bang & Olufsen) and the sound quality was a lot
worse: probably because the audio bandwidth of the sound decoder was wider
but the amplifier wasn't similarly improved so sibilance was a problem (as
it is to this day with female newsreaders' voices on Radio 4 in FM - the
Charlotte Green effect!). The shop where they bought it said they'd had
quite a lot of complaints and came out to tweak things - not sure whether
they improved the amplifier bandwidth or filtered out the higher audio
frequencies from the IF decoder.

Quite a bit of the B&O range was little more than Philips evaluation circuitry
for their various TV/radio/hifi building blocks integrated together and stuck in
a posh box. But Philips tended to design relatively good kit albeit with some
really whacky variations on almost identical modular TV boards for no apparent
reason.

When I got my first VCR, which had SCART and phono outputs, I connected the
sound to my hifi and realised what I'd been missing by listening through a
tiny speaker and poor amplifier in my TV. When I got a later VCR with NICAM,
the difference was even more noticeable. I don't think I ever used the TV
speaker after that - I always used headphones and my hifi from then on.

Had a VCR relatively early on but never connected a VCR to an amp and speakers
until much much later, maybe around the time of S-VHS. The real improvement was
with NICAM though. I can't recall exactly when NICAM came along (very early
90's?) but Sony did a mod kit for their TV's with a replacement IF board and a
handful of interconnects and mounting hardware. Cost maybe about 80 quid. The
TV is long gone but the bits removed for that upgrade are still in a box in the
loft along with the instructions.

--

On Friday, 23 June 2017 14:55:08 UTC+1, NY wrote:
"Max Demian" wrote in message
o.uk...
There were also controls at the back - I think you had to insert a
screwdriver through holes - one was "Height" which I had to adjust to show
the whole picture from my BBC Micro.

Yes, the PAL (either colour or plain 625/25 monochrome) outputs from a lot
of computers were a bit borderline-compliant. I had a Wren CP/M computer in
the early 80s and that had 625/25 RGB output, rather than the more normal
US-standard 640x480 in 525/30 format. The waveform was evidently a bit
borderline (if you connected one of the three colours to a TV's composite
video input) because the TV picture would roll briefly and suffered a bit of
tearing near the bottom of the picture. The waveform looked OK on an
oscilloscope: it had line sync etc included with each colour, as well as
having a separate sync pin, but evidently the timing was slightly out.

I made a PAL converter using a 4.43 MHz crystal and an RGB-to-PAL IC, and
this produced better results as regards sync - no rolling or tearing - so
maybe the presence of the PAL colour burst and clamping of sync, black and
white levels improved things. But although TVs could display the signal
fine, VHS VCRs couldn't lock and the head servo and tape-transport motor
made some alarming noises as they had a jolly good try!

The Sinclair ZX80 produced a good (though monochrome) signal from its RF
modulator: that would display and record fine.

625 line PAL VCRs recorded 405 line material happily enough. They didn't give a damn what was in the signal as long as the frame pulses were the right time apart.


NT

"The Other Mike" wrote in message Had
a VCR relatively early on but never connected a VCR to an amp and speakers
until much much later, maybe around the time of S-VHS. The real
improvement was
with NICAM though.

The big disadvantage with playing a non-NICAM VHS machine through a good
amplifier is that non-NICAM VCRs are usually those which don't have hifi
(FM) sound on the tape either, so the enhanced treble response of the hifi
amplifier magnifies the tape hiss from a very narrow track and the slow
speed (1.3 ips for SP, half of that for LP and quarter of it for EP).

NICAM really was the dog's ********. Damn good reproduction compared with
MPEG-2 at 256 or 192 kbps which is still good but can sound slightly raspy.

I have fond memories of a VHS tape getting creased and depositing oxide on
the spinning heads. A bit of iso-propyl alcohol on a cotton wool bud, dabbed
on the heads, usually solved this when it happened, but on this occasion I
got the picture back but there was no hifi soundtrack detected so the VCR
fell back to linear, with all the hiss that this entailed. It took a long
time and several applications of alcohol, both on a bud and on a cloth
cleaning tape, to get the sound working again. After that, I learned my
lesson: if a tape appeared to have jammed, pull the power immediately (to
prevent the auto-unthreading from making matters worse), remove the lid, and
pull the tape-jam apart while trying to keep it clear of the drum (or at
least, where the heads were on the drum). Don't try to extract the cassette
(even gently) through the normal slot.

There was no lasting damage to the VCR: it still played existing recordings
and made/played new recordings right up until 2007 when I began using
Windows Media Centre and a USB DVB-T decoder to record everything. I felt
slightly miffed because a few years before I retired it, it developed an
unrelated fault in the tape-transport logic and began shuttling the tape
from spool to spool at high speed (though not full FF/REW speed) as soon as
you put the cassette in. I took it to a shop who said it was unrepairable
and gave me a choice: either pay for their time in investigating or give
them the machine for spares. Luckily I chose the first option. I went out
and bought a replacement, and then a few months later tried the old one
again and it worked perfectly - and continued right up till retirement. I
consoled myself that with two VHS machines I could copy programmes from one
tape to another for archiving and could record two different programmes
simultaneously.

wrote in message
...
625 line PAL VCRs recorded 405 line material happily enough. They didn't
give a damn what was in the signal as long as the frame pulses were the
right time apart.

Yes, I've heard this. The only thing that matters is the spacing of the
frame sync pulses; the number of line sync pulses (i number of lines)
doesn't matter.

The difficulty is getting access to a 405-line signal. The tuner in all UK
VHS recorders was UHF/625-line only, so you'd need a VHF/405-line tuner that
could output baseband video and a modulator to convert the off-tape signal
back to a form that the TV could play. And you'd need to do it before
broadcasters stopped broadcasting 405-line in the mid 1980s.

Nowadays there are a few hobbyists who have developed modified PCs which
produce standards-compliant 405/25 video by driving the graphics card in a
special mode, and so they could play any video file (off-air MPEG, Youtube).
You could even convert from DVB-T2 1920x1080 high-definition to 405-line!

As you say, that 450-line signal could be recorded and played back on VHS.

Then you need a modulator or else a modified TV which allows you to inject
baseband video.


As an aside, I wonder what your average 625/25 telly would make of a 405/25
signal (assuming you got past the different modulators and fed baseband).
The frame would sync perfectly but the lines would be all scrambled. Is 625
divided by 405 a simple enough relationship that you'd see a static pattern
of lines, I wonder?

It always amazed me that modern European tellies and VCRs can usually copy
with NTSC tapes and signals: I have played a US VHS tape in my player and
got a stable picture (reduced height, corrupted colour due to alternate
lines not having the required phase reversal) - usually accompanied by a
loud clonk as a relay in my telly switches in a different frame-sync
circuit.

The converse is not true: much less US kit can play PAL tapes and signals -
presumably because of The World Ends At The US Borders syndrome :-)

On Friday, June 23, 2017 at 12:33:43 PM UTC+1, Terry Casey wrote:
In article -
september.org, lid says...

In article b1d536d4-b8e9-431f-a989-
,
says...

Showing images extracted from a length of rust-coated
plastic tape dragged past a spinning magnetised metal disc
tilted at an angle.

If the metal disc was magnetised, the plastic tape would
carry the images for long!

OOPS! ... would NOT carry ...!


Heh, call it an OOPS draw...

On 23/06/2017 13:55, Max Demian wrote:
On 23/06/2017 00:47, Steve Walker wrote:
On 22/06/2017 17:17, pamela wrote:
On 08:26 22 Jun 2017, wrote:

On Thursday, 22 June 2017 08:17:08 UTC+1, DerbyBorn wrote:
Remember trying to improve an old TV by adjusting the
Convergenece Controls.
I recall, my old Murphy had about 20 potentiometers and other
ajustements.

Probably lots of them conveniently close to tingly high voltage
bits.

I remember when all the 2ps we'd saved for the telephone became
useless as the telephone got changed to 5ps and 10ps. (This was
of course the telephone box down the road -- we didn't have one
in the house.)

That's posively modern. Before 2ps were used in public
telephones it was 'Press Button A'.

And if you were to pay a visit to Crich tram museum, you could use the
only working Button A/Button B payphone still in operation to make a
call.

What do you put into it? 4d?

It's been adapted to take current coinage.

SteveW

On 23/06/2017 09:09, wrote:
On Friday, 23 June 2017 00:49:11 UTC+1, Steve Walker wrote:
I think it was only in the '80s that they changed the tone received by
an operator from a payphone - until then they could not tell them from
private phones and people had learned that you could make free reverse
charges calls *to* phoneboxes.

This was because the 1980s GPO/BT owned all the payphones and knew which lines were coinbox lines. It was possible to make reverse charge calls to a payphone because the operator could ask the person at the payphone to insert money to pay for the call (and on the old Button A/B boxes listen to the separate 'dings' for sixpences and shillings).

When private payphones were introduced they were connected to ordinary lines so the operators had to have some means of knowing a payphone was connected, hence the 'cuckoo' tone.

Owain

Well BT didn't use their knowledge well, as people were making such
calls without the operators catching on from what I remember

SteveW

On Friday, 23 June 2017 18:41:14 UTC+1, NY wrote:
tabbypurr wrote in message
...
625 line PAL VCRs recorded 405 line material happily enough. They didn't
give a damn what was in the signal as long as the frame pulses were the
right time apart.

Yes, I've heard this. The only thing that matters is the spacing of the
frame sync pulses; the number of line sync pulses (i number of lines)
doesn't matter.

The difficulty is getting access to a 405-line signal. The tuner in all UK
VHS recorders was UHF/625-line only, so you'd need a VHF/405-line tuner that
could output baseband video

no-one broadcasts 405 so not much point. It was similarly pointless pre-82 for different reasons.

and a modulator to convert the off-tape signal
back to a form that the TV could play. And you'd need to do it before
broadcasters stopped broadcasting 405-line in the mid 1980s.

Easier to inject the baseband signal into the tv after the tuner. That's what I did, not a live chassis set. If it is I won't mumble anything about neutrals & RCDs.

Nowadays there are a few hobbyists who have developed modified PCs which
produce standards-compliant 405/25 video by driving the graphics card in a
special mode, and so they could play any video file (off-air MPEG, Youtube).
You could even convert from DVB-T2 1920x1080 high-definition to 405-line!

As you say, that 450-line signal could be recorded and played back on VHS.

Then you need a modulator or else a modified TV which allows you to inject
baseband video.

no mod needed on mine. I don't know if tuner output levels & polarity were standardised though.

As an aside, I wonder what your average 625/25 telly would make of a 405/25
signal (assuming you got past the different modulators and fed baseband).

total scramble. I tried getting a B&W to slow down to 405 and it just would not pull down far enough no matter what I did. If you look at old 405/625 dual standard sets they had massive slide switches to switch a long list of circuit operations.

The frame would sync perfectly but the lines would be all scrambled. Is 625
divided by 405 a simple enough relationship that you'd see a static pattern
of lines, I wonder?

ISTR that with the right line speed adjustment I got an image that was clearly mathematically related and lined up every several lines. So I could see roughly what was on the reording, but it wasn't watchable.

30 line TV is fun too - very different.


NT

It always amazed me that modern European tellies and VCRs can usually copy
with NTSC tapes and signals: I have played a US VHS tape in my player and
got a stable picture (reduced height, corrupted colour due to alternate
lines not having the required phase reversal) - usually accompanied by a
loud clonk as a relay in my telly switches in a different frame-sync
circuit.

The converse is not true: much less US kit can play PAL tapes and signals -
presumably because of The World Ends At The US Borders syndrome :-)

In article ,
wrote:
625 line PAL VCRs recorded 405 line material happily enough. They didn't
give a damn what was in the signal as long as the frame pulses were the
right time apart.

Interesting. Most early VCRs didn't have a line in. Or a VHF tuner. And
can't say I've ever seen a 405 line set with a line out either.

--
*A plateau is a high form of flattery*

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
NY wrote:
NICAM really was the dog's ********. Damn good reproduction compared
with MPEG-2 at 256 or 192 kbps which is still good but can sound
slightly raspy.

You do realise it was 11 bit companded? CD being 16 bit?

--
*How do they get the deer to cross at that yellow road sign?

Dave Plowman London SW
To e-mail, change noise into sound.

On Saturday, 24 June 2017 00:33:37 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
625 line PAL VCRs recorded 405 line material happily enough. They didn't
give a damn what was in the signal as long as the frame pulses were the
right time apart.

Interesting. Most early VCRs didn't have a line in. Or a VHF tuner. And
can't say I've ever seen a 405 line set with a line out either.

Let's see if you can work it out.


NT

On 23/06/2017 23:44, Steve Walker wrote:
On 23/06/2017 09:09, wrote:
On Friday, 23 June 2017 00:49:11 UTC+1, Steve Walker wrote:
I think it was only in the '80s that they changed the tone received by
an operator from a payphone - until then they could not tell them from
private phones and people had learned that you could make free reverse
charges calls *to* phoneboxes.

This was because the 1980s GPO/BT owned all the payphones and knew
which lines were coinbox lines. It was possible to make reverse charge
calls to a payphone because the operator could ask the person at the
payphone to insert money to pay for the call (and on the old Button
A/B boxes listen to the separate 'dings' for sixpences and shillings).

When private payphones were introduced they were connected to ordinary
lines so the operators had to have some means of knowing a payphone
was connected, hence the 'cuckoo' tone.

Owain

Well BT didn't use their knowledge well, as people were making such
calls without the operators catching on from what I remember

SteveW

It wasn't BT's problem, they just billed the calls to the line renter.
The renter could have incoming calls blocked if it was a problem.

On 24/06/2017 00:29, Dave Plowman (News) wrote:
In article ,
NY wrote:
NICAM really was the dog's ********. Damn good reproduction compared
with MPEG-2 at 256 or 192 kbps which is still good but can sound
slightly raspy.

You do realise it was 11 bit companded? CD being 16 bit?


I don't think MPEG-2 was even an audio standard.
It was MPEG layer 3 that was the audio standard and that was abbreviated
to MP3 so you can guess how poor that sounded.

11 bit companded is likely to sound better than MP3 but not CD.

"dennis@home" wrote in message
web.com...
On 24/06/2017 00:29, Dave Plowman (News) wrote:
In article ,
NY wrote:
NICAM really was the dog's ********. Damn good reproduction compared
with MPEG-2 at 256 or 192 kbps which is still good but can sound
slightly raspy.

You do realise it was 11 bit companded? CD being 16 bit?

Yes I was comparing NICAM to MPEG Layer 2, as used by SD broadcasts. The
fact that NICAM was 14 bit with only the most significant 11 bits being
transmitted - so for loud sounds that was the most significant 11 bits, for
quiet sounds where the top three bits were zero, they transmitted the least
significant bits, and there were a few intermediate stages; the same gain
setting was used for a block of several (32?) samples. IIRC no compression
was used so effectively it was like a CD but with only 11 instead of 16
bits.

I'm not sure what the situation is with MPEG. Do they use the full dynamic
range of 16 bits? The compression used by MPEG is the problem, because you
don't get back what you put in, only an approximation which varies from
atrocious to indistinguishable from the original using a British Standard
ear.

I cannot distinguish MPEG from CD for 256 kbps and above. 160 kbps is
usually good enough not to notice artefacts, except on sounds with a lot of
high frequencies (cymbals, applause). Any less than 128 and the artefacts
become intrusive. 64 kbps mono, as used by some commercial radio stations on
Freeview, sounds baaaaad.

I realise that TV sound is MPEG Layer 2 whereas the compression used for
downloadable music etc is MPEG Layer 3, usually abbreviated to MP3.

On 24/06/2017 11:14, NY wrote:
The fact that NICAM was 14 bit with only the most significant 11 bits
being transmitted - so for loud sounds that was the most significant 11
bits, for quiet sounds where the top three bits were zero, they
transmitted the least significant bits, and there were a few
intermediate stages; the same gain setting was used for a block of
several (32?) samples. IIRC no compression was used so effectively it
was like a CD but with only 11 instead of 16 bits.

It's better than CD type (raw PCM) at 11 bits. CD has to have the disc
mastered so the largest signals are full scale, and for a lot of music
the quietest bits are _lots_ quieter than that. 20dB is hardly rare, and
that's 6 bits gone straight away that will be all zeroes in the quiet
bits. It's the loud stuff where the quality would suffer.

I never noticed NICAM distortion, and I used to have a TV with good
speakers. (DAB sounds rubbish)

Andy

On 24/06/2017 10:18, dennis@home wrote:
On 23/06/2017 23:44, Steve Walker wrote:
On 23/06/2017 09:09, wrote:
On Friday, 23 June 2017 00:49:11 UTC+1, Steve Walker wrote:
I think it was only in the '80s that they changed the tone received by
an operator from a payphone - until then they could not tell them from
private phones and people had learned that you could make free reverse
charges calls *to* phoneboxes.

This was because the 1980s GPO/BT owned all the payphones and knew
which lines were coinbox lines. It was possible to make reverse
charge calls to a payphone because the operator could ask the person
at the payphone to insert money to pay for the call (and on the old
Button A/B boxes listen to the separate 'dings' for sixpences and
shillings).

When private payphones were introduced they were connected to
ordinary lines so the operators had to have some means of knowing a
payphone was connected, hence the 'cuckoo' tone.

Owain

Well BT didn't use their knowledge well, as people were making such
calls without the operators catching on from what I remember

SteveW

It wasn't BT's problem, they just billed the calls to the line renter.
The renter could have incoming calls blocked if it was a problem.

In the case of a red phone box BT (or rather, the Post Office) owned them.

Andy
--
Well, I think they did...

In article ,
Vir Campestris wrote:
It's better than CD type (raw PCM) at 11 bits. CD has to have the disc
mastered so the largest signals are full scale, and for a lot of music
the quietest bits are _lots_ quieter than that. 20dB is hardly rare, and
that's 6 bits gone straight away that will be all zeroes in the quiet
bits. It's the loud stuff where the quality would suffer.

True - but TV sound generally has low dynamics - because of the appalling
amps and speakers fitted to most sets.

I never noticed NICAM distortion, and I used to have a TV with good
speakers. (DAB sounds rubbish)

Good speakers on a TV? That would be a first. Unless you were using
external ones.

Thing when comparing NICAM to analogue (apart from NICAM being stereo) is
that most TVs had anything but state of the art FM tuners on the audio
side. NICAM chips were produced to a rather higher standard.

But absolutely no doubt it was an excellent and very clever answer to a
problem.

--
*Husbands should come with instructions

Dave Plowman London SW
To e-mail, change noise into sound.