The Secret Life of Machines (1988) s02e06 Episode Script
The Video Recorder
[Door opens, footsteps.]
[Jazzy music: 'The Russians Are Coming' - Val Bennett.]
[music fades out.]
[clanking, pneumatic hissing noises.]
Tim: Something bizarre like this set which Rex and I were working on last year is obviously an illusion.
But in fact me and everything else on television is really just as much of an illusion.
While you're sitting at home watching this programme, I'll probably be sitting at home watching it too.
What you're actually looking at is an elaborate illusion created by a reel of video tape.
The video recorder, like the other machines in this series, has become quite indispensable, yet very few people have any idea how the thing works.
In this programme, Rex and I are going to try and demystify it a bit.
[clank of lid.]
Inside, it does look quite baffling.
One half is full of a mass of electronics and circuit boards.
And the other half where the cassette goes in, is full of equally baffling mechanisms, gears and pulleys and things.
But despite all this complexity, the basic principles of magnetic recording are really very simple.
They were first developed nearly 100 years ago for recording sound.
A Danish telephone engineer called Valdemar Pullson, convinced that there was a need for a permanent record of business transactions conducted by telephone.
Started experimenting with magnetic recording in 1896.
Pullson had found he could magnetise a bit of steel [magnet clicks against table.]
And then see exactly where he'd magnetised it by dipping it in some iron filings.
He could magnetise the steel in just the same way with an electromagnet, this is just a coil of wire wrapped round a lump of steel.
But he could also use the electromagnet like the iron filings to see where he'd magnetised it.
I've connected this electromagnet to a meter here.
And erm, if I bring a permanent magnet anywhere near it I think you can see the meter move.
It's actually creating some electricity.
So if I now pass the er, electromagnet along the strip of steel.
You can see it moves, at the point where I magnetised it earlier.
This may seem surprising, but the properties of electricity and magnetism are intimately connected.
Well now I can use the endless loop of steel of my bandsaw [horribe grinding noise.]
To make the bandsaw into a primitive tape recorder.
First I've got to connect the whole thing up.
To a battery and a switch.
Well now I can magnetise a few places of the, on the steel strip.
Or, in other words, record a few magnetic pulses [bandsaw grinding noise.]
And now I can see where I have magnetised it on the strip, simply by continuing to run, in other words I'm playing the signal back.
[bandsaw grinds.]
This is the basic principle of magnetic recording, and it's just the same on the most sophisticated modern video recorder.
The heart of the machine is this spinning drum.
Underneath if I undo this screw This is the actual tape head.
And you can see its tiny coil of wire.
It's an electromagnet, and it's doing exactly the same thing as the electromagnet on the band saw.
Well without all this sophistication, Pullsen had enormous difficulty recording the tiny electrical signals he was picking up from the telephone.
However, he applied for patents all over the world, and found eager backers in America.
Pullson: Hellooooo.
Pullman: Now don't worry about the science.
My invention is foolproof.
All you need to know is you make lots of money.
Men: chatter Great.
It's a deal.
Pullman: Thank you very much.
Man: Okay Ladies and Gentlemen, this is your chance now to buy buy buy and make a fortune of a lifetime.
Yes I'm talking about money.
Tim: The backers were more interested in trading the stocks and shares than making telegrophones.
But 7 years later, a saleable machine finally did appear, [Man babbles into telephone.]
advertised as a dictation system.
Man: We have no option except to foreclose on this.
Yours sincerely, Iron T Washbucket.
Secretary: I'll type this up right away.
[crackle.]
Secretary: Oh oh oh.
I can't hear a thing! Secretary: It's impossible, no I can't! Man: Ohhh.
I'll go back to doing things the old way! Business Man: Thursday 25th January, Secretary: Okay.
.
[rattly wheels.]
Tim: This is one of the science museum's wonderful stores.
And this is one of the few surviving telegrophones.
In a way it's quite like a modern tape recorder, with its two reels, and the tape head in the middle.
This contains the tiny electromagnet that actually records on this fine steel wire.
The trouble was though, that the sound it reproduced was really just too faint to be of any practical use at all.
Rex and I had a go at making a working model of one of these and we couldn't hear anything through it at all.
But the idea wasn't totally forgotten.
And as valves and electronic amplifiers improved the idea became progressively more practical.
Also a German Dr.
Stille spend most of the 1920s methodically analysing the theoretical principles of magnetic recording.
And eventually in conjunction with Marconi started producing massive machines like this.
[motors whirr, forklift wheels squeak.]
This particular machine was bought by the BBC in 1933.
The tape heads are up at the top here.
And it uses this very fine, razor sharp, steel tape.
It's all incredibly large because to get a good enough sound quality it has to run very very fast, so it uses up a lot of tape.
Its high speed has some disadvantages; you had to keep the tape oiled - there's an oiler over here.
And it was also quite dangerous, you had to keep well out of the way because if the tape broke, this razor sharp steel would fly all over the room.
Recording on steel still has one specialist use, where heat resistance is important, in black box flight recorders.
The boxes are actually orange, not black, and they're extremely strong and well insulated.
Inside you can see the bright stainless steel wire being replayed.
[quiet whirring noise.]
The recorder is connected to a computer, and it prints out the positions of rudder, elevators and other controls.
On a modern jumbo jet, over 60 items are recorded.
Experiments with plastic tape were started by the German magnetophone company in the 1930s.
The tape's coated with a magnetic powder that actually records the signal.
This powder is a sort of iron oxide, or rust, which is why the tape's always brown.
Well we can make a primitive sort of recording tape using sticky tape, and sprinkling some rust powder on it.
Probably need a little bit more You just have to rub it into the sticky side Get off all the excess Rex: That's it.
Tim: Right.
Right, now we record some sig we put it in an ordinary audio recorder.
Err, yeah I think I've got it in the right place [clunk.]
Rex: Ready.
Tim: Play.
.
yup! [click.]
Rex: (loudly and clearly) This is recorded on sticky tape and rust.
This is recorded on sticky tape and rust.
Tim: Right! And now all we have to do is play it back again.
Err, that's the right way round Put it in Right, okay.
[clunk.]
Rex's voice: This is recorded (quieter) on sticky tape and r.
.
(distorts).
This is recorded on sticky tape and (inaudible) Tim: Well the start of it was very good.
[both giggle.]
Rex: Try it again.
Tim: I dunno, why the, why did the quality go down do you think? Rex: I think it probably fell off the capstan there.
Tim: Well it proves the principle anyway.
Tim: The ring shaped recording head with a gap, that's been used ever since, was also perfected by the magnetophone company.
Here Rex has made a giant model of one.
If he covers it up and sprinkles on some iron filings, you can see how the gap concentrates the magnetic field.
[quiet shaking noise.]
Now when he pushes a model of the tape past the gap you can see how it's magnetised.
The smaller the gap, the smaller the magnets created on the tape.
And the more information that can be recorded on it.
That's why video heads are so small.
The gap on the heads on a domestic video machine have to be exactly 3/1000th of a millimetre across.
They're the most accurately made thing in the home.
It's amazing that something so tiny can record anything at all.
But there really is something quite magical about the properties of magnetism.
Rex: Usually my work is making models and special effects for the film, television and advertising industries.
And I use magnetic effects an awful lot.
Simple ones for conjurers and illusionists: party tricks to get something which is obviously not magnetic like an ordinary match And you can actually make them dance.
For a simple magnetic trick like this, you need two obvious things.
you need to drill the middle of the match and put an iron pin inside, and of course you also need Tim underneath the table with a magnet.
You alright under there Tim? And there's the magnet which we did the trick with.
But of course, sometimes you need much more sophisticated applications for magnets, and I did one years ago with a friend of mine, and we had to make a magnetic mint.
You can hear it rattles [quiet rattling noise.]
And er, with a magnet under the table again, you can control it beautifully.
You can make it go backwards.
You can make it turn.
You can swing it round again.
So you've got full control over it [Duck quacks as if it thinks it's a chicken.]
Tim: Magnetic recording of sound is relatively simple.
[duck quacks.]
Tim: Recording moving pictures is much more difficult.
[Duck hisses.]
Man: Ow! [Footsteps and wheels squeak.]
Tim: In one second, a video recorder has to record 25 complete separate pictures.
Even on a domestic video recorder, each picture is split up into over half a million elements.
And the colour and brightness of each has to be recorded.
[footsteps and rattling.]
[scratching of pen on paper.]
In one second, an audio recorder only has to record about three words.
The average speaking speed.
Hundreds of times more space on the tape is needed to record pictures instead of just sound.
Dimbleby: Good evening, I want you first of all to look at this clock, And remember the time that it says: just after 9:16.
Now the reason for asking you to do this, right at the beginning of Panorama tonight, has all to do with VERA.
The Vision Electronic Recording Apparatus.
The new machine which is in programmed service tonight for the first time at the BBC's research department at Nightingale Square in South London.
There she is.
Tim: Richard Dimbleby demonstrated the BBC's first attempt at video recording in 1956.
To record enough information, VERA had to move the tape past the head at about 20 mph.
The results were shown by replaying the start of the programme.
[Dimbleby in background.]
Dimbleby: to do this right at the beginning of Panorama tonight, has all to do with VERA.
The Vision Electronic Recording Apparatus (fades out) Tim: It got the nickname of wobbly television, and was very short lived.
Dimbleby: Well, there you are.
That's where we came in, in a way.
That was the beginning of Panorama tonight, just about 5 minutes after I first did it.
This is now me again, really.
Tim: Today all video recorders work with slow-moving tape.
to make enough space, the heads have to record a series of diagonal stripes across the tape.
These stripes are created by spinning the heads round on a drum while the tape moves slowly past.
Here we've replaced the heads with pens and and if I thread up a bit of paper with Rex - yeah I think that's in alright now.
Okay, you should now be able to see a stripe being created.
It's the tilt of the drum which makes the stripe be diagonal.
And by the time that one stripe's reached the top.
The tape will have moved on, just far enough so that the next stripe doesn't overlap.
[quiet drum and clicking noises.]
But of course in a real machine the stripes are much closer together.
Tim: This machine's all still connected up.
And if Rex and I lace up a bit of tape.
Bit tricky to get it right okay [quiet motor noises.]
You can see that when the tape's stationary.
The heads are, the spinning heads are reading one stripe over and over again and this produces the still picture.
Moving the tape backwards and forwards we're not on a moving bit at the moment Er, here.
Moving the tape backwards and forwards changes the picture.
It's not a very good picture because my fingers are creating quite a lot of interference.
And of course if you move it at 25 stripes a second.
it replays the tape exactly as it was recorded.
whoops [clicks and rattles.]
Spinning the heads is a much more practical way of recording pictures than speeding up the tape.
The idea comes from this German military machine the Tonschreiber.
Based on the magnetophone of the 1930s, er, this machine was used throughout the second world war for broadcasting propaganda speeches and marshal music.
Its sound quality was much better than anything the Allies had.
It's a bit difficult to get it to run at the right speed.
Erm [German music starts slowly, then speeds up and runs too fast.]
[Music settles to correct speed and plays.]
After the war, many of these machines were captured.
And two found their way to a Russian engineer living in California called A.
M.
Poniatov.
He ran a small firm producing electric curling tongs, called Ampex.
AMP after his initials, plus EX for excellence.
Poniatov wanted to develop the machine, but lacked the capital.
Fortunately he found an enthusiastic investor keen to develop new ways to immortalise his stage performances.
Bing Crosbie.
With Bing's money, Ampex audio recorders soon became the industry standard.
Unlike other companies, Ampex started its work on video by experimenting with spinning heads.
There were formidable electronic problems to be overcome to squeeze the video signal onto the tape.
But by 1956 they had perfected a broadcast quality machine.
This is their earliest surviving recording [silent.]
This is one of their first colour recordings, unfortunately the sound has been lost.
[High pitched tape motors.]
The quality of the pictures on these Ampex machines became very good.
This machine in the BBC video library was built in the late 60s.
Ampex had updated the styling but it still worked in basically the same way.
[motor noise.]
However, the heads gradually wear the oxide off the tapes.
They can only be played about thirty times, and the loose oxide has to be regularly swept up.
This is the next generation of Ampex machine The tape is half the width, and the machine doesn't wear the oxide off.
These machines provided a basis for the first domestic video recorders.
And have also remained a broadcast standard ever since.
Machines like this could be made much much smaller.
But by 1970 the audio cassette had become established and it was obvious that a cassette video system would be more suitable for a domestic machine.
Particularly because it would protect the fragile heads.
Philips introduced the first machine like this.
The N1500 in 1972.
This one's actually a bit later.
But it uses the same square cassettes with one reel on top of the other.
[clank rattle clank.]
This was followed by the, another Philips system the V2000.
The Sony Betamax.
The Sony Video Eight.
And of course, VHS.
[Whirr and click of tape-load mechanism.]
The cassette system does add greatly to the mechanical complexity of the machine.
Bringing the cassette in and wrapping it around the drum needs two completely separate mechanisms.
[VCR whirring.]
It's all wonderfully ingenious, but it does look a bit out of place in this age of solid state technology.
[motor noise.]
[whirr-clack-whirrr.]
The electronics are just as ingenious, although it's not quite so obvious.
A domestic machine only records half as much information about each picture as a broadcast quality one, but the difference is hardly noticeable.
It is only when you record from one tape to another a few times, that the electronics have problems and the imperfections start to show up.
This is an original recording.
[Derrr derr der-derr - 80s Channel 4 music.]
The quality's really very good.
But unlike broadcast machines, the quality of the second and subsequent generations quickly deteriorates.
[music becomes more crackly.]
First the picture gets less sharp.
[sound increases in crackliness and tinniness.]
Then the colour stops fitting the picture and the vertical lines get more ragged.
[very crackly, some whistle.]
Then the sound deteriorates and the colour, which is recorded separately, disappears.
[sound cutting out.]
Finally the picture and the sound break up completely.
[infrequent bursts of sound.]
Video recorders have now been around for over 10 years.
And in that time their design has changed quite considerably.
Some things have definitely improved.
The early machines used to have lots of belt drives, basically rubber bands.
And these things used to stretch and perish.
Rex and I had this problem with these beavers.
We made 12 for a publisher to go in shop windows.
And they had belt driven motors in the base.
None of them worked for more than a week, and I've been very wary of belt drives ever since.
Today the rubber bands in video recorders have been replaced by gears and other mechanisms that are much more reliable.
[click click click.]
The old machines were twice the size and weight of the new ones.
Without modern microprocessor chips, the old machines had three times as many components.
This miniaturisation does have some drawbacks though when it comes to repairs.
Rex: These little black dots on here, are actually this component in miniature.
and it's bad enough replacing one of these tiny things, without trying to replace one of these little tiny, er, modern resistors.
You need a remarkable eyesight to be able to do it.
And of course problems we do have, as children see mummy and daddy pushing videos in here, so they have a nasty habit of putting things there as well, they can be anything from sticky jam sandwiches and toast to toys and all sorts of things.
And of course that doesn't do the tape transport mechanism any good either.
Dad: Okay, so I just put it on Yah? Tim: The other problem with video recorders, is that they're not getting any easier to use.
Dad: What am I doing wrong Melia? Melia: Is there a green liiight? Dad: No.
Melia: Is it 22:00 hours or eight? Dad: Well how can I see.
Melia: I say.
.
I think it's page 43 Dad: Maybe we need the thingy? Melia: Oh, the thingy? Melia: Oh, you mean the remote thingy? Dad: Yah! Dad: Just numbers, you know, it means nothing.
Dad: Ohh! Well, it's all wired in at the back! Melia: Not there Not there [MEROWWW!.]
Melia: Oh, here it is! Dad: Great, oh but it's not going! Dad: Hi Cressida Cressida: Let me do it dad, it's really easy.
[Channel 4 music.]
Dad: Oh.
Great.
Tim: Well video recorders may not be perfect, but I still think it's a miracle that they work at all.
The illusion of reality they create is so convincing it's very hard to believe that what you've been watching for the last half an hour is really just a load of rust.
[Jazzy music: 'Take 5' - Dave Brubeck.]
[Jazzy music: 'The Russians Are Coming' - Val Bennett.]
[music fades out.]
[clanking, pneumatic hissing noises.]
Tim: Something bizarre like this set which Rex and I were working on last year is obviously an illusion.
But in fact me and everything else on television is really just as much of an illusion.
While you're sitting at home watching this programme, I'll probably be sitting at home watching it too.
What you're actually looking at is an elaborate illusion created by a reel of video tape.
The video recorder, like the other machines in this series, has become quite indispensable, yet very few people have any idea how the thing works.
In this programme, Rex and I are going to try and demystify it a bit.
[clank of lid.]
Inside, it does look quite baffling.
One half is full of a mass of electronics and circuit boards.
And the other half where the cassette goes in, is full of equally baffling mechanisms, gears and pulleys and things.
But despite all this complexity, the basic principles of magnetic recording are really very simple.
They were first developed nearly 100 years ago for recording sound.
A Danish telephone engineer called Valdemar Pullson, convinced that there was a need for a permanent record of business transactions conducted by telephone.
Started experimenting with magnetic recording in 1896.
Pullson had found he could magnetise a bit of steel [magnet clicks against table.]
And then see exactly where he'd magnetised it by dipping it in some iron filings.
He could magnetise the steel in just the same way with an electromagnet, this is just a coil of wire wrapped round a lump of steel.
But he could also use the electromagnet like the iron filings to see where he'd magnetised it.
I've connected this electromagnet to a meter here.
And erm, if I bring a permanent magnet anywhere near it I think you can see the meter move.
It's actually creating some electricity.
So if I now pass the er, electromagnet along the strip of steel.
You can see it moves, at the point where I magnetised it earlier.
This may seem surprising, but the properties of electricity and magnetism are intimately connected.
Well now I can use the endless loop of steel of my bandsaw [horribe grinding noise.]
To make the bandsaw into a primitive tape recorder.
First I've got to connect the whole thing up.
To a battery and a switch.
Well now I can magnetise a few places of the, on the steel strip.
Or, in other words, record a few magnetic pulses [bandsaw grinding noise.]
And now I can see where I have magnetised it on the strip, simply by continuing to run, in other words I'm playing the signal back.
[bandsaw grinds.]
This is the basic principle of magnetic recording, and it's just the same on the most sophisticated modern video recorder.
The heart of the machine is this spinning drum.
Underneath if I undo this screw This is the actual tape head.
And you can see its tiny coil of wire.
It's an electromagnet, and it's doing exactly the same thing as the electromagnet on the band saw.
Well without all this sophistication, Pullsen had enormous difficulty recording the tiny electrical signals he was picking up from the telephone.
However, he applied for patents all over the world, and found eager backers in America.
Pullson: Hellooooo.
Pullman: Now don't worry about the science.
My invention is foolproof.
All you need to know is you make lots of money.
Men: chatter Great.
It's a deal.
Pullman: Thank you very much.
Man: Okay Ladies and Gentlemen, this is your chance now to buy buy buy and make a fortune of a lifetime.
Yes I'm talking about money.
Tim: The backers were more interested in trading the stocks and shares than making telegrophones.
But 7 years later, a saleable machine finally did appear, [Man babbles into telephone.]
advertised as a dictation system.
Man: We have no option except to foreclose on this.
Yours sincerely, Iron T Washbucket.
Secretary: I'll type this up right away.
[crackle.]
Secretary: Oh oh oh.
I can't hear a thing! Secretary: It's impossible, no I can't! Man: Ohhh.
I'll go back to doing things the old way! Business Man: Thursday 25th January, Secretary: Okay.
.
[rattly wheels.]
Tim: This is one of the science museum's wonderful stores.
And this is one of the few surviving telegrophones.
In a way it's quite like a modern tape recorder, with its two reels, and the tape head in the middle.
This contains the tiny electromagnet that actually records on this fine steel wire.
The trouble was though, that the sound it reproduced was really just too faint to be of any practical use at all.
Rex and I had a go at making a working model of one of these and we couldn't hear anything through it at all.
But the idea wasn't totally forgotten.
And as valves and electronic amplifiers improved the idea became progressively more practical.
Also a German Dr.
Stille spend most of the 1920s methodically analysing the theoretical principles of magnetic recording.
And eventually in conjunction with Marconi started producing massive machines like this.
[motors whirr, forklift wheels squeak.]
This particular machine was bought by the BBC in 1933.
The tape heads are up at the top here.
And it uses this very fine, razor sharp, steel tape.
It's all incredibly large because to get a good enough sound quality it has to run very very fast, so it uses up a lot of tape.
Its high speed has some disadvantages; you had to keep the tape oiled - there's an oiler over here.
And it was also quite dangerous, you had to keep well out of the way because if the tape broke, this razor sharp steel would fly all over the room.
Recording on steel still has one specialist use, where heat resistance is important, in black box flight recorders.
The boxes are actually orange, not black, and they're extremely strong and well insulated.
Inside you can see the bright stainless steel wire being replayed.
[quiet whirring noise.]
The recorder is connected to a computer, and it prints out the positions of rudder, elevators and other controls.
On a modern jumbo jet, over 60 items are recorded.
Experiments with plastic tape were started by the German magnetophone company in the 1930s.
The tape's coated with a magnetic powder that actually records the signal.
This powder is a sort of iron oxide, or rust, which is why the tape's always brown.
Well we can make a primitive sort of recording tape using sticky tape, and sprinkling some rust powder on it.
Probably need a little bit more You just have to rub it into the sticky side Get off all the excess Rex: That's it.
Tim: Right.
Right, now we record some sig we put it in an ordinary audio recorder.
Err, yeah I think I've got it in the right place [clunk.]
Rex: Ready.
Tim: Play.
.
yup! [click.]
Rex: (loudly and clearly) This is recorded on sticky tape and rust.
This is recorded on sticky tape and rust.
Tim: Right! And now all we have to do is play it back again.
Err, that's the right way round Put it in Right, okay.
[clunk.]
Rex's voice: This is recorded (quieter) on sticky tape and r.
.
(distorts).
This is recorded on sticky tape and (inaudible) Tim: Well the start of it was very good.
[both giggle.]
Rex: Try it again.
Tim: I dunno, why the, why did the quality go down do you think? Rex: I think it probably fell off the capstan there.
Tim: Well it proves the principle anyway.
Tim: The ring shaped recording head with a gap, that's been used ever since, was also perfected by the magnetophone company.
Here Rex has made a giant model of one.
If he covers it up and sprinkles on some iron filings, you can see how the gap concentrates the magnetic field.
[quiet shaking noise.]
Now when he pushes a model of the tape past the gap you can see how it's magnetised.
The smaller the gap, the smaller the magnets created on the tape.
And the more information that can be recorded on it.
That's why video heads are so small.
The gap on the heads on a domestic video machine have to be exactly 3/1000th of a millimetre across.
They're the most accurately made thing in the home.
It's amazing that something so tiny can record anything at all.
But there really is something quite magical about the properties of magnetism.
Rex: Usually my work is making models and special effects for the film, television and advertising industries.
And I use magnetic effects an awful lot.
Simple ones for conjurers and illusionists: party tricks to get something which is obviously not magnetic like an ordinary match And you can actually make them dance.
For a simple magnetic trick like this, you need two obvious things.
you need to drill the middle of the match and put an iron pin inside, and of course you also need Tim underneath the table with a magnet.
You alright under there Tim? And there's the magnet which we did the trick with.
But of course, sometimes you need much more sophisticated applications for magnets, and I did one years ago with a friend of mine, and we had to make a magnetic mint.
You can hear it rattles [quiet rattling noise.]
And er, with a magnet under the table again, you can control it beautifully.
You can make it go backwards.
You can make it turn.
You can swing it round again.
So you've got full control over it [Duck quacks as if it thinks it's a chicken.]
Tim: Magnetic recording of sound is relatively simple.
[duck quacks.]
Tim: Recording moving pictures is much more difficult.
[Duck hisses.]
Man: Ow! [Footsteps and wheels squeak.]
Tim: In one second, a video recorder has to record 25 complete separate pictures.
Even on a domestic video recorder, each picture is split up into over half a million elements.
And the colour and brightness of each has to be recorded.
[footsteps and rattling.]
[scratching of pen on paper.]
In one second, an audio recorder only has to record about three words.
The average speaking speed.
Hundreds of times more space on the tape is needed to record pictures instead of just sound.
Dimbleby: Good evening, I want you first of all to look at this clock, And remember the time that it says: just after 9:16.
Now the reason for asking you to do this, right at the beginning of Panorama tonight, has all to do with VERA.
The Vision Electronic Recording Apparatus.
The new machine which is in programmed service tonight for the first time at the BBC's research department at Nightingale Square in South London.
There she is.
Tim: Richard Dimbleby demonstrated the BBC's first attempt at video recording in 1956.
To record enough information, VERA had to move the tape past the head at about 20 mph.
The results were shown by replaying the start of the programme.
[Dimbleby in background.]
Dimbleby: to do this right at the beginning of Panorama tonight, has all to do with VERA.
The Vision Electronic Recording Apparatus (fades out) Tim: It got the nickname of wobbly television, and was very short lived.
Dimbleby: Well, there you are.
That's where we came in, in a way.
That was the beginning of Panorama tonight, just about 5 minutes after I first did it.
This is now me again, really.
Tim: Today all video recorders work with slow-moving tape.
to make enough space, the heads have to record a series of diagonal stripes across the tape.
These stripes are created by spinning the heads round on a drum while the tape moves slowly past.
Here we've replaced the heads with pens and and if I thread up a bit of paper with Rex - yeah I think that's in alright now.
Okay, you should now be able to see a stripe being created.
It's the tilt of the drum which makes the stripe be diagonal.
And by the time that one stripe's reached the top.
The tape will have moved on, just far enough so that the next stripe doesn't overlap.
[quiet drum and clicking noises.]
But of course in a real machine the stripes are much closer together.
Tim: This machine's all still connected up.
And if Rex and I lace up a bit of tape.
Bit tricky to get it right okay [quiet motor noises.]
You can see that when the tape's stationary.
The heads are, the spinning heads are reading one stripe over and over again and this produces the still picture.
Moving the tape backwards and forwards we're not on a moving bit at the moment Er, here.
Moving the tape backwards and forwards changes the picture.
It's not a very good picture because my fingers are creating quite a lot of interference.
And of course if you move it at 25 stripes a second.
it replays the tape exactly as it was recorded.
whoops [clicks and rattles.]
Spinning the heads is a much more practical way of recording pictures than speeding up the tape.
The idea comes from this German military machine the Tonschreiber.
Based on the magnetophone of the 1930s, er, this machine was used throughout the second world war for broadcasting propaganda speeches and marshal music.
Its sound quality was much better than anything the Allies had.
It's a bit difficult to get it to run at the right speed.
Erm [German music starts slowly, then speeds up and runs too fast.]
[Music settles to correct speed and plays.]
After the war, many of these machines were captured.
And two found their way to a Russian engineer living in California called A.
M.
Poniatov.
He ran a small firm producing electric curling tongs, called Ampex.
AMP after his initials, plus EX for excellence.
Poniatov wanted to develop the machine, but lacked the capital.
Fortunately he found an enthusiastic investor keen to develop new ways to immortalise his stage performances.
Bing Crosbie.
With Bing's money, Ampex audio recorders soon became the industry standard.
Unlike other companies, Ampex started its work on video by experimenting with spinning heads.
There were formidable electronic problems to be overcome to squeeze the video signal onto the tape.
But by 1956 they had perfected a broadcast quality machine.
This is their earliest surviving recording [silent.]
This is one of their first colour recordings, unfortunately the sound has been lost.
[High pitched tape motors.]
The quality of the pictures on these Ampex machines became very good.
This machine in the BBC video library was built in the late 60s.
Ampex had updated the styling but it still worked in basically the same way.
[motor noise.]
However, the heads gradually wear the oxide off the tapes.
They can only be played about thirty times, and the loose oxide has to be regularly swept up.
This is the next generation of Ampex machine The tape is half the width, and the machine doesn't wear the oxide off.
These machines provided a basis for the first domestic video recorders.
And have also remained a broadcast standard ever since.
Machines like this could be made much much smaller.
But by 1970 the audio cassette had become established and it was obvious that a cassette video system would be more suitable for a domestic machine.
Particularly because it would protect the fragile heads.
Philips introduced the first machine like this.
The N1500 in 1972.
This one's actually a bit later.
But it uses the same square cassettes with one reel on top of the other.
[clank rattle clank.]
This was followed by the, another Philips system the V2000.
The Sony Betamax.
The Sony Video Eight.
And of course, VHS.
[Whirr and click of tape-load mechanism.]
The cassette system does add greatly to the mechanical complexity of the machine.
Bringing the cassette in and wrapping it around the drum needs two completely separate mechanisms.
[VCR whirring.]
It's all wonderfully ingenious, but it does look a bit out of place in this age of solid state technology.
[motor noise.]
[whirr-clack-whirrr.]
The electronics are just as ingenious, although it's not quite so obvious.
A domestic machine only records half as much information about each picture as a broadcast quality one, but the difference is hardly noticeable.
It is only when you record from one tape to another a few times, that the electronics have problems and the imperfections start to show up.
This is an original recording.
[Derrr derr der-derr - 80s Channel 4 music.]
The quality's really very good.
But unlike broadcast machines, the quality of the second and subsequent generations quickly deteriorates.
[music becomes more crackly.]
First the picture gets less sharp.
[sound increases in crackliness and tinniness.]
Then the colour stops fitting the picture and the vertical lines get more ragged.
[very crackly, some whistle.]
Then the sound deteriorates and the colour, which is recorded separately, disappears.
[sound cutting out.]
Finally the picture and the sound break up completely.
[infrequent bursts of sound.]
Video recorders have now been around for over 10 years.
And in that time their design has changed quite considerably.
Some things have definitely improved.
The early machines used to have lots of belt drives, basically rubber bands.
And these things used to stretch and perish.
Rex and I had this problem with these beavers.
We made 12 for a publisher to go in shop windows.
And they had belt driven motors in the base.
None of them worked for more than a week, and I've been very wary of belt drives ever since.
Today the rubber bands in video recorders have been replaced by gears and other mechanisms that are much more reliable.
[click click click.]
The old machines were twice the size and weight of the new ones.
Without modern microprocessor chips, the old machines had three times as many components.
This miniaturisation does have some drawbacks though when it comes to repairs.
Rex: These little black dots on here, are actually this component in miniature.
and it's bad enough replacing one of these tiny things, without trying to replace one of these little tiny, er, modern resistors.
You need a remarkable eyesight to be able to do it.
And of course problems we do have, as children see mummy and daddy pushing videos in here, so they have a nasty habit of putting things there as well, they can be anything from sticky jam sandwiches and toast to toys and all sorts of things.
And of course that doesn't do the tape transport mechanism any good either.
Dad: Okay, so I just put it on Yah? Tim: The other problem with video recorders, is that they're not getting any easier to use.
Dad: What am I doing wrong Melia? Melia: Is there a green liiight? Dad: No.
Melia: Is it 22:00 hours or eight? Dad: Well how can I see.
Melia: I say.
.
I think it's page 43 Dad: Maybe we need the thingy? Melia: Oh, the thingy? Melia: Oh, you mean the remote thingy? Dad: Yah! Dad: Just numbers, you know, it means nothing.
Dad: Ohh! Well, it's all wired in at the back! Melia: Not there Not there [MEROWWW!.]
Melia: Oh, here it is! Dad: Great, oh but it's not going! Dad: Hi Cressida Cressida: Let me do it dad, it's really easy.
[Channel 4 music.]
Dad: Oh.
Great.
Tim: Well video recorders may not be perfect, but I still think it's a miracle that they work at all.
The illusion of reality they create is so convincing it's very hard to believe that what you've been watching for the last half an hour is really just a load of rust.
[Jazzy music: 'Take 5' - Dave Brubeck.]