Oral-History:Rudolf Drabek
About Rudolf Drabek
During his career at Philips, Rudolf Drabek worked on the influential recording and video technologies of the 1960s, 1970s, and 1980s. This interview details the development of radio and video recording technology, compact cassettes, and Video 2000. From an international perspective, Drabek analyzes the technological and economic influences on the development of video recording and VHS technologies.
About the Interview
RUDOLF DRABEK: An Interview Conducted by David Morton, Center for the History of Electrical Engineering, 25 July 1996
Interview #290 for the Center for the History of Electrical Engineering, The Institute of Electronics and Electrical Engineers, Inc.
Copyright Statement
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It is recommended that this oral history be cited as follows:
Rudolf Drabek, an oral history conducted in 1996 by David Morton, IEEE History Center, Piscataway, NJ, USA.
Interview
Interview: Rudolf Drabek
Interviewer: David Morton
Place: Vienna, Austria
Date: July 25, 1996
[Note: additional comments by Erich Länger]
Video recording
Responses to Länger comments
Drabek:
My name is Rudolf Drabek, and I will make some amendments to what Erich Länger said regarding video recording. First of all, after the N1700 two-hour machine, it was very interesting that during the development process, we had the problem to improve the playing time by a factor of two and it is little bit more. And one major point is the so-called line criterion. The line criterion is very necessary, because adjacent tracks have to have the same phase of the color. We made a small trick: one video head was shifted from the opposite position by one TV-line at the circumference of the head drum. So we had adjacent tracks, we had one with a line criterion of 3.5 and the other track has 5.5. So this if you have still mode the color is still functioning well. That's one point. Another point is that the N1700 as well as Video 2000 systems had a weight of approximately 17 to 20 kilos. Now if you weigh a video recorder of today, it weighs about 3.5 kilos. So here you see also the improvement that was made during the last years. Not to speak about the improvement in quality. So in principle, the quality has, we are now above the Japanese quality reporting from the market. That is from independent sources. So it's not our own judgment, it's from independent sources, from the main dealers.
Weight reduction
Morton:
I have a question about the reduction in weight. How was that accomplished in general?
Drabek:
The reduction in weight was accomplished first of all in the weight of the mechanism, and in the construction of the mechanism. Because the video recorder, and also the electronics, it is clear. In the N-1700 for instance, the tape deck, the mechanical part, was not very stiff, so we need a very good base, also from the housing. So we used an armor plate to make the mechanism more stiff.
Länger:
Base plate.
Drabek:
A base, an additional base plate, to make the deck stiff. And this always goes into weight. And also the power consumption of the circuit was very high. So in principle we had a mains transformer that weighed about two kilos or so.
Länger:
Yes.
Drabek:
So the main transformer, now, as a, is nearly the whole weight compared to the recorders of nowadays.
Drabek:
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Also the electronics that were not so much integrated circuits available as now. And we had also in Video 2000, we had direct drive motors for the reels, so it was, in principle it was a five motor concept: one motor left reel, one motor right reel, a threading motor, a capstan motor, and a drum motor. And so you had to have a lot of electronics necessary to supply the energy into the circuits, and in Video 2000 also the dynamic track following system, needed extra electronics. And also for quality reasons in that time, that was in 1979 when we introduced Video 2000 system, the quality was not the quality of today. And so we tried to separate the electronic parts into modules, and the price of one module should be so low that it could be thrown away and replaced by another one, because electronics were so intensive, and there was so much in the set that it was thought that no repairman could manage the whole process. So in the build-up of the recorder, we had a basic PCB, printed circuit board, and we had a lot of modules, with a very heavy transformer on the one side, a heavy deck, and so on, so the 17 kilos came up. And this was always for the laboratory people a real drawback, because we always made field testing, especially in France, because of the systems there. And it was horrible to use this, with such a suitcase, [laughter], walking around all through Europe and so on. That was regarding the weight. Regarding the Video 2000 system, we were on the technological edge. You have heard that the track width was 22 microns, the track length of one track is about 100 millimeter or so, a little bit more. So if you look 100 millimeter by .022 millimeters.
Tape consumption and picture quality
Drabek:
And you have to follow that angle, therefore we used dynamic track following. But not only the reduction in tape consumption made it difficult to have a picture quality, it was, there were, some new systems for the picture improvement necessary. In the N1700 model the signal to noise ratio from the video heads was sufficient to have a noise free picture at playback. This is no longer, this was no longer so with the Video 2000 system, and it's still not so also with VHS system. There is use of dynamic pre-emphasis. That means you have more de-emphasis in areas, and you switch off the de-emphasis at transients. So you have sharp steps, and clean areas. Clean and noise free areas. This was also necessary to have the Video 2000, and VHS also clear for the customer with a difficult signal to noise ratio. And you have also heard that Video 2000 has nearly half of the tape consumption compared with VHS, and still we made a system, in the latest years of Video 2000, we made a 8 hour machine, with a video track width of 11 microns. And so you have with one video cassette, you have sixteen hours of playing time.
Morton:
How big was the, what size was the cassette?
Drabek:
The size of the Video 2000 cassette was the same size of the VHS cassette. Only that it is "flippable." So it is a drawback that you have to flip it over after 8 hours, yes? It's clear. [laughter]
Länger:
Excuse me. I give you a copy of this graphic, where you see the tape consumption in square meters per hour. And I give it in a logarithmic you see, and it was nearly linear. So you can imagine what will happen in the future if you follow this line. [laughter] So you see what system has what tape consumption, and I saw it quite interesting to see that in logarithmic scale, it is not nearly linear. And there are always differences, if you have a system in European or in NTSC or in PAL. So you see the crosses of PAL and then NTSC. Take it with you if you are interested.
Morton:
Thank you.
Collaborations of Grundig and Philips Eindhoven
Drabek:
And this struggle for picture quality was done for Video 2000 system in the years '78 and '79. And we did it together with Grundig, the development, the system development was done together with Grundig, and we had the struggle between both companies. And if I can put in a small story, the first time we were in Nurenburg with our prototype, there was also a director of Eindhoven with us, and in this time Mr. Grundig was active, and we were in his studio, and he was sitting there, and he was a non smoker, as it is now very often. [laughter] And the Eindhoven director always took out the cigarettes, [laughter], and handled them, and then finally, because Max Grundig has not reacted on his behavior, and then finally he asks if he can have an ashtray, and Mr. Grundig said, “No.” [laughter] This was the only one time I met Mr. Grundig personally. So then we made our technical comparisons and it showed that we were on comparable levels regarding the picture quality. And during that time, I have had my first contact with these Grundig people, and later on in my life, in 1993 to 1995 I was in Nurenburg, and I met some of the engineers there and was their boss.
Morton:
Aha.
Drabek:
And also the secretary was the same and so when I went into the room "Oh," she said, "Hi, Mr. Drabek." [laughter]
Morton:
I don't know much about Grundig as a company. Do they do research on the level of Philips, do they have big laboratories?
Drabek:
They do not research, have not research on the same level as Philips. They are more or less, they have a product, a prototype research, so not the basic principles, they are not working....
Influence of Japanese technology
Morton:
Do they tend to take technologies from other companies, and manufacture them?
Länger:
Yes. I can say that video heads basically at Grundig were made in the same manner as Japanese. So Grundig applied Japanese technology on video heads, and we did it with our own technology, with laser cutting.
Drabek:
Then we brought out a system in 1979, and we produced it until I think 1983, and 84 we changed over to VHS, but this is not of the system Video 2000, it's mainly a point of marketing intensity from VHS, and in this time, the quality of the Japanese products are better than European products, that is also a little drawback we had. But that is only a private remark from me, [laughter] it's not an official one.
Early video recorder quality
Länger:
If you do not mind I can add some things which I have seen now. I said the first video recorder EL-3400 was produced in the range of about few thousand. I saw it is about 3000 pieces. If you look at LDL 1000, the small system with half inch tape but reel to reel, I see that we had at a certain moment already achieved the range of twenty thousand pieces, so it was quite higher. And in N-1500, the new cassette, VCR cassette system, which we started in 1972, we had up to the same month in 1974, already achieved about 75,000 pieces. So it continued still. So it is only to give you a feeling what happened quantity wise. I think it is maybe of interest to you, for the history. The other sets I don't have figures for.
Drabek:
So that is one, what I want to add to Eric's remarks. I want to come now to the point of combisets, and I will start with the video recorder and TV combinations. This is an strong evolving market in the last years, and we have also products on the way, on the market regarding "combies." I want to add that in 1970 we had only in the laboratory, we had a prototype of a black and white TV with a black and white tape, video tape recorder with open reels. It was only a lab model. But it shows that whenever technologies are on the market that are comparable or do need each other, it is a intention to combine them. So in 1970 it was a first approach, but it doesn't lead to a market product, and now it is really on the market.
Radio recorder product
Drabek:
And now I came to this product, you will see, here is the first radio recorder product, that of really a large amount of millions of products that are produced every year. In 1966 we put out a model of a radio with all bands, and with an integrated cassette recorder. And this has several features, and is really the grandfather of all radio recorders. And it's still functioning and it incorporates some patents. One of the major patents is that if you have a tape recorder you have always an eraser oscillator inside. And if you want to record a medium or a long wave station, you can have a beat note there, and there is an automatic system, that in the moment you go onto record, it is measured if there is a beat note measured via the AGC of the radio part, and if yes, the frequency of the erase oscillator is switched to another frequency, and there it was no beat note. Other models on the market had a simple switch, if you had a beat note then it is switched to the other frequency, but this is done automatically, and this set also does not have any record button, you only had to fix the range and press the playback button and that is the recording mode. And during that fixing process and pressing process, this automatic beat note identification systems.
Morton:
I have a couple of questions about that product. One is, again, I asked the same question about the video recorders. This type of product is very important now. What kind of numbers were sold of these back then?
Drabek:
Of this model was produced with a successor nearly of the same size, and inside also, was produced three years, and in that time we have produced nearly half a million products. And you have to remember, that the price of this product was nearly the wage of one month of an average worker. So compared to the prices today, you see, it was a very expensive product. And still we have produced half a million in several years.
Morton:
Another question. It's my understanding, maybe it's not really true, but it's my understanding that today radio recorders like that are used a lot to play back recorded cassettes, that they're attractive because they're portable.
Drabek:
Music is it, yes.
Morton:
But I don't get the sense that they're used very much to record the radio.
Drabek:
Ah yes that is very clear because in 1966, when we started with that product, there were no software on the market. Software appears only after you have a medium available, and at that time you had only the possibility to record off the air.
Morton:
So do you think as the software became available, that the recording features became less important to people?
Drabek:
That is correct, and as it is also valid for video recorders, there are a lot of models available on the market only for playback purposes, yes. And also if you look to the video discs for instance, available now, at the moment they are only for playback purposes, software is only for playback.
Philips compact cassette development
Morton:
If you don't mind, I'm very interested in the early history of the Philips development of the cassette. Maybe you weren't involved in that, but....
Drabek:
Of the compact cassette?
Morton:
Yes. Do you have any knowledge of that earlier development?
Drabek:
Yes. It started in Hasselt in Belgium. There was a man named Mr. Haarler, who was named to be as inventor of the compact cassette. You will find a, within the Philips organization you will have enough sources to trace that back.
Morton:
So their small recorder was already in production. Was it in production here when this development began?
Drabek:
I said the development of the compact cassette was made in Belgium, but this tape part of this set here was developed and produced in Vienna. In two different factories. Because we had the so-called Wierack factory, that was more or less a tape factory, and also the beginning of video recording activity, as Eric said-
Länger:
Bandgerechtewerk.
Drabek:
Bandgerechtewerk, yes, and there was another, a radio factory. And in the radio factory we did a lot of whole product. But still the tape came from the other factory of Vienna.
Morton:
When was that? Why did they do it that way?
Länger:
'63, I think, the compact cassette appeared, and close to that date the first recorder was produced, at Bandgerechtewerk in Wierack, but it was only for recording/playback purposes, without radio, naturally, I remember this thing. Do you remember that type number?
Drabek:
I think drei und dreißig nul .
Länger:
EL 330, I think, was the first tape recorder based on compact cassette, of Philips.
Drabek:
And this tape deck was adapted with new electronics for the integrated version.
Länger:
Yes. I remember this very well. It was more or less in parallel with our EL-3400 machine, so the developments were very much close together. At different labs but at the same time.
Drabek:
And Philips is such a big company that it is always so that a specific sub-part of the complete set is taken from a factory all over Europe or the world or whatever.
Morton:
One of the really interesting things I think about the history of the cassette is the way it sort of became this hi-fi medium. It started out as a portable, its chief advantage was portability. If you wanted hi-fi you had the big reel to reel. Then later it sort of evolved into hi-fi.
Drabek:
It started with mono operation, and the maximum frequency was about, within 6 dB range was, I believe it was a 10 kilohertz. And in the meantime you have it in stereo, and you have it with full hi-fi range, that means 15.6 kilohertz, that is defined as a DIN norm regarding hi-fi.
Hi-fi equipment development
Morton:
So that's, did any of the development of the hi-fi equipment take place here?
Drabek:
Yes. That was done also, not only here because in the early, in the 70s for instance, the profit possible on the market was so that you can have several laboratories, working on the same product range. So, but still, here in Vienna, in the Bandgerechtewerk, there was a crew developing hi-fi sets. And we made also combinations of hi-fi sets with an integrated stereo part, that was 881. As a product name. That was very interesting. I was always in the audio times. I was electrical development engineer, and one of these simple hi-fi sets was produced 15 years later in South America, still unchanged. Really.
Morton:
By a different company or by the same?
Drabek:
No, no it was in a Philips factory. But still, more than ten years later, still in production. That is remarkable.
Morton:
That's amazing.
Drabek:
In Columbia.
Market competition and product development
Morton:
I have a few more questions. There's an interesting contrast between the history of the cassette, and the, as a Philips product, and the various video technologies. It seems like the Japanese came to Philips to manufacture these products, the Japanese did not have a successful competitor, as far as the Japanese were more successful with their video systems, competing with the Philips products. Were you aware of the relationships between the Japanese companies and Philips?
Drabek:
I have not enough information to say relevant things regarding that. I only know that regarding several technologies there are close contacts between the major competitors on the market. Because today the electronics business is so expensive in development, that it is not possible to throw out money. The last products that were made regarding orders, it is a mini-disc of Sony, and the, how is it called? The 16 track audio system? Digital Compact Cassette, that is the DCC. And the DCC was also made together with Panasonic and Philips. But still both systems are not very well distributed on the market.
Philips patent policy and manufacturers
Morton:
That's true. I think the Digital Compact Cassette seems to be disappearing rapidly. The mini-discs are still around in the United States, but I don't know what's going to happen to them. But, do you know anything about the patent situation? Was Philips's policy about the patents on this, or the rights to manufacture the cassettes, was it strict, was it open?
Drabek:
Regarding the compact cassette it was an open situation. This is most very useful for the broadening of the system on the market, yes. But in general I do not know.
Morton:
So do you think the strategy was to let other manufacturers, to make it easy for them?
Drabek:
In the field of compact cassette it was made easy from Philips for other manufacturers.
Länger:
They widened the system.
Morton:
Oh, so they thought everyone....
Länger:
They opened for introduction of others.
Drabek:
Was that the case with the Video 2000?
Länger:
In Europe, we have had our partners all over Europe, for Video 2000. I think it was also, and we were also open, to others outside Europe. Yes, I know this. I had some trips around the world with Video 2000 at that time, in the States, in Japan. So basically we were interested to spread over the whole world Video 2000.
Morton:
So were the Japanese just not interested?
Länger:
I do not know what they really thought about it. But it was offered.
Drabek:
VHS was brought onto the market in 1976, I think, or so? Eric, you said that.
Länger:
Yes, it was twenty years ago.
Drabek:
And we came as a successor later on, three years later, with a better system. It is I think in the Japanese mind, it, they would have lost the war if they had accepted a European system. They are thinking very strong in those components.
Länger:
It was not their invention: "not invented here."
Drabek:
Yes. We have, we both have some experiences in this field with the Japanese feeling or behavior.
Evolution of compact cassettes
Morton:
Getting back to the compact cassettes, what was Philips's role in the evolution of the medium and the corresponding adaptation of the machines?
Drabek:
Yes, this I do not really know, because I was only in that time an electrical development engineer, but the success of this compact cassette was enormous. It's the only system that was on the market. Just in between, Grundig had also a so-called DC10 system, with a little bit of the form of the cassette with other parameters. This product disappeared from the market, it was only on the market for two years or so.
Morton:
When was that?
Drabek:
Also in 1970-, 1966 or so. Around then.
Morton:
And was that something they developed themselves?
Drabek:
They have developed themselves, the system, ja.
Morton:
I'm completely, I've never heard of that one.
Drabek:
Yes DC-10.
Länger:
We are not the right people to speak about compact cassette, it is a pity. Mr. Rupp would know much more, because he was tightly involved in any way, in Eindhoven and in Hassel. You have to put forward such questions to him.
Drabek:
But if you are interested mainly in magnetic recording, so please if you ask regarding the history of the compact cassette you have I think to go to Eindhoven. I only want to show you an integrated product of both components.
Länger:
It was not a basic development here in Vienna, but in Hassel. Therefore all the related questions could be easier answered there, and basically in Eindhoven.
Morton:
Okay.
Länger:
Only other video recording activities really were forced by people here in Vienna, so we were really active and we said what is possible and we put the prototypes on table and so on, so we can say much more about video cassette development and I did it, I hope so, than on audio cassette development, because it did not start here, and it was not really invented here. The first product was made here, I think it was EL-330, I remember that very well.
Drabek:
And it was a flat version, it was in this direction, yes. And we have adapted this type of basic product.
Drabek's career at Philips
Reception and playback technology
Morton:
Well, why don't we talk more about your earlier career? You became a group leader at Philips Videowerke, am I pronouncing that correctly?
Drabek:
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Yes, regarding that, Eric, has spoken about the N1500, and the N1500 was not only a basic video recorder, it had a receiving part. And still I was in the other factory where we have developed the radio recorder, and he was in the Bandgerechtewerk. So they made the video recorder part and the receiving part was developed from me as a group leader. And so in principle it was TV technology, regarding the receiving part, what we had to add was an antenna amplifier, because we had to supply from the antenna as well signals too for the video recorder part, so for the receiving part as well as for the TV part. So we needed a modulator to supply the signal back to the TV. This was a new product. And this modulator was developed in Einthoven, and in principle in today's terms it is a color balance mixer, and this I think there was operated on 600 megahertz.
Länger:
VHF.
Drabek:
VHF, and it was the first product with such a high frequency of operating, modulator for TV signals for home use. And all the TVs in that time, that was 1972, they had no automatic frequency control for tuning, so we had very stringent demands regarding the stability, and the oscillator in this modulator was a Hohlraum what is that? A cavern oscillator. It was a metal box and no coil, it was a metal strip as for the coil, I do not know the right word in English. I don't, it was a very stable oscillator, you can see the stability mechanically. Because it was totally in copper, with silver and so on. The stability was smaller than 100 kilohertz deviation for a frequent temperature range of about 30 degrees. Today it is not so stringent because all the TVs have automatic frequency control. And another point that is very interesting from the time we appeared on the market with video recorders. A friend in Eindhoven that has given the name for the video signal. He said the playback signal of the video recorder is a mechanical TV signal. Yes, that's very interesting. Because the time frame depends upon the mechanical stability of the tape deck. You have the wobbling of the head disc, you have the wobbling of the tape transport, "wow and flutter," so the signal is not stable, regarding time stability. Ampex, for instance, no problems, they have a time base corrector and so on, in this simple products you have no room for a time base, no room in the price for a time base corrector, and therefore, two men, Mr. Karl and I, were active in all of Europe, visiting all TV manufacturers, because the TVs from that time, they had always a button for the VCR channel. And in, and this VCR channel had a changed time constant of the horizontal phase lock loop. This was really necessary. Today not, because all the phase lock loops for the horizontal frequency are switched automatically to a lower time constant if the signal strength is good enough. And so you will not have any effect of this and you could take every channel, or every frequency, or every program place you can supply signals from a VCR to that. But in that times it was not easy, because the TV manufacturers are in a such strong position. . .
Länger:
They have been in such a strong position.
Drabek:
They have, they were such a strong postions as I said, what is a video recorder, how many pieces you are selling? And in the first years of the video cassette recorder, we had low quantities. If you sent up 10,000 pieces it is clear they want to know nothing about video recorders. It was really hard.
Länger:
Yes the mechanical faults of the video recorder should be corrected by a reduced time constant of the TV set, not to have disturbances on the screen. So this introduction period was a very....
Drabek:
Was also a struggle for to convince the TV manufacturers that this would become a common product.
VCR and channels
Morton:
There is something that's always fascinated me about VCRs. The, since you worked on the video modulator, you may be the man to ask. Why is it always channels three and four? Why not some other channels? [laughter]
Drabek:
It is, it is, it is only channels 3 and 4 in the States, it channel 37 in Europe, and you can change it in Europe from plus-minus 5 channels.
Morton:
And what's the advantage to that?
Drabek:
This, in that times, in Europe, it was in the year '72, there was always a gap around 600 megahertz. This was the channels 36-37. And therefore we decided to go into that frequency.
Länger:
It was not used by normal transmitters.
Drabek:
Normal transmitters. And it was not possible to go on the upper edge of the UHF band. I told you the IC was on the technological edge regarding the frequency. So we have chosen that frequency.
Länger:
In Europe it was quite clear because it was the only part of the frequency band which was free and widely not used. And in the States it is in the lower area, in channel 3, 4.
Drabek:
And now in the times of cable TV it is, sometimes it is necessary to change the frequency.
Länger:
Yes, but I think a lot of TV sets now are operating with the so-called Scott plug. Scott plug, this 21 point plug on the rear side of the TV set, where you can plug in video signals, audio signals, not on an RF basis but on a lower basis, on a standard frequency basis. And if you connected VCR and a TV set by a Scott cable, there, they don't have all these problems. The TV set will automatically switch over to playback if you go to playback on the set.
Morton:
I see. Well, thank you very much.
