Oral-History:Irving Wolff

About Irving Wolff

Irving Wolff received his BS in physics from Dartmouth and a Ph.D. in physics from Cornell in 1923. He joined RCA in 1924, working in the Technical and Test laboratory of the acoustics department. Here, he was involved in loudspeaker development as well as sound recording work for the film industry. In the early 1930s, he shifted his interests to microwave development and was instrumental in RCA's development of microwave aviation navigational equipment. He retired from RCA in 1959.

The interview begins with a discussion of Wolff's early projects in acoustical engineering, which included loudspeaker testing, and the development of an open loudspeaker with a diameter under ten inches. Wolff discusses the commercial success of this speaker and patent issues surrounding its manufacture by John P. Minton. The interview continues with a discussion of the establishment of RCA's test laboratory and the role of Alfred N. Goldsmith. Wolff goes on to recount his work on theater loudspeakers and his work in Hollywood with Harry Olson dealing with film sound-recording difficulties. Wolff touches upon his early experiments with high-fidelity sound at radio station WCAU in Philadelphia, and the lack of interest on the part of RCA's commercial department. In 1932 Wolff began working on microwave projects. The interview continues with a discussion of his early experiments to investigate the feasibility of using microwave for naval navigational purposes. This work led to the development of aviation radar, and Wolff offers an interesting account of Soviet involvement in RCA's project during the late 1930s. The interview concludes with a discussion of RCA's role in the development of FM radar and the role of military contracts in accelerating radar research.

About the Interview

Irving Wolff: An Interview Conducted by Mark Heyer, IEEE History Center, 1976

Interview #030 for the IEEE History Center, The Institute of Electrical and Electronics Engineers, Inc.

Copyright Statement

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Request for permission to quote for publication should be addressed to the IEEE History Center Oral History Program, IEEE History Center, 445 Hoes Lane, Piscataway, NJ 08854 USA or ieee-history@ieee.org. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user.

It is recommended that this oral history be cited as follows:

Irving Wolff, an oral history conducted in 1976 by Mark Heyer, IEEE History Center, Piscataway, NJ, USA.

Interview

Interview: Irving Wolff Interviewer: Mark Heyer Date: 1976

Education and Decision to Join RCA

Heyer:

Why don’t you give me your name and the approximate times that you were working with RCA?

Wolff:

All right. My name is Irving Wolff, and I’m a native of New York City, educated with a B.S. at Dartmouth and a Ph.D. from Cornell, both in physics. I came to RCA in October of 1924 and was retired in August of 1959, and thereafter worked an additional three years for RCA under contract.

Heyer:

So you got a degree in physics at Cornell? That must have been in the early 1920s or even earlier?

Wolff:

Yes, my degree came in 1923, and I stayed an additional year on a Heckscher research fellowship. In 1924 I had to choose between taking a job at General Motors Research or RCA, in what was then called the Technical and Test Department. It wasn’t specified as research, but the man who hired me gave me such a good line as to what I’d be doing that it seemed that RCA offered a better chance to do research than General Motors did. I’ve never regretted that decision; I think it was correct. I would have worked on General Motors ignition systems, and I don’t think that has been anywhere near as interesting as the things I’ve done at RCA.

Heyer:

They haven’t changed their ignitions systems until the last two years.

Wolff:

That’s right, and then that was done by the electronics industry!

Heyer:

So what were your main interests at the time you were interviewing for these jobs? Were you specifically interested at that time in electronics?

Wolff:

No, I wasn’t at all; I was interested in physics. I would just have soon as started work on X-rays or any other kind of physics as I would in electronics, but I was offered a job in electronics, and it sounded interesting. The field of electronics that I was offered a job in was acoustics. That’s where I started work, in the acoustical department at RCA. The work I had done at Cornell was completely unrelated to acoustics. The project was completely unrelated to electronics; it was in physical chemistry, chemical physics. The only electronics that developed in this program was a need for making capacitance measurements over a range of frequency, for which test oscillators at the time didn’t exist. So I developed a test oscillator to make the measurements at higher frequencies than existing units could produce, and that was the electronics.

Oscillators and Loudspeakers

Wolff:

It turned out that the project of making the oscillator became very useful when I first came to RCA — in fact, that gave me my start at RCA. At the time, the laboratory, which was called the Technical and Test Department, was concerned largely with making tests on loudspeakers to determine if they were suitable for sale. The loudspeakers were made by Westinghouse and the General Electric Company because RCA wasn’t in the business of manufacturing anything at that time, in 1924. So we had the problem of making tests on these loudspeakers. A Western Electric oscillator was used to make these tests; you would set a frequency and then measure the output of the loudspeakers at another frequency, and that was a very laborious process.

I developed an oscillator which operated on the basis of getting a beat tone between two higher frequency tones, so it was continuously variable because the high-frequency tones could be several thousand times as high as the tone you wanted to produce. You didn’t have to have a very big shift in the tone, which was used to beat against a fixed tone in order to go through the whole audible range. We were able to get a continuously variable tone to test the loudspeakers, which, in the first place, did away with the laborious method of point-to-point searching for a tone to use. But more important than that, we were able to tie the lever, which changed the frequency, to a lever on a piece of recording paper, so one had a continuously recorded output of the loudspeaker. That was the first thing I did at RCA, which impressed my boss very much. It did allow us to test loudspeakers very much more rapidly, and to get information you couldn’t have gotten otherwise — and it’s a method that’s been used ever since. With a point-to-point method, loudspeakers at that time had some very large peaks of response, and you might slip by such a large peak of response without noticing at all, unless you took your points very close. With this system you didn’t skip anything.

Heyer:

The more points you took, the more expensive it was.

Wolff:

Yes, and with this you just went through it very quickly. That was the first thing I got mixed up in. The second thing was unrelated. At that time, General Electric, I believe, had developed a loudspeaker, and everyone complained that it had a bad rattle. The sales people said they couldn’t sell it. So we started a project to find out why that loudspeaker rattled. They said in the original tests that it didn’t have that rattle. It turned out that it had originally been tested on a certain set that had a fairly large powered output tube, and the set it was to go on had a much lower powered output tube, so there was distortion caused by the tube, which developed high frequencies and combination tones.

We discovered that the rattle in that loudspeaker wasn’t due to the loudspeaker at all: it was due to the set. That still didn’t solve the problem. How do you then get rid of the ostensible rattle? It was quite simple: we put a low-pass filter on the loudspeaker so these high-frequency rattle tones couldn’t get through, and the loudspeaker didn’t rattle anymore. That was an electrical filter. So the electrical tones didn’t get to the loudspeaker. It didn’t change the acoustical response of the loudspeaker at all; so all those loudspeakers were made with a low-pass filter inserted in them, and then they didn’t have that trouble. That was my second job.

Small Open-Faced Loudspeaker

Wolff:

The third one was quite interesting. At that time, we were notified by the patent department that the loudspeaker that was being made, which was a cone about ten inches in diameter, apparently conflicted with a patent that was in existence, called the Hopkins patent. The Hopkins patent said that--essentially, he patented an open-faced loudspeaker that was more than six inches in diameter. That perhaps needs a little background. Many of the loudspeakers made at that time were a diaphragm attached to a horn.

You see, you’re going way back to 1924. The open cone loudspeaker had just been developed. Western Electric had developed an open cone loudspeaker, which I would say was about twelve inches in diameter, and GE came out with this one, which was ten inches in diameter. Our patent department said, “Look here, as far as we’re aware, this Hopkins patent is a valid patent: at least, we can’t assume it isn’t.” It would be very valuable to RCA to have an open loudspeaker under ten inches in diameter. So General Sarnoff, who at that time was closer to things than he was later, said it would be very valuable if we could develop such a loudspeaker. Some of us put up to the various groups that could do such work — including the RCA group in New York, in Van Cortland Park, which at that time wasn’t supposed to do research — to try to develop such a loudspeaker. And we did! It turned out to be better than this ten-inch loudspeaker, much to everyone’s surprise. There were two tricks. I won’t go into the technical details.

Heyer:

What was the difficulty in making a smaller loudspeaker at that time?

Wolff:

It’s the same as it always is. If you move a diaphragm back and forth, a small diaphragm, it doesn’t get a good grip on the air, and you don’t get any low tones. The trick was to put a resonance at about a hundred cycles or something like that. That loudspeaker would have a big peak in motion where you wanted it, a very big peak in motion. Even though it had a poor grip on the air, it moved so far and so violently that it did give a response. Then that would give a boom, a bad boom, so we put some damping material behind it. The trick in getting the low-frequency response was to extend the armature arm. Previously the loudspeaker had been attached between the drive point on the armature and the pivot point, and we extended the place where the cone was attached beyond the drive point. That made the whole thing a heavier unit. That put the peak at a lower frequency, and then that displaced the loudspeaker I first talked about because it didn’t violate the Hopkins patent. It was an extremely successful loudspeaker. In fact, I think millions were sold. It became a very valuable thing for RCA. It was made by General Electric and Westinghouse. Incidentally, my boss, a guy by the name of J[ohn] P. Minton, thought it was so valuable that he left RCA and began making it himself. He did make a lot under the name Peerless.

Heyer:

How did he avoid patent infringement?

Wolff:

He didn’t. We discussed it, and the patents on this loudspeaker, as near as we could tell, were joint between Minton and a man named [Abraham S.] Ringel and myself, who had done various parts of the job. So he refused to sign a patent assignment. He left RCA, and then the patent department discussed whether they should sue him. They said, "Look, see what position RCA would be in if this big corporation sued a poor inventor. That would give us very bad publicity. We'd better let him go ahead and make his loudspeaker!" So that’s what happened. He made a lot of money, and converted his money into stock in the company that he was associated with, and lost it all in the Depression.

Heyer:

There’s a lesson in there somewhere.

Wolff:

He was an extremely rich man for a while. Multi-millionaire.

Heyer:

That’s interesting: up and down.

Rice-Kellogg Loudspeaker

Wolff:

Does that give you enough detail on that particular project?

Heyer:

Sure. I don’t mind going into detail; I’m very much interested in electronics generally.

Wolff:

Yes, those were the early days of loudspeakers. These loudspeakers were all magnetic armature speakers. In due course they were all replaced by what was known as the Rice- Kellogg loudspeaker, which was developed at General Electric, as a collaborative venture between E[dward] W. Kellogg and Rice. It was too expensive at the time, but they later learned to cost-reduce it, and that became the standard loudspeaker and still is. It had more freedom of motion than the so-called magnetic loudspeaker. From 1926 I guess, when this loudspeaker was first put out, until the early 1930s, it was the number one loudspeaker on the market. The ironic thing about all this is that one of the other radio companies — and I am trying to think of the name — decided that this patent wasn’t valid. They were going to fight it, and they won the fight against it. RCA was "chicken," but it worked out very well because we wound up with a much more sellable loudspeaker. It was in a much smaller and nicer cabinet from the standpoint of placing it in a room, and everyone was happy with the outcome.

Heyer:

It amazes me to see how many of these really early inventions turned out to be so basic, and like you say, the Rice-Kellogg loudspeaker literally hasn’t changed.

Wolff:

Yes, that was very basic. It was just a coil held in a strong magnetic field. At first, we didn’t have permanent magnets strong enough to make that field, so they had to make an electromagnet, which was a fairly expensive thing. It was only really when magnets were produced that were strong enough, which had nothing to do with RCA, that loudspeakers became cheap.

Heyer:

When I was thirteen or fourteen I did a lot of electronics experimenting, and I remember somewhere acquiring a magnetic loudspeaker. I don’t remember now what it looked like.

Wolff:

Yes. A little armature and a piece of metal.

Heyer:

I could never make it work: I just couldn’t get it together.

RCA Technical and Test Laboratory

Wolff:

I should perhaps say something about this Technical and Test Laboratory, maybe. Has anyone talked about that at all?

Heyer:

No, I don’t think so.

Wolff:

As I said, it was set up. It was the only laboratory at the time, except for the communications laboratory at Riverhead and Rocky Point, which Beverage could tell you about. That was RCA. The others were all General Electric or Westinghouse because at the time RCA was just a sales organization and a patent-holding organization. All the manufacturing was done by General Electric or Westinghouse. When this was set up, obviously, it was necessary to coordinate the equipment made by General Electric and Westinghouse. When you have separate engineering departments, they never want to make the same thing. So this laboratory was set up to make tests, to make sure the RCA sales department was satisfied, and then to get some joint drawings on things, so the same thing could be made by both companies. Perhaps if that had continued, the Pennsylvania and New York Central Railroad wouldn’t have gone bankrupt because we gave them so much business in travel from Pittsburgh to New York to Schenectady!

But anyway, that laboratory was set up under Alfred N. Goldsmith. It’s unfortunate that you didn’t get a chance to interview him before he died, he could have given you one of the best histories of RCA. Anyway, it was set up originally at City College in New York. Goldsmith was a professor of physics or engineering, at City College; and how they ever allowed him to set up a commercial laboratory in the college physics or engineering department, whichever it was, I can’t fathom. By the time I came there, they had just opened a new building adjacent to Van Cortland Park, in New York. Do you know Van Cortland Park? It’s a beautiful park up on 242nd Street in the Bronx. The golf links ran right adjacent to our laboratory, and it was very nice. An interesting sidelight on that is that Goldsmith didn’t like the noise that these golfers made, passing by his window. We had a man there who was quite a politician, and he got the parks department to plant a forest in front of Goldsmith’s window. By proper distribution of radios you could do most things with the New York Parks Department! I think he even got them to landscape our grounds!

Heyer:

That was when?

Movie Loudspeakers

Wolff:

That was in 1924. Then in about 1927 or 1928, I think it was, RCA became interested in talking pictures; that’s when they first started.

Heyer:

Steamboat Willie came out in 1928.

Wolff:

Yes. It was our job to develop a loudspeaker that could be used in theaters. The pick-up and recording of sound for the pictures was done mainly by some of the people at Schenectady. I forget the names. I know Kellogg was involved, but I don’t know who the others were. Kellogg, by the way, was a very brilliant engineer.

Heyer:

He worked for Westinghouse?

Wolff:

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No, General Electric. He was one of the old gang at General Electric. Anyway, we developed some loudspeakers using these larger open cones because the small ones were used for the home speakers. We measured the response of these loudspeakers we had, and our competitor was the Western Electric Company, that’s Bell Telephone, and they were using a horn. But our tests were made outdoors, in order to get far enough away, and they showed that our speaker had a better response than Western Electric's did. We put them in theaters, and there were immediate complaints that the intelligibility was crummy, while the Western Electric intelligibility was good. That is, you couldn’t understand voice. It was all right on music, but intelligibility was no good. We were very puzzled by this because as far as we were aware, high frequencies, which these loudspeakers showed, should have led to good intelligibility.

We began to make some tests in New York City. At that time RCA was associated with RKO, so we went to one of the RKO theaters. But the union situation was so troublesome. In order to turn on a loudspeaker, you had to have a film operator and a screen operator, three or four men just to make a test of the loudspeaker. We decided it was very difficult to operate in New York. At the same time shortly thereafter we had a complaint from the Paramount Theater in Rochester. Paramount was a very important customer. We thought we ought to investigate that, and at the same time it would get us away from this New York situation. So we went up to Rochester, and I and an associate, Lou Malter, who didn’t end up with RCA but finally ended up with Varian, went up to Rochester and stayed there all summer, trying to find out what was wrong with these loudspeakers.

In due course we found out that, although these loudspeakers had a very good vertical directional characteristic, they were not directional horizontally. So the sound bounced off walls and spread all over. We hadn’t realized this was important in a theater. It had very bad acoustical effects. Although the loudspeaker was good, the acoustical effects were very bad. So we developed a kind of a horn to put on it; it wasn’t really a horn, but a row of these cone loudspeakers, and we put a baffle on, so the sounds, instead of spreading out all over, would be directional. That solved our problem. That loudspeaker then was used for many years in theaters and gave very good response.

At that time, Dr. Goldsmith had changed his job from that of being in charge of this Technical and Test Laboratory to head of RCA Photophone, which had to do with the theater operations of loudspeakers and pickup and so forth. I don’t know whether he was president of Photophone or just chief engineer. I was in touch with him as to this loudspeaker situation because it was very important to have that solved. We had all these complaints coming in as to the poor reproduction of the RCA speakers. I called him up. We got to talking together one night, and I said, “I think we’ve solved the problem. We put a horizontal horn on the thing, and now that made it directional, and it’s fine.” And he said, “Oh my gosh, you can’t have a horn on that loudspeaker, because we’ve been telling everyone that our loudspeaker was better than the Western Electric because a horn speaker’s no good for this kind of work!” So I said, “Well, why don’t you call it a directional baffle?” So he said, “That’s fine, let’s call it a directional baffle.” So we put out these loudspeakers with directional baffles and everyone was happy. Some of the things that happened in those early days...

Heyer:

That’s interesting. I’m trying to get a perspective on when sound movies were becoming commercial in relation to that work. It must have been very soon...

Wolff:

It was at that time, in 1928, that The Jazz Singer came out. What was his name? Al Jolson. That was one of the first great sound pictures, and we were making them at the same time. By the way, after Minton left I was put in charge of the acoustical operation at RCA. Then in 1928 they were having trouble with recording. They had fuzziness in the recording and so forth, and so I and Harry Olson, who joined us in 1926 [1928], I think, went out to Hollywood and spent two or three months helping them get going on this recording problem. Now he undoubtedly told you about that.

Heyer:

He told me a little bit. I'd like to hear a bit more.

Wolff:

The sound people knew nothing at all about sound recording; they were silent motion picture people. I remember one particular problem, one picture they were making with a violinist. The violinist sounded terrible on the recordings. They tried all kinds of things to fix up this violin. They had him put a mute on the violin, which you know takes high frequency tones out, and that made it a little better, not really good. We found that the trouble in his violin was that our sound recording equipment had what we call a "wow" in it — an irregular motion, a very fast irregular motion. That wow is like the tremolo that a violinist always puts in with his fingers. That’s fine if you put in the right amount, but if you extend it too much, it distorts the whole tone. This frequency irregularity put what was essentially a super tremolo on it and just distorted it completely. We found out that when we ironed out the recorder so it didn’t have this frequency variation anymore, the violin was all right.

Heyer:

What was the recorder like that you were using. I presume it was an RCA recorder?

Wolff:

Yes, but made by General Electric.

Heyer:

Was it on a sprocketed tape?

Wolff:

Yes, and this was a sprocket wow. As a matter of fact, it was due to the sprockets.

Heyer:

Jerking the tape? So you put in an idler?

Wolff:

Yes, I remember that particular part about the trip. The other parts that I remember about the trip have nothing to do with the recording. Hollywood at the time was a most delightful place. There’s no resemblance to that Hollywood anymore in any part of Los Angeles. I remember getting off the train in the morning at San Bernardino — you had to take the train, of course, there were no planes — and there was this wonderful aroma of orange blossoms. There were orange blossoms all around. As a matter of fact, throughout Los Angeles and Hollywood was this aroma of orange blossoms. There was no smog; it was a little kind of country town. Hollywood was a real glamorous place. I didn’t go back to Hollywood until twenty years later, in 1948, and was shocked at what a honky-tonk place it had become.

Heyer:

It had passed the golden age.

Wolff:

It was nothing like it.

Heyer:

Do you have any recollections of the sort of atmosphere that surrounded the film community of the time?

Wolff:

Not being familiar with the film community, I don’t know that it was any different than it was any other time.

Heyer:

I have a feeling that it went through a...

Wolff:

They were very scared of talking pictures, because all of these people were silent actors. There weren’t any actors who could talk. They were afraid they were going to lose their jobs. and a lot of them did.

Heyer:

Have you seen a picture called "Singing in the Rain"? Do you remember that? Made in 1952, with Gene Kelly and Cyd Charisse? It was about the early days, and the transition from still to sound.

Wolff:

No, I didn’t see it.

Heyer:

Terrific picture. It comes around every year, and Gene Kelly is an actor who had a leading lady, and they make the transition from silent to sound. He makes it fine and she doesn’t make it at all. It’s the whole story of the turmoil, just a terrific picture. I think you’d get a kick out of it, having been close to that situation.

High-Fidelity Reproduction

Wolff:

Well, those are the events that I particularly remember. There must have been some other things during that period, but we come up to when RCA in 1929 bought out the Victor Company. There was no need for this laboratory in New York anymore, so it was sold. It was such a strong building that they added another floor to it and it became a convent. What’s happened to it since I don’t know. It was a beautiful location right opposite Van Cortland Park.

So we moved to Camden, and General Electric and Westinghouse acoustical engineers also moved to Camden. I was put in charge of the acoustical division of the research activity in Camden. Harry Olson didn’t want to move to Camden, and he stayed with Photophone for a number of years in New York. That’s the motion picture activity — he probably told you about that.

Anyway, I think the thing I remember the most about that activity was our attempts to make high-fidelity reproduction. We improved the loudspeakers, and we improved the pickups with phonographs. One of the men working with pickups developed a very light pickup, and I think we had a reproduction with a very fine frequency response, as good as the high-fidelity now. At the same time, we realized we were losing binaural reproduction. We set up some experiments with Station WCAU in Philadelphia, to have two microphones pick up and two loudspeakers reproducing — this was just in the studio, since there was no means of putting it on the air, or putting it on a phonograph record — to experiment with stereophonic, high-fidelity sound. My memory is that we did have something pretty good, in stereophonic, high-fidelity sound. This was not on a phonograph, but was direct pickup from microphones in the studio. That was around 1931 or 1932.

Well, our commercial department wasn’t interested in it. They were interested in cost reduction; they said the public wasn’t interested in high-fidelity, and it’s true. The commercial people never did advance high-fidelity sound. The big companies did not. The people who advanced high-fidelity sound were, you might call, the amateurs, who put together the amplifiers and loudspeakers and got high-fidelity. The commercial companies were pushed into it: they didn’t lead at all. They could’ve been leaders, but they weren’t.

Heyer:

I guess that’s very often the case.

Wolff:

Yes. Anyway, in about 1932, after having done this high-fidelity job, I decided that as far as I was concerned the excitement was going out of acoustics. There wasn’t much to do anymore, and I was lazy and wanted to get into something where it was easier to make progress. There was no problem getting out at that time, because Julius Weinberger, who was in charge of the Photophone laboratory in New York, was transferring to Camden, since that laboratory had now been disbanded (I forget why, but I think it was all moved to Camden), and he could take all of the acoustical. So I started off in a brand new field, which I think was a sensible decision, although Harry Olson since then has made a lot of progress in acoustics.

Vinyl Discs

Heyer:

I had one question. Going back to old recordings, there seems to be a big change between say 1933 and 1935 in the quality of the recordings. I think it was probably Harry Olson, who mentioned the change from lacquer recordings to vinyl.

Wolff:

That’s right. In that period, these high-fidelity recordings we made in the laboratory that I talked about were made on acrylics. We knew at the time that they were going to become available commercially.

Heyer:

What was the material used before that?

Wolff:

Black shellac.

Heyer:

Just a solid shellac record?

Wolff:

Yes. It was fairly heavy. It was much noisier than the acrylic, and a little thicker.

Heyer:

No wonder there was such a difference.

Wolff:

Yes. You see the acrylic was a material that hadn’t been developed at the time records were originally made. The original records of course were wax. Some of the old ones, the old cylindrical records, were wax, but I don’t think that the disc records were ever made on wax. I think they were made of shellac right from the start.

Heyer:

And they made shellac until? When?

Wolff:

The early 1930s. You apparently know the exact date if Harry gave it to you.

Heyer:

The 1930s were really the golden age for radio, I guess.

Microwave Transmission and PPI

Wolff:

In the early 1930s, I decided it might be very sensible to start some work on microwaves, microwaves being frequencies about 3000 megacycles and higher. There was work going on in Germany and Japan, but nothing in the United States. I had no idea that Germany and Japan would be our future enemies in a world war — that was purely fortuitous, that they were doing the work and we weren’t. So I started a project on microwaves just to see what we could do, and hired Ernest Linder to help me.

In due course, he developed a tube that could produce microwave signals. We were wondering what to do with it, and read about some French experiments in which they were using microwaves for navigation purposes on a boat, and we thought maybe this was a good thing to do. So we set up this equipment. We were in touch with the various military departments — RCA kept in touch to keep them advised of what we were doing. We had no really good place to test our equipment, so we were invited to Atlantic Highlands to try it out.

Do you know Atlantic Highlands? There’s this big bluff at Atlantic Highlands above Sandy Hook with an old lighthouse, so we set up this equipment at the lighthouse and wanted to see how far we could transmit the microwaves. The Signal Corps finished a tug and we went all the way across New York Bay to Fort Hancock and could still get our signal, which made us feel very, very happy. At the same time, they asked if it would be possible to detect a boat? Would these microwaves reflect off a boat? And so we said we might just as well try. There was a boat coming in the harbor, and sure enough, we pointed it towards the boat and we could get a signal off the boat, which combined with a little bit of the signal coming directly off the transmitter to give us a beep tone, and I guess that was our first radar experiment. It wasn’t radar as we know it; it was just direction, whereas radar is distance and direction, but it was the first experiment. That was in 1934.

Having done this, we decided that if we wanted to really do something with microwaves, the thing to do was to use it for navigation purposes. At that time we had no hope of doing anything with airplanes. What we wanted to do was put this on boats to discover — this was of course post-Titanic — if there’s an iceberg in the way, or a boat, or something like that. Let me go to 1936. This equipment we had at that time is what would be called continuous wave. It was just a continuous wave modulated with a tone. We decided if we really wanted this for navigation purposes, we should have an indication of distance as well as direction. So we developed a pulse technique, and that’s where television came in. For if it hadn’t been for developments in television, which permitted us to amplify a small pulse about a microsecond long, we never would have been able to do this. But the tubes had been developed for television, to amplify. See, that’s just what you needed for television.

So we built some equipment using these tubes and were able to amplify these short pulses. To test the equipment, we set it up on the roof of one of the buildings in Camden which faced the river. We had a transmitter emitting the pulses on a separate receiver which received them. We looked at it on the cathode ray tube; we had this sweep circuit on the cathode ray tube which would indicate the distance because the sweep started the time the pulse was emitted, and then you’d see the receive pulse some time later, depending on the time lapse. We were very excited: we were able to see ferry boats in the river; we got reflections from the buildings on Philadelphia. They had an elevated railroad at that time on the other side of the river and we could see the trains moving on the elevated railroad, and so we had then a reception of a pulse. We then decided we ought to get a picture of both distance and direction on the same screen, so we tied these two dishes together and put another control on our cathode ray tube, which indicated the direction in which they were pointing. On a single screen we were able to show the distance of an object and the direction in which it was. And that, so far as I am aware, was the first PPI — Plan Position Indicator. It showed distance and direction.

Well, right after that experiment was finished, we ran into something completely new, which turned out to be fortunate in some respects and unfortunate with regards to the patent on the PPI, because a French company at that time had a paper patent on the thing. This was a subsidiary of IT&T, and their paper patent was put in the Patent Office a little ahead of ours, and so we had patent interference. We lost the interference largely on the basis that we made this test and then after that didn’t do anything with it. As it turned out, I think we still sustained that patent in Europe, but RCA had to give up all their patents in the 1958 court decision, so we wouldn’t have had it anyway. But it was a big disappointment to us to lose this suit because we really were the first people to invent the PPI, which is used in all radars.

Now, for the reason for giving this up. In the winter of 1937, there were quite a few airplanes running into mountains. You wouldn’t remember that. It was very worrisome. RCA was in the aviation radio business at the time, but not cutting much of a swath. We had a meeting on aviation radio in New York or in Camden. General Sarnoff was there: he had a very good sense of what was needed from a publicity standpoint, or from the standpoint of equipment. He asked, “Can’t we do anything to stop these airplane crashes into mountains?” He said, “If we could do something for that, that would really rebound to RCA’s credit and put us right into the aviation radio business.”

After thinking about it, I guess various ideas may have been suggested. We suggested the possibility of using this radar technique — we didn’t call it radar. We called it radio vision, which instead of television was radio vision! So we said we can maybe try to use this radio vision; put that on an airplane and see what’s ahead of us. We realized we could never put that microwave equipment on a plane; it wasn’t strong enough and it was too bulky at that time, so we decided we’d have to go to a lower frequency. Since that was supposed to be so important and we were looking for an application for the work we were doing, we decided to stop this microwave work the next day. We stopped it. It just so happened these two things happened at the same time, and we started to make equipment to put on an airplane. We set this equipment up in our laboratory, and again bounced signals off the buildings in Philadelphia, the ferry boats, and whatnot, and this time we had a much stronger signal, because we had more power and could amplify better and so forth. We also had better receivers. One day a fellow from the Navy came to see this equipment, in just a general tour of the laboratory. He looked at it and was very impressed. This was in 1937 or 1938, I guess.

I’m getting myself ahead of myself a little bit. Before that visit we had put this equipment on an airplane, and had tried it out, and we flew against mountains in the Appalachians and Pennsylvania and up the Hudson River to the Catskills and we found we could see the mountains all right. We had an antenna on the plane, at that time an old Ford trimotor plane, which actually had been bought for RCA by the Russians.

Work with Soviets

Wolff:

That’s another story. Have you heard that story, of our venture with the Russians? In the 1930s there was a detente, which was initiated by Roosevelt with the Russians. One of the things that the U.S. agreed to, was to export U.S. technology to Russia. One of the things they wanted was television technology. So RCA agreed to have a large number of Russian engineers come to this country to study what we were doing. We had two or three in our microwave laboratory, and they had quite a few in Harrison in the tube laboratory, and they were in the television laboratory — they were all over the place! Amongst our other projects, one was to use a television pickup in the airplane to see objects on the ground. Now, surprisingly enough, our military said, "That’s fine; we’re not the least bit interested in that. You can give it to the Russians." Zworykin had the idea at the time of taking a bomb and controlling it by television. Looking at the object on the ground and having the bomb in the television camera also and sending it right to the object. Whether that’s what the Russians were interested in we don’t know.

Anyway, in order to test and make sure the RCA equipment could see an object on the ground, we had to have an airplane to do it. So the Russians bought this Ford Trimotor airplane for RCA so they could take television equipment up in the plane and look at the object on the ground and see whether they could recognize it. Well, there’s an interesting sidelight on that. If you want to put an object on the ground to see, what would you do? One of the most likely things you’d do is make a little plus sign: that’s a very good thing to see. I heard this story and I’m sure it’s true. Our people couldn’t figure out why the Russians were so opposed to putting that little plus sign on the ground to look at. We finally agreed to putting an E on the ground or something like that. But later we found out that the reason they objected to that plus sign on the ground was that it looked like a cross, and if word got back to Russia that they'd put that cross on the ground, they probably would have their heads chopped off or something like that. The guys in charge of that mission never would permit anything like an X. Well anyway, this television equipment was sent to Russia. I think that you could get a very interesting story from Loren Jones, who was mixed up in that project. It was a very interesting project. He went to Russia at the time, and delivered that equipment and delivered a television station.

Heyer:

Somebody mentioned that RCA sold a lot of television equipment to Russia.

Wolff:

Yes, at that time. Loren Jones and Wally [Waldemar] Poch. Actually Loren Jones was in charge of that coordination with the Russians, and he could tell you about his trip to Russia, and the problems we ran into in that project. I think it would be a very interesting bit of RCA’s history. He’s in Philadelphia now. I can give you his address and phone number later.

RCA has never wanted to publish this much, but I don’t see any reason why they shouldn’t. It was all done with the consent, actually with the push, of the U.S. government. We had a great many Russians here, and we got paid for it! The Russians paid us for doing it. It was done by Amtorg or whatever that Russian service is, and it obviously wouldn’t have been done without the consent of the government. At that time [President Franklin D.] Roosevelt apparently had very great faith that it would be possible to work with the Russians. I think he did, until the end of World War II — it was only then that we found out that we were on opposing courses. He wouldn’t have made some of the agreements he made with them at Yalta if he hadn’t thought that he could work with the Russians.

Radar Research

Wolff:

Well, that’s a little off the subject. Anyway, that gave us this airplane, because they sold it back to us for practically nothing. So we had this old Ford Trimotor, and a Ford Trimotor was a wonderful plane for experiments, because it wasn’t skinstressed the way these later planes are. It had a framework and the skin was built around the framework. You could do anything you wanted to the skin. You could put holes in for antennas and mount things on it — it was very strong — which we did. In these first radar experiments we had an enormous antenna on the roof, a big "A" thing. It had it from the front of the plane all the way to the back as an antenna. As I said, we could see the mountains, but the most striking thing was a reflection we’d get directly from the ground, which indicated the altitude, and that was a very strong reflection. So far as I am aware, that was the first time radar had ever been flown in an airplane. It may have been done in England, but I don’t think so. I’m sure it wasn’t done in Europe, so I believe we had the first use of radar in an airplane in our lab. I don’t recall the exact date — it was in 1937-1938 maybe.

Heyer:

Did you realize at that time the importance of the altitude?

Wolff:

I’ll come to that later. We also tried putting an airplane in front of us to see if we could get a signal from it, to see if we could prevent collisions with other planes. We found that that didn’t give us a very good signal. So with that equipment at least, it didn’t prove very lucrative — although we could definitely see the mountains.

We had a prototype of this equipment set up on the roof of our building to test it, and one of these Navy people came around, a man in charge of what was called the Radio Division of the Bureau of Ships [Radio Division, Bureau of Engineering], a man by the name of [Commander W. J.] Red Ruble, a very strong-willed individual. He came around; he looked at this, and he said, "Well, what are you doing with this? What do you intend to do with this?" We said, "We put it on an airplane, and we’re going to improve it some, and then we hope to get some publicity out of it." He said, "No you don’t! From this day on, this is made secret. You can’t talk about it at all, and I’ll give you a Navy contract to work on equipment for us."

So we were never able to publicize what we had done, by putting this equipment on an airplane, until it didn’t amount to anything after the war, of course. MIT had made much better microwave equipment to put on airplanes, because they had a big group who could work on it. Well, as a result of that, we were given a contract to put some radar equipment on a plane to be used for detecting ships from an airplane. That was eventually put into production, but I don’t know how many they sold.

Heyer:

And used in World War II?

Wolff:

Yes, in the early part of World War II it was put on the flying boats, PBY flying boats. I don’t know if they sold too many of them, because what they really wanted it for was detecting submarines rather than ships. It wasn’t good for detecting submarines. At the time, the military told us that they would like to be able to bomb more accurately. The trouble with their bombing wasn’t that they didn’t have a good bomb sight — they had a wonderful bomb sight and wonderful bombs and everything — but they didn’t have a good enough measure of altitude. If we could build an alternative for them that would measure altitude accurately — I think the specification was 50 feet and 20,000 feet — they’d be able to bomb very accurately. That was no great problem to make such an altimeter; so we did develop such an altimeter, and many hundreds of them were made. The net result, I believe was that they couldn’t bomb any more accurately knowing the altitude than they did before. The problem wasn’t the altitude, it was the bomb, and the wind, and other things. That was just a miscalculation on their part, but we made a great many of these accurate altimeters.

Heyer:

That was around?

Wolff:

That was 1940 or 1941, when we knew we'd be involved in the war. By that time, money began to flow. In the 1930s, $50,000 was an enormous contract to get. The government department just didn’t have any money! If you got a $50,000 contract from them, you really had a lot of money for research and development. Production contracts of course were more.

Heyer:

In a lot of ways World War II was a big impetus to research.

Wolff:

Government spending! Radar wouldn’t have been developed for ten or twenty years at the normal pace, if it had just been up to industry, whereas the impetus of the war gave it a tremendous push. At the time we were working on radar, we were working on it with a small group. I guess I had ten people on it at the most. The Naval Research Laboratory had a certain number, not many, and Signal Corps had some. That was all the radar work being done in the United States. No commercial company except RCA was working on radar until they were pushed into it by the military later in the late 1930s.

Then when the war started, the English came over here. The English were extremely cooperative, and they have never been given sufficient credit for what they contributed to our radar. In fact, I don’t know how long it would have been delayed if it hadn’t been for the English. When they got into the war before we did and immediately set up this large radar research laboratory, they sent this commission over to tell our military people and our science people what they were doing, and how they were organized. So our people set up this laboratory at MIT. MIT at first was a big project, before the Manhattan Project. They recruited some of the best physicists, the best physicists they could find in the country. Engineers, and mainly physicists, came to this laboratory and started research on radar, and they must have had, I think, three or four thousand people at this laboratory. Of course our small group of people didn’t amount to anything after that laboratory started, and then some of those people later decided that radar wasn’t exciting any more, and they went to the Manhattan Project.

Roy Sanders and FM Radar

Wolff:

Then we had another stroke of luck. Our patent department got a note, or a phone call, from a young fellow who just happened to live near Camden, in a place like Haddon Heights [NJ]or something like that, saying he had an invention he wanted to sell, one he’d like us to look at. I went there with C[larence] D. Tuska, who was the head of our patent department at the time, to look at it. It was another form of radar.

See, we’d been working on pulse radar, and this boy had what we call frequency modulation radar. In pulse radar you send out a pulse and then calculate the length of time it takes for the pulse to come back. In frequency modulation radar, you vary the frequency of a tone rather rapidly, and then when the tone comes back, you’re getting the original frequency that went out all right, but by then your frequency has changed. It’s varying rapidly, so you get a beat, and the frequency of the beat tells you how far away the object is. Well, Western Electric at that time had developed a frequency modulation radar — distance measuring equipment, you could call it, not radar, because it didn’t have direction. They had given it quite a lot of publicity. This young fellow had had two years of schooling at Rensselaer [Polytechnic Institute] in New York State. He was I guess nineteen at the time. He decided that he had this invention — he didn’t know anything about the Western Electric work — and he was so excited about that invention that he left college and decided to work on it at home. He set up a demonstration in the field opposite his house on some wires of how this thing would work.

And it had some very good points to it, which were improvements over the Western Electric system. We decided to hire him and pay him for his patents. Not only had he done this, but without any experience as a patent lawyer, he had filed his own patents, written up his own patents! He was a real smart fellow, a genius. A man by the name of Roy Sanders. You may have heard of a company called Sanders Associates? His company was one of the big prize boomers on the stock exchange before 1970 or 1973.

I wanted him to work on pulse radar, but he insisted he was going to work on FM radar, which he did, and he developed this FM radar, which was useful not for this high altitude work the bombing people wanted, but for flying airplanes at low altitude. This was very accurate at low altitudes, and it was not to use on the ground. It was to be used over water. They wanted to do the same thing that they do now, to bring airplanes in at low altitudes so they wouldn’t be detected by the Japanese radar, and in order to do that at night they had to have some way of telling what the altitude was. This was very good for telling within a foot the altitude at a hundred feet or something like that. It was a beautiful radar for doing that. It was so good that it was sold commercially to the military. This is very unusual — it was standardized as the only radar of that type by the Air Force, the Navy, and the British. It was sold to all of them, and I think tens of thousands of them were sold.

Heyer:

That’s interesting.

Wolff:

We’re lucky that it came out of this boy. He was a very remarkable individual. As a further development of that, they decided, why couldn’t we bomb automatically? Was it possible to use this to control the altitude of the plane, use it also to measure the distance to a ship, let the radar decide when it was the right time to drop the bomb, and let it do the whole thing? So we developed equipment to do that. At that time, then, the Radiation Lab decided that they weren’t interested in FM radar, so they would leave that up to RCA. RCA would be the main promoter of FM radar in the country. In fact, we were the only one working on it. We had several people who manufactured the equipment — a company called Belmont, and what’s that big radio company in Chicago? Not Motorola [Magnavox].... I forget the name. They were making these radars as well as RCA. RCA couldn’t make enough of these FM radars.

Well, on the bombing project, we got something working very well, and by that time they decided we couldn’t do that kind of bombing anymore. We had to bomb with rockets. Their technique of bombing was faster than our technique of getting radar out for them, so we developed a radar that could develop either control [of] rockets or bombs, and that became more complicated. By that time the war was over, and they lost interest in it.

There were some other things we did in radar, subsidiary things that were very interesting. By the way, this radar, this FM radar, is the thing that the police use now to detect automobiles. That’s the type they use. For measuring speed, you get a. You see, we developed a very intriguing little system there, so with one sweep, you could measure both distance and speed. Speed of approach was important in order to drop a bomb accurately, and it was a very ingenious little system. The sum of the upsweep and the downsweep frequencies gave you the distance, and the difference between the upsweep and the downsweep frequencies gave you the speed. It was that simple. Because in one case the frequency was going up, in the other case it was going down, and you’d get the speed also. So it was really a very ingenious, beautiful system for automatic bombing, and we tried this out. There were lighthouses in the Delaware River, and we’d try it out with water bombs to see if we could hit these lighthouses. There usually were fishermen in these lighthouses, and they were really surprised when these water bombs began raining down on their heads. They really scampered away!

Heyer:

They must have thought there were crazy people —

Wolff:

We learned how to control the altitude of the plane automatically, so you’d set it for fifty feet and it would fly at fifty feet. I think they have that system now on the [Boeing] 747 — the 747 is so high above the ground that the pilot can’t judge his altitude, and they have a radar like that to tell the pilot what his altitude is above the ground. 747 pilots have told me they use that to make their landing, just before touchdown. Of course, those things are a lot more sophisticated than they were; we went from the first experimental equipment to production in two or three years, and it’s been many years since then.

Heyer:

It takes longer now.

Equipment to Measure Ground Speed

Wolff:

Another piece of equipment that we didn’t produce but [that] I have a patent on was equipment for measuring ground speed of a plane. On these long flights they didn’t have any means of telling where they were. They would fly over the ocean and they couldn’t know what the wind loft was, so they wanted to know what ground speed was.

Heyer:

Is this on commercial flights?

Wolff:

Yes, this is on commercial flights. This was after the war that it was used, but originally the military wanted it during the war. So we had an idea for measuring ground speed, which has actually been used.

Heyer:

How did that work out?

Wolff:

Well, it was quite simple. We sent one beam of radar forward and another backward, and measured the difference in the frequencies.

Heyer:

So it really was just the Doppler shift?

Wolff:

Yes, taking reflection from the ocean waves. If wind was still on the surface you wouldn’t get much reflection, but apparently that doesn’t happen very often. Well, a lot of these things you can do if you think about them. You have to think about them a bit, and you wonder how you do them, and then you get an idea.

Roy Sanders Anecdotes

Heyer:

That story about the boy with the FM radar is really interesting. He’s like a classic backyard...

Wolff:

Inventor. Yes. He left RCA after the war, and he was a hard guy to get on with. Personally, I was always getting him out of trouble. He had trouble with the guards at the laboratory, and so forth. I could tell several stories about Sanders. One time he came into the laboratory — they knew him of course — and they said, “Show me your button.” You had to wear an identification button. So he opens his shirt and shows them his belly button! The guards said, "The next time that happens, I’m going to sock it!" Then we had trouble with him. I don’t know if you want to hear these stories, they have nothing to do with —

Heyer:

It doesn’t make any difference. Sure, why not?

Wolff:

He was a very obstinate fellow, but he had a group of people working for him who were extremely devoted to him. When he left RCA, they left at the same time. This company formed, in due course, was called Sanders Associates, and I’ve never seen a company more aptly named, because these guys were Sanders’s associates! The Fourth of July came on a weekend, and this was during the war. Engstrom said, “Now, you people have been working very hard in the laboratory here, and I think it would be good to have a rest. So the laboratory is going to be closed from Thursday until Monday.” Well, Sanders says, “They can’t keep me from working, I want to come in and work! This is the war time.” Well, they said, absolutely, "you won’t be able to get in, the laboratory will be closed."

So he did some work at home, and at RCA we had a deal whereby you assign all your ideas, your patents, to RCA, and they patent it and you get a dollar or something like that for the patent. When the time came, Sanders turned in these patent disclosures on this work he’d done over the weekend but he said, "I’m not going to sign them to RCA, because I was told not to work for RCA over this weekend, so these patents belong to me!" He had a big scrap with the patent department before he agreed to turn them over to the patent department. Anyway, after he left RCA he went to Raytheon after one unsuccessful job with another company, and was largely responsible for the development of the Hawk missile, which has been big business for Raytheon. Then he did what I always knew he would do eventually, he went into business for himself and formed this company, Sanders Associates. And the same people who worked with him at RCA went to Sanders Associates.

Jerry Wiesner

Wolff:

As I was saying, MIT decided that they would leave the FM radar work to RCA, since we were so far advanced, and by that time we must have had thirty or forty people on it. So they assigned one of their young people to be an observer, and who lived here in Princeton, to see what was going on. That was Jerry Wiesner, who later became Kennedy’s science advisor, and still later president of MIT.

So he was the one who reported to MIT on what we were doing on FM radar. One of his first assignments.

Heyer:

Well, he was in the right place, I guess!

Wolff:

The big contribution of the English was made by a professor by the name of Oliphant, I think at Oxford [Cambridge] University, who developed a microwave tube that was enormously more powerful than anything we had had before. That was further improved at MIT, and that was the basis for the microwave radar that was developed at MIT. In addition to that, the English turned over, without any restrictions, all information they had on radar, because they realized we were in so much a better position to work on this than they were. We had more people, and we weren’t being bombed.