Oral-History:C. Chapin Cutler
About C. Chapin Cutler
C. Chapin Cutler is a communications engineer known for his development of and work on the corrugated waveguide, the traveling wave tube, and differential PCM. After receiving a B.S. from Worcester Polytechnic Institute in 1937, Cutler was hired at Bell Labs; although he took courses at Stevens Tech and Princeton, he never fulfilled the requirements for a formal postgraduate degree. During World War II he worked on radar and the development of a proximity fuse; after the war he began work on the traveling wave tube and eventually, after his invention of differential PCM, worked on picture-phone and satellite technology. He is currently retired.
The interview begins with Cutler's education and his decision to follow a general science curriculum instead of an electrical engineering course. After discussing the circumstances of his interest in Bell Labs, he describes his early experiences at Bell Labs and his eventual assignment to Bell's laboratory in Deal, New Jersey. He discusses at length his and Bell Labs' participation in the Carnegie Institution's proximity fuse project; his work on waveguides and his consequent development of the Cutler feedhorn; his work on demodable tubes and on the traveling wave tube; his invention of differential PCM; and his management of Bell's picture-phone and satellite projects. Throughout the interview he discusses both his own and Bell Labs' general attitudes towards research and research management; he stresses the importance of management staying active in technical work and speaks highly of his collaborations with John Pierce, Cal Quate, Rudy Kompfner, and John Whinnery. The interview concludes with his discussion of his collaboration with Marion Hindes on a paper on electron beam focusing.
About the Interview
C. CHAPIN CUTLER: An Interview Conducted by Andy Goldstein, Center for the History of Electrical Engineering, 21 May 1993
Interview # 160 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:
C. Chapin Cutler, an oral history conducted in 1993 by Andrew Goldstein, IEEE History Center, Piscataway, NJ, USA.
Interview
Interview: C. Chapin Cutler
Interviewer: Andrew Goldstein
Place: Palo Alto, California
Date: May 21, 1993
Childhood and Education
Goldstein:
Thank you for agreeing to talk with us. Let's start with some biographical information, your background and education.
Cutler:
Well, let's see. I was born and brought up in the middle part of Massachusetts, near Springfield, and went to the Springfield public schools for junior and senior high, public schools in Ludlow and North Wilbraham earlier. These towns are now commuting area for Springfield. I graduated from Springfield Technical High School with a college preparatory degree and a rather moderate scholastic record in the early part of the Great Depression (1933). I was brought up to believe that college was a natural thing and that one should expect to continue one's education through four years of college. However the family was pretty broke when I finished high school and it really didn't look like college was possible. Somehow, though, things opened up a bit so I could at least start, and I went to Worcester Polytechnic Institute (WPI) in Worcester.
Goldstein:
And at Worcester, what did you study?
Cutler:
I started in Electrical Engineering, stayed in EE for two years, and then after that, why, it appeared to me that the electrical engineering course was like a strait jacket, and I wanted to do more different things. A buddy (my sophomore roommate, Nate Korman) and I found that the college catalog listed many entrancing elective courses, and we thought there must be some way that we could take them instead of following the routine electrical engineering schedule. Indeed, the catalog listed "General Science" as an alternative. It was managed by the Physics department and was almost entirely elective for the junior and senior years.
Electrical Engineering, at that time, was power oriented, and we were much more interested in radio and electrical communication; what today you would call electronics. Electronics was not a popular word at the time and was not accepted as an engineering subject at WPI. Indeed, some folks did not consider it to be a college level discipline at all.
Goldstein:
What years were you at Worcester?
Cutler:
I graduated in 1937, so I must have started in the fall of 1933. In 1935, my room mate, Nate Korman, and I talked to a lot of people and we got a lot of advice. Almost unanimously our advisers said, "Take the electrical engineering course, anything else wouldn't have standing in the outside world, you'd graduate from here with only a degree in General Science." General Science had been a catch-all for people who, for some reason or other, couldn't or wouldn't take a standard engineering course. There were only two recent graduates, one was a fellow who had a nervous disorder and couldn't do the laboratory things, and the other had decided halfway through engineering school that he wanted to teach high school physics. We were strongly tempted by the catalog listing of a number of advanced electrical, math and physics courses, mostly for graduates working toward a master's degree, the highest graduate degree then offered by WPI.
We both were very attracted to higher mathematics, and wanted more physics than the engineering curriculum allowed. We thought such courses would be more useful and helpful to us than taking hydraulics, civil engineering, and engineering thermodynamics. The latter was really about steam power plants; you know, how to handle the steam boiler and get electricity out of a turbine. On the other hand, Thermodynamics in Physics was really a theoretical, mathematics-oriented study of kinetic theory, thermal phenomena. So we talked to a lot of people, professors, graduate students and others. The more arguments we heard against switching to GS, the more convinced we were that was right for us.
I would have told you a few weeks ago, the advice we received was unanimous that we shouldn't switch to GS, but we did anyway. However, recently I read a letter that I wrote to my mother at that time in which I said, "Talked to Professor Roys." He was the head of the mechanical engineering department.
Goldstein:
What was the name?
Cutler:
Francis ("Spider") Roys. I didn't take any courses from him, but he was a good friend whom I had met through his son, a fellow radio ham. Roys said, "By all means, take General Science, do what you want to." And we did.
GS was managed by the physics department and a degree in Physics was not offered. In our junior and senior years we only had one or two "required" courses. We took more math, we took advanced physics, and we took about half of the courses the electrical engineering students took in the engineering curriculum. We would have preferred to keep our affiliation with EE and graduate from that department, but the administration would not permit it. Some of the courses we took were listed as graduate courses, and we found ourselves competing with masters' degree candidates. It was difficult, but it was fun. We had a good time studying the things we wanted to study. We organized one or two of unique courses with the aid of a very sympathetic and helpful electrical engineering professor: Professor Hobart H. Newell, a pioneer in radio communication. Newell gave us special assignments in lieu of the standard EE Electronics Laboratory. It was a wonderful experience.
Cutler:
When we graduated, Nate Korman got a "Coffin Award" scholarship at MIT, went on to more graduate work and joined RCA. I was the only undergraduate at WPI to get an offer from Bell Laboratories. Many of our classmates joined the unemployment lines. I think we made a pretty good decision. I was determined to go to Bell Labs. And, as you know, jobs were very scarce in the 1930s.
Goldstein:
Actually, I think there was a hiring freeze on, up through 1936.
Cutler:
True. A few years later, when I visited Worcester, I found that the electrical engineering department had established a communications elective, and about half of the electrical engineers were taking it. The courses offered were very nearly the same ones that we, innocently enough, had selected when we were sophomores.
Goldstein:
Were there courses in electronics — things like radio? Or were those the ones that you had to put together yourselves?
Cutler:
Those were the things we had to organize ourselves. One was on electrical communication; theory, based on a new book that had just come out by Bill Everett, at the University of Illinois. His book was a classic for many years. A lot of the course was based upon our own study of recent journal articles and finding out what was being done at places like Bell Labs, Columbia, GE and RCA. Because of this, I was certain where I wanted to work after graduation. I wanted to work where this kind of stuff was being done. We devoured the Bell System Technical Journal and the Bell Laboratories Record, you know, because that's where the action was. Radio technology was still a very new thing. And when I say radio, I don't mean the kind of things that you think of, probably: (Broadcast radio, programming.) It was the technology: how do you get a large signal at higher frequencies. The frontier of research, then, was higher frequencies and higher power.
Goldstein:
It's interesting that you say that, because I'm not aware that microwaves were a conscious area of research for anybody before, say, the late 1930s, so when you were in school, were you thinking up in the microwave range?
Cutler:
Oh, yes. That was a big mysterious, challenging, area. That was like exploring the dark unexplored continent of Africa, which was still a dark, unexplored, continent. What could you do with those frequencies up there? They must be useful for something. How do you get them? You've got to generate them, you've got to be able to detect them. It was like gravity waves in today's research, you know. What can you do with gravity waves? Well, gravity waves are still far out and if they ever are detected, that will be sort of a miracle. But microwaves, not yet named, was in that state. How could one generate these waves, and how could one detect and control them? That was a very exciting area, a frontier that we would just love to work in. We were very impatient to get out of school and do that — rather than take courses and pass examinations. I fantasized and dreamed of mysterious high frequency radio waves. We both did.
Joining Bell Labs
Goldstein:
When you got to Bell, what did they have you working on?
Cutler:
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In 1936 Bell Labs hired a bunch of guys, thirty, I think — including John Pierce, whom you've talked to. In 1937, when I graduated, the job market was probably a little bit better than in 1936. In 1938 employment was down again. In 1937 I think Bell Labs hired a hundred and twenty members of the technical staff (MTS), which (since they were hiring from all across the country) was not a great number.
In the fall of 1936, before I graduated, I wrote a letter to the employment office at Bell Labs and I told them I was coming to New York City; I was going to be in that area on Thanksgiving and could I come in for an interview? I got a nice letter back, saying, "We're not hiring until the spring, don't bother coming, but if you're down here anyway, stop in."
That was enough of an invitation. I went down there anyway, just to make sure they would remember me. I went down and located the personnel department. They received me cordially, took me around and showed me a lot of magic: measuring equipment, oscillators and all that. It just whetted my appetite. I felt I couldn't wait for graduation so I could get into their labs and be a part of it. They told me to write to them in the spring, and then they would probably have somebody in Worcester to interview, but they couldn't do anything until then. So I waited till Spring, and I wrote a letter. I wrote it very very carefully — it was a masterpiece. Oh, I typed and re-typed it, and it was smudged, so I typed it again. I typed it about four times, and I finally had it perfect — I didn't have a very good typewriter, it was a cheap Corona typewriter with three rows of crooked keys and a double shift for numbers and punctuation. Finally? I had this perfect letter in front of me, and I said, now, I'll ship that off and hope it works.
Then I looked over my desk, and there in front of me was a copy of the Bell Laboratories Record, and I thought, gosh, that's strange, they have an extra letter in that word. They have an extra "o" in "Laboratories." I didn't. [laughs] Where I grew up, it was "Labratories," I guess. So I retyped the whole darn thing, sent it off — with better spelling, I guess, and a prayer.
The next weekend, on a Sunday, — Saturday night, I guess, before Sunday — I got a telegram (from Raymond Deller, Bell Labs personnel) saying, "Our interviewer is going to be on WPI campus Monday. Be sure and talk to him." Well, my hair — in those days, people didn't wear long hair, you know, and I hadn't had a haircut for probably four or five months, so it was down around my ears. And there was no barber shop open on Saturday night or Sunday in all of Massachusetts. So I went to a guy, Clark Goodchild, in the freshman dorm who was cutting hair for his classmates. For thirty cents he cut my hair. I told him, you've got to do a good job — my life and career depends on it. He did, and I made sure I was the first one in line for interviews on Monday morning. I had a very nice interviewer, a fellow named Delchamps. Of course, he's long since gone, but now his son, I think, is in Bell Labs, the name is still in the phone book. We had a very nice interview, I found it very encouraging.
A couple weeks later, I got an offer of employment from Bell Laboratories, conditional on passing a physical examination.
Goldstein:
When you came in, were there many other people with just the undergrad degree?
Cutler:
There were a few. And there were many with masters' degrees. But at that time, people — at least undergraduates — were hired by the personnel department. You see, I hadn't been hired into a particular area at Bell Labs. The personnel department did the recruiting and then they had to find a place in the organization where there was an opening. So when I arrived there in June, Ernie Waters in Personnel told me to go call on this fellow, and go call on another fellow, and he gave me the room numbers. So I was all over the building, interviewing different people. I interviewed in the switching department. I interviewed in transmission. I interviewed in development. I interviewed in a lot of places and snooped into many laboratories. And after doing that awhile I realized maybe I was putting my foot in it, because the standard question they always asked was, "If you had your own choice to do exactly what you wanted, what would you really like to do?" And I said, I want to work on high-power, short-wave radio transmitters, but then, I'd say, I'm interested in anything that's electronic, you know. Switching? Sure! Transmission? Yeah! Anything like that. If I really had a choice, the honest answer to your question . . . "Well, there's no chance at that, that's all in Research, and Research is only hiring Phd's." You've got to go out and get another four or five years of education before you have a chance of getting into Research." OK, fine, show me switching.
That went on for about three days. And every time I went back to the personnel department, they'd say, "You know, you can't get into Research, you've got to have more education for that."
But on Wednesday night Ernie said, we've made a date for you with the director of radio research, Ralph Bown: "Good luck."
So I went and talked to Ralph Bown. He was a lovely man. He was a father figure. I look to him still — like he was God. But he was very down to earth, very friendly. We must have talked for an hour and a half. "I was a radio ham? What did I do as a radio ham? Did I ever invent anything?" Yeah, I invented some things. I invented carrier suppression modulation when I was still in high school. Of course I realized by then that a lot of people had invented it before that, but for me it was new and my circuit was novel. "Well, explain how it works." Blackboard. And so forth. And it was wonderful. He loved me; I loved him. I went back to Personnel. Ernie: "We want you to go down to Deal Laboratories and talk to John Schelling (in Bown's department) tomorrow." So I caught the train. Deal was a field laboratory where people were working on high-power short-wave radio.
Deal Laboratory & John C. Schelling
Goldstein:
What's the name of the laboratory?
Cutler:
Deal. It's located at what they called Deal Beach, right next to Elberon, which is adjacent to Asbury Park. Do you know New Jersey at all?
Goldstein:
Yes, I'm from New Jersey.
Cutler:
OK. This was a laboratory, a few small buildings in a 360 (maybe 420) acre hay field, perhaps a mile and a half or two miles from the ocean.
Goldstein:
And AT&T ran it, or is it a different company?
Cutler:
It was Bell Laboratories, part of AT&T. It was a small laboratory with probably fifteen or so engineers. Half of them were in what they called radio research, the other were in radio development, both were called sub-departments within what was then the Department of Radio Research. There really wasn't much distinction between the two sub departments. they were each doing essentially the same thing, but the research objective was more exploratory. The development people, led by A. Oswald, sub department head, and Norm Schlaak, supervisor, had more specific applications: "We've got to build something to be used this way, and it's got to be ready next year," or something. But we in the research sub department were doing exploratory things and the development people, hopefully would pick up from us. There was a lot of overlap.
And, so, at Deal I met another God figure — John C. Schelling. This was a wonderful man, and we talked half the day, went around and saw what people were doing — met a lot of people. I had found where I wanted to work. And when I went back to the New York headquarters, Ernie told me to catch the train again and go to work at Deal. And I did.
You know, prior to this trip, I had probably stayed in a hotel only once — with my parents. Any other time that I was out of town, I stayed at the YMCA. That's where young men went. And for, oh golly, I forget whether it was twenty five or fifty cents a night — why, they bunked one. It was wonderful. I have a great reverence for the YMCA.
So I took the train to the Asbury Park station. I arrived in the evening — the YMCA was bolted up tight. It was Thursday night, must have been nine o'clock, and there was just no way to get into the Y. What am I going to do? I stopped a man on the street and said, are there any boarding houses — rooming houses — around here in Asbury Park? He says, that's all there is! Go down the street, stop at the first house, that'll be a boarding house. And I did just that. And sure, they had a room. They were delighted to take a dollar from me for the night: More than ten percent of my net worth! And I spent the night with bedbugs.
Have you ever experienced bedbugs? Don't Ever! I got off to a good sound sleep and all of a sudden — . I turned on the lights, pulled all the blankets off the bed, stretched the sheets tight and there they were, scooting off. I spent the rest of the night sitting on that stretched-tight sheet. Catching bedbugs.
The next day I found another rooming house. One of the Labs fellows, Jim McRae who had come to the Deal Labs the year before took me to his boarding house where I stayed for the next year. That was my introduction to Asbury Park, New Jersey.
Advantages of Bell Labs
Goldstein:
You said that as an undergrad, you knew from the beginning that you wanted to work at Bell Labs. Were you aware of what was going on at RCA, or some of the other labs, maybe GE? Had you looked at their work and decided, there's something missing there, something not good?
Cutler:
At that point, there was no comparison. RCA was still quite new, but there were good things at RCA. Actually, I was sold on Bell Labs many years before that. When I was about fourteen, my dad took me to a popularized science session in the Springfield, Massachusetts Civic Auditorium. It was a big auditorium, and as I recall it, there must have been five or six hundred people there. We had good seats down in front. The talk was by an engineer from Bell Laboratories. It was sponsored by the local chapter of the Institute of Radio Engineers.
There was quite a bit of radio activity around Springfield. Westinghouse had a research plant there, and of course there was one — maybe then two — radio stations. So radio was a fairly important part of the civic activity. Springfield must have had a pretty active section of the IRE.
I sat on the edge of my chair, and this guy, he popped corn with radio frequency energy. He popped corn forty years before I ever saw another radio frequency (sic. microwave) oven, he modulated a light beam using a neon tube. Neon tubes, bulbs, were a very new thing. He had a neon tube which he could modulate with sound waves and a microphone, with a reflector behind the neon tube and another big mirror up in the auditorium to reflect the light beam back down to a photo-multiplier to convert the light energy to electric current. The photomultiplyer was also quite a new thing. Tubes, you know, aren't all that old — this must have been about 1928. So, you know, broadcast radio was still mostly a crystal set kind of thing Superheterodyne and screen grids were brand new inventions. Photo multipliers and neon bulbs and things like that were very new. So he modulated a Neon tube, sent the light in a beam to the balcony and back down again and received it. He interrupted the light beam with his hand, no sound, take the hand away . . . And here we are, now, 70 years later, light communication in the nineties becoming ubiquitous ...
What a stretch of the imagination, what have we done? Only 70 years and the world is forever changed. The demonstration in 1928 just entranced me. At that point I knew what I wanted: Radio Research. A good part of my objective from then on was to get there. I had lots of good advice. There were engineers around. I was a member of the local Springfield Radio Association, and I received two kinds of advice from the members, bad and good. One was, "Don't bother with a college education, you don't need that for radio." The other advice was, "Get the best college education you can, and when you get through four years of college, go to graduate school at a different school so you get a different viewpoint on things." You know, there's such a thing as intellectual inbreeding. That is my advice to undergraduates today. If you're going to go to graduate school, it's best to go somewhere else. Most graduates like to stay right where they are: enduring friendships, school loyalties are an attraction. But it's better to get a broader viewpoint, to know more people, different people, and experience different values of things.
The Great Depression being what it was, I had to earn my own money and send money home rather than get it from home, all the way through the last three years of college. Graduate school for me was almost out of the question. If I hadn't been offered a job at Bell Labs, I'd have gone to MIT somehow. I applied to MIT, and I was accepted, but I would have had to come up with my own money to do it. I would have had to work pretty hard that final spring and summer getting ready for the first tuition payment. Scholarships were scarce. I probably would have had to work all the time. I would have had to have almost a full time job in Boston to stay at MIT. So it was a godsend to be accepted at Bell Labs. And it was also a godsend to be thrown into the group at Deal. There, I found a mix of old-time radio people who didn't have any more — or much more — education than I did, and a young Ph.D. from Cal Tech. James, "Mac" McRae. John Pierce and Dean Woldridge in the New York lab were classmates of McRae, and were generous with their time and attention.
I shared an office with McRae and worked with him in the laboratory. And there was nothing these smart guys from Cal Tech wanted to do more than teach. So I was getting private tutoring from some of the smartest guys in the world.
Goldstein:
Was this at Deal?
Cutler:
This was at Deal. And I was the young pup at Deal, I was at least seven years younger than most of the people there, beside McRae, whom I mentioned — oh no, one more, Tom Morrissey, came the year before I did, from Colorado. He was in the radio development part of the Lab. He also had an undergraduate education. What was the question you asked?
Goldstein:
I was wondering whether you were aware of the research at other labs.
Cutler:
Oh yes. My friend Nate Korman — whom I mentioned — and I, we had devoured the literature. We couldn't understand it very well, but we read Physical Review, we read all of the IRE Proceedings, of course, we devoured that, and back issues, and things like that. We attended seminars in the physics department, talks which were way over our heads. Physicists were reporting on atomic structure, relativity, reports of the latest advances in Physics at Columbia, Berlin and Copenhagen, and things like that, you know. Osmosis worked. Little by little our vocabulary increased and we understood a little more. So we were pretty well read. There wasn't a lot from RCA. It was sort of an upstart, as far as we knew, but we knew there was a long history of communication in Western Union. Not much in the literature. But still, Western Union was a name — that's where telegrams came from, and telegrams were sent overseas by radio, and that sort of thing. Most overseas communication was through Western Union. So I wanted to talk to Western Union. Indeed, I interviewed with Western Union. I was prepared to interview with General Electric, but I had a job with Bell Labs before GE came through. I went to Schenectady with part of the class and attended the recruiting show that the rest of my class got. To me, it would have been an imposition to ask GE for an interview when I already had a job at Bell.
I did get a good look at General Electric research laboratories. Western Union was a terrible disappointment. Their research laboratories would have fit in a good size garage. There was just the one big room, with a little (mechanical) multiplex switching stuff going on. The big impression I got from Western Union was: girls on roller skates! You can't imagine! If you have a chance — well, I don't know, it may not be that way anymore. But that building on Hudson Street — I don't think they had telephones on many of the desks. Each desk had a basket. And these girls were whizzing around putting messages in the baskets: picking up from another basket and swishing off, you know, about twenty miles an hour, up and down. Oh, they were so good on roller skates! And they were beautiful. It was — I was impressed by the fact that WU didn't bother with telephones, and that they had all these roller skates. But the research was minimal. Western Union essentially committed suicide by not advancing with technology. The history books are full of stories, a lot of them anecdotal, a lot of them probably not true, about how WU resisted the telephone. They should have been investing in it, and buying it, but WU thought it was cheap competition in the early days and they lost the opportunity. The scuttlebutt around Bell Labs was, at that time, (1937) that WU was being kept alive at the mercy (sufferance) of AT&T, which felt that they needed to have some showing of competition in communication, so AT&T went out of the way to make things reasonably profitable for Western Union. If WU failed, AT&T would then be more vulnerable as a monopoly, damned for dominating communication.
AT&T and Patent Issues
Goldstein:
That brings up a question I wanted to get to later. But I'm curious how conscious the scientists at Bell Labs were of AT&T's strategies — whether the scientists were ever asked to suggest the appropriate way to exploit a particular invention economically? Things like that.
Cutler:
We were encouraged to patent things. We were not encouraged to publish, but neither were we discouraged from publishing in the open literature. But to me, it was a remarkable thing when somebody published a paper in the open literature. That must be really hot stuff; I hoped someday I could publish — in the distant future, something like that. It didn't occur to me to submit things for publication. By the time I might have, why, the war was on and our research was classified, so publication was out of the question anyway. But Pierce was publishing. He'd been publishing since he was in grade school, it was a natural thing for him. And a lot of my associates with Phd's were much better prepared for writing. Actually, I did have a letter on a shortwave antenna problem in QST in 1934, my first publication.
When it came to exploiting research — of course the Bell System wanted to exploit it, they were always interested in applying new technology. During the Depression they even built sewing machines. Western Electric built anything they could in order to keep the factories busy. I didn't see much of that. But one of my buddies (Dean Wooldridge) worked on — I was going to say a tape recorder — a magnetic wire recorder. He used magnetic wire, which was available before the invention of magnetic tape. He used a very thin steel wire, and he made a wonderful recording machine, which I think got some use inside the Bell System. I thought it would be a wonderful commercial product, but that was about the time when Bell spun off a branch that made loudspeakers and other audio products and got out of radio broadcasting and cinema. You see, Bell had pioneered electronics in the moving picture industry, in sound movies especially. Sound movies came right out of Bell Labs. Most of the sound theater installations were Western Electric products right through the early part of the 1930s. It was about the time that I came, that Bell began to pull away from that. They still made some excellent loudspeakers, one of which I bought around 1940, but they divorced themselves from retail trade. Again, they were too big, and they felt that telephony was their business. They were very aware of Government regulation and trade laws. If they were going to dominate communications, they couldn't afford to spread out into all these other things. Very different since divestiture.
There were things like frequency modulation broadcast radio. Frequency modulation was sort of sneered at — wrongly — at the time that I came to Bell. Here was Armstrong, who was trying to make a big thing out of FM. Labs people had been using FM in experimental radio links for a long time. They didn't understand it but they were using it.
My colleagues had anecdotal stories on how they built a self excited oscillator for a communication link for some experiment long before we heard of Armstrong's FM. Our people used conventional Heising amplitude modulation but observed that reception was clearer when the receiver was tuned a little off the frequency of maximum carrier strength. They realized that the oscillator was not very stable and that the oscillator frequency changed with modulation, increasing the effective amplitude modulation on reception. In an intuitive sense, they knew what was happening and took advantage of the effect. So when Armstrong came out with his system, got a patent and commercialized the effect, there was a feeling that it was old stuff: "We did it a long time ago." Armstrong was enterprising and he was smart. He understood what he was doing and he analyzed and engineered it better and invented the amplitude limiter. He foresaw the commercial possibilities of FM and was enterprising.
In those days, my associates depreciated Armstrong's FM. They had the attitude that they had been doing it for long time, and there are many other ways of modulating that would give the same signal to noise advantage. Some schemes might be a little more complicated, but electronics were getting cheaper. So people did anything they could do to get around Armstrong's patent. Frequency modulation with feedback, invented by Chaffee at Bell Labs, was a way of avoiding the limiter, which was a big feature in Armstrong's system. We used FM with feedback in Project Echo in the 1960s. It was a different way of making use of frequency modulation by using a circuit that Armstrong didn't own, and in that context it had additional advantages. Armstrong was a great inventor and was very badly treated by David Sarnoff at RCA and by others: a tragic hero.
Another patent litigation I was aware of, was over the Heil Electron Gun. This was in the late 1940s. There was a fellow named Oscar Heil, an immigrant from Germany after the war, who made an electron gun with an ellipsoidal cathode, superior to anything that had been built before. He was at Ohio State, was very patent-conscious, and he had a good, but narrow, patent. Bell needed it and Heil wanted to sell it to us. He wanted some outrageous figure for the patent rights. Our management wanted to know if there was some way to accomplish the same thing without using his patent. Our tube people managed to build an adequate gun without using his patent, but I felt bad about it. He was asking too much, I suppose. It was a holdup. So, a colleague found a way to focus the electrons without using Heil's patent, and Heil didn't get anything out of it. If he had asked for fifty thousand dollars instead of two hundred thousand dollars for the rights, we would have paid it easily.
That was about the same time somebody copyrighted the AT&T flag. That's another story. I suppose it's true since I never heard it denied. Somebody saw the Bell flag with the AT&T insignia on it, copyrighted it, and then sold the copyright to Bell. He just wanted enough money to build a house with, about thirty thousand dollars, I heard. It was much cheaper to give him thirty thousand dollars than to fight for the copyright. Is that a true story? Have you heard that?
Goldstein:
No. No, I haven't.
Cutler:
Anyway — so, yeah, we tried to avoid using other people's patents. On the other hand, government regulations would not allow AT&T to capitalize very heavily on its own patents. They were essentially free to the industry. There were patent exchanges, and I got involved through the years a number of times. We visited other laboratories, RCA for instance, and General Electric and Sylvania, to see what they were doing, what they had to offer in the way of patents that they could bargain with. Most of the Bell Labs patents at that time were just bargaining chips. You know, you've got so many patents, we've got so many patents, you throw in a hundred thousand dollars and you can use our patents, and we can use yours. That way one never get a clear monetary value on a patent. Some of the patents that Stanford owns have paid royalties of seven or eight million dollars in a few years. We had nothing like that that I know of. All we could say is, well, we're allowed to use the RCA stuff and the General Electric stuff, without paying them for it, and they can use ours. And because of that — that freedom gave us a great advantage in collaborations across company lines. So at IRE meetings and conventions we rubbed shoulders and shared ideas with fellows from other laboratories, principally RCA and General Electric but some fellows from Westinghouse, Sylvania and university laboratories.
Westinghouse destroyed itself during the Depression years by cutting off research. Took them a long time to recover. We had wonderful technical exchanges with other laboratories and some universities. We made best friends, called each other up frequently and served on professional society committees together. If we had an idea that was patentable, we were told to be careful to not talk about it, and we were a little careful. Never got into trouble, so I guess we were careful enough. If we'd come to an electron tube conference, and they'd come with a good idea, why, we'd go right back to our lab and see if we couldn't improve on it. It was that kind of friendly competition between the organizations. Very fruitful.
Radio Telephony
Goldstein:
When you began there at Deal, what did you start working on?
Cutler:
When I joined Bell Labs, the Bell System was about ten years into overseas radio communication — radio telephony. They had started using long waves, i.e., signals at frequencies of sixty to one hundred kilohertz, as had been used for telegraphy before that. They had super-high-power transmitters out on Long Island and similar equipment in Scotland (I think). When they started the first overseas telephone link it worked pretty well, I understand, but within a year, the circuit went to pot because of atmospherics. It got worse and worse with the next sun spot cycle. And so within the year, I think it was 1927 or 1928, they set up a short-wave circuit. Short-wave was good when it was good, terrible when it was bad, and sometimes it was nonexistent. But short wave circuits were developed, and Bell increased their short waves activity. They had probably two or three over-sea telephone channels when I arrived.
Imagine the size of Europe and its population and only two or three telephone channels to America. Overseas telephony was saturated all the time, and station management had to switch frequencies by the hour. They'd tune around and find where the best frequency was, they'd take the coils out of the transmitter: big "tank" coils, one-inch tubing wound the size of a small barrel or jug, big things like that — take them out of the transmitter, and bolt in some other ones for a different frequency — and change the oscillator — and tune this and tune this and tune this & that — then back on the air. They could do it in thirty seconds. It would take anybody — the first time — an hour. They'd switch these frequencies and get on with only a short break in the telephone connection.
AT&T had stations at Lawrenceville, New Jersey, (that's near Princeton,) Netcong and at Ocean Gate. The Ocean Gate one, I think, was for ship-to-shore communications. The one at Netcong was for receiving. There were several places which we would visit, helping and looking for ideas. But through the early part of the 1930s and until the time I came, they only had only a few short-wave channels, and the circuits were very erratic. They wanted to make circuits more stable, more trustworthy. They wanted to have more channels. How could they get more channels in this very limited spectrum? All of it had to be below a frequency of twenty megahertz; get above that and there was nothing really to work with. High power hardware did not exist that would work at much higher frequencies, and transmission through ionospheric reflections was very limiting above 20 or 30 Megahertz. So between three and twenty to thirty megahertz, with everybody under the sun doing their ship-to-shore telegraphy and that sort of thing, and radio hams — competition really filled up that frequency band. It was very hard to get channel allocations from the Federal Communication Commission.
Goldstein:
Let me just interrupt you for a minute. So when you say, nothing above twenty megahertz, do you mean no electronics to work above that range?
Cutler:
No, it wasn't only that. There was no transmission. The Heaviside layer. In order to get a signal over the Earth's curvature, you had to bounce it off the Ionosphere, the Heaviside layer, a few dozen miles above the earth. Higher-frequency waves above twenty or thirty Megahertz go FFFT! Right on through. They are great for communicating to satellites. But there were no satellites. Satellites were a far-out dream.
Goldstein:
OK.
Cutler:
So, Bell wanted to build a multiplex radio transmitter. The objective was to put twelve telephone channels on one transmitter, and to multiplex telephone channels like they do in wire circuits — or did for wire circuits at the time. That was really a far-out, adventurous thing. That was the objective. And I worked on circuits for doing that — high-power radio transmitters was the thing. I had blinders on. I really loved that challenge. Tuning big circuits, and drawing the sparks on those — boy, sparks all over the place. Experimenting with the latest measuring gear! We were right at the forefront of high power radio. Some of the fellows in the next laboratory were pushing to higher and higher frequencies for land use, the sort of thing they use now for television transmission, I guess they still did, for many years, before optics came in for television relay and even broadcasting. For TV relay across the country one could place relay stations twenty or thirty miles apart, but because of the curvature of the earth and the nature of the atmosphere, you couldn't go farther than that. They were working on higher frequencies, pushing toward microwaves. But microwaves at that point weren't what you call microwaves now. They were looking to work at a hundred megahertz and two hundred megahertz. A thousand or two thousand or ten thousand megahertz — that was a far-out dream.
But we worked on high-power transmitters at Deal. I invented a rather novel circuit, a self-neutralized amplifier which incorporated a lot of radio frequency negative feedback and was inherently stable. It was very exciting. We built a twelve-channel circuit, which we might or might not have been able to use because the FCC wasn't licensing channels like that. What came out of it, however, was a four-channel circuit, which the military used throughout the war. Short wave radio was the lifeline between Europe and America. My partners in the development side of the laboratory designed the four channel single side band circuits in the early part of the 1940s.
I couldn't follow that development after 1941. It wasn't until after the war was over that I was even allowed to know what the others were doing. It was classified, and I was working on something quite different. What got me away from high-power radio transmitters was the imminence of the war, and Roosevelt getting us into a supportive position for England in 1939 and 1940. In 1940 there was a project generated — do you know what the proximity fuse is?
Goldstein:
Sure.
Proximity Fuse
Cutler:
The radio proximity fuse was something that the military wanted in the very worst way, and they started a crash program to make a radio product — an antiaircraft shell which could sense the presence of an airplane and explode when it was near. Before that development, explosion was triggered by impact or a timing device armed on the ground before firing. To hit an airplane from the ground when it's three thousand feet up or higher, you know, was one of those things that almost never happened. One just scared enemy aircraft by sending a lot of tracer bullets. The Carnegie Institution of Washington, through Merle Tuve, a renowned physicist was charged with the project. Tuve managed a massive program. And they must have had twenty — I don't know, a lot of different companies — all taking part. I know General Electric was involved, Burgess was making batteries for it, RCA was involved ...
Goldstein:
In a coordinated way?
Cutler:
Yeah. Oh, yes, we had joint meetings, and went away with all sorts of different assignments. How to do it? Should you do it optically, perhaps using infrared? Should you do it by sound waves? After all, airplanes are noisy. Or should you do it using radio? There were two possible ways of doing it by radio. You might track the an anti aircraft shell with a radar while also tracking the airplane, and when the ranges coincide, automatically trigger the shell by a radio impulse. Bell Labs was assigned to explore that alternative. Somebody else — and I forget who — had the job of seeing if they could make a sensor carried in the shell that didn't require any communication from the ground. You just arm it — that is, activate the receiver when the thing goes out of the gun, and then when it gets near the target aircraft, fire the explosive by (hand capacity) proximity effect. You know — do you know what hand capacity is?
Goldstein:
No.
Cutler:
In old days, radios weren't shielded. We all knew what hand capacity was. You reach to a radio to tune it and it'd go VREEP! If you have a weak station on your FM or on your television, you may find that where you sit or where you move around the room makes a difference in tuning. Well, that's the kind of thing — since the radio can sense change in the surrounding, your body capacity tunes the radio. So it was possible that an airplane in space would change things enough to generate a signal that could trigger the shell. We all thought it could be done, any of us would put our money on that. But — who knows? Because of the urgency, other modes of operation were explored.
So the teams were trying alternatives — they wanted something immediately that would work. So instead of trying these things serially, they worked on them all.
Initially I was building little bitty circuits — some change from huge high-power radio transmitters. I'd build a three-tube receiver circuit using hearing-aid tubes about the size of a pencil eraser in an assembly the size of the end of my thumb. It had to fit into an anti-aircraft shell with a battery to power it for a minute or so. So I built a receiver, tuned it up, adjusted it, tuned the antenna — which was very difficult, not much room for an antenna on a shell. We were working at higher frequencies, one or two hundred megahertz. And we built something that would work.
That was very exciting. I was back and forth to Washington. Railroad, over night in a sleeping car. Sleepers are now museum pieces, I guess people don't ride sleepers anymore. I rode on a sleeper for the first time. Walked around Washington, went to the Lincoln Memorial. I'll never forget, every time I go down there, I repeat the experience — I find it a very, very moving thing. I hope you've done it.
Goldstein:
Yes, I've seen it.
Testing Anti-aircraft Shells
Cutler:
Go down there and read the writing on the wall and realize what a great guy Abraham Lincoln was. I met a lot of interesting people, some of whom I've tracked ever since. Very exciting stuff.
I've got to tell you this anecdote. How do you test the operation of electronics in an anti-aircraft shell? How do you know they're going to survive when they go through a shell? So our managers got a hold of some anti-aircraft rifles. These were things about fifteen feet long with about 1 1/2 inch bore, used for trying to shoot down airplanes. Big husky things. They set one up in a field adjacent to the Potomac River, Indian Point, south east of Washington. They leased a big field, fenced it in, classified it so nobody without a top-secret clearance could get near it. We went down there and put our experimental devices in anti-aircraft shells and shot them vertically into the air. Then we would wait a whole minute. Pretty soon, plop! The shell would come down from the stratosphere into the field. We had sandbag roofs atop telephone poles as shelters, six feet thick roofs, which we could stand under. Hopefully if the shell came down on the roof, we wouldn't get hurt. We had three of those set up at positions surrounding the field. We would look for a puff of dust or a motion in the grass or sound from where the shell landed. On muddy days there wasn't much to indicate the landing. We would triangulate. We would eye it and would converge on the spot from three directions and look for a hole in the ground where we met. And then we would start digging. Do you know what a post-hole digger is?
Goldstein:
No.
Cutler:
Well, it's like two shovels, about so big, that are hinged together, so you can push them into the ground, pull the handles apart so the shovel blades come together like a big tweezer, and you can pull the dirt out. With one, you can dig yourself a hole that's nine or ten inches in diameter, three or four feet deep, (if there are no roots or rocks). It's wonderful in soft ground, not very good on roots or rocks. The field was soft, muddy, red swampy stuff, sometimes sticky but not difficult. We'd go out there with these post-hole diggers and dig up the shell. Then we'd take it apart and see what had happened inside. Oh, on the way down, when the shell got down to within a few hundred feet from the ground, we would trigger by a radio pulse signal and fire a little charge in the shell producing a visible puff of smoke. If we saw smoke we knew the circuit was working. If there wasn't a puff of smoke, it didn't work, so we would take it apart and to see why. The project was so classified that we couldn't hire people to come in and dig holes. Most of the fellows had doctoral degrees in physics or engineering — I was probably the only guy there who didn't have a Ph.D. (beside the farmer's uninhibited 12 year old daughter). We decided that "Ph.D." means Post-Hole Digger.
Recently Virginia and I were invited to dinner by some neighbors, Al and Mae Kenrick. They introduced me to Doyle Gray, "This is Mr. Cutler, he used to work at Bell Laboratories." "Oh," he says, "Bell Laboratories? Yeah! I had a run-in with some Bell Labs people years ago." He says, "What do you do there, anyway? I just don't understand. What does Bell Labs do? What would they be doing with anti-aircraft rifles?" He said, "It was about 1941, probably, that I was — I was in the… " what did they call it, people who supply guns and material for military —
Goldstein:
Right. Ordnance.
Cutler:
(continuing quote) — "I was in Ordnance Supply and I was asked to deliver an anti-aircraft gun to some guys at Bell Laboratories, down at Indian Point on the Potomac. And," he says, "a couple of days later, they wanted another gun. They're burning those things out! So about the sixth time around, I said, no more! No more! You've had enough!"
He says, "I got a note that afternoon from the White House saying `Give 'em all the guns they want.' What was Bell Labs doing with these things?"
Honestly, I went into a cold sweat. Because on my first trip to Washington, when Merle Tuve (who was responsible for the proximity fuse development) looked around the room and spotted me, he said, "Who are you?" I started to speak but and my boss, Schelleng, said, "He's Chape Cutler, he's with me, he's all right, Merle." They'd been friends at school, years before. Tuve glared and me and said, "If I thought you would say a word outside of this room about what goes on here, I wouldn't hesitate to shoot you!"
And here's this fellow, knows nothing about our activities, forty years later asking what we were up to! So I had to admit, in 1942 we couldn't tell him what they were for. He was just an ordnance guy supplying guns and didn't have the appropriate clearance.
Goldstein:
You said you were testing the ruggedness of these circuits. Were different people responsible for engineering the ruggedness? Compared to getting the electronics right?
Cutler:
Oh, yes. I had the help of some of the best mechanical engineers in Bell Labs. And they were down there, too. The first receiver I built: I made just as sturdy as I could. I potted it good in tar, you know, heavy wire, and so forth. All these little components set on a sheet of micarta do you know what that is?
Goldstein:
It sounds like some sort of mica derivative.
Cutler:
Yes. It's a hard plastic insulating sheet. It was about the size of a quarter. Little holes in it, you know, so that leads could go through holes and we could solder them on the other side. And we took it down to the Carnegie Institution in Washington and put it into a centrifuge. They revved it up to, I think, twenty thousand G. These anti-aircraft shells are accelerated to about twelve thousand, so we were higher that. When they took my circuit out and handed it to me you could have put my precious work through a salt shaker. We needed good mechanical engineers. Remarkably, if they were supported properly, the little hearing-aid tubes could take the acceleration. We put the leads vertically on top, so the leads were in tension, drawing them straight down. If the parts weren't aligned with the acceleration vector, you know, the acceleration force would bend all the elements over and probably crush them. We ran many circuits through the centrifuge and a lot of them would work afterward. Those that didn't survive, we would take apart and test. What's wrong in there?
At one time we received a bulk shipment of tubes. I think it was supposed to be a batch of a thousand. There were seven hundred and fifty good ones selected in the first test run. Test them again, and about two-thirds of them wouldn't work. And then we put the good ones in a circuit and tested the circuit. Two-thirds of the circuits would fail. We put the circuits through the centrifuge and when we got through none of them would work. Finally we found there was dust in the tubes from the dirty tube assembly rooms. The dust would get carbonized when the tube was processed. The carbonized dust would float around, loose, and as soon as one moved the tube, of course, the dust would move to some other place and short circuit some element. That was a real headache. They had to air condition and filter air and do all sorts of things to make these little close-space tubes good enough. Today, with transistors, of course, and integrated circuits, electronic factories have achieved a thousand times better cleanliness.
Wartime Secrecy
Goldstein:
Right. All the security you're describing, how did that affect the progress — or rather the logistics — of the research project?
Cutler:
It was terrible, you could eat lunch with colleagues, but you couldn't talk about anything important. Before, we were stimulating each other, exchanging ideas. Who could I now stimulate? Who could I get stimulated by when gagged by secrecy orders? My closest colleagues couldn't tell me what they were doing.
One time I was trying to make some measurements in my laboratory. The meters were jumping around, erratically, all sorts of nonsense readings! Crazy! I turned this off, turned that off. Why were these meters still jumping around? Finally I turned everything off, turned off the main power to the room, disconnected all of the batteries, and the meters still read! What is going on? So then I went downstairs to the laboratory below. Secret! I wasn't allowed in. I went in anyway. They were testing — they were working on electronic countermeasures. They had a little radio transmitter radiating about a thousand watts from a wire suspended from their ceiling, right under my feet! No shielding! There was no way, when they were testing their stuff, that I could do anything useful in my laboratory. Lucky I wasn't gelded. I had to break the rules of secrecy to find that out and somehow get them to stop. It was just crazy. So that part was very bad.
There were many people working on proximity fuses all over the country, but we couldn't talk on the telephone about this stuff even to them. When I made field measurements on my receiver, in a model of an antiaircraft shell, I did it in a cheesecloth tent to foil observers.
We did visit the other laboratories. I went to RCA, I went to General Electric, I went to the Carnegie Institution, and of course we met together in Washington, at Dahlgren Proving Grounds, Indian Point, and places like that. So within the group that was working on the same thing, there was a lot of, but occasional, interchange. If it hadn't been for that, it would have been hopeless project, entirely. But the fact that I couldn't talk about it with my best buddy sharing my office: that was frightful. However, that situation changed fairly soon because our part in the proximity fuse project came to a halt when the self triggered fuse experiment succeeded.
Proximity Fuse & Transmitter Projects Ended
Goldstein:
Bell Labs — did they elect not to go with the remote detonation?
Cutler:
Bell Labs was through with the project. They had accomplished what they had set out to do. Development of the fuse went in another direction. The whole weight of activity was then put onto the self triggered mode, not signaling from the ground. The part that we were doing was discontinued suddenly and completely and we could not be told anything about the continuing development. I couldn't know that was the reason until years later. All I knew was that they stopped funding our activity. It was only after the war that I learned of the success of the project.
And there was another problem. I wanted to get back on the high-power short-wave transmitter project. Somewhere along the way, my boss said, "Look, we've got to finish that up. Can't you write a final report?" And the fellow I was working closely with, Jim McRae, by that time, was a Colonel in the Army, masterminding radar operations in Washington. So it was left to me to write the final report. I read the report recently and I am still happy with the it. We had made a lot of progress, but how much our contribution was used I couldn't know because suddenly it also was classified. Years later I learned the four-channel version went forward. The lower-power circuit with four channels became the lifeblood of radio communications across the ocean.
Goldstein:
So what do you mean, that you were writing the report? What does that say about your responsibility within Bell?
Cutler:
I was the only one left that was familiar with the high power linear amplifier part of the project. McRae would have written the report if he was available. Our immediate supervisor, Pete Shafer, and sub-department head Schelling were not familiar enough with what we did to write about it. I sent my draft down to Washington for McRae to look at. and he sent it back with a few suggestions, but he was effectively out of it. At that point, I was the only one left at Bell Labs that knew what we'd been doing, and I had all the data. It was a big challenge for me to write the final report, and I think I met the challenge pretty well. But I don't know if anyone else ever read it.
When the war was over, microwave radio relay and submarine cable took priority in the Bell System.
Aircraft Radar & the Cutler Feedhorn
Cutler:
Meantime, radar needs had become a national emergency, and people at the Whippany Labs and in New York were working on aircraft carried radar. There were a number of projects, and project leaders needed all the help they could get. We at Deal became a consultant group contributing to several projects. Our peacetime activity, our main projects, had to be set aside. Could I work on a system of waveguides for a "spinner," an antenna that was going to be used in aircraft? I and McRae, just before he left, and Eberhart were assigned to the thing, to design the waveguide connections. Of course, waveguides came right out of Bell Laboratories. George Southworth, who invented the waveguide, was at Holmdel. The understanding of waveguides centered there and with Sergi Schelkunoff in the math department. So we talked to Southworth and his colleagues and learned all we could about waveguides. We designed waveguide elbows, rotating joints and connectors, and sent the designs to the machine shop. We got parts back and tested them. We built our own standing wave detectors. There was no commercial instrumentation, one had to build one's own tools. In those days, one even built one's own power supplies. So we designed and tested, tested the dickens out of things until we were sure we had a good waveguide structure.
We didn't have an antenna, though, to put on the end of our waveguide circuit. Someone else, Hull, had the responsibility of building the radiator (antenna). He was stationed at Whippany, thirty-five or forty miles away. He sent us drawings for the antenna he had designed and tested — the antenna that he thought was just fine for the radar. All we had to do was make a copy from his sketches, connect our waveguide and test the assembly and our job would be finished.
So we built the antenna according to his drawings, and put it onto our spinner and connected the waveguide. We matched the impedance and measured the directivity pattern, field intensity vs. elevation angle and azimuth. The impedance match was awfully narrow, and the antenna could not be adjusted to have low side lobes in both azimuth and elevation. The antenna did not come near meeting requirements for radar operation. It was no good!
So we finally convinced ourselves that the antenna design was faulty. We took the company car and went to the Whippany labs to see Hull's set up. What he had was, oh, the most haywire thing you could imagine. Wonderful young man, but he didn't know what he was doing.
Goldstein:
Do you know who this is?
Cutler:
He was a physicist. He had a brand new Ph.D. degree, son of one of the best known physicists of the period — but he obviously didn't know what he was doing. He probably had had no hardware experience and had been left to his own meager resources, no George Southworth advising him. He put the contraption he built on a surveyor's tripod, measured something, got a good pattern. Fine. Now he had to measure it again in the orthogonal polarization, but the tripod had only had one axis for rotation. He had to take the antenna apart and put it together again on the tripod in another orientation. Twist it so he could measure the other polarization. Adjust it, get a good pattern. But it wasn't the same antenna anymore. He had changed some of the dimensions.
Oh, did Mac and I sweat that night. What are we going to do? And I still remember that night, thinking about what to do, what to do? The whole project was failing, and the war would be lost! We both felt personally responsible.
We cut up a lot of copper foil, solder, chewing gum, sealing wax, put something together, tried it, modified it, tried it again, trial and error. And in a few days I made an entirely different antenna structure that worked on our spinner. I drew it up, made a better one, and soon had a reproducible design. Eventually my design was reproduced in the Hawthorne Western Electric factory by the thousands, silver plated and beautiful.
Three years later I figured out why Hull's design wouldn't work. It had a ring focus, not a point center of phase.
Goldstein:
I've actually never seen a waveguide before.
Cutler:
My design came to be called a Cutler feedhorn. It worked perfectly. It satisfied everybody, and overnight I became an antenna expert.
Goldstein:
I was very curious about that. If you take a look at your papers, you seem to have this vertical integration in the whole communications field, not only working on the electronics to amplify the high-frequency signals but also the antennas. You don't see that very often. I was just curious about what the story to that would be. Was it just a necessity, you're saying? You had to?
Cutler:
Yeah — necessity, drive. There was a war on. At the same time, I was wondering whether I was going to be drafted and shipped overseas. I was subject to the draft, and, like most everybody else maturing in 1930's, nothing could be farther from my mind that I would ever carry a gun. Oh, no! People talked about Hitler and the war, something very remote. I would have no part of it. I was as peace-loving a guy as there was, and quite a-political. But by the time, I was on the proximity fuse and radar antenna problems, I was enough aware of the world scene to be concerned. It was clear that our way of living was in jeopardy, something had to be done, and I was ready to go and fight if I was asked. I'm a very religious guy — I said, God, you tell me what to do... I was interviewed by the local draft board who clearly saw that I was eligible to be drafted into the military. But I was working seventy-five hours a week on radar. I was newly married, I had a child coming. It was a difficult, worrisome time. But let's face it, something had to be done, you just couldn't let the world go the way Hitler wanted it to go.
Bell Labs talked to the Draft Board, the Draft Board said, you're too important doing what you're doing on radar. And that was the end of that. There were some disadvantages to not being in uniform, because after the war when I wanted to build a house, I couldn't. The veterans got back, they got free education and they got to build houses. I couldn't. They (rightly) had high priority in a time of scarcity. So anyway —
Goldstein:
Tell me about the Cutler feed horn — where it was used.
Cutler:
It was used in aircraft radars, lots of them. Many were put in structures that were hung under the wing, radar assemblies which looked like bombs themselves. The transmitter and receiver. One model was perhaps two feet in diameter, and four or five feet long, including the parabolic antenna with my feed horn, just full of electronics. The little paraboloid antenna in the front end with my feed horn swept a pencil beam of radiation back and forth over the surrounding space or the ground terrain. Some of them were used in bombers, which meant that they were installed down in the belly — the front belly of the aircraft, underneath the seat of the pilot — with a radio-transparent radome in front of it. A lot of them were carried on B-17s and B-24s, which were the primary bombing aircraft at the time. Many of them went on fighters, which were a smaller. Some hung under the wing and could be jettisoned like a bomb if the pilot got into a tight spot. Some were specifically for anti-submarine work. The radars were used in both theaters of war in large numbers. Of course I was unaware of how quick and fast these things were made and used until it was history. Operations were classified, and I had no "need to know."
I had a brief introduction to the manufacturing problems. My first child was due in early in January in 1944. On the week his arrival was scheduled I received a telephone call. "Your antenna doesn't work, they're building them out at the Hawthorne plant in Chicago, they've got a thousand of them, but they don't work. You've got to go out there and fix them." I said "I can't do that, my child is due." "There's a war on, Chape!" This was from Oliver Buckley — I don't know if he was the president or the vice-president of Bell Labs at the time. He said, "You've got to go out there." Well, yeah, OK, but... "Take somebody with you, but you go out and find out what the trouble is." That was perhaps the only time at Bell Labs that I received a direct command. I talked to the Hawthorne people at length on the telephone: "Have you followed all the drawings carefully, we built them here, they worked fine, how come they don't work there..." No, everything's just exactly the way it is on the drawing. I said, "Did you measure this dimension, and did you measure that dimension..." They said, well, yes, yes, everything's just like in the drawing. But I put a micrometer in my pocket, kissed my frightened wife and went to Chicago.
I took George Eberhart, one of my chief aides at the time, with me. Hawthorne had barrels of parts. Barrels! All these parts, and when they assembled a feed horn, it wouldn't work. The impedance mismatch was awful. I took the micrometer, checked dimensions. Some of those things were off in tolerance by a factor of ten. Drawings called for a two thousandths tolerance — that's not a terribly difficult tolerance. They was off twenty-thousandths. I suggested they start over again. "Can't do that, there's a war on." You've got to tell us how to fix those things without changing them. How do you fix them without changing them? Well, I said, if you put a three-eighths forty-eight screw at the right place in the wave guide wall, you can adjust it to match the impedance and it will be all right. Well, where can we get — there's a war on, we can't get taps and dies and so forth. There's no way we can do that. There must be some other way. I was nonplused. But George Eberhart disappeared while we were arguing, came back within an hour with a three-eighths forty-eight tap and die. Where did you get that? Well, he figured there must be one somewhere in this huge manufacturing plant. He went touring the plant, up and down the halls, into places, you know — secret places where he shouldn't be, and he found a place where they were building something that used that very tap and die. He borrowed one, promised to have it back within an hour. Within an hour we had drilled a hole, put a screw in, one on each side of the guide. (One would do but if you used two of them, you could adjust better.) We adjusted it once and it was perfect. Wonderful!
They thought we were magic. I came back home, my child didn't come for two weeks. I was beside myself. George stayed out there. There, he was the big expert from Bell Labs. He made sure they did the horn right, checked things with them. He didn't want to come back. He was the expert. — All of a sudden, this guy who'd been a gopher around Bell Labs, high school education, knew a little bit of algebra, probably didn't know any trigonometry but had a green thumb. Everything he did worked. He just had a feel for things. And he understood this waveguide completely, well enough, anyway, for what he needed to do. So he was the "expert" from Bell Laboratories, and he loved it. There was a similar occasion, he was sent out to Kwajalein when their giant antenna ceased to function. There again, he was the big man from Bell Labs, and he loved it. At Hawthorne he finally got a phone call from one of the vice presidents, saying, "If you're not back here next week, you don't have a job." He came.
George Eberhart
Goldstein:
Do you think he was under appreciated at Bell? Or did he feel that he was?
Cutler:
No, he was appreciated for what he could do. He was appreciated for what he couldn't do, too, and we loved him. Management finally pushed him clear to the top of the salary that they could pay him as a non-exempt employee under the Wagner act. So they promoted him. He became a member of the technical staff (MTS). With no theoretical background to speak of, just a green thumb. A man who knew how to get things done, and knew enough of the technology from the seat of his pants, radio-ham kind of thing. He was tremendously useful. He came to work at Bell Labs in 1922 as a messenger boy. Now we're talking about 1942. He was probably 39 and I was 28 years old.
In the early 1950s the United States got into the Korean War, and all of a sudden the military systems departments needed more people over at Whippany, and Research was told to supply so many hundred bodies. He was one of the "expendable" guys that were sent over there to be interviewed. They liked him, they put him to work. The first year was a catastrophe. They gave him some equations to solve. And I got a phone call. "What's the matter? This guy can't do anything! You told us he was good!" I said, "Look, he can do these things. Don't ask him to do those things." So he became a gopher over there, and after they found out what he could do and what he couldn't do, he was a godsend to them. They sent him to Kwajalein when their big hundred-and-twenty-foot spherical antenna wouldn't work. He went out there, he looked it all over, he took a carpenter's brace and bit and bored a hole in it and drained the water it had absorbed. He went around, bored a lot of holes, more water came out and the antenna started working. Those guys out there didn't know enough to do that: but he did. Last year he called me up. He's over ninety years old and still working. He's the gopher and the getter for electronics at Drew University in Madison, New Jersey. They gave him an honorary doctorate when he became 90.
Goldstein:
In Madison — Drew.
Cutler:
Drew. Yeah. When he retired from Bell Labs, about 1967, he went to Drew and helped them equip their language laboratory with tape recorders, which were the "new art." They found he knew electronics like nobody else over there did. They've drawn on him, and he's still on their payroll. He also has a pension from them from when they (theoretically) retired him, but he never went off the payroll, and he's getting a pension from Bell Labs, dating from 1922, and he's still on Drew's payroll, doing the kind of thing he does so well.
He told me that another time the Whippany people sent him down to the South Carolina Western Electric plant, where they were building one of my antennas, and the antennas were not functioning. He went down there, showed them what to do and fixed it. Again, he was magic. He knew just what to do. He didn't know how that antenna worked in an analytic sense, but he knew what was important because he helped me build the first one. Anyway — that was fun. I was told after the war that there was one of my feed horns on every bomber that flew over Japan.
Shovel Antenna & Corrugated Waveguide
Goldstein:
What was your methodology in designing this? Was it trial and error, or mathematical? How did you work at that?
Cutler:
Just a little math. Anything I did mathematically was just a little algebra and a little trigonometry and occasionally calculus, but not much high-level math. It was mostly seat-of-the-pants. Knowing the size of things, the kind of things that worked and didn't work and so forth. Some of the other things I did — I got into some deep mathematics when I built what I call the shovel antenna and corrugated waveguide. Did you run across the shovel antenna? It used a pillbox. Do you know what a pillbox is?
Goldstein:
Yes.
Cutler:
It was the 3 foot pillbox used to illuminate a cylindrical reflector with horizontal polarization that was sent into South Carolina. They couldn't make those pillboxes work — The spacing on the pillboxes was very important. They were made of sheet metal and the sheet metal wasn't flat, and Eberhart had to show them how to put spacers in there to make them flat enough. They needed horizontal polarization to be able to use this antenna in the belly of an airplane and get a good signal near the ground.
At another time the radar project wanted vertical polarization but the same directivity as the one with horizontal polarization. I built a corrugated structure which didn't work the first time around, and it did some very peculiar things, quite beyond my understanding. I was really puzzled, and I went to my boss, John Schelling and said, "I don't know what to do about this, I think I know how to make it work, but I don't understand what's happening." He says, "Chape, you won't be happy till you understand it. Figure it out." But I said, "There's a war on. I'm working on classified things, the government's paying for this." He says, "You can do it." And so I got out the textbooks. I learned Maxwell's equations like I never knew them before. And worked out the corrugated waveguide thing. We fixed the antenna, and I got maybe a half a dozen patents based on the corrugated waveguide and applications.
I don't think the corrugated waveguide was used seriously for another seventeen years, so I don't think Bell Laboratories got much out of it. Oh, also, it was classified secret for almost twenty years, I didn't get the patents until well into the 1950s. So maybe the patents might have been useful to the company. It was almost 1960 I think before that patent was declassified. But, meantime, the corrugated waveguide was in textbooks from England and Australia. No American textbooks. I suppose the Brits and Aussi's didn't care about US secrecy classifications. The internal memoranda that we put out in the 1940s were circulated amongst the Allies, so that those inventions showed up in some declassified textbook literature from Australia and from England, probably ten or fifteen years before our patents were officially declassified in this country. That's the only way that my name ever got associated with corrugated waveguides and antennas. But the textbook authors credited us, they quoted "Memorandum Number So-and-So" from Bell Laboratories, C. C. Cutler. So I got some credit for it in the literature.
Postwar Academic Career
Goldstein:
Did you continue your education after the war?
Cutler:
I was associated with people like John Pierce, who were terribly bright and wanted to tell everything they knew. I got a lot of education from them. I took some night courses at Stevens Tech, and took out of hours courses in the Labs. I took a couple of courses at Princeton. By the time I realized I'd taken enough courses so I might get a masters' degree, I was too proud, I didn't want it. I could do high level research, and I had the respect of leaders in my field without an advanced degree. It seemed more distinguished to have accomplished what I had without the formality of an advanced degree. But I was very surprised years later when I was invited to come as a visiting scholar — visiting professor, they called it — at Berkeley. Are you seeing John Whinnery?
Goldstein:
Yes.
Cutler:
Well, he hired me to come in as a visiting professor in 1957. I had a wonderful semester there, and I learned a lot, because I was trying to teach some of the things that I only really half learned from seat-of-the-pants experience, from the research I was doing. I was trying to teach the stuff I'd worked on and published papers on, but which I really didn't understand in depth. So I owe a lot to John Whinnery and Berkeley for giving me that opportunity. It meant a lot to my pride to be a visiting professor at the most prestigious universities, without the formality of an advanced degree.
Goldstein:
Were you able to communicate an intuition about it? About these the work you did?
Cutler:
I think so. John Pierce credits me with having insights on that sort of thing. And that was probably what I drew on most — intuition. In college, I mentioned Nate Korman. He was great analytically, he could really write the equations, but I think a lot of that things he analyzed, he didn't understand. He'd write the equations and I would explain what they meant. I couldn't write the equations the way he did. So, it takes both kinds. I'm very happy with the talents I have. I'm sometimes envious of people like John or Nate, who could sit down and mathematically analyze complex relationships. I would spend all night sometimes trying to understand what he'd written. He would write it right off the top of his head. It was wonderful to have that kind of associations. Bell Labs was a wonderful source of expertise. The math department — wonderful fellows who just wanted to use their mathematical prowess — if you'd come to them and say, "Gee, how do I solve this problem?" — nothing would please them more than to show this young fellow how to do it.
Bell Labs Atmosphere and Colleagues
Goldstein:
I'm going to talk to John Pierce. He was telling me how much he admired Harald Friis and his operation at Holmdel. And I'm going to go talk to John Whinnery Monday. I was speaking to John Moll this morning... Anyway, the point is that everybody's from Bell Labs and they have these different perceptions of the place. I wondered what perception you could offer that's unique. How do you think your experience differed from some of the other people?
Cutler:
Well, probably it was different from everybody else's. In the first place, coming in as I did and being thrown in the position I was in with my mediocre education. Don't take that statement too seriously — Worcester Tech was marvelous as far as I was concerned, they gave me the flexibility to do what I wanted to do. And they reinforced it with a kind of expertise and teaching excellence that is hard to match. There were wonderful people there, and the position I was in at that time — they were just right for me.
Goldstein:
You're talking about prestige more than quality.
Cutler:
I mean quality, not prestige.
Goldstein:
No, when you said "mediocre" you didn't mean it was mediocre in quality, you meant prestige.
Cutler:
No, I meant — yes, I meant level — the level of education. I needed another four or five years of education to do what John Pierce was doing. What I had to draw on was the excellence of what I had as a background to build upon. And some innate intuition that just led me and drove me. I think drive had a lot to do with it. I was determined. And also, you know, it meant a lot to me that I had the respect of people like John Pierce and others like that, that they didn't treat me as second-rate. It didn't make a difference to them that I only had a bachelor's degree. A degree was an entrance requirement at Bell. Once there, degrees were not important — but productivity was. So I was in just a wonderful environment with some great people. Harald Friis, one of my heroes.
Goldstein:
Why a hero? On an intellectual level because you admired his work, or you admired his skills?
Cutler:
I admired him as a person. I admired his judgment. He was inspiring — if you explained something to him, he understood it right away, and he was very enthusiastic about it. "Do more! That's wonderful! Show me what you've got next week." He always wanted to know what you did, how you did it, and making it feel good, feel that you'd really done something well. I appreciate that. I've had bosses that couldn't care less. Not very many. But mostly, they were enthusiastic about what I was doing and encouraged me to do more. I don't think everybody had that good an experience. And also, my own attitude was different. Some people talk about "Management by walking around." I think you could call Friis's method "Management by being available."
George Dale, who was a little bit my senior, one time early in my career, said, "You're working for John Schelling?" He said, "I used to work for Schelling. I never knew what I was supposed to do." I said, "But that's what's great about him."
At one time, I had a hare-brained idea, I set up some stuff on the table, measuring things, and one of the other fellows, Morrissey, came along and said, "What are you doing?" I explained it to him, and he says, "Does Schelling know you're doing this?" I said, "No, I want to see if it works before I tell him about it." "My boss would raise hell!" Gee, maybe I shouldn't be doing this. So I trotted right up to Schelling's office to tell him what I was doing. He says, "You don't have to bother me with that. Show it to me when you get it working." His attitude was, let them go — push them, but let them go. In that respect Schelling was much like Friis. He didn't have the forceful personality, he was a much quieter person than Friis. Friis had an aura about him, something like Churchill, I guess. Whereas Schelling was a very modest kind of guy. I needed them both, they were both just great for me. And they both encouraged me to do what I wanted to do. And you know, I had all this freedom, and yet, most every new activity that I got into, I got into because they thought it was a good idea and suggested it. Like switching from antennas to amplifiers and to satellite communication.
I learned something about management from two fellows later, when I was director. I was director, I gave a hard time to Kumar Patel, a brilliant 24 year old graduate of Stanford who was bankrupting the Lab with new and complex equipment for his laser work. His department head, PK Tien, stopped me in the hall and said, Chape, when you have someone like that, don't get in his way. He was so right. Patel and Tien were perhaps the two brightest and most productive fellows I ever knew. The best thing I did for them was to stay out of their way.
Few major changes in the direction of my work came out of my own initiative. Minor changes in goals came from my own initiative, yes, but when I stopped working on antennas and worked on tubes, I wanted to work on antennas, but Schelling and Friis said, no, the war's over, we don't need antennas now, there are enough people working on antennas, but we have this tremendous problem of how are we going to amplify microwaves to send them across the country? And so I picked up and started to work on tubes. The switch to satellite relay was forced on me by patriotic necessity, and to coding, TV and Cellular by reorganization and promotion.
Tubes, Triodes and Klystrons
Cutler:
For a while I worked on microwave circuits for a General Electric tube, closed-space triodes that they were developing.
Goldstein:
I know that GE had these sub-miniature tubes, very small, but I mean, Bell had the Morton triode, so it's not —
Cutler:
This was before the Morton triode. Morton was just beginning to work on this sort of thing. And GE had some small tubes that might be made to work in the microwave range. They built what they called lighthouse tubes — for radar. I don't know, maybe it was not radar. They may have been intended for communications of some sort. But they had close-spaced triodes that worked at lower frequencies, and I designed waveguide structures to accommodate them at four GHz. They were not anywhere near as close-spaced as the Morton tube but might be useful at four GHz. After the war, GE wanted to go another step further, and they made some advanced lighthouse tubes. They had a little one, and a middle-sized one... I've got some of them in a box around here somewhere, too. The question was, could we make the GE tubes work at four GHz? So for a better part of a year, I tried to adapt experimental GE lighthouse tubes to four gigahertz. There's a big one in there and a little one in there, but you can't see the tube because it's all boxed up in the waveguide.
I built a couple of amplifiers using the GE tubes, measured the dickens out of them. The tubes had a very short life, they faded, but they had some great possibilities. You blow air through there, because — oh, that's broken off. Where's the rest of it? I haven't taken it apart in fifty years, but — Oops! There's — wow! Something extra! — Anyway, you see, you'd come into this with a waveguide, excite the tube, the other side — this is the input — in here and out here. And you've got an amplifier. And they worked at four gigahertz. And they had characteristics that might be useful for the microwave radio links. But while I was working with the GE tubes, Morton was working on his own ideas and he built a successful tube, and he said, you know, "Are we interested in what other people are doing? Why should we use the GE tube? We've got our own tube." And so Bell Labs proceeded to go ahead with the Morton tube.
Goldstein:
Now, were you and Morton working at cross-purposes? Or duplicating each other's work, I should say?
Cutler:
- Audio File
- MP3 Audio
(160 - cutler - clip 2.mp3)
Well, we were overlapping — We were quite independent. I wouldn't say cross-purposes, I wouldn't say competitive. I was almost totally ignorant of what Morton was doing until he was having some success, and then here all of a sudden was the Morton tube, and a number of people working on that. And we didn't need the GE tube anymore. Something important came — the traveling wave tube. John Pierce was back from an overseas trip where he met Rudi Kompfner. He come back with this wonderful idea. He quickly built a traveling wave tube of his own with important modifications from Kompfner's tube. He introduced attenuation where Kompfner had tried to make the circuit as loss free as possible.
So one day there was a conference in Schelling's office with Pierce. Pierce told us about this wonderful new kind of an amplifier. Pierce was building his tube in the tube research department in New York, in the biscuit building, and he needed somebody to work on the circuit aspects. Schelling suggested I drop the triode work and support Pierce work on the traveling wave tube. I didn't want to drop the triode work! But on the other hand this traveling wave tube thing was very exciting, a new thing, — oh, boy, that's great! So I started learning all that Pierce could teach me about the traveling wave tube — and studying helixes as microwave circuits — I wound large helixes and measured the fields on them at many frequencies. But, once I understood the helix, what should I do next? Tubes — Everything's inside the glass bulb, and Pierce didn't want to part with a tube while it still had cathode emission: His experimental tubes didn't work very long. There's no circuit outside the glass bulb to speak of. And so I said, "Really, the only way I can work on that circuit is to build my own tubes.." And I got the go-ahead to buy a vacuum pump and do this thing — to build demountable, continuously pumped traveling wave tubes. Nobody at that time, to my knowledge, had done much with demountable tubes, and I was about to find out why.
Goldstein:
Yeah, you were writing about demountable tubes. What does that mean?
Cutler:
Oh you know what a tube looks like — sealed in a glass envelope. You want to change something inside it, what can one do? Break the glass. Then you start over again. Glass blowing is a very special skill, it takes a lot of years of practice to be an expert glass blower so you can build tubes. People with that skill are rare. So why can't we put it together with gaskets? Rubber gaskets? Here again, the multiple facilities of Bell Lab served me well. Russ Ohl told me how to get gaskets already saturated with pump oil, and the chemistry department supplied me with special vacuum proof neoprene gaskets.
Goldstein:
And then you'd evacuate it?
Cutler:
With a vacuum pump. Gasket it. Pump it continuously, measure the things you want, turn the pump off, pull it apart, make whatever changes you want, put it back together, pump it down again and measure. The alternative, practiced in the development department and other laboratories, was to make tubes in quantity, perhaps with some slightly different dimensions if you wanted to empirically find optimum proportions.
A few years before, back before the war, I had wanted to make my own transmitting tubes, but I was told it was totally impractical. But this time there was no objection. OK! I was so surprised! I must have gained some credibility, as an antenna expert or something.
Goldstein:
Do you think that's it? Or maybe, had the economics of the system changed?
Cutler:
Oh, a lot of things had changed. Management had changed. Not much, I was still working for Schelling and I think at that point Schelling was still working for Bown and in the shadow of Friis. But they all had moved up a notch in authority and responsibility.
Goldstein:
So do you think the obstruction was somewhere up there?
Cutler:
I don't know. No, I think probably the obstruction was logical: here's this young fellow who doesn't know what he's doing. Five years later, I had some credibility. Maybe the need was greater, or something, too. My boss's ideas on that sort of thing may have been dominated by the tube people, a little proud of their domain. And, in 1947 we were interacting with a whole different group of tube people. Now, it would be Pierce, and Kelly, and before it would have been an entirely different group, Sid Ingram and Ray Wilson. Anyway, I was encouraged to do it, and I bought a vacuum pump. Then I lost about a year out of my life, because making tubes with vacuum pumps — oh, so many things didn't work. I tried this, I tried that, I did all sorts of things, they wouldn't work. I'd build a tube, I'd get everything in it all set, and turn it on, and, no emissions, no electrons are coming out of the cathode. What is wrong? In desperation, finally, in my demountable rig, I put a commercial tube under an anvil. I turned the tube on and measured the current through the tube, had all the characteristics of the tube showing on the cathode ray tube screen. Then I hit the anvil (through a flexible bellows) and cracked the bulb of this tube, inside my own evacuated enclosure. I let my vacuum seep into the tube. SHOOP! In a few seconds the tube died. I had to learn about what poisons cathodes, and what cathodes don't poison easily. The commercial tube had a common oxide cathode and was most easily poisoned. Thoriated tungsten was hotter and better, but not good enough. So I went from oxide to thoriated tungsten cathodes, which died, to pure tungsten cathodes, which had to be heated a lot hotter. Really bright, white-hot instead of red or yellow.
Goldstein:
I'm surprised that you didn't simply imitate the cathodes in the existing commercial tubes.
Cutler:
Commercial tubes used oxide cathodes having a critical balance of bismuth and/or Strontium oxide on a very special carbon base having a critical level of dissolved impurities, an extremely critical balance of stuff. And my gaskets and my vacuum pump were not clean enough even for thoriated tungsten, let alone the more common oxide cathodes.
Goldstein:
Oh, I see what you're saying.
Cutler:
The oil — whatever was in my vacuum — something in the pump poisoned things. Here you've got something which is called a vacuum, supposed to be nothing there, about one-billionth of an atmosphere. Little tiny bit of sulfur, a little tiny bit of chlorine — or one of many other things. Just the least little trace of an active element is enough to kill conventional cathodes in a few seconds. But pure tungsten, heated hot enough, drives all that bad stuff away. So I went to pure tungsten and or molybdenum. So I designed the kind of a cathode that would work in an impure vacuum. It took me a year of trial and error to get to a place where I could build something that worked. But all of a sudden, instead of having tubes built six at a time by skilled craftsmen in a remote shop: hand built tubes that wouldn't work too long and were totally inflexible, I could build my own, I could move things that were sealed in the vacuum chamber through a bellows and thus tweak things inside of the vacuum, I could take it apart, put in a different thing here, there, trim or bend a component and so forth, and try it again. So by trial and error, I could move, I could run circles about the people that were doing things the old-fashioned, semi mass production way. And I ran circles around them. I was able to get a lot done in a short time, and it was very exciting. So, that got me into the tube business in a big way. I could build a unique tube in a day without having to wait for special shop processing by skilled technicians. What I built might be good for a few days of experiment, but not good for operational applications. Eventually my laboratory experiment would have to be built into a sealed off glass envelope for system use. Our task was to establish principles of design and operation, not to supply a product.
Goldstein:
I understand now that you were making tubes in support of traveling wave tube circuits. But what would the tubes do? What were the design characteristics that you had to ...
Cutler:
Well, the wonderful thing about the traveling wave tube was, that it had an immensely broad band width. Television takes about four megahertz of band width and you want the gain to be uniform over the band. You could barely do that with a triode, you couldn't do it with a Klystron then — you've probably heard about those things ...
Goldstein:
I was going to ask, actually, if you had any experience working with klystrons.
Cutler:
We tried klystrons before the traveling wave tube. Some of our first circuits were with klystrons made by A. L. Samuel in the tube department. We called them Velocity Variation amplifiers, resisting the Varian's designation. Other people (Raytheon} and Bell Labs used klystrons in the first experimental microwave relays between Boston and New York. I think the Bell relay was called TDX. But klystrons were limited in band width, and television pictures amplified in the restricted bandwidth were not as good as you would like. The triode would do it better, the traveling wave tube would do it still better, we thought. So we built experimental traveling wave tubes for that purpose.
Triodes have resonant circuits and are narrow in frequency but since the impedance low the band widths are broad enough for the television circuits. The Klystron requires higher impedance circuits, and therefore the circuits were narrower. But with the traveling wave tube, there's no resonant circuit at all. The beam comes down there and goes by that helix, and they travel at uniform rates. Whereas people wanted four megahertz band width for television circuits, the traveling wave tube had a hundred or several hundred megahertz band width. So one wasn't limited by the tube. You could include band limitations in specially designed filters, as needed, in other parts of the system to optimize performance, and you could tune the filters to make them just the shape needed. So that was the principal reason for developing the traveling wave tube.
But it took a few years of work to optimize traveling wave tube design principles, to know how big to make the helix, how long to make the helix, how to make the tube stable so it wouldn't oscillate, how to get the noise figure down so that the tube would be useful in a telephone relay system. The big, longest-lasting problem was getting the vacuum good enough. If the vacuum is not good enough, the electron flow creates ions, the ions move around, they put fuzz on the signal. How do you get rid of the fuzz? At the point when the decision had to be made, whether to go with the triode or the traveling wave tube in the microwave radio relay systems, that problem hadn't been solved. So the relay systems went on with the triode.
Goldstein:
Was that very contentious? Were there strong advocates for these?
Cutler:
I think it was a very foolish decision to make. But they were under pressure at the time, Jack Morton had a very forceful personality, management loved him. He was working on both his triode and the development of the traveling wave tube. He had worked on the traveling wave tube and the triode from the beginning. His heart was on the triode, that was his invention. So I'm sure he influenced the decision. But the decision was made at a management level that was way over my head. I was not a part of that decision and I doubt that Pierce was consulted. I think it was made at the management level in the systems and development areas, and I think that Morton had management's ear. The triodes supposedly did everything perfectly, and the traveling wave tube had a serious unidentified defect. We might never be able to solve the ionization problem. But a few months later, when Western Electric started building the Morton triode the grids vibrated. These very high-tension grids: they couldn't keep them from vibrating. That was a worse problem than the ionization in the TWT. By the time they faced up to the problem, the tubes were in manufacture, they had an awful time with low frequency modulation caused by grid vibrations. And the life was never more than a few hundred hours for the triodes. Traveling wave tubes — well, now I think traveling wave tubes are built in quantity for military applications and they last forty thousand hours. We solved the ionization problem long before the triodes were satisfactory. It was too late. But the traveling wave tube went into lots of military systems. The TWT was eventually used in a few radio relay systems, how much I don't know. I think they're used predominantly in communication satellite radio relay systems.
Goldstein:
OK. So I'm still not sure I understand what your precise involvement was. Were you building the circuitry that supports —
Cutler:
I was involved in just about all the aspects in establishing the scientific and practical aspects of TWT design. There was an immense research program required to determine optimum design for a given frequency band of operation (even within a factor of 2), efficiency, and other operational characteristics, electron beam focussing and noise characteristics. The tube was unlike anything used before. The first tubes, proportions by guess, had maximum gain too low in frequency by a factor of 3.
Goldstein:
Were you building traveling wave tubes themselves?
Cutler:
I was building demountable tubes. When I came up with a design, wrote a paper, solved a problem — of course further development for manufacture went on, and other people built sealed-off tubes for system tests and operation. Yes, I built a few sealed-off tubes, through the technicians in our own small branch shop. The technicians built the tubes, I told them what to build: Experimental tubes. But I solved noise problems, to make the tubes low-noise. I solved problems in the cathode focusing, to get a better, cleaner focusing so more electrons would make it down all the way through the tube to the end. At one stage of the work I built a ten foot long scale model tube, scaled to work at 100 volt and 100 MHz with a one inch diameter helix. With it I could study the electron beam modulation to determine the limits to efficiency. I was party to solving the problem of proportioning the helix. The first tubes we made had a too big helix for the frequency we desired, they had greatest amplification at about a third of the frequency we were aiming for. We had to get that calibrated, so we could optimize proportions for the helix.
Regenerative Pulse Generator
Goldstein:
You said their main amplification — was the curve not flat? Did it amplify some frequencies more?
Cutler:
Well, yeah. I said it was a very broad band width. If I drew a curve of the amplification versus frequency it would be like this — And we're working over here. And the tube would oscillate here, maybe 6 dB more gain where the stabilizing attenuation was perhaps 6 dB less. We observed what seemed to be tremendous, crazy oscillations. We'd only detect the oscillations at the frequencies passed by the waveguide, and that the oscillations were pulsing at a very high rate was not immediately evident they were coming out on a wave guide, and the wave guide cut off, i.e., filtered out the fundamental frequency of the oscillation, and even the second harmonic. The oscillations were at a high level and produced strong harmonics. We were only seeing harmonics of the oscillation. We didn't know it. So why could it act that way? It didn't seem to make any sense at all. Well, it took some — you think Sherlock Holmes had a job! — We had a real puzzle on our hands. But I figured it out. I finally realized what was happening, it was oscillating at a low frequency, near 1 GHz, and we were seeing harmonics above 3 GHz. It was not just a simple whistle, continuous wave oscillation. It was pulsing and jumping frequency. It was pulsing at a rate of seventy three megahertz, pulsing oscillations of about twelve hundred megahertz. We were detecting harmonics at four thousand megahertz, harmonics which jumped and swept in frequency erratically, it seemed. And you know, there was no obvious seventy three megahertz around because that was outside the frequency range of our receiving equipment. There was no obvious thousand megahertz around, because it wouldn't come out of the wave guide. All we had was a curious mishmash of signals covering the bandwidth of our receiving apparatus at and above four gHz. How could that happen? And I figured out, finally, that it was pulsing.
It occurred to me, in due course that what we had was a good way to produce extremely short pulses. Let's do it purposely and see if we can control them. So I put controlled feedback around a stable amplifier, invented something which I called an expandor, which was a nonlinear circuit in the wave guide. And then I had controlled pulses. I called it a Regenerative Pulse Generator. And got some patents, and then I thought, how would you use that in a telephone system? And I got some patents on systems which would use that pulsing characteristic.
Goldstein:
How did they use it? What did they do?
Cutler:
The development department picked it up and they worked on a system using a Regenerative Pulse Generator. I don't know how far they went with it — I don't think it went anywhere then. I think they didn't know what to do with pulses that were that short. These pulses were three nanoseconds long, one thirtieth of a microsecond. At that time, it was probably a record for short pulse length. We couldn't look at them on an oscilloscope because oscilloscopes wouldn't reach that far. John Pierce thought, if you can do that way, there must be other ways, and he invented another circuit that also generated 3 nanosecond pulses just about like mine. He had a big tube shop working for him and he built a very special micro-oscilloscope. It had a tiny screen — you looked at it through a microscope, because the deflection was about thirty-second of an inch maximum deflection. With a microscope and a camera, why, you could photograph the (detected) pulse response. And with the special micro-oscilloscope tube that he built, I could see these pulses that I was generating.
There were a lot of things like that, grew out of sort of sidetracks in our research. Beside solving the problems and getting an engineering background so one could sit down and design traveling wave tubes, we had fun inventing things with and for the new technology we had. We didn't have computers, but I finally put together a nomograph chart, a very complex family of nomograms, so you could start with basic requirements and read off the critical electrical and physical dimensions. It took about twelve steps in the nomogram to come up with a tube design. You build it, and it works. I don't know whether that was used very much. But it put all those equations into a graphical form so somebody could do it without having to stretch their slide rule or use a computer (which didn't exist).
The Regenerative Pulse Generator was reborn many years later in the laser and called Mode Locking, but I had little to do with that.
There was a classic tube experiment which I'm very proud of. A lot of people were working on tubes, people here at Stanford as well as at Bell Labs. Pierce came up with a theory of noise and electron beams interacting in electron wave tubes. And he said that the noise on the electron beam had a standing wave-like nature. Noise! Noise is random I thought. It seemed just crazy to me. Well, if it's like that, I bet I can measure it. So I devised an experiment to measure noise standing waves. I just about had it working, when — did you say you met Cal Quate here at Stanford?
Experimental Work
Goldstein:
No, I just saw his office.
Cutler:
Well, Cal came to Bell Labs at about that time. And he was thrown in with me. He and I worked on the noise measurement — he worked mostly on calculations, and I worked on the measurements. We put together something which later was called the Cutler-Quate experiment. That confused a lot of people who didn't know us. Every once in awhile I'd meet someone who would call me Cal because they'd relate me to that experiment. That was our first joint activity together and his first serious publication. That experiment, that measurement was crucial to the design of low noise Twits. So that was, after antennas, an important part of my experience.
Goldstein:
I was a little surprised to hear you say that you were told that nobody needed antennas anymore. I mean, why would that be, if people were still working on microwave transmission? Was it all going to be over cable?
Cutler:
There was a fellow named Kock, Winston Kock, and there were several other people, too working on various aspects of antennas, antennas for the army, and things like that. Kock had antennas he proposed for use in microwave radio relay, and his group continued working on them when I started on tubes. I would have preferred to work on antennas, but my instinct was wrong. The challenge and adventure was with in the tube area. There wasn't need for so many people working on antennas. We weren't working for the military any more.
Goldstein:
So it's not as if there were no more use —
Cutler:
There were a lot of good ideas around and I continued to get a few patents, but the Bell System had little need for antenna development. It wasn't until many years later when satellites became important that there was a new challenge and breakthrough in designing antennas. I would have loved to build some antennas, use my corrugated wave guide to make things prettier and better and so forth. But there wasn't the need for them. But there was a crying need for microwave relay circuits and components other than antennas.
Goldstein:
You were saying before that Cal Quate worked on the theory, you worked on the experiment part of it. In your papers, it almost looks like there was a purposeful division of labor. I was thinking about you and Pierce but maybe you and Quate — you doing the experimental work, other people doing the theory-was that — ?
Gilbert Stiles and Other Technicians
Cutler:
Yeah, I was an experimenter. I was credited with being able to make things work in a laboratory. And I had some very good technicians working with me. I can't take too much credit for that. We had a real crackerjack technician. And a couple of those technicians that I worked with the longest, I inherited because other people couldn't work with them. That was a strange thing. One young fellow was hanging around my laboratory, getting in the way. So I gave him things to do, and he never went away. I found out that he'd had a run-in with his boss, who couldn't put up with his youthful mischiefness. He was a kid, about eighteen, I guess, just barely had his working papers, and he had been fooling around, and the guy he was working with said "Get out of my lab! I don't want to see you again!" Well, he was drawing a salary and had been kicked out of the laboratory he was assigned to. What was he going to do? His buddy, Jack Gardner, was working for me, so Stiles came over to see what Jack was doing. So here he was, hanging around, and I said, "Look, if you're going to stay around here, would you saw that in half for me?" And I began using him. I found out that he couldn't go back where he came from and he didn't want to lose his job; I inherited him! And he was wonderful. He was bright. He was full of mischief, but so was I, and we enjoyed each other. So I put up with his mischievousness and put him to work. He worked with me for a year or so until he was drafted into the army.
When he came back after two or three years at the end of the war, he worked for me another several years, maybe a decade. And then I had this strange phone call from the personnel department, saying, "We need somebody to teach digital electronics to our draftsmen who are working in this area and don't know what they're drawing up. We need someone to teach an in-house course. We've been looking for somebody who might do it. We found this fellow working for you and attending night school. He's now graduating from Newark College of Engineering, with an all-A record. It seems to me that we have an unusual opportunity for him. He could come with us and teach this course for a year, and we would then transfer him into a development area as an associate member of technical staff (AMTS), which would be a promotion for him. This is a good avenue for promotion, a fine opportunity for him. In research as a night school graduate, you know, he may not have that much of an opportunity for advancement. We'd like to offer him this chance. How about it?" I didn't know he'd been going to night school. So I went and I talked with him, and I realized he had a future in Bell Labs that I couldn't offer him in my part of the organization. I cried that night! Off he went, he taught the course, and in a few years — I tracked him — he became a supervisor in the development area, a full member of technical staff, had a great career.
This was a mischievous eighteen-year-old that I took into my lab when discarded by another researcher.
Goldstein:
Who was that?
Cutler:
Gilbert Stiles, was the lad. I still miss him. My good friend Bill Goodall was the engineer with the short fuse.
George Eberhart was another very unusual fellow, who was — I told you that he was such a skilled guy. His position changed, the fellow he worked for, Sterba, died, and could I use him? Of course I could use him. And we worked very closely together until he went off to Whippany to work with people over there. There again, he was rated as a full member of the technical staff. He wasn't paid as much as most members of the technical staff, but with a high school background and limited theoretical understanding, he had a great career. And he has continued — as I said earlier. He's ninety years old and he hasn't stopped working.
Traveling Wave and Electron Tubes
Goldstein:
I'm unaware of any work on traveling wave tubes outside of Bell Labs. Do you know of any?
Cutler:
Oh, yeah. It was worked on here at Stanford. John Whinnery also did a lot of work on it at Hughes Aircraft before he came to Berkeley and continued with it at Berkeley. Ask him about it. John had a bunch of graduate students working on traveling wave tubes when he brought me in for a semester back in 1957. There was a lot of activity at RCA. Some, I don't know how much, at GE, and some other universities. A lot of work at the University of Michigan, and Ohio, and Illinois. And at MIT. Many of us met once a year or more a technical meetings, there was something called Electron Tube Conference. I sent you a paper.
Goldstein:
Yes, you did, I wanted to hear more about that.
Cutler:
Well, that meeting was a wonderful —
Goldstein
This is the Electron Devices Society Tube Conference.
Cutler:
Right, it was the 50'th anniversary of the old "tube conference," now called the Electron Device Research Conference. The "Tube Conference" predates the EDRC and the society. It was theoretically sponsored by the IRE, which gave it legitimacy, but it was pretty independent. Those meetings were where we got together and competed our ideas against each other. And that's where I met so many of people from other laboratories. It was there that I got to know Whinnery better. I met Whinnery at my first visit to General Electric in 1944, before either of us had heard of the TWT. I didn't remember that until many few years later. I discovered his name in my notes. There was a guy named Jim Lafferty at GE that had been working on a proximity fuse thing. I didn't remember that connection until last December when I called him up on some errand for the AIEE. I remembered him from the traveling wave tube work because he was at the 4th Tube Conference meeting at Yale, but he had been at Dahlgren Proving Grounds testing proximity fuses with me in 1941. These things come together.
Goldstein:
Small world. How did the work at these other places compare to that at Bell? In terms of the approach or the results?
Cutler:
It looks better to me in retrospect than it did at the time. Oh, I had the greatest respect for those people. They were doing fine things. They respected our work; we respected theirs. We had Western Electric, too — we had an outlet for our tubes, an advantage which they didn't have. Most of them were writing papers or hoping somebody would want to buy their output, I suppose; or perhaps it was a vehicle for teaching. I suppose most of them were supported by government or industry contracts. I don't think I ever questioned their means of support. But Western Electric — it was one of the things made possible by the unit of the Bell System. Vertical integration in the Bell System made lots of adventuresome things possible. If you had a good project, a good thing that might be useful to the telephone company, why, there was a customer right there in the family. One of the fellows that worked with Pierce very closely, Les Field, left Bell Labs about 1947 or 1948 and came here to Stanford, set up a traveling wave tube group. He was Cal Quate's thesis professor. So we had relationships, wonderful community relationships all across the nation. The Tube Conference, and, of course, committee meetings preparing for the conference, was a wonderful vehicle for exchanging ideas, and got to know each other, became best friends. There were about four or five people at RCA that I got to know quite well through tube conference activities in the committee as well as selecting papers and so forth. Some of the people I've lost track of. Most of them have retired by now. But they're great people. And I respected their work. Professor Bill Dow at University of Michigan said tube people are interesting because one must be an optimist to survive working on tubes.
Goldstein:
If you take a look at the different commercial interests of the different labs — AT&T as compared to RCA or GE — did those commercial interests influence the thing that they were working on, about the traveling wave tube? Were they trying to turn it into a different component or apply it in a particular way?
Cutler:
Well, Hughes Aircraft, that's where Field went when he left here, were very much interested in military applications. And I guess all the laboratories were, had military system applications. Later on, of course, satellites came along, but during the early days satellites weren't even a dream. RCA has always had a lot of communication activity, overseas radio particularly in the early days, and they were supplying other telephone companies. There was a company called Sylvania, which is part of GTE now, which was active. I didn't mention them before. Rudy Hutter, I remember, was there. Oh, gosh, yes, Sperry, Sperry Gyroscope, C. C. Wang. I had patent competitions with C. C. Wang on electron beam focusing in traveling wave tubes. Wonderful, wonderful fellow.
Goldstein:
I'm just wondering if these different companies were looking for different operating characteristics.
Cutler:
Well, the military of course was looking for higher power, they didn't care so much about band width. They were interested in countermeasures, a lot of things like that. So their requirements were different. But not greatly different. In other areas, there might have been a bigger distinction. A lot of them — you see, I couldn't tell you, really, what GE wanted them for but perhaps only for addition to their product line. But it must have been the same kinds of things. They were tube suppliers, and I suppose anybody would buy their tubes, why, they'd make tubes for them. So there's probably a lot of that. Sylvania certainly was into telephony, same kind of thing we were. I guess I can't answer your question better than that. Here, Stanford was interested in high power accelerators, i.e., physics applications, and most of their effort finally went into the Klystron, because they could generate a higher-efficiency tube with the Klystron than they could with the traveling wave tube. But Marvin Chodorow — do you know Chodorow?
Goldstein:
Sure.
Cutler:
Well, he was instrumental in a lot of that. He had a fellow working for him, a Norwegian fellow, I just got a fax from him today, Tor Wesselberg in Norway, he's writing a paper for me mow. But he was very active in the traveling wave tube work that was done here back in the early fifties.
Goldstein:
How did the applications for the klystrons differ from those for the traveling wave tube?
Cutler:
The Klystron as a communication device was faulty because of the limited band width, as I mentioned before. It is a great source of power at microwaves. It is more efficient, where you don't need wide band width and can accept output from a high Q cavity instead of a distributed low impedance helix. The biggest application of the Klystron was high power for linear accelerators and things like that. Also for high power television broadcasting. Most UHF television stations now use klystrons. There, engineers do some tricky things to get the band width just about big enough for the television signal. They are high-power tubes, very high-current tubes, high voltage, so the proportions are different than they are for a low-power applications. I don't think that in this application there is quite as serious a band width problem as there is in trying to use it for communications, even though the frequency is lower. Also, since the energy at the extremes of the band is not very high, they can predistort the signal — so they put a signal into the tube, which has very high amplitude at the edges of the band, and let the tube flatten it out. The tubes are huge things, these fifty kilowatt, a hundred kilowatt, and higher, tubes for broadcasting, and the pulse tubes for linear accelerators.
Pulse Code Modulation (PCM)
Goldstein:
Getting back to the chronology, the next stage of your career is satellites? Is that right?
Cutler:
There was an intermediate stage which overlapped with that. Bill Goodall worked on digitizing television. PCM was a new thing, people were beginning to use PCM in experimental communications systems and for secrecy in computers, and so forth.
Goldstein:
I just want to ask one question. When you say it's a new thing, I think it was proposed conceptually in the thirties, maybe —
Cutler:
Well, yeah, PCM was invented in 1938 in France by A. H. Reeves, I think, but nothing much had been done with it. It had been used a little bit in the military, for secrecy in telephone communication.
Goldstein:
So why then? Why was it coming out in the late 40's?
Cutler:
Well, the military — if you have things defined by numbers, you can always switch the numbers around. It was an easy way for secrecy and that sort of thing. Also there was activity in trying to code speech — the Vocoder and Voder and so forth — researchers were doing clever things with speech. And with the radar activity, we got into pulses. Because of pulsed radar people were skillful now in handling pulses. So there was a germinating of ideas. Imaginative people were thinking, it is wonderful — it's a new field! It's exciting! And I don't think that people like Pierce and like myself were primarily motivated by doing something for the telephone company. It was an exciting new idea, what can we make with it? Maybe it'll be useful and maybe it won't. So, these ideas were jelling, and a lot of people were beginning to work on digital pulse systems. The digital computer was still an experiment. It was part of falling in love with pulses that led to the digital computer around the same time. The best answer is that the time was right and technology was ready.
So Goodall made PCM television, published a wonderful paper in the IRE Proceedings showing the pictures one gets with one bit, two bits, three bits per picture sample and so forth. He showed that a 7 bit picture was marginal and eight bits necessary for any operating margin. His was a very sophisticated and fundamental paper on PCM. I used to eat lunch with Goodall. He was always wanting to tell about the wonderful things he was doing, a lot of which I didn't understand, and of course I wanted to boast about the things I was doing. I learned a lot from Bill Goodall. I credit him greatly. He was more like myself — he didn't have a strong theoretical background, but he had a green thumb. He knew how to make circuits work. He was a much better circuit man than I. And he just loved to build very complicated vacuum tube circuits. He built pulse circuits, put them together, did some theoretical work, learned about other people's theoretical work, but built things other people couldn't build. And he managed to get the band width high enough and the pulses short enough so he could do television with PCM.
So we were having lunchtime conversations and I was trying to understand all this pulse stuff. And I made what was, to him, a silly suggestion: why do you send a whole new sample every pulse period? You know, each sample is very nearly the same as the previous one, so why don't you just send the difference? He said, well, that's the same thing as sending the differential of the amplitude, we put a filter in front of the modulator and differentiate the signal. So we're really only coding the differential of the signal. So the pulses are bigger — there's a bigger difference between them. We're already doing that by predistorting.
I said, Bill, there's a difference. But I couldn't really figure out what the difference was, and he didn't see that there was a difference. So after lunch I stewed about this, and drew some diagrams and so forth. I came to the conclusion that there was a real difference: If we would code, not the differential of the analog signal, but took the difference between the previous coded sample value, which had a quantizing error, and the next uncoded value, and coded that, every time you coded one sample, you're compensating for the error you had in the previous sample. I called that Differential Pulse Code Modulation, DPCM. I sketched it up, wrote some equations and so forth, and sent it into the patent department and forgot about it. Well, almost ten years went by — I'd got some patents, but I was working on something else. It was one of those things you dream about in the afternoon while waiting for the machine shop to machine something for your next experiment. Machine shop delays were sometimes productive. Is that a familiar situation?
Goldstein:
No, no.
Cutler:
About ten years later, we were through the satellite game, satellites had come and gone. There were big changes in the organization of research, Pierce and Kompfner were next up my management scale. Kompfner was associate executive director of our division, Pierce was Executive Director — They had inherited the remnants of a division that they didn't need or really want. It had been led by Deming Lewis, who spent a time in Washington, responsible for Bellcom and then became president of Lehigh University. The division had several laboratories and had had most of its best talent transferred to the new switching development division at Indian Hill. There were several departments that Pierce and Kompfner became responsible for and didn't know what to do with, really. So Kompfner spent a lot of time learning all he could about what the departments were doing. He came to me one day and he says, "I was just downstairs with Jim Young and his people, and they're working on something called differential PCM, and they said you invented it!" I said, "Yeah?" (I didn't know what they were doing!) I said, "Tell me about it!"
Well, he says, "You tell me what it is. I couldn't understand them." So I explained what I knew about DPCM, and showed him my patents. Rudi and I were on the same wavelength: we communicated easily.
He says, "Now I know what to do with that department. It's yours." So he gave me the department to worry about. That was pretty interesting, you know, I could understand what they were doing partly because it was a development of my own ideas — but I had to learn a lot, they had gone a long way beyond my invention, but that was pretty exciting. And it got me thinking about pulse systems again, got me into the television activity, which was growing fast. There were two departments, actually, that were working on differential PCM and drew me into it.
Goldstein:
What did Bell do with the differential PCM?
Cutler:
Well, do you know about high-definition TV?
Goldstein:
Yes.
Cutler:
HDTV grew out of adaptive and predictive PCM. Arun Netravali is now Executive Director for that part of research. He eventually took my place in research managing a group working on Picturephone and Facsimile. Other parts of the lab used DPCM and other predictive coding schemes in sound transmission and recording. Predictive coding was really an idea whose time had come and blossomed in many areas.
We saw differential PCM, greatly broadened, as a way of sending television pictures around for the telephone and for facsimile. So my invention shows up in your facsimile pictures, your high definition television pictures and things like that. But that's a long ways - it was in 1950, 1951 that I invented this thing and now we're in 1990. Thirty, forty odd years later. But DPCM was foundational to the kind of things, predictive coding, that shows up in many applications. In the case of television, I was just looking at one signal sample after another, a continuous, one-dimensional signal. But in television scanning, one line looks like the next line. One frame looks like the next frame. You can predict in three dimensions. That greater concept grew out of the group that I had working on Picturephone. The group developed a whole series of systems, which led to what they're now doing with high definition television.
Picturephone
Goldstein:
When did you start working on the Picturephone?
Cutler:
1962 or 1963, I guess.
Goldstein:
And how long was that stretch?
Cutler:
Until I retired in 1978, and of course it has continued after that. I was inventive, I managed to get a few television coding patents in my own name. I would have liked to have done a lot more, but one of the things I've always believed is that a manager should not compete technically with the people he is responsible for. It was hard not to compete, I could make suggestions, but I followed the example of Rudi Kompfner. Rudi said, "You know, I want this fellow to work on this idea, but if I invent it — if I tell him about it, he won't want to do it, because he's an independent guy. How am I going to get him to invent this thing?" And he did. This guy suddenly comes in, "Mr. Kompfner! Look at this!" Kompfner never blinked an eye. The fellow went gung-ho on it, because it was his idea. Kompfner gave lots of his ideas away. Well, I wasn't THAT inventive, but if I had a good idea, I'd encourage these guys on with it. So my contributions to some things is frequently relatively invisible. But the people appreciated it, I appreciated it, and of course IEEE was very generous and gave me a medal which recognizes their contributions as well as mine..
Goldstein:
I know AT&T marketed Picturephone, I think twice.
Cutler:
They tried.
Goldstein:
Right. What happened? What's the story there?
Cutler:
Well, you'll get a lot of different stories on that. But I think the biggest problem on that was economic. AT&T tried to market Picturephone just as the country went into the 1971-2-3 financial slump. Western had made a few hundred sets, they had fifty of them around Bell Labs in executive offices, I had one on my desk, I loved it. Pierce had one, he didn't care so much for it. I worked for Ed David at that time. Ed David and I had long conversations about it, long enough so we'd forget the picture was between us. I remember one time telling somebody, "I was in Ed David's office yesterday, and he said..." How did I do that?" I wasn't up at Murray Hill. Our conversation was over the Picturephone. It was very real open communications as far as I was concerned. And Western Electric made a many sets and put them out in different places. I think they had forty-five or fifty at Westinghouse, in Pittsburgh.
Before they marketed it, they went around and they asked a lot of questions, you know, did they like it? They had some at the World's Fair, a bunch of them. Everybody was enthusiastic that had it.
They asked the people at Westinghouse how many they would want? Would you want to buy a set now? You know, we gave them to you for a trial. They're going to go on the market. "Oh, yeah, we'd like to buy at least fifty sets to start with." The system people had all this assurance. And they finally built them for sale. Then they went to Westinghouse to sell them. Guys at Westinghouse said, "We're going to have to tell our stockholders, there's no profit this year. We can't pay dividends. Can we tell that to our stockholders at the same time we put fifty Picturephones on our management's desks?" That was part of it. The other part was that the New York Telephone company was in trouble with the rate commission. They had held back on new construction and were short on operatioins. They had so much telephone traffic in New York City, they couldn't handle it. They were running out of capacity. The telephone company was in the doghouse because people were picking up the telephone and there was no dial tone. They might wait for a minute or more to get a circuit. And the commission, the rate commissions, said, "No, you can't do a Picturephone experiment here, not until you get dial tone working right. Fix the New York telephone system first, then you come and ask us." So they were denied permission to use Picturephone in New York.
AT&T did go ahead and put it in — in Chicago. But part of the plan was to have a transmission channel to Pittsburgh and to New York. Westinghouse, and many companies had offices with related responsibilities in all three cities. If you've got half of your management in New York and half of it's in Chicago, it's a wonderful place for Picturephone, between management offices. But you don't need it in Chicago if you don't have it in New York. So they tried to sell it in a market that wasn't big enough. Somebody proposed that they should make a few million sets, give them away to get a big enough customer base, and then start charging. But of course that would have cost a few billion dollars, and the telephone company didn't take that suggestion seriously. It might have made a difference, but it would have been terribly expensive.
Well, I think there's another chance coming, It wouldn't be nearly as expensive now. We've succeeded in getting the transmission rate down, so it can be put over wires or — also we've got optical fiber which would handle the band width much more easily, and electronic — integrated circuits — has made the whole circuit — active elements so much cheaper. And of course now they're building camera tubes for home use. By the millions. So cameras aren't expensive anymore.
Goldstein:
Did the original one work over normal twisted-pair lines?
Cutler:
New twisted-pair lines. Every few thousand feet or so, I guess, they had to put in a repeater and a regenerator of some sort. So it was expensive to run over twisted-wire lines. But a lot cheaper than putting in coaxial lines.
Goldstein:
But you're saying that now the current one —
Cutler:
Oh, the current ones do it much better. Also, equalizers and so forth are much cheaper to build with integrated circuits. We were trying to do this before integrated circuits were common or very integrated. Our delay lines that were used took big relays racks full of stuff, and now you can buy complicated circuits and put them right in your microphone.
Goldstein:
You said that the phone company didn't take seriously the proposal of giving away a million of Picturephone sets. Do you know how much money they were willing to invest?
Cutler:
I don't know. They invested a lot as it was. I guess they made some five hundred sets and sold them around Chicago at a fraction of what it cost them to build. That was to get things started, but it just didn't take off.
Goldstein:
What were your responsibilities as manager of this project? You said that you tried to stimulate people to produce the things that were needed. How else did —
Cutler:
If Picturephone was to work, they had to be able to transmit many megahertz of band width around the country. For black-and-white picture then, even for a 250 line picture and not much resolution it required a half a megahertz per channel. To send a few thousand channels would oversaturate the microwave channels that were available. So we wanted coding simplified. Pulse transmission was then getting into the system, but one would like to cut the pulse rate a lot. And we could see, the redundancy in the picture was such that we might be able to send those pictures at a small fraction of the half a megahertz that was required for the analog picture. And so we were devising coding, measured things — like Differential PCM — but three-dimensional. We knew that a lot of any picture is stationary, if you have a stationary picture you don't have to send anything, just enough to indicate that it's stationary now. So we learned ways to trigger storing of pictures at the receiver, and at the transmitter, you update the picture at the transmitter, then send only the differences to the receiver.
We were sending Picturephone signals on as little as fifty kilohertz, but not without considerable degradation. Wonderful picture of somebody stationary, but the lips would break up if you just talked. Well, they do better than that now. Where once it took 1.5 megabits to send a Picturephone signal, now you can cut the one-and-a-half megabits down to about two or three hundred kilobits. Now you could stack a whole bunch of those on a radio relay across the country.
Of course we were always generating new ideas that carried on further. Netravali showed that you could track changes. Something moves in the picture, you don't have to code the new picture on top of the old one, you could say, "code this over here." So by tracking the velocity of sections of a frame, they could carry and code a piece to a new position. There must have been hundreds of patents that came out of my group. Very innovative, exploratory kind of work going on. And mostly what I did was to encourage them. I took a page out of Harald Friis' and John Schelling's book — do you know? — "Praise them! Praise somebody and they love it and they'll work harder than ever." I loved those men, and I think they loved me just as much, it was — we had, really, a fine team.
Television Research Department
Goldstein:
Were there any — apart from trying to inspire them — were there any difficult decisions you had to make? In terms of closing down one line of research?
Cutler:
Yeah, a lot of them. The Laboratory Kompfner and Pierce gave me in the early 60's was headed by Enoch Ferrell, to whom I was "Assistant Director." I had great respect for and affection for Enoch, who had preceded me by 20 years at Deal and had moved into switching development (crossbar etc.) when I arrived. Enoch had been recently side tracked by the younger generation of upper management. He was unappreciated. I was told to work through and around Enoch until he retired, and to reconstitute the whole laboratory. This seemed very underhanded to me, and was possible only because of the sufferance and patience of a wonderful man. He was too smart not to know what was going on and gave me lots of room. He taught me patience and diplomacy, but it was a tough assignment.
There was one of the several departments in Enoch's laboratory headed by Maurice Karnough who was attempting to work as general analytical consultant to the Labs. He lacked the confidence of the people he sought to serve, and there were some bad feelings within his department, some underhanded rivalries between some members, who indeed sought to undermine the department head's (Maurice's) authority. The situation was very sick, and was seen to be so by our vice president for research, Bill Baker. I guess I helped with the disbandment of the group, but nature deserves most of the credit. Earnest Kimme was encouraged to leave, and Maurice eventually got the message and went to IBM, where I think he prospered. They were both very bright energetic people but were caught up in impossible perceptions of each other and their environment. I transferred four of the group to Wintringham's TV research (Brainard, Candy Rubinstein and Rawlins) where they made good relations and prospered, adding a lot of strength to that group. It was grevious to me, and I sometimes think I could have done better.
Enoch was responsible for Research Drafting, a drafting organization which had been divorced form Central Drafting 30 years earlier when it was necessary in order to give some independence to research, free from domination of development priorities. It was an oddity no longer needed and a diversion of research management talent, (mostly Enoch and me) but some people held onto it jealously. It took me two years to get the drafting group reassigned to the plant department, Central Drafting, and I never heard any complaints about the change after the fact.
Reconstructing the Television Research department was tough. It was headed by a wonderful man, Bill Wintrigham, with a long history of accomplishment, but it had been emasculated by in recent years. It appeared to me that Ed David had split the department into an Acoustic Research group, which he favored, and left the poorer talent in TV, which department he had traded off to the Laboratory directed by Deming Lewis. The department, as I inherited it, had one clever and inventive mid-career person, Frank Mounts, and several good but not brilliant aides having good backgrounds and experience with vintage TV. With the people I moved from Karnaugh's department, and eventually the addition of Enloe and Hempstead from Electronics and Radio research, we eventually had a formidable department working on video research.
There were several clever technicians who could repair TV's, having grown up with the field. Wintringham was not appreciated by our upper management, and he needed all the support and encouragement that I could give him, mostly by recruiting some new talent. I recruited Lou Enloe and Chuck Hempstead from Radio and Electronics Research, my old Labs, and they did most of the rest. When Wintringham retired, Enloe became Head.
One of my first experiences with the new responsibility was a telephone call from a VP of AT&T asking me to send Art Murphy to his home to fix the TV that the company had supplied him a few years earlier (when it was deemed that AT&T management should be familiar with the new medium). Evidently this service was customary, but I quickly responded "We don't do that any more." That was brazen and I was a little scared, but nothing happened. I guess I set a new precedent because I was never again asked for any such favors by our Brass.
The biggest difficulty was getting salary support for some unappreciated talent. I had to stimulate some to find other employment in other parts of Bell Labs, or outside. One talented young technical aid came to me with a fresh college diploma and asked me for promotion. In recent merit reviews he was compared with, and came out below guys with 30 years experience and there was no way I could see him being appreciated for his talent directly in my part of Bell Labs. I told him to explore the recruiting market, and gave him the best recommendations possible. I hoped he would stay because I felt that his potential was way ahead of the more experienced competition and he eventually would prosper and we needed him: but he got a good job as a sales rep for a local company. He came back several times to thank me for the push.
The TV group had a young associate MTS (Debner) working on frame repeating. He had a system working sporadically, but it was so haywire that it only worked on prime number days of the month. It was a great project, and I put a couple of clever engineers, Ralph Brainard and Frank Mounts, on it, who engineered the system into what grew to be, eventually, conditional replenishment and predictive coding. They produced some dozens of patents leading to what is now HDTV. Their work created the heart of the next decade of progress. I encouraged Debner to return to school, and I think he did well.
Cellular (Mobile) Radio
Cutler:
Cellular (mobile) radio was another activity I was responsible for.
Goldstein:
When was that?
Cutler:
- Audio File
- MP3 Audio
(160 - cutler - clip 3.mp3)
Same time period, around 1962 to 1978. When Pierce and Kompfner got these new groups, there was another they didn't know what to do with. It was a small group working on mobile radio. "Is there any future to it?" I was asked, "Should we disband this group or should we encourage it to go ahead?" It was a rather desultory group, it had one good engineer in it — Luke Schimpf. and a brilliant department head: John Johanessen. I was director then. The department had mostly a bunch of radio hams who knew how to build things but were not innovative. And they were weak analytically. It seemed to me there was great promise in some of their ideas, however.
Mobile radio in the field as operated by the telephone company, I learned then, was supersaturated, you could buy a car radio and put it in your car. You would then share one telephone line with fifty other people, you almost never could get the line, because there was always about fifty customers sharing one radio link. The service would lose a customer after a couple of months, but there was always a backlog of other people who wanted that circuit. Even so, the service was not profitable. The company did things to improve it, to get more band width and so forth, but the service was fundamentally limited — flawed. Customers who could afford to installed individual private (radio) intercom circuits (taxis and police for instance).
But here was this cellular idea, where you could use the same frequency over and over and over again, spacing it geographically. It was a very different way of handling things. An awful lot of work, measurement work and analysis had to be done, circuit design work, to use the frequencies efficiently and so forth. It just captured my imagination. I was still deeply interested in radio anyway. So I said, let's go with it, and I went out and did some recruiting. Johanneson had an opportunity to go into switching, a promotion to Director, and he jumped at the chance. So I got Bill Jakes to come over from Crawford Hill (Radio Research, satellites) to head that department. He was the fellow that mastered the satellite radio stuff (Project Echo) for us. And he did a marvelous job of pulling the mobile radio department together, hiring some new people and setting new objectives.
About difficult decisions: Jakes hired a young fellow from Ohio State, Chinese, who was very, very clever, got wonderful grades and so forth. We gave him a job to do. It was an invention of John Pierce's, — field energy reception, a diversity antenna — to analyze, do experimental work with. He latched on to that and managed it, wrote some good papers on it, made some measurements, did some fine work — but he couldn't write English! He had no grammar at all. I've known some Chinese that could write wonderful English. But he couldn't write English, he couldn't speak it so you could understand. I had a paper from Lee come to my desk. He wanted to publish the paper but it was unreadable. I took it back to Bill Jakes, I said, "Jakes, you know, you've got to help this fellow" He says, "I've been over this paper three times already, that's the best I can get out of him. I wash my hands of it."
So I red-penciled the dickens out of the paper myself and went through it with him three or four times, finally got a paper that was halfway readable, and he published it. This went on for awhile. He was a wonderful young fellow. But, how do I get rid of him? He's too good to fire but not likely to prosper in Research. If I put him out on the market, how's he ever going to find a job? He can't express himself. One time, in exasperation, I said, "You don't have a career. You don't have a technical career unless you learn how to speak and write English." I said, "I saw an ad in the paper the other day. There's a Dale Carnegie course in public speaking being done over here in Red Bank. Why don't you go take it? I can't ask you to do that, you know, but it would be a good idea to do it if you want to." He came in two weeks later, "I love it! They gave me a prize for the most improvement!" He not only took the public speaking course, next thing I knew, he had enrolled in the Toastmasters' out-of-hours Bell Labs Club.
Eventually, the FCC gave permission to go ahead on cellular radio. The development department picked it up, research moved out of it. I sold Bill Lee to the development people. They sent him out to Indian Hill to work on switching, and computer-type programming for the mobile radio thing. He threw up his hands. He couldn't do it! They moved him back to Murray Hill again. He worked with them for awhile, it was not a very good fit. Next thing I knew, he'd gotten a job outside, he was working for IT&T. A little after that, I found, he was working for PacTel, Pacific Telephone company, as vice-president. He gave a paper down here, last week. I went to hear it.
Now, you'd think this guy might be mad at me. I came into the auditorium just as they were beginning — People were milling around, picking up Xerox copies and view graphs. He started talking. I sat in the back of the room, there were about three hundred people, there. He said, "I want to tell you first about a wonderful experience — I couldn't have done this work if I hadn't had the wonderful experience I had at Bell Laboratories. I've got to tell you about my old boss." And then he proceeded to praise his old boss to the sky and then said, "And he's right over there."
One of the hardest things I did was to get rid of that fellow. But I did it in a way that found him a path to the future. He's vice-president of Pac-Tel! I can't get over it! And he speaks very intelligible English, he gives a Dale Carnegie-type talk. He stands, he faces the group, he uses hand motions, he speaks clearly, he lets people interrupt, he picks up where he left off when he has answered their questions. He wouldn't go to Congress, but as a technical talk it's much better than most I've heard. Two of his books are there on my shelf. He's written a couple of books on mobile radio. That blue book with "MOBILE" on it, that's his book.
Goldstein:
What's his name?
Cutler:
William C. Y. Lee. I've had a few experiences like that, where I saw that people didn't have a future in research, but were too talented to just throw out, and whom I helped find a job. I probably had to part with some thirty, forty, fifty people at one time or another, who really didn't have their promise in research but really were talented people. You don't throw them to the dogs. I have a very clean conscience on that. That answers that question. Yes, I did face some serious challenges and hard decisions,
Satellite Communications and Telstar
Cutler:
Back to Satellite communication. In 1955 Pierce wrote a wonderful introductory paper on the potential of using earth satellites for radio communication relay, but few people took it seriously, until ... . The Russian satellite, Sputnik, went up and it became obvious we should be doing something. It sort of fell upon me to try to get some activity started in Research. I got my people in together: what can we do? Well, we can measure the signal. So we tracked the signal as Sputnik was going over, and we measured frequency, direction and signal strength, and related it to orbital constants. We did lots of brainstorming. Pierce and Kompfner, and later Tillotson and Cutler went to NASA and JPL to learned what we could about what others were doing in satellites, and began to theorize. How would you — what kind of geometry is involved here? transmission, attenuation through the atmosphere, at high-altitude things and so forth. So we just began to calculate path geometry and attenuation while hypothesizing systems. Roy Tillotson, who was at Crawford Hill, and Rudi Kompfner and I, had some serious bull sessions. When we learned of NASA's plan to put a 100 foot diameter balloon in orbit to measure atmospheric drag, Pierce had the idea of using the balloon to reflect radio signals, making radio relay across the continent without having to put active repeaters in orbit. We started an ad hoc group to learn all we could about components one might use in an active orbiting repeater. We had biweekly meetings of a group of people from all across Bell Labs, asking, "What would you design for a satellite, for an active communication satellite?" At the same time we were working on ground stations for an orbiting repeater satellite. We latched onto Bill Jakes, — this was before the mobile radio stuff — to lead a group, and we proceeded to design ground stations and make measurements. I was young enough and eager enough so that not only did I supervise Bill Jakes, but I worked for him. Bill, at one time, had probably fifty people around the Bell Labs working for him on a passive satellite repeater system including people from several levels of management. It was a temporary appointed position: He was still classified as an MTS, member of technical staff, without any official management responsibility. But he was the project leader for the Project Echo activity, and he did a wonderful job. At one time, Pierce, Kompfner, and I, three levels of management, were there in the building when the satellite was about to come over the horizon. Bill Jakes says, "Satellite's coming up — everybody out that doesn't have a job to do!" Pierce and Kompfner obediently went out the door. — I grabbed some knobs and looked busy. I had a job to do, I ran the tape recorder and took notes. I was very happy about that. It was a very exciting time.
Goldstein:
When you, Pierce, and Kompfner were talking about it informally, can you recall any debates — different ideas about how to handle this job? I'm trying to get an idea of the conversations that you had, the ideas that you mulled over, and how these disputes were resolved.
Cutler:
I can't think of any disputes.
Goldstein:
"Disputes" is too strong of a word.
Cutler:
No, no, I know what you mean. We reflected off from each other. Somebody would come up with an idea, somebody else would say, here's a better one, and we'd shoot that down and go on to the next one. But all of us were very enthusiastic about low-altitude reflecting satellites. It seemed like the active satellite was beyond the technology at the time and that we should work very hard at developing the technology while we proceeded with the passive satellite, Project Echo. So we had this ad hoc group looking at solar cells and batteries and amplifiers and modulators and everything that you would use in an active satellite: Calculating orbits, transmission, and all that sort of thing. But at the same time we were working on ground stations and collaborating with JPL at Southern California and NASA, to put this whole passive repeater system together. But it was a collaborative, cooperative effort, when somebody had an idea, the rest of us would act on it.
Goldstein:
I guess what I'm thinking is that if there weren't differing views on how to do things, it seems like the alternative is that it was sort of self-evident, and that seems hard to believe.
Cutler:
It was more self-evident than you think. We needed low-noise amplifiers. Rudi Kompfner came back from development, he says, "You know, they've got this Maser amplifier, a three-level Maser amplifier, if we could use that." Now I probably put some resistance to that, because experimental things in the laboratory are haywire, heck, how are you going to make the Maser work on schedule? But I was easily convinced that the Maser had the promise of being much better than any alternative, and that we could use more conventional circuitry for back-up. And the people in the research area working on the Maser were very enthusiastic about doing it. I was — I stood back, sort of appalled, because it was beyond my comprehension how this thing worked. But they made it work. Biggest conflict I had was with one of the engineers Ed Ohm, when it came to publishing when Echo was done. He wrote a very self-serving description of how things were done. He had to be talked into crediting other people adequately.
Later, on another level, the same kind of thing happened. When it came to the final report for publication in the BSTJ of the research contribution to Telstar we wrote, which I thought was beautifully descriptive of everything we did; people in development were very upset with us. They put their best diplomat to work, to work on Cutler, to see if something couldn't be done about it. And he used his diplomacy, and he used his diplomatic skills well. That was Gene O'Neill. I never saw a better diplomat. He convinced me, we in the Research department should back off and not try to claim so much for ourselves. That was the nearest thing to a conflict — Oh, there was one area where there was — which wasn't within — The three of us, you know, we agreed very much. We saw alike, we worked together, that was part of our wonderful activity, that we could see each other's point of view and never really got into an argument. Lots of discussion — let's try this, let's try that — but when it came to a conclusion, we always agreed. Someone listening might think we were fighting, loud, excited voices, but indeed it was a wonderful companionship.
But there was a question of what we would use for a tube in Telstar. We wanted to use the traveling wave tube. The people in the development area working on traveling wave tubes, Ken Poole and company, they were very enthusiastic, as part of this committee activity that I mentioned before. They had worked up a traveling wave tube design just for Telstar. But there were people — Jack Morton's people-wanted to use the triode. They had good arguments for using the triode. There was another group of people, in Systems, that wanted to use the Klystron. Boy, there was a real hot argument about this whole thing, you know. And here are these three strong groups, pushing their thing. I think the other two groups are totally unreasonable, they weren't listening to reason at all: and they thought the same of us. It was an impasse. Finally, on a Saturday morning, Julius Molnar got us together at Murray Hill to hear the whole thing all the way around. And I guess we probably spent six hours there making our cases for the amplifier. But Julius, who was executive vice president, had to make the decision. He made the right decision. But that was the biggest kind of a conflict I guess I ever got into at Bell Laboratories. No one was angry but there were strong opinions. I don't think anybody called anybody names.
Goldstein:
No, well, I wouldn't have expected that. Even on a technical level.
Cutler:
It was on a technical level, and we parted friends. We parted — I don't think any of us were particularly upset about the decision that Molnar made. But Molnar had to make the decision. We could not agree.
Goldstein:
What were the technical arguments against the traveling wave tube?
Cutler:
High voltage. It takes a big heavy magnet, and so forth. The Klystron wasn't too different. The Klystron is more efficient, we didn't need the total band width, this was a telephony not a television experiment, mostly.
Goldstein:
Well, they did do a television —
Cutler:
Oh yeah, they did television too. But they could have made a Klystron that would do the television adequately. And of course the triode was in mass production, but the triode was not a very efficient tube and it didn't have much life. It didn't have the reliability. But it was lower voltage, you didn't have the problem of — you know, you're in a vacuum, and if any of those electrodes get exposed to the vacuum, you get an ionization breakdown and so forth. There were weight problems against the traveling wave tube and so forth. I don't know, I can't think of all the arguments now. But they were strong. I'm trying to think of differences that we would have — Pierce and Kompfner, and Jakes, he was much in on this, too.
Goldstein:
I guess one thing that I'm trying to get at when I am asking about differences of opinion is a search for ideology influencing somebody's technical judgment. It sounds like the different groups were actually just partisans for the technology that they were closest to. And then, you know, arguments follow from that prejudgment. That's what I was curious about.
Cutler:
I think we had a very unusual group. I've been in lots of other groups, but this bunch, (early on, with Quate), was almost unique. First it was Pierce and Quate and Cutler, then Kompfner joined. Pierce sort of moved out into management. But that group — that group of four people was a phenomenon, as far as I'm concerned. Just one of those godsent — things that just doesn't happen very often. It just happened to us and we were so fortunate. I admired those men so much that I probably couldn't disagree with them seriously. And they respected me. We bounced ideas off of each other, if a guy had the best idea, the rest of us accepted it and were proud of it. It wasn't like one of these things — this is my idea, I'm going to hold onto it. I knew people like that. I had an engineer who worked for me at the start of the laser stuff. And he was in at the ground floor, and he had this long list, he shared with me these wonderful ideas that he had, things that he was going to work on. I said, "Look, we've got some new people here, can't we get so-and-so to work on this?" "No, no," he said, "I'm going to do that myself. No, no, I'm going to do that myself." He wouldn't share his ideas. As a result, they got reinvented, and he got nothing out of it to speak of. He wasn't willing to share his inspiration.
Reflections on Colleagues at Bell Labs
Goldstein:
We are going to have to wrap up. But I wanted to give you a chance to fill in some big stuff that I may have overlooked. Is there anything that you think merits treatment?
Cutler:
One of the unusual things about the group I am telling you about — Kompfner, Pierce, Cutler — never stopped doing technical work. A lot of management gets taken up with their management responsibilities and don't have time to think about technical things. They may glory in what their fellows are doing and so forth, but to go on and do innovative things, innovative experiments or analyses of their own, is unusual. An awfully important part of our relationship was that none of us were selfish. Pierce was very happy to have a wonderful idea, work up what he could on it in a hurry, and give it to somebody who would pick up on it and run. There were dozens of people that that worked with. There were a lot of people like that in Bell Labs. The fact that they developed this expertise without a destructive competitive spirit — here is an anecdote about that. I was invited to give a talk in South Carolina, and there was Bill Kefover from the patent department on the same program. He gave a talk about patents in Bell Laboratories, and studies they'd made. One of his anecdotes was, "The patent people one time made a study to find out what is responsible for innovation? What do people who have been so inventive have that characterizes them? We studied them for to find what made them different. We couldn't find anything common in religion, we couldn't find anything unique in schools or education — although they generally came from better schools, they came from all over the place — and, oh, color of hair, background, all these things. The only thing we found that seemed to be common amongst Bell Labs innovators was: most of them had had breakfast or ate lunch sometime with Harry Nyquist."
Nyquist was a father to a lot of guys. I had had lunch with Nyquist. I'm sure Pierce did. I'd be very surprised if Kompfner hadn't. But Nyquist was one of those men like Harald Friis that drew people out. It might have been Friis, of course instead of Nyquist, but the story was Nyquist. And it's a good point. Nyquist was full of ideas, full of questions. He drew people out, got them thinking. There was a lot of that going on at Bell Labs. And part of the competitive thing — if we had been — Well, just after the war, I was put on a committee by Ralph Bown with three other people, there were four of us. And we were to go around the laboratories and talk to people and see what might be done to maintain and favor productive activity in research. They fed us some questions, and then we went around and talked to people. Questions like: should there be a monetary reward for patents? How about publication? I forget what all the questions were. But we went around and we talked to people like Nyquist — that's probably why I had lunch with him — and a bunch of other people, and came up with lots of questions, and we wrote a report. We put it on pink — pink paper, preliminary memorandum for criticism and suggestions — and gave it to our bosses for comments. Later — I kept waiting for this thing to come out in final form and get circulated — it never did. But Ralph Bown said "that was a wonderful report, it's been read widely, we're acting on it, you can be sure that this was very much worthwhile, but don't expect us to publish or circulate it. It was for our help." Barney Oliver was on the committee — do you know who he is?
Goldstein:
Sure.
Cutler:
Barney, Win Kock, whom I mentioned before, and Warren Tyrrell, who was assistant to the president for many years before he retired, (We were the young, eager pups — about thirty years old) — we went around and talked to all sorts of people. It was a wonderful thing, wonderful thing for us, because we got all these viewpoints, and that's when I really became aware of the management style that was responsible for the kind of environment I was in. If we had been awarded a hundred dollars for a patent, it would have been much easier for us to hold onto our ideas and get destructively competitive. As it was, when you'd mention some idea to a guy like Pierce or like Kompfner: "that's a wonderful idea! Have you thought of this?" And you may end up with joint patents.
Oh, I'll tell you another anecdote on that. I did a study of electron beam focusing, trying to understand better how this electron beam acted in a traveling wave tube. And I made an analysis, which turned out to be pretty good. I had help from the math department — I couldn't have done it without drawing on those people. They were always anxious to help. It was real good and I put it out in memo form. Then I discovered that Marion Hines over in the development area had done a similar thing using computer analysis
Goldstein:
Is it that rubber sheet?
Cutler:
No, no, I think was a very early digital computer. But anyway, he'd done a similar thing. He hadn't come up with a mathematical description, but he'd worked out some relationships that the computer could handle. The computer came out with big sheets of numbers. And he hired half a dozen high school girls — maybe college girls — in the summertime, to translate, to plot all those numbers on a giant graph. Laboriously, he drew these massive curves that showed the electron flow. My equations agreed with his curves. He came to my office, he says, "Hey, that's wonderful, the thing you've done. Between my curves and what I've got and what you've got, we have got a wonderful paper. Let's not publish separately, let's publish a joint paper." Oh, I said, "Go away! My thing stands by itself!" But we talked awhile, and he went away, and I thought more about it, decided, that's the right thing to do. We published a joint paper. As a joint paper, it's a wonderful paper. It's been quoted and used all over the place. As separate papers, they couldn't have been worth much. That was a collaboration that was forced on me, almost forced on me, not by management, but by Marion Hines, who was persuasive and had a right idea. I didn't want to give up what I had because I thought it stood by itself. But combining our contributions was much better; we emerged great friends.
Goldstein:
You have talked about short wave radio (Self Neutralized Amplifier), microwave antennas (the Cutler Feed, Corrugated Waveguide), microwave amplifiers (Regenerative Pulse Generation, Mode Locking), television coding (DPCM, Conditional Replenishment), satellite communication (ECHO, TELSTAR), special people and management. That covers a lot of ground. Is there anything more about your experience at Bell Labs that we should include in this report.
Cutler:
No much, I guess, but I wish I had the time and energy to expand on all of those matters. To me, being party to the revolutionary activity in lasers, and fiber optics, and digital computers also was a wonderful blessing. My contribution in these areas was in management, and in recruiting. I should say privilege rather than contribution. I was in the midst of the swirl of a huge revolution in technology that has impacted every aspect of civilization, and nothing could be better than that.
Retirement and Stanford
Goldstein:
You retired in 1978 from management responsibility in most of those areas and also switching research to go to Stanford. Was that an early retirement, and why to Stanford?
Cutler:
I retired at 64, one year early because the rules at Stanford would not permit appointment as "Full Professor" at age over 64. I sent my resume' to Berkeley too, but Stanford made an offer right away. I worked with Cal Quate, Marvin Chodorow and John Shaw there, mostly on microwave acoustics fiber optics and the fiber gyro. The only patent royalties I ever received were from Stanford patents! I was at Stanford for 18 wonderful years, with a brief interlude at Cal Tech, associated with Bill Bridges and Amnon Yariv. I worked with graduate students in the Department of Applied Physics, mostly, advising on their research projects and undergraduate student advising. I did a modest amount of consulting for outside firms, and did some writing. The students were no older when I left than when I came. Nor was I. It was better than being retired.
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