# Oral-History:Leonard Thomas Sr.

Leonard Thomas

Leonard Thomas, Sr. was born in Birmingham, Alabama, and enjoyed working with radios as a boy. He received his B.S. in electrical engineering from Alabama Polytechnic Institute in 1931. After college he worked with a wholesaler for Philco radios and then became an engineer with radio station WAPI in Birmingham. In 1939 Thomas transferred to radio station WJSV in Washington, D.C. In 1942 he joined the war effort and went to work for the Bureau of Ships. Thomas spent two decades with the U.S. Navy, focusing on transmitter and receiver interference problems. He developed technology to reduce and eliminate electronic interference in Defense Department equipment, and helped write the national standards by which future apparatuses would be built. Thomas' suggestions were instrumental in the construction of the SPS10, and interference-free radar system. After World War Two he became the first U.S. representative to the International Special Committee on Radio Interference (CISPR). In 1960 Thomas went to work for the U.S. Department of Defense, in the Electromagnetic Compatibility Analysis Center (ECAC), where he reviewed frequency assignments and studied interference problems. After retiring in 1970, Thomas began working as a consulting engineer. He was very active with the IEEE Electromagnetic Compatibility Society and authored many technical papers. He is an IEEE Fellow and recipient of the IEEE Standards Medallion and the Lawrence J. Cumming Award.

The first part of the interview describes Thomas' childhood interest in electronics and his education at the Alabama Polytechnic Institute. Thomas discusses his years at WAPI and WJSV radio stations in some detail and then focuses on his experiences working with the U.S. Navy. The interview covers Thomas' work with electronic interference reduction and examines his years spent with the American National Standards Institute, CISPR, ECAC, and the IEEE Electromagnetic Compatibility Society. Thomas concludes with discussing his publications, awards, personal papers, and early electronic devices in his possession.

LEONARD THOMAS SR.: An Interview Conducted by Frederik Nebeker, IEEE History Center, May 6, 1993

Interview # 153 for the IEEE History Center, The Institute of Electrical and Electronics Engineers, Inc.

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

Leonard Thomas, Sr., an oral history conducted in 1993 by Frederik Nebeker, IEEE History Center, Piscataway, NJ, USA.

## Interview

Interview: Leonard Thomas Sr.

Interviewer: Frederik Nebeker

Place: Washington, D.C.

Date: May 6, 1993

### Childhood and Early Interest in Radio

Nebeker:

This is May 6, 1993, talking with Leonard Thomas. I am Rik Nebeker.

Thomas:

I always use the "Senior" after my name, because I have a son who is "Junior" and he is a member of the IEEE too. He also went to the same college I went to, and I always designate the "Senior" to keep from getting it confused.

Nebeker:

All right. Is he also active in IEEE?

Thomas:

He sure is. He is a senior member and he is working at Robins Air Force base in Georgia, Warner Robins, Georgia, where he is an electronics engineer. Well, I just wonder, what would you like to know?

Nebeker:

What I thought we could do first, if it is okay with you, is review your own career and then talk more generally about electromagnetic compatibility. I am also curious about your upbringing and education. I read that you were born in 1909 in Birmingham. What electricity in the home was there when you were a boy?

Thomas:

Not much. We had in the home in which I was born, 110 volt knob and tube wiring which came in from the outside. It was distributed throughout the house. Wires came in from the center of the ceiling down to a socket with a light-bulb on it. There were no wall switches.

Nebeker:

Was that the only use of electricity in the first years?

Thomas:

That was about it. That was the only use there was, just for illumination. And then of course, as time went on, electrical things came in use such as the electric iron and the electric refrigerator.

Nebeker:

Do you remember when your family got those things?

Thomas:

I remember when the family got rid of the old ice box for an electrical refrigerator.

Nebeker:

When was that roughly?

Thomas:

That was in 1934.

Nebeker:

I see. So you didn't have a refrigerator in the home when you were growing up.

Thomas:

Nebeker:

You had an ice box. Didn't they have a kind of electric ice box with a fan that circulated? I think there was an electric ice box before there was really a refrigerator?

Thomas:

Right.

Nebeker:

You didn't have that yourself?

Thomas:

No. We had the old ice box; you put in a fifty pound chunk of ice.

Nebeker:

How often?

Thomas:

It depended upon how big it was, how much you had in the ice box, and how often you opened the door. The ice man came around every day and you had a sign which you put up in the window. If you wanted fifty pounds today, well you put the fifty sign up to show it. If you only wanted twenty-five pounds, you posted that amount wherever it was shown. He would know what to bring in. He brought it in on hooks and put it in the ice chest in the kitchen. Of course, then you had underneath a drip pan.

Nebeker:

So you didn't have a radio in the 1920s era at home?

Thomas:

I fooled around with crystal sets and I can remember my first vacuum tube set that I constructed myself using the old WD11 radio tube.

Nebeker:

Is that an RCA?

Thomas:

Yes. Have you ever seen one of those?

Nebeker:

I don't know whether I have.

Thomas:

Well, I have a WD11 at home. The tube base, the big terminal, a big prong, was the plate and the other three were the grid and filament. I think it was a one and one- tenth volts filament. You can look in the RCA tube handbook and it will tell you; it is still listed in there too. The WD11 made way for the WD12, which has the old four-prong, two large prongs and two small ones. Then came the UV199s, and those were the tubes available.

Nebeker:

Do you know what the UV stood for? I have seen that series referred to.

Thomas:

That was the type of socket. Later it went to UX.

Nebeker:

So you built first the crystal set. Was that in your high school years?

Thomas:

Yes.

Nebeker:

Charles Townes was telling me he built one, but never got it working. Did you get yours to work?

Thomas:

Oh, yes. I had a little piece of galena for the crystal and a "cat-whisker" was put on the top of it. Of course there was the tuning device, and you wound your coil on an oatmeal box or something. I can remember those days...

Nebeker:

You actually could get several stations?

Thomas:

Sure, right. I remember the first out of town station I got was KDKA, Pittsburgh.

Nebeker:

All the way to Pittsburgh. Did you buy some kit to build this tube set?

Thomas:

Yes, I believe I did. I think Remler had some kits out or some parts, and I put them together.

Nebeker:

A one-tube set?

Thomas:

Yes. In those days you had the loose coupler, the variable coupler and the variometer. Those three things were the tuning devices, and then of course you had a condenser. In the first days, instead of the mesh plates you had the type that was a "book condenser." The two plates were varied like that. I think Crosley pioneered the book condenser years ago.

Nebeker:

When was it that you got the tube or built that tube set?

Thomas:

Probably in 1925 or 1926 or something like that.

Nebeker:

You were in high school?

Thomas:

Yes. I know I had to talk real loud in order to get my dad to put out seven and a half dollars for that tube.

Nebeker:

The tube was that much? That was a lot of money in those days.

Thomas:

I'll say it was.

Nebeker:

Probably worth ten or twenty times that same dollar price today. Did you decide in your high school years that you wanted to go into electrical engineering or chemical engineering?

Thomas:

I had two high school teachers; one taught physics and the other taught chemistry. The one who taught physics was Earl Sechrist and he fired my imagination for electrical and radio. I used to stay at high school after hours and work with him in the physics laboratory there, playing with things and learning things. He and J.R. Gardener, another teacher of mine, persuaded me to go to Auburn University in Alabama.

Nebeker:

Another question about those early radio sets. You used headphones for all those? Did you get any kind of speaker?

Thomas:

Later on the speakers came in but the headphones were the rage in those days. They were good. Those were the Baldwin Type C, and they had a mica diaphragm driven by what you might today say was a miniature loudspeaker. They were very good headphones. I think the impedance was 5000 ohms. Later on the speakers came into evidence, and Magnavox was the maker of prominence in those days. They were located at that time in Oakland, California.

Nebeker:

Couldn't you hook up a phonograph horn to a crystal set or an early set?

Thomas:

The crystal set didn't have enough output to drive anything. You could if you were ingenious connect in place of the pick-up reproducer in the phonograph, a modified headphones to drive the air column and you would get some sound that way.

Nebeker:

But pretty much people had to have headphones in order to hear?

Thomas:

Yes, right. That is, until amplification became available.

Nebeker:

You told me on the phone, but I have forgotten. What was Auburn called in those days?

Thomas:

Alabama Polytechnic Institute, API. Hence the call letters for the radio station which at that time was located in Auburn, Alabama — WAPI.

Nebeker:

I see, and that was one of these university or college stations.

Thomas:

WAPI was located in Auburn. They decided to transfer it in about 1927 or 1928 to Birmingham, Alabama. It was supposed to be jointly supported by Auburn University, which was then Alabama Polytechnic Institute, the University of Alabama in Tuscaloosa, and the Women's college in Montevallo, together with the city of Birmingham. That was a four-tier arrangement, but times got hard and money was scarce and then the station was sold to private interests.

Nebeker:

I see. It kept the same call letters?

Thomas:

WAPI. It still had those call letters. When I got out of college in 1931, there wasn't any work anywhere. So, I finally got a job in 1931 repairing radios, and that lasted until the work gave out. Then I got another job installing radios in automobiles. I got a magnificent sum of $5.00 a week and that was my pay. Now, my pay before that, the job that petered out, was twelve dollars a week repairing radios. The place I worked at was the wholesaler for Philco radios. I became very familiar with the Philco line, and I still have a lot of the training manuals at home right now of the Philco radios vintage 1927-1930. Nebeker: Is that right? I talked with Harold Wheeler who was at Hazleton Corporation but designed some of the circuits for Philco radios, perhaps the first of the Model 95. I am forgetting now. The first one with automatic volume control that came out in 1929, a big seller, a big success. Philco became the leader very soon. Thomas: Philco came out when the RCA patents expired on the superheterodynes. They came out with Models 70, 90 and 111, all three superheterodynes. I know; I have repaired them, worked on them. ### Alabama Polytechnic (Auburn University) Nebeker: Before we get into that work experience, I would like to hear something about your college years. So this high school physics teacher inspired you to go into electrical engineering and go to Alabama Polytechnic? Thomas: Yes, he did. So I went down to Auburn, Alabama. The town was built around the college. I am very close to Auburn, now Auburn University, because my son-in-law is the Assistant Dean of the College of Veterinary Medicine at Auburn and my oldest daughter lives there. So I visit there quite a bit. Of course, I am very familiar with people in the faculty of electrical engineering and so forth. Nebeker: So you started in 1927, was it? Thomas: In 1927. I graduated in 1931 and knew from the beginning that I would study electrical engineering. That was the course I took; EE was my major. Nebeker: Was it mainly an engineering university, the Institute? Thomas: No. Auburn University, according to its name, the Alabama Polytechnic Institute, had a very strong engineering school. They had a strong agriculture program, and for being a technical school, had a very ambitious education program in the liberal arts. They taught architecture, civil engineering, chemical engineering, foresting and things like that, and veterinary medicine. So I became acquainted with all of those people there. The first year I was at Auburn, I stayed in a boarding house, and the price for room and board, was twenty-eight dollars a month. That is really something. I got acquainted with many, many people there and in addition to my studies I became interested in music. I sang in the glee club, the church choir and things like that, and I enjoyed all of it. Nebeker: You said on the phone that there was some option for a radio engineering program? Thomas: That was one of the minors and I took all I could get in radio engineering, all the course had to offer. There was another course called telephone engineering, and I took that too. There was no such name as "communications engineering" in those days; it was radio. Nebeker: I think it is very unusual for API to have had a minor in the late 1920s in radio. I think in a lot of schools it wasn't really taught. Thomas: The professor of radio engineering in those days, I think, was Woodrow Darling. He was a good teacher. ### Installing Philco Model 4 Car Radios Nebeker: The radio industry was growing fast in the late 1920s. Thomas: It was. When I got out of college in my job installing radios in automobiles, in those days the installation of the radio in an automobile, consisted of a Philco Model 4 which used six volt tubes, which operated off a six volt car battery. For the high voltage for the plate, you installed three forty-five volt big “B” batteries in a box and drilled a hole in the floor pan and hung that in there and ran the leads to the radio. Nebeker: That was pretty early for car radio. Thomas: It was. A Philco Model 4, one of the first ones. Nebeker: Do you remember what it cost in those days, the radio in the car? Thomas: No, I don't remember. Nebeker: It was probably an expensive option. Thomas: Oh, yes, it was. It was usually in new cars. Another thing I had to do was take down the head lining on the inside and put in some screen wire to be used as the antenna and run the lead down through the windshield posts to the receiver. I had to learn to take down the car head lining and put it back so that you couldn't tell that it had been removed. Those were the days before the solid steel top on the automobile. They were of fabric. Nebeker: It had some frame there. Thomas: Yeah, right. Nebeker: How long did you continue with that work? ### WAPI and Early-1930s Radio Thomas: Well, that lasted about six months and then I was out of work again because times were getting bad. So then I finagled myself into a job with radio station WAPI. Nebeker: Had you had any contact with them when you were at API? Thomas: Very little. But they moved into Birmingham on the top floor of one of the buildings there, and I got my start there as an operator, as they called it in those days, running the controls, volume and so forth and changing recordings. Records were 78s and then along came WBS 331/3 rpm long- playing recordings. Nebeker: When did that come around? Thomas: About around 1932-1933. WBS was a product of the Western Electric Company, and they called it the World Broadcasting System. The recordings, of which I have some home even today, would last about fifteen minutes. Nebeker: I read in this book you may have seen, called Of Mikes and Men by a woman who worked at small Portland, Oregon radio station in 1930-1931. It is the story of that small-time radio station and that was a period when it was still thought (I think it must have changed rapidly) that most programs should be live. They didn't play a lot of recordings. Do you remember that? Thomas: I do. Nebeker: They were going more and more to recordings. Were you involved in the business side of trying to get advertisers for the station? Thomas: No, but I knew the people who were. The time was so bad that we were selling spot announcements for fifty cents each. Nebeker: This woman writes that they often bartered their announcements for some product, because it was so hard to sell advertisements. Thomas: I know, I know. There was another thing while I was working at the radio station. We used to have what we called "pick-ups." The pick-up was a remote broadcast, say from some source of music. We had two pick-ups regularly at WAPI. One was the Del Monte Cafeteria and the Thomas Jefferson. Nebeker: What was that? Thomas: They had an orchestra on the balcony which played during the evening dinner hour. Then on other days at the big Thomas Jefferson Hotel, they had an orchestra there too. We had a pair of phone lines going on down to each of those places and I would take the remote control equipment which was "portable". They weren't really portable. You got to figure who said they were portable. The "portable" remote control equipment consisted of two great big suitcase-sized devices. One was the pick-up, the preamplifier and the mixer; the other was the amplifier to connect to the telephone lines. Both of them had quarter-inch steel panels and they were heavy; about forty to forty-five pounds apiece. I went lugging those things into the remote control places. Nebeker: How reliable was that equipment? Thomas: Well, it was very reliable because it was made by Western Electric. The definition of "portable" according to Western Electric was, "If you had a handle on it, then you could lift it." Nebeker: If you were strong enough. Thomas: Yes, if you were strong enough. It was really a job to carry both of them, one in each hand. Nebeker: Stations then were regulated in the power with which they could transmit. Thomas: That's right. Nebeker: Were you involved in checking that you were up to power or not exceeding it? Thomas: Yes, I used to work a transmitter two, so I knew what that was like and you couldn't go over the power. WAPI was licensed to transmit 25KW. The max in those days was 50KW. But we were restricted at 25 because in Charlotte, N.C. there was another station on the same frequency and we had to transmit at a lower power to keep from interfering with them. Nebeker: In those days you didn't have the directional antennas. Thomas: But later on, they did. Nebeker: How long did you work at WAPI? Thomas: Until 1939. ### Transmitters and EMF Nebeker: Did the station do okay in those years? Thomas: When I first went to work there, the control equipment, the master control, consisted of Western Electric equipment. They had the Western Electric Amplifier which had the mixers on it. Then they had another amplifier which was a 17B and that went to the transmitter, which was about fourteen miles out into the country. Nebeker: Is that right? Thomas: On top of a hill called Sandusky in those days. I used to work out there too. Nebeker: Is there anything more that you can tell us about that? It sounds like you probably had some interesting experiences in those years, at that radio station. Thomas: Audio File MP3 Audio (153 - thomas - clip 1.mp3) At the transmitter in those days, everything was vacuum tube and the source of the high voltage was rotary machines. They had a double-ended two commutator DC generator, two thousand volts on one armature and commutator, and two thousand on the other end. Put them together and you had four thousand volts. It was driven by an AC motor. They were off in a room, to one side and I can remember working on that transmitter. It was very, very interesting. The towers were right on the outside, and of course, I was within the field of the towers. As an aside I get rather interested in the present concern about the effect of electromagnetic energy on people. I worked for years and years in the transmitter in Birmingham and it hasn't affected me. Then I transferred in 1939 from Birmingham to Washington D.C. I went to work for the Columbia Broadcasting System at radio station WJSV. JSV were the initials of James S. Vance, the owner of that station. At the time I moved here it was located in Alexandria and I worked the transmitter down there. I also worked on the construction of the new transmitter in Wheaton, Maryland, which was a 50KW job. That was located next to the towers, which were directional, and we had to transmit at nighttime in a directional pattern because a station in Tulsa, KVOO, had the same frequency. They broadcast directional with the null in our direction just like we did with the null in their direction. That was changed from general coverage to directional at sundown. Nebeker: That's because the broadcast range increases at sundown...There would be too much interference. Thomas: The propagation characteristics, right. Nebeker: So you'd have a certain configuration of the antennas and then switch it at sundown. Thomas: I get rather interested in this present concern over EMF, figuring, "Well, look. I have worked for years and years at transmitter stations, and it hasn't harmed me." Nebeker: And those fields were much higher than the ones they are now talking about. Thomas: I was in fields of volts. I mean volts, plenty of them, because we measured them. I am the proud father of two girls and a boy, and all of them are healthy. ### WJSV and Arthur Godfrey Nebeker: How is that you got the job in the Washington area? Thomas: My former chief engineer in Birmingham... Nebeker: How many engineers by the way were employed by WAPI? Thomas: Probably about three or four. The chief engineer at that time was James L. Middlebrooks. I don't know whether you have ever run across him or not. He was there in Birmingham, and he got offered a job with the Columbia Broadcasting System in New York as chief construction engineer. He took it, and I was still working with WAPI. One day he called me on the phone and he said, "Hey. I got a job for you." I said, "Where?" and he said, "Washington D.C. Come on up here." So I hopped on a train and came up here, and met the chief engineer, Clyde Hunt of WJSV and got the job. I moved my wife and daughter up here, couple of months later, and have been living in Washington ever since. James L. Middlebrooks was a very close friend of mine. In fact, my oldest daughter Dorothy is named after his wife Dorothy. Nebeker: Were you doing the same sort of thing with WJSV that you were doing earlier? Thomas: Working the transmitter, master control and things like that. When I was at master control I used to put Arthur Godfrey on the air every morning. He was certainly a fine gentleman. Nebeker: What do you mean by that, putting him on the air? Thomas: In other words, I was the engineer. Nebeker: For his program? It was produced there in that state? Thomas: For his program, produced live, and it was in what we called in those days the Earl Building. It's now the Warner building — 13th and E. He used to live in Virginia and he would fly low coming in his car every morning, and if he was not on time, I would just play a record until he got there. One Christmas, he gave every last one of us at the station a war bond. He was very generous. ### Wartime Work and Interference Reduction Thomas I stayed with WJSV until May 11, 1942. I left WJSV because there was a war going on and here was I with a degree in electrical engineering, entertaining people. It so happened that Jim Middlebrooks, A.B. Chamberlain, and a lot of other people in Washington and New York who worked for CBS went en-masse to the Bureau of Ships as engineers to do something constructive for the war effort. I went to work there, and I stayed with the Navy for twenty years. Nebeker: What were you assigned to do when you started working for them? Thomas: Radio. I went to work in the Radio and Sound Division, and I had to do with the selection, purchase, and maintenance of radio equipment. That was before the days of "electronics". The term hadn't become used at that time. Nebeker: Were you shipboard? Thomas: Mostly shipboard and Marine Corps. My first job was in the Marine Corps section of the Radio Sound Division of the Bureau of Ships. My boss at that time was Major W.P. Battell who later went up the line in the Marine Corps; and ended as a general. I really enjoyed working for him. Incidentally, the head of the Radio Sound Division at that time was Captain A.B. Chamberlain, who was formerly Chief Engineer of CBS in New York before he quit and went to work for the Navy. Of course he was very good engineer. He had on his staff a Commander Rogers. Commander Rogers interested me in the problems of radio interference with communications. My first job in radio interference for the Navy was going to Norfolk to find out why radio receivers in small boats couldn't receive because of interference from the engine-driven DC generator that charged the batteries. The engines were diesel so they didn't cause any interference. Nebeker: What were the batteries used for? Thomas: To run the receiver and transmitter in the radio. The receiver at that time was the Model TCS receiver, which I am very familiar with. I went down there to Norfolk, and found out the problem was that the commutation and regulation of the direct current from the generator got into the electrical wiring on the entire boat and precluded the reception of the signals that they were trying to receive on the TCS receiver. Nebeker: Is it the case that the generator was producing these radio frequency waves at the same frequencies they were receiving? Thomas: Well, the interference created by the generator/regulator was broad band. It started at the lower frequencies and went way above the frequencies of the desired reception. The desired reception was in the frequency range of one and a half megahertz to twelve MHz. That was the frequency range of the receiver and transmitter. But the interference created by the commutation in the generator, which was DC, and the regulator, which was a vibrating type, was so severe that nothing was capable of being received. Nebeker: Is it easy to explain to a layman how that regulator is generating these frequencies? Thomas: The regulator consisted of a vibrating reed, the vibration was governed by the voltage of the system and of course, whenever you have vibrating contacts, there is the production of interference. So, I at the time developed two things. One was a means of shielding between the generator and the regulator. The second was a filter between the regulator output and its output to the battery. I developed on paper a series of LC networks that I had built in the electrical shop that night. We put them on the next morning and they worked. The reason it was so important was that those boats had to go to Africa for use on the invasion from Africa to Italy. That prototype, the filter that I developed, we finally had GE make hundreds of them, and we put them on the boats. Nebeker: So all those boats had that kind of generator in the engines. Thomas: Yes. The generator that they used in those boats, I found out later, was the worst generator there was in the field of interference production. They were "Leece Neville" and they were awful. Nebeker: Maybe that was something that generator manufacturers had never paid attention to. Thomas: They didn't. All they were interested in was producing direct current into the battery at the proper voltage. From then on I was designated as the poor fellow in the Radio and Sound division who could maybe help out with some interference problems in the Navy. From then I went aboard ships and we did a lot of clean-up jobs. In other words, after the fact. Then I developed a... Nebeker: What you mean by that? Thomas: In other words, they put something together and then lo and behold found out that they had interference. Then it was the first time they had thought of interference. "Get that guy down in Radio and Sound; maybe he can help you out." Nebeker: I see. Was it always the case that this was some other device interfering with the radio reception on the ship? Thomas: I could remember one time they had interference problems on PT boats. Now you know what PT boats are, and you know how important they were. Well, my boss Captain Rogers and I went over to the PT boats type desk in the shipbuilding portion of the Bureau of Ships outside of the Radio and Sound Division. The guy who was head of the type desk and PT boats said he wasn't going to put anything in the way of filters or shields or anything else on his generators on the PT boats. If we wanted to do something about interference we could fix our receivers so they weren't interfered with. My boss said, "Look. Unless you do something about those generators, what we want you to do, we will take off your boats all the radio and radar equipment. Let's see you operate then without radio." So he gave in. Coincidentally, I gave a contract out of the Bureau of Ships to a company called Tobe Deutschman. Do you remember that name? Tobe Deutschman had a factory in Canton, Massachusetts, outside of Boston, which manufactured capacitors. I got a hold of them. How I don't remember, but we in the Bureau of Ships gave them a contract to develop a family of radio interference filters that could be used in new design, and also in old design as an afterthought. He developed all of those filters, starting with filters as low as one and a half amps, on up to as high as four hundred amps. Nebeker: Now these are filters that you put on other devices? Is that the way it works? Thomas: Yes. I still have some of those filters at home. Preproduction samples, and they worked. You put them in a shielded case, and went in and connected to the source of interference which was shielded. The other end went to the place where you wished to use the current, which did not have to be shielded. The filters took out all the interference. Now to get back to Theodore Deutschman. Did you ever hear of Radio Shack? He started Radio Shack way back in the 1920s, and if you would look at some of the old QSTs, you will find Radio Shack ads. In one of the QSTs about a couple of years ago there was a little notation that Radio Shack was started by Theodore Deutschman in such and such year. If you have time, get the book Tandy's Money Machine. It is a history of Radio Shack and it covers Theodore Deutschman. I have a copy of it, because my son-in-law works for Radio Shack. I thought you ought to be interested in that. Nebeker: Was this type of filter relatively new for that purpose? Thomas: Yes. There was no such animal before I got into the mess. Nebeker: Was it first in the Navy, do you think, that they were encountering this stuff? Thomas: The Navy was the leader in that type of work. The Signal Corps took it up at a later time and then the Air Force did when it became the Air Force. Of course, I worked very closely with those people, knew everybody. Nebeker: What about radar and radio? The ships were also being outfitted with radar. Did that cause any interference problems? Thomas: Yes, it did. But before I forget it, let me bring up another point in filters and so forth. I got tired and frustrated of having people build something which, when it is delivered to the Navy, we find out it won't work because of the fact that it makes interference. So I got ahold of the manufacturers of office machines, drills, hand drills, any kind of equipment that used electricity and I said, "Let's build these things right." Take a hand drill for instance. You had a field, usually two fields, one on either side, a two-pole machine, and you have a commutator, if it's an AC-DC variable speed machine. I said, "Look. Why don't you put the commutator in the middle of the two fields coils and then on the outside of the field coils where you feed the current, put in either a capacitor or a capacitor and an inductor, and cut out putting all that interference back on the supply line." ### Advising Manufacturers on Interference Nebeker: Is that what happens? Is that how the frequencies are broadcast? Thomas: Right. From the supply line to right here. So I finally got the manufacturers of office equipment, hand tools and things like that to design their equipment right. The first outfit I got in touch with was IBM. They made the electric typewriter. The first one that came out had a DC motor on it. It made worlds of interference. I got them to change that to an AC motor that didn't make interference. Take the hand tool manufacturers. I gave a couple of lectures at their meetings about designing things right to begin with and I went all over the country. In fact, it was all over the world. Nebeker: Was that something that bothered people in the 1930s, that maybe an electric mixer or something could interfere with radio? Thomas: They didn't do anything about it. It was inevitable, but you find now that electric mixers and everything else make very little interference if any to the associated TV and radio. Nebeker: That's because the manufacturers have been persuaded to put a filter in or build it in such a way that it doesn't do that? Thomas: "Persuaded" is a very good word, because of the fact that the Navy Bureau of Ships under my interaction put in the requirements in the purchase specifications that the radio interference level should not exceed so much. Nebeker: Is that something that is easy to measure? Radio interference stuff. Thomas: Yes. I have been doing that for fifty years. Nebeker: So you are just measuring the frequencies generated by the device? Thomas: Yeah, right. Nebeker: And the power in each one? Thomas: You also want to look at some of the American National Standards, the C63 series of standards, and you look at the military's standards. The Military Standard 461 contains levels of interference that are permitted in military equipment. 462 tells you how to measure it, and 463 are the definitions of interference. I know, I helped write them. Nebeker: Can you give an overview? How do you measure exactly the interference? Thomas: Well, we had what essentially was a frequency-calibrated receiver. The receiver is precisely constructed to pick up certain frequencies only and when it picks them up to measure the level over a given impedance. Nebeker: So you have some specification of how close to the device, how it's... Thomas: American National Standard C63.2 gives you the specifications for the device and how to use it. C63.4 continues with how to use it; C63.12 gives recommended levels of interference. I am a member of the ANSI Committee C63 and have been since 1946, so that's my background in writing standards. ### Radar and Radio Interference Nebeker: The concern in those days was mainly interfering with radio reception? Thomas: Yes, and then along came radar. I am glad that you brought that up, because radar was one of the sources of interference to radio. The biggest source of interference from radar to radio was the pulse cable between the transmitting device and the antenna. It was not appropriately shielded and as such it radiated a lot of interference. Radar frequencies are way above the radio frequencies, but to arrive at that high frequency in a radar, you have to take a lower frequency which is sometimes in or below the radio frequencies and multiply it. Those multiplications came out of that pulse cable and radiated everywhere. It finally got to where we used double and triple shielded pulse cables between the radar transmitting equipment and the antenna. Nebeker: Is that something that you worked on during the war? Thomas: Yes, I worked on it. Incidentally, I did have my arguments with the radar people in the Navy. They didn't want to do anything. I finally got a hold of some of them and said, "If you guys can design it right instead of building it and getting it on the ship, and finding out that you can't operate it and the radios at the same time, if you build it right you won't have to do that." I found one guy who was sympathetic to my entreaties, building the SPS10, which is one of the shipboard radars. Nebeker: Where was this person? Thomas: In the radar division of the Bureau of Ships. So he said, "Okay. Look. We will take your advice, and we'll let you go over the plans, drawings, of the SPS10, and you tell us what we should do before we let the contract out." So I went over, and I said, "Put a filter here. Shield this, do this, and do this." The SPS10 was built and it did not make any interference. One more plus: the guy told me, "Look. We followed your instructions and saved$35,000 in building it.

Nebeker:

How was that? They must have added additional things prior to what you said.

Thomas:

Also I re-routed certain cables and eliminated places where interference would go from one unit to the other.

Nebeker:

So the total redesign actually saved...

Thomas:

The total redesign saved money.

Nebeker:

Was that the first time you think a radar set was specifically designed to avoid that problem? Was that a problem that occurred whenever they put radar sets on ships?

Thomas:

Sure, right.

Nebeker:

And they didn't anticipate that problem?

Thomas:

Nebeker:

They later found that they couldn't use radio at the same time and then they put the shield in?

Thomas:

Right, right. Too late. I can remember some cases where they had shipboard interferences of radar and radio. It cost a million dollars to correct that.

Nebeker:

Did it become standard practice to take that into account and design the radar set?

Thomas:

It did.

Nebeker:

Eventually or fairly rapidly?

Thomas:

Fairly rapidly. Right.

Nebeker:

I see. We have talked to a number of people who were designing radar sets at MIT's Radiation Laboratory and the Bell Labs in the war. This is just something that I never thought of asking about.

Thomas:

### Development of Interference Standards

Nebeker:

It's interesting. How did you get involved with what's now ANSI, but what was it called in those days? Do you recall?

Thomas:

The American National Standard Institute's first name was the American Standards Association, the ASA. I got involved with them in 1950-something and I was designated by my boss, Captain Rogers, to go to New York to attend the meeting of ASA. I went up there, and have been involved in it ever since. It finally evolved into ASA Sectional Committee C63, and as you know, now the IEEE is a sponsor of C63. The chairman of C63 is Dr. Ralph Showers, from the University of Pennsylvania.

Nebeker:

Were there interference standards before ASA got into the game? Did the Navy set up some standards during the war?

Thomas:

Yes. We had a standard which was JANI225. I wrote it. I have a copy of it at home. That was the first standard on radio interference. When the war came it was adopted by the ASA.

Nebeker:

When the war came along?

Thomas:

When the war was in being, they adopted that as American National Standard C63.1.

Nebeker:

I thought you said ASA didn't come about until the 1950s?

Thomas:

The ASA was in existence for years before then, but as far as interference was concerned it wasn't. JANI225 had a cover placed around it, saying C63.1. There was my old JANI225. I felt real good about that.

Nebeker:

When did you write that standard?

Thomas:

In the 1950s.

Nebeker:

Were there earlier standards in the Navy?

Thomas:

I had some more before JANI225, which were Bureau of Ship standards.

Nebeker:

The Bureau of Ships would say that you can't have a generator with this kind of...

Thomas:

Right. My standards started out first as Radio and Sound Division standards and then Bureau of Ships and then Navy and then military.

Nebeker:

How many people would you estimate were working as you were on these interference problems for the Navy during World War II?

Thomas:

Nebeker:

So that was something that they had to deal with whenever they put radar on a ship?

Thomas:

Even before they put radar on ships, you had the interference problem. It was solved by people who didn't know what they were doing, and they stumbled onto the solutions.

Nebeker:

Maybe just by locating the radio on a ship?

Thomas:

That's right. Now to get back to ASA C63; there was called a meeting in 1946 in London. It was a meeting of the International Special Committee on Radio Interference (CISPR).

Nebeker:

Is that a pre-existing organization?

Thomas:

Yes, it was a pre-existing organization which was started in Belgium before the first World War, and in 1939 it was discontinued. This was the first meeting after the war in 1946 in London.

Nebeker:

Was that an organization trying to reduce radio interference across borders?

Thomas:

They wanted to have some kind of international semblance of agreement. Before 1939, the Belgians, the French, the Germans, and the English got together and developed this international committee on radio interference, which is known now as the CISPR. You have heard of that?

Nebeker:

Thomas:

Yes. The CISPR had its meeting in London and I went there as the first USA representative to attend that organization's meetings.

Nebeker:

The U.S. had not been represented earlier?

Thomas:

No.

Nebeker:

I just want to be perfectly clear. Their job was to set power limitations on broadcasts across international borders?

Thomas:

On interference across international borders, not broadcasts. In other words, how much interference does this device manufactured in Belgium produce? I want to sell it in France.

Nebeker:

I was thinking of the same kind of regulation the FCC does.

Thomas:

No, they had their own counterparts of the FCC over there, and we worked with them.

Nebeker:

This is about some generators or other devices that create radio frequencies, and having standards of how much they can produce when they are sold.

Thomas:

The Belgians and the British had developed an interference measuring device, and I think I still have the specifications for it at home. It measured the interference output of the device on the power lines. It didn't have an antenna, and when I went over in 1946, I suggested that they follow our procedures and put an antenna on their measuring device to measure the radiated field in the vicinity of the device under question, so they did. I took over copies of my JANI225 and the C63 documents.

Nebeker:

But that was in the 1950s right?

Thomas:

That was in 1946.

Nebeker:

I thought that you had said that those documents?

Thomas:

Were 1950 documents, but I took them over there. And I took over our ASA documents and showed them those. Obviously I got placed on several committees and I attended them.

Nebeker:

London must have been quite a sight in 1946, after being bombed out.

Thomas:

It was awful. I can remember it was a wreck.

Nebeker:

Their economy was really awful.

Thomas:

It was really in bad shape. I had two aunts and cousins who lived in England. I knew I was going over to England and got a hold of my two aunts and cousins. I said, "Look. I am coming over there. What shall I bring you?" I loaded a footlocker full of everything: clothes, food, shoes and coffee, and all sorts of things. Of course, I was traveling with a Navy passport and nothing was inspected; I was treated like a royal VIP over there. I took that foot locker from Washington D.C. to London and from London to Penzance, where my cousin and aunt met me. From there I went to where they were in Porthcurno, and I spent the weekend with my relatives.

Nebeker:

I've taken that train ride down to Penzance, the end of the line.

Thomas:

That's right. It was the Great Western Railway. I enjoyed that.

Nebeker:

So this was a fruitful meeting of 1946?

Thomas:

It was and they had another meeting in 1947 in Paris, and another meeting every couple years thereafter.

Nebeker:

Did you attend the others?

Thomas:

Yes. I attended those meetings up until 1970. I enjoyed them.

Nebeker:

Were you representing the Navy?

Thomas:

No, I represented the United States.

Nebeker:

But who was it who designated you as the US representative?

Thomas:

The American Standards Association.

Nebeker:

I see. You were in the ASA.

Thomas:

When I went over there in later years, I took several people with me, Ralph Showers and Harold Dagger, who has now passed on. I had people from GE with me, and we had a nice delegation. We found those Europeans were most cooperative and most anxious to work with us.

Nebeker:

How did the state-of-the-art compare between this country and Europe?

Thomas:

They were behind us in the beginning, but they are, I think, caught up with us now and ahead of us in certain areas. I still maintain my contacts with CISPR. In fact for four years, I was the secretary of Subcommittee A of CISPR and went to meetings in Italy, France, London, and Scandinavian countries. I enjoyed that very much.

Nebeker:

I am surprised, though. You said that this European organization existed before...

Thomas:

It did.

Nebeker:

Was there anything like that in this country, setting standards before the war?

### Car Radios & Early Interference Concern

Thomas:

Yes, yes. There was an organization which consisted of members of RCA, GE, Westinghouse and several other companies who got together and developed a document which was adopted by those people as a program of reducing interference. I have a copy of it at home; I don't recall the full title of it now. But that was the first document, done before 1939.

Nebeker:

Their motivation was that people were being bothered by the radio interference?

Thomas:

That's right, and the reason for that was when radios were placed in automobiles. They found that the ignition system of the automobile interfered with the radio, and so did the generator and regulator. So they got this interference out.

Nebeker:

Is that where you think the concern really started, with car radios?

Thomas:

I think so.

Nebeker:

That's interesting.

Thomas:

So I worked on that commission too.

Nebeker:

And you were in on car radios from the beginning.

Thomas:

Yes, right.

Nebeker:

Do you remember that problem from the early 1930s, that the reception would be bad in the cars?

Thomas:

Well, I'll tell you. In those days, when we had ignition interference, we had little devices which were resistors. We placed them in the high voltage leads to the spark plugs. That reduced the interference by maybe 40db or something like that and made it somewhat tolerable.

Nebeker:

Was that an empirical thing that somebody discovered?

Thomas:

The committee discovered that, and I have got some of those sets of resistors that were placed in the spark plug leads.

### World War II: Portable Radio

Nebeker:

I wanted to hear about your job. What was your job with the Navy actually called? You were with the Bureau of Ships?

Thomas:

I was with the Bureau of Ships Radio and Sound Division which later became the Radio Division. My job there was first in the office of the Marine Corps Division where I was looking after the equipment that the Marines used. A lot of it was hand-held equipment: transmitters, receivers, and things like that.

Nebeker:

Thomas:

Portable radio, looking at the design specifications and writing them, and also having to do with the purchase of them. We had a division in the Bureau that bought things for us. They bought what we wanted and we wrote specifications. When they had contractors they brought them to us and we explained the technical requirements to the contractors.

### Interference Work at ECAC

Nebeker:

Was this the work that you were doing throughout the roughly twenty years you worked for the Navy?

Thomas:

Yes, that's correct. The latter part of my Navy career focused more on radio interference. When I left the Navy in 1960, I went to Annapolis to work for the Electromagnetic Compatibility Analysis Center, ECAC they called it, which was the continuation of the work I was doing in the Navy.

Nebeker:

Was that when that center was formed, in 1960?

Thomas:

Very shortly afterward, that's correct.

Nebeker:

That was not within the Navy but with the Department of Defense?

Thomas:

It was a DOD activity located on a Navy base administered by the Air Force.

Nebeker:

Thomas:

That's correct. The organization consisted of two different groups of people: one was military civil service, which I was part of, and the other was a contract. The contractor at that time was the Armor Research Foundation, which became later ITRI. They still, I think, have the commercial contract to run the nuts and bolts work and operate the computers and so forth.

Nebeker:

This is all for dealing with interference problems?

Thomas:

That's all there was to it — dealing with interference. There were four military uniformed representatives there: Army, Navy, Air Force and Marine Corps. There was a civil service retinue in each of those offices plus the planning office, and I was in the planning office.

Nebeker:

How long did you work at ECAC?

Thomas:

Ten years.

Nebeker:

Were there other kinds of interference or other kinds of compatibility that were dealt with?

Thomas:

Yes. The one ECAC was concerned with was interference due to ill-assigned and ill-used frequency assignments. They took on the job of reviewing all frequency usage plans and pointing out where the problems arose. In many instances they were able to point out problems before even the equipment was built or installed.

Nebeker:

Now what are some of the other sources of this interference? Is it more than the things you have mentioned — generators, radar sets?

Thomas:

Anything that uses electric current which is either turned on or off or has intermittent or continuous making and breaking of contacts; anything like that can be a source of interference. It doesn't have to be if it's properly designed.

Nebeker:

I see. So this is making sure that all sorts of military equipment is designed correctly. Who is bothered, to personify the problem, by these unwanted frequencies generated? Of course, radio reception is one thing, but what else?

Thomas:

We have found that electronic equipments are affected. They don't have to be receiving equipments. For instance, we have many machine tools that are electronically operated; they can be interfered with too.

Nebeker:

Even if it is a hard-wired thing?

### Interference and New Technologies

Thomas:

Sure. Hard-wired is now being replaced in many instances and we have a new era of lasers and so on.

Nebeker:

I guess that gives rise to a lot more interference problems?

Thomas:

Yes and no. In some instances, yes, and in some instances, no.

Nebeker:

In the time that you were active in this, probably beyond your time at ECAC, what were the new devices (you mentioned radar) where you got a new source of interference? Are there other things that sort of stick out in your memory that were giving rise to new problems?

Thomas:

Well there is satellite communications, obviously. That's important. Any new system which uses any portion of the frequency spectrum is always subject to analysis. That's the reason that place exists, the Electromagnetic Compatibility Analysis Center. Their job is analysis and with their analysis comes recommendations.

Nebeker:

Would another example be the navigation systems of ships?

Thomas:

Loran?

Nebeker:

Right, Loran, or there's also...

Thomas:

Any of them. Any kind of system that uses transmitted or received energy is subject to analysis.

Nebeker:

Since the war, probably the military is trying to anticipate the problem in any such system.

Thomas:

A lot of the work that is done by ECAC has been for other agencies. Satellite communications and the mission to the moon and this, that and the other, are all subject to analysis for interference, not only from external sources but from within themselves. In other words, a device that has a missile or something like that has a lot of electronics in it for guidance and other things. Put all of those things together in one little case, and it will interfere with itself.

Nebeker:

Is that what they call the near fields? Is that the equivalence?

Thomas:

It could be. It doesn't have to be near fields; it could be the wires adjacent to another one, picking up interference which will prevent a portion of the device or missile from operating properly.

Nebeker:

Is that a problem that became noticeable with the miniaturization of electronics after the war when you were putting more and more into a small area, and satellites, and so on?

Thomas:

Right.

Nebeker:

Is that an area that you got into yourself, that kind of interference problem?

Thomas:

Some, but not too much. We had people who did the technical work under our direction.

### Interference and Electrical Equipment

Nebeker:

We should get some overview of this whole field of electromagnetic compatibility. You have given us a very good account of the beginnings of it, radio interference especially, and some of the other things that you have talked about. Are there other areas of compatibility that we haven't talked about?

Thomas:

Well, it is a very broad field as you might know. As I previously mentioned here, anything that uses electric power with making and breaking of contact, whether it is well-operated or badly operated, it can be a source of interference.

Nebeker:

But the thing that is surprising to me is that even something that is not receiving signals or magnetic waves can still be interfered with. Can you give me an example of that? What problem is created by that kind of interference?

Thomas:

Well the interference that you just referred to can be internally generated interference which interferes with the proper functioning of the device as was intended. There again, proper design should take care of that. One other thing we have not mentioned is immunity or vulnerability of electronic receiving equipment to being interfered with.

Nebeker:

Intentionally or otherwise?

Thomas:

Intentionally or otherwise. The new specifications, both military and civilian, have sections that have to do with vulnerability or susceptibility. Let's look at it this way: it was customary in building receivers to have an RF front end, but maybe the cheaper ones didn't. Those receivers, in addition to being able to receive on the intended frequency, received on other frequencies as well. In other words, if there was a superheterodyne receiver and the IF was 465 kHz, and it was supposed to receive at 1500 kilohertz and it also receives frequencies lower than that and above 1500, you are in trouble.

Nebeker:

At least you are in trouble in certain environments.

Thomas:

Yes.

Nebeker:

And that is something that changed with time?

Thomas:

Right. There is another thing too: if those receivers could receive everything in addition to their intended receiving frequency you had problems. In the case of the cheap radios which had no RF amplifier in front to cut down on the broad selectivity... RF amplifiers cut out a little bit in front to begin with and block the receiver of the 465 IF from an adjacent receiver or something like that.

Nebeker:

Is that something where the receiver has to be close to another one to cause that problem?

Thomas:

They could. Also the new specifications have requirements for vulnerability or susceptibility built into them. That is new. The feeling is this: why should the people who produce the interference go to all-out ends and expense to reduce the interference to prescribed levels when the manufacturers of those devices haven't done a thing to make their devices less vulnerable to general interference?

Nebeker:

When did that start?

Thomas:

Several years ago.

Nebeker:

Fairly recently?

Thomas:

Yes. It was, "look, let's tackle this from two points of view." It won't be as hard on the manufacturer of the device that makes the interference and it will also make the person who makes this cheap piece of equipment susceptible to everything to reduce his vulnerability to only that which he needs. Now that was the thinking and that is demonstrated in the current specifications.

Nebeker:

You said that ECAC made this study of the different frequencies intended to be generated. Were they involved at all in the assignment of frequencies. Any recommendations?

Thomas:

They have a very close liaison with the military body that assigns frequencies. I think the person from that organization meets with ECAC regularly, and vice-versa.

### Biomedical Devices

Nebeker:

I was surprised in talking to Herman Schwan, a biomedical and electrical engineer, to learn that in this country, (I don't have this story completely right) the hospitals could not use microwave diathermy equipment because they couldn't get the frequencies. The frequencies were already claimed that that equipment would be generating. Even though it's strictly a local effect, still they were not permitted to use them.

Thomas:

I think part of that is correct, but there are several frequency bands designated throughout the frequency spectrum which are called ISM frequencies — Industrial Scientific and Medical. Radio frequency devices, electronic heating, and this, that, and the other, are not the whole story. There are new biomedical devices that are so sensitive that they have to be used in shielded enclosures. Those shielded enclosures have the power lines into them. They are clean, they are filtered. The patient is inside the enclosure in many instances. Now in other instances, say the EEG or EKG, I have been wired up several times, and I know what that is like. They put about twelve electrodes all over you and then they monitor what they pick up, and if the ambient in the room is low, they don't have any problems. But if the ambient is high and some diathermy machines or something else are operating, it masks the responses and they have to do it over again. On ANSI Committee C63, there are representatives from the biomedical field, and they have their own specifications as to what is required and tolerated in our medical equipments.

Nebeker:

Every different device has sort of a level they can tolerate.

Thomas:

Yes. I use to know it quite well. I am not too active in that area, but I still get all of their communications.

Nebeker:

There is also a real change that came in during the 1930s with television and radar. You got pulse electronics as opposed to the continuous wave electronics of radio. Did that in itself create special problems with interference or compatibility?

Thomas:

No. We have one representative from that pulse technology community on C63 and on the local IEEE group. Henning Harmuth is the man's name. He is an adjunct professor at Catholic University here in Washington D.C. He is foremost in the use of those broad band emissions. In many ways it prevents or negates the effect of interference on some communications which are compatible with each other in the broad band area. He is very active in that and you might want to touch base with him. Henning Harmuth is in the electrical engineering branch of Catholic University of America, at Michigan Ave and about Fourth or Fifth Street Northeast, in my neighborhood.

### Retirement and Consulting

Nebeker:

How long did you work for ECAC?

Thomas:

Nebeker:

And what then?

Thomas:

I retired in 1970.

Nebeker:

You retired at that point.

Thomas:

They keep me busy down here too much to do anything else! I did do some consulting for friends of mine, for Jansky and Bailey, and Atlantic Research, and Bill Green Associates, and so forth. But when my wife contracted Alzheimer's disease, I had to take care of her. I had about seven or eight years of that, until she finally passed away.

### IEEE EMC Society

Nebeker:

You have been active in the IEEE Electromagnetic Compatibility Society. Can you tell me a little about that?

Thomas:

Well, I was one of the founders. It's about twenty-five or twenty-six years old now. A group that got together here in Washington and another group in New York decided to set up the group within the aegis of the IEEE and we got permission to do it. From then on it kept growing.

Nebeker:

Were you active in IEEE work? Or it wasn't IEEE at the time?

Thomas:

It was IRE. I was active in IRE, and then IRE and the AIEE went together to form the IEEE.

Nebeker:

That's why you and some of the other people thought it would be natural to be with that organization?

Thomas:

Right.

Nebeker:

I saw that you were for many years secretary of the society?

Thomas:

Right.

Nebeker:

Can you tell me what the main activities have been? Did they have a newsletter or journal?

Thomas:

Yes, they do have a newsletter, and it is a very good one. I think it has received several awards and it has a quarterly publication, in the Transactions.

Nebeker:

It is part of the Transactions.

Thomas:

Right. Of course, our objectives are like the other IEEE societies, one of which is writing standards. I have been active in writing many of the standards.

Nebeker:

And that is for this society?

Thomas:

Yes. The IEEE standards first developed with the view of becoming ANSI standards and with the further viewpoint of becoming an IEC standard. So when you first start writing standards in IEEE you bear all of these things in mind. If this is virgin territory then when you start writing your standard, you remember to use metric designations in addition to the designations we used — foot, inch, and so forth. You also acquaint yourself with the requirements of the IEC. Now, the CISPR is one of the IEC committees, the IEC committee concerned with interference, and I have served on that too.

Nebeker:

I think Chester Smith talked to Bill Aspray.

Thomas:

I know Chet real well.

### Electromagnetic Pulses

Nebeker:

He mentioned that a topic in your society was and still is this matter of vulnerability to sudden pulses cause by explosions. Do you recall when that concern started?

Thomas:

Yes, it started right after the war when nuclear devices became prominent.

Nebeker:

Was that something they experienced with some of the bomb tests, that some devices were knocked out?

Thomas:

You'll never know. They won't tell you, but their actions since then indicate that must have been the case.

Nebeker:

So that was something you dealt with the Navy and ECAC, this vulnerability of devices to pulse.

Thomas:

Yes. They called that EMP, electromagnetic pulse. That is a real concern.

Nebeker:

And it led to design standards?

Thomas:

Yes, and we had one project down at ECAC called "TREE." It was the making of new devices that were under design and development consideration, to make them less vulnerable to electromagnetic pulse.

### EMC Society Accomplishments

Nebeker:

What about the society? Has that been a very active society? Has it been dominated by particular groups or people?

Thomas:

There are three kinds of people in that: company-oriented people, university or academic people and ordinary people like me.

Nebeker:

Is it clear when dealing with others where they come from?

Thomas:

It doesn't make any difference. For instance, we have representatives from the FCC, the old NBS, the health people, and the computer people. All of those people contribute. You feel that there's not much clash of interest dependent on where the person is employed, since you are all engineers. We have even brought in the American Association of Railroads, AAR. They are working with C63.

Nebeker:

Why are they particularly concerned with that?

Thomas:

They don't have cabooses on trains anymore, and you know why, don't you? They have electronics. They talk from one end of the train to the other. They are interested in interference too, and also the trains these days have telephones. You can go to the train between here and New York and talk to somebody in any city you want to. They are interested in interference.

Nebeker:

It's a big enough concern for them that they take part in it?

Thomas:

One of the recent meetings of C63 was at the AAR headquarters, which is close to Union Station.

### Computers and Inteference

Nebeker:

What about when computers arrived on the scene and started to be put in more places? Did that give rise to a lot of new problems?

Thomas:

Oh, yes. Computers can be interfered with and computers can cause interference to other devices because they are full of RF. You can operate something too close to a computer and get it all screwed up and lose all of its memory.

Nebeker:

As computers were coming in, standards were being worked out.

Thomas:

Right, we've got computer representatives on the various committees we have, working with us very closely. They realized what a problem they had.

Nebeker:

Did that cause a real boost in interest in electromagnetic compatibility and more people or engineers working in that?

Thomas:

It did.

### Growth of EMC Field

Nebeker:

Can you sketch out the history of that field starting with, I presume, the kind of radio interference you were concerned with and then other problems with more electronic devices that were built too close together and so on? Can you think of other milestones in developing that field?

Thomas:

Whenever any industry had an interference problem, we somehow got word of it and invited appropriate representatives of the industry to join us in studying problems, to see if we could mutually help each other out. Now there the Computer Business Machine Association, CBMA, and they have regular representatives on the interference groups in C63 and others; they are very active. They have staffs of people within their organizations who work on this problem and be sure it doesn't become unmanageable. They are doing a good job.

Nebeker:

You served as secretary for many years. You saw the growth of the society. Was it a steady growth over the years?

Thomas:

Yes.

Nebeker:

Any sudden peaks or drops?

Thomas:

It has been steady growth. I don't think there are any peaks; of course there may have been a little slowdown due to economics, with the people who have had to drop out. In many instances the organizations were firms employing the people who were members of the IEEE and ANSI groups. They used to pay the dues, let's say the IEEE dues, but that dropped by the wayside with many companies, and the people had to pick them up themselves. Many were unable to do it.

Nebeker:

That's a factor. I heard that for the first time ever, last year total IEEE membership declined.

Thomas:

That is the very reason. Of course, when you get like me, you are a life member.

### Honors and Awards

Nebeker:

You earned that status. I have noticed that you received the IEEE Standards Medallion. Can you tell me about what that award is?

Thomas:

Yes. It was a medallion based upon my work in the development of EMC standards over my career in the IEEE. That medallion was accompanied by a very, very nice Hewlett-Packard calculator. That was awarded to me a couple of years ago in New Jersey.

Nebeker:

You also received the Laurence G. Cumming award. Is that the main award of the EMC Society?

Thomas:

The EMC society has two awards. One is the technical award, which is the Richard R. Stoddard Award. The other is for the work like I was doing as a secretary and officer. It is the Laurence G. Cumming Award. Did you know Laurence Cumming? He is passed away now. Laurence Cumming was a very, very close friend of ours in the EMC society. He helped us out in our organizing days and gave us guidance as to what to do. He was in the IEEE New York office. I think he was Technical Director or whatever it is. Since he was such a close friend of ours, we set up two awards, one for technical and the other for management. I was the recipient of the first Laurence G. Cumming Award and Ralph Showers was the first recipient of the Richard R. Stoddard Award.

### Other Engineers in EMC Field

Nebeker:

Are there many engineers working as consultants in this field?

Thomas:

Yes, quite a few. Lots of people are working as consultants in EMC.

Nebeker:

It seems like the sort of thing for which a company may not want to hire someone full-time?

Thomas:

That's right.

Nebeker:

But has to deal with.

Thomas:

Many firms are organized to provide that. Many people individually can do that. I used to do some of that when I first retired but since I had to take care of my wife, I had to drop all of that work.

Nebeker:

I noticed that you also have membership in the IEE in England?

Thomas:

Nebeker:

We also wanted to ask you about other people that we might talk to?

Thomas:

Well, one is Ralph Showers, however, many of the old timers have passed on. You are going to have to talk to some of the newer people, one of whom is Bob Goldbaum, the editor of the EMC newsletter. He is close to Philadelphia. You also want to talk to Mr. Donald White, the head of White Electromagnetics. He lives in Gainsville, Virginia, a few miles from here. He runs a publishing, consulting organization just like Bob Goldbaum in Philadelphia. I collaborated with Mr. White in developing some of his publications. I had a chapter on standards in one of them and I received royalties from that book until it became replaced with others.

Nebeker:

Are the engineers in the field especially located in the DC area?

Thomas:

How do you mean?

Nebeker:

I am just thinking that maybe because of the federal government's interest, a lot of electromagnetic compatibility engineers would be here?

Thomas:

Yes, there are a lot of them around here, working for various organizations, the FCC among them. The companies that have business with the government are here; their representatives are here.

### Files, Books and Papers

Nebeker:

You mentioned that you have five filing cabinets of papers. I think it is very praiseworthy that you have held on to things. So often there hasn't been anything to show. Historians like to look at documents as well. Do you know of any other collections of papers in this field that might be accessible? Maybe other individuals or ANSI has archives?

Thomas:

Bob Goldbaum had copies of all the newsletters of the EMC Society. You could see him. I think I have copies of all of them too. Don White may have some of that. Before he died, one of the members of our local chapter of the EMC Society was going to get my files and reduce them to some kind of easily accessible format. I still have my files, and I am not getting rid of them either.

Nebeker:

We have an archives at the History Center, but it is pretty much restricted to IEEE, IRE and AIEE records, things having to do with the Society. If at some point you wanted to find a repository for some of your things, the papers relating to the EMC Society would certainly be of interest.

Thomas:

I have all of the minutes of the EMC society at home right now. I just wonder if you would be interested in obtaining those?

Nebeker:

I would certainly like that. I have found from looking into the earlier work of IRE, trying to learn some of the work on testing radio receivers and some of the subcommittee group in the 1920s and 1930s, that the papers don't exist. They are lost. Loren, do you have anything to say? [towards other person present]

Thomas:

She hasn't said one word since you have been here.

Butler:

I came along to watch Rik in action, doing an interview. I have learned so much today. I don't think I have processed it enough to ask you a question.

Nebeker:

I think you have given us a very good background to this field.

Thomas:

I would like to go into my five file cabinets to get out of them some of the bits of information that maybe you would like to have.

Nebeker:

It would be very useful to us. I was hoping that maybe at some point when we get to the writing of certain parts of this story that we could call on you and take a look at some of your things.

Thomas:

You are certainly welcome to see what I have at home. I just brought this stuff today. Did you find anything interesting there?

Butler:

I would need to take hours. I think the most interesting thing to me is that both parts are equally warranted. I am impressed.

### Mahlon Loomis and Pre-Marconi Wireless

Thomas:

I have a lot more stuff like that and I have also at home one of my radio textbooks from Auburn. It is very, very interesting. Did you ever hear of Dr. Loomis?

Nebeker:

There were a couple of Loomises associated with the Radiation Laboratory at MIT. I don't know if there are any connections.

Thomas:

This is Mahlon Loomis, and years and years ago he went into West Virginia and demonstrated the ability to transmit intelligence without wires from one place to another.

Nebeker:

When did he do this?

Thomas:

In the 1800s or something. I have some books which cover that. Also, one of the texts we used in Auburn to study radio was Radio Engineering by Mary Texanna Loomis. Somebody borrowed that book from me, and I have never been able to get it back. It is in the Library of Congress. I found that out and it covers a lot of Dr. Loomis' experiments out in West Virginia. Incidentally, he was a dentist but he had that interest in engineering.

Nebeker:

I have heard of that now that you describe it. He was using kites to transmit the signals. This was before Marconi.

Thomas:

That's correct, it was.

Nebeker:

Do you think that a relative wrote the book?

Thomas:

This woman who wrote the book was his niece.

Nebeker:

That is interesting.

Thomas:

I have got a lot of stuff.

Nebeker:

I hope maybe some time one of us can visit you and take a look at the papers and any artifacts you might have. We often put together little exhibits sometimes, in display cases, in the engineering building in New York, of people and artifacts.

Thomas:

I have, as I told you, a WD11, the first radio tube I ever had, and the WD12 and the UV200, 200A, 201, and 202. Are you familiar with those?

Nebeker:

I have heard of those names, but I don't really know radios.

Thomas:

The UV200 was a six volt filament tube intended as a detector. The 200A was a further development in the tube. The voltage for the 200 was twenty-two and a half volts; it was designated as a soft tube. In other words, its plate grid characteristics were such that you could vary them and receive a rather weak signal. The 200A was a further improvement of that. The 201 was a hard tube which was an amplifier tube, which would amplify what came out of the 200. You could put it on the loudspeaker. The 201 went on to other tubes later on. I have a lot of them at home. And the UV199s came in.

Nebeker:

That's a story I have to learn, the story of the branching development of these tube types. In the 1920s they started out with a dozen or so and they just grew more and more specialized.

Thomas:

I think I have home an old Western Electric 212D. The base is about so big around and it is about so high...

Nebeker:

Is this for transmitting?

Thomas:

That might be interesting for some of your displays.

Nebeker:

That would be nice for display.

Thomas:

You also know about the peanut tubes? The 900 series, and so on. I have got some of them.

Nebeker:

It's funny that the work "peanut" is used to refer to these miniaturized tubes. Today they ought to find a different metaphor.

Thomas:

Well, you've got a one o'clock meeting, don't you?

Nebeker:

I want to thank you.