Jacob Shekel

Jacob Shekel

Interview Date: Friday February 28, 1992
Interviewer: Mike Jeffers
Collection: Archer Taylor Technical Collection
Note: Audio Only

JEFFERS: The following is an interview with Dr. Jacob Shekel in which he relates his overall work experience with emphasis on his time spent in the cable television industry. The interviewer is Mike Jeffers also a veteran of the cable industry. Dr. Shekel is affectionately known as Jake to his friends and associates. Occasionally, you will hear me address him in that manner.

Dr. Shekel, please give us a run down on your personal background–where you were born and raised, your education and anything else you think is significant prior to your starting your technical career. Then, move directly into your work experience, generally, in a chronological order.

SHEKEL: I was born in Poland but when I was seven years old my family moved to Israel which was then Palestine. So I grew up and had all my education–grade school, high school, college education–in Israel.

I graduated from the Technion in Haifa with the degree of engineer in electrical engineering. I graduated in 1948 and that was the time that the State of Israel came into being and everybody at my age went into the army. I did my army service and after that I stayed in government service in developing the new laboratories for research in electronics. So, I got my first experience actually working in the government development lab.

After six years, in 1954, I came to the United States to pursue my graduate studies at MIT for the degree of doctor of science. And, that is when I first came in touch with cable television. I did not know at that time that I was going into cable television. I didn’t even know that such a thing existed.

What happened is that, as a graduate student always hungry for some more money, I was looking for a part-time job some place to supplement what I had. So, I looked at various companies around MIT in the Boston area and one of them was Spencer-Kennedy Laboratories (SKL) which was at that time a very small company on the second floor of a very small building within a block from MIT. I knew that SKL did work on and was marketing wide band amplifiers, tube amplifiers based on distributed amplification. That is a circuit where you have a transmission line in the grid and transmission line in the plate to get wide band amplification. As part of my work before coming to MIT, I had published several papers on the design and analysis of this type of transmission line and distributed or lumped transmission lines coupled to each other. So, very proudly I brought three reprints of this to SKL and said, “Look at what I’ve done; look at what I know. I think there is something we can work out together.” So, they hired me as part-time engineer while I was in school and I did some small design work for the company.

In 1957, when I received my degree, I went back to Israel.

JEFFERS: That was your doctorate degree?

SHEKEL: My doctorate, doctor of science in electric engineering. I kept in touch with the people at SKL and four years later, in 1961, they offered me a position with the company. So, I came to the United States again, in 1961, and have stayed in the United States since then.

JEFFERS: Jake, something you said interested me. It was my impression that one of the owners or founders of SKL had a patent in distributed amplification.

SHEKEL: Well, Fitzroy Kennedy. Yes.

JEFFERS: Was that done before you did your work on distributed amplifiers?

SHEKEL: The patent, I think, is dated back in 1948. My work was not really on the distributed amplifier. It was more on the circuitry around it, the passive part of the circuit, the transmission lines. I was not aware of the patent at the time. But, it just happened to be a match between some work that I did and some that they were doing. So, it could then lead to refinement of the design and so on.

JEFFERS: I see. Yes.

SHEKEL: So, in a couple of years, before I went back to Israel, I got a little familiar with cable television from what SKL was doing and then when I came back in 1961, I got fully immersed in it in my work.

When I came to SKL, they had a line of amplifiers, wide band amplifiers, for the trunk of cable TV and they really started out with a trunk amplifier but then they had to know that to complete their line, they had to build all the other components … the bridging amplifier, the line extension amplifier and the taps. What was interesting is that at that time, which was 1961, the prevailing technique in cable TV was still strip amplifiers, single channel for the trunk. And, SKL was the maverick in that sense of trying to push wide band distribution from the start. Of course being a small company, they couldn’t take a big part of the market. But, they had their small niche in that market. So, they had the distributed amplifiers. They had the line of equalizers which I think were also unique at that time because they had thermistors as part of the components, so that equalization did change with the temperature and somewhat compensated for the change of cable loss with temperature and for the change of slope with temperature.

And, another interesting thing is that the taps that they used from the beginning were directional taps. They were quite clumsy, too, to say the truth. They had a length of cable–a quarter wave length of dual coaxial cable–coiled up in a box which gave the directional coupling. And, you had to cut into the cable in order to install them. So, it was not much of a match, that is commercially against the prevailing pressure tap, which you connected by drilling into the cable.

JEFFERS: Uh! I just want to make sure I understand. All your distributed amplifiers at that time used vacuum tubes. Is that correct?

SHEKEL: Yes. We are still talking about vacuum tube amplifiers. So later, I was put in a very interesting position because when I was with SKL, I knew about Jerrold and knew that Jerrold was in the forefront of the development. I felt that SKL had some ideas which may be, well a little ahead of the majority of the equipment in the field. But, because we didn’t have the clout, we always felt that we had to run to beat … try to keep up with Jerrold. And, I was elated when I later joined Jerrold. I was now with a company that was in the forefront. It was a very heady experience for me.

JEFFERS: Well, let’s continue on with your experience at SKL. What did you personally do at SKL? Did you work on all those products you talked about or were you more a specialist in the distributed amplifier-type of product? I mean, did you work directly on the taps, the directional coupler taps?

SHEKEL: The distributed amplifier was quite well established by the time I joined them but I worked a lot on all the assorted equipment, especially on the distributed taps.

JEFFERS: I see. Did they go into line extenders and things like that at the time you were there?

SHEKEL: They did use distributed amplifiers also as line extenders. So, there was really no special design for line extenders. There was just, maybe, a toned-down version of the regular trunk amplifier used as a line extender and, also then, as a bridging amplifier which had a feed through for the main line and a side line amplifier.

JEFFERS: Why don’t you refresh for me the model numbers. From my own experience, I am familiar with SKL. They had one that covered the low band and then they had another product which was very successful that covered all the way from Channel 2 up to Channel 13. What were their model numbers?

SHEKEL: The model number for the wide band amplifiers started out as Model 212 and then there was the Model 222. Really the idea, at the beginning, was that the line amplifier should be flat, as flat as possible. The way that SKL got into this really was that they did have a distributed amplifier which was used in laboratory work to amplify short pulses which was built on the basis of a distributed line and that had to be very flat and very linear phase. And, that went out to about 250 megahertz. I suppose then the people at SKL realized that they were talking about the band used at that time for cable TV, so they modified the amplifier. The main modification was to change the input and output to match it to 75 ohms. So, the amplifier was completely flat and all the cable equalization was done by passive equalizers. The Model 222 then was designed to have some slope in it to start with to compensate partially for the cable, so there would be less work on the passive equalizers.

JEFFERS: I recall a project that I worked on for Bell Labs in Southern Bell and while we used the Jerrold amplifiers, we also used at about every 8th or 9th station, an SKL automatic gain and slope amplifier. Can you give me some information on that?

SHEKEL: Yes. This is not one of the efforts of work that I was involved in. It started out with the equalization being thermal equalizers. Then, SKL got the idea of changing the slope of the equalizer by sensing two pilots and we tried to work out on passive equalizers to do that. However, then, looking into the theory of the distributed amplifier, we found out that by using two amplifying paths with a phase difference between the two paths, the combined amplifier has a slope and, by changing the phase difference, you can change the slope. So, we ended up actually making an amplifier that was still a tube amplifier based on the distributed amplifier principle but with gain and slope that could be changed by sensing high pilot and low pilot. So, this was the automatic level and slope control.

JEFFERS: Was that ever patented?

SHEKEL: I believe there was a patent application for that.

JEFFERS: Were you one of the inventors?

SHEKEL: I don’t think so but I don’t know what the patent number is.

JEFFERS: I see; that’s unimportant.

SHEKEL: Now there are other applications of the same wide band amplifiers in different systems that I was involved in. One application was in the school system in Hagerstown, Maryland, where the idea was not to have a central studio to broadcast all the lectures but to be able to broadcast from different points in the system and then send the information back to the studio and then distribute it down. And what we came up with is the design that the system had a ring, a closed ring, as the heart of the distribution system and then with feeders, feeding off that ring to the various schools. So, what we had to do is to have a closed cable that you can introduce a signal at any point and then not have it cause oscillation when it comes back around the ring. We designed this by having a set of very sharp, and deep attenuators that blocked that channel. So that any time you wanted to introduce a channel in the ring you put a blocking filter before it. So, therefore, for any channel the ring was not closed but you had the signal go around the ring, and come back to the point where it had started and stopped there. So, this kind of closed ring system is something that we built and installed in Hagerstown.

JEFFERS: Yes. I remember at that time that the Bell Systems … different systems around the country got very interested in the use of cable equipment for educational purposes and I’m sure that’s what Hagerstown was.

SHEKEL: I seem to recall that Hagerstown was some kind of a model school system that Bell put in a lot of money just to show the feasibility of the idea.

JEFFERS: Yes. I am personally familiar with the one in Southern Bell at the time because it used some of our equipment. But, it was really an offshoot of what we normally called CATV. But it was interesting in that we were doing essentially the same thing.

SHEKEL: There was another unique project that we did at the time trying to start working with a two-way system and what is now commonly known as the high-low split system and I designed it and SKL marketed it. It was the passive bridging network consisting of high pass and low pass filters that you put the trunk at two corners of the bridge and the amplifier the opposite two corners and we even called it a primary TWA network. I don’t think we would be sued by the airline, but we changed to using the full name–Two-Way Amplification.

JEFFERS: We are talking about the tube–the vacuum tube equipment–that SKL made at that time. They eventually had gone into transistor equipment. Did they not?

SHEKEL: Yes. I think it was about 1964 according to a note from Mike, that everybody was going to transistors and SKL felt they had to go to transistors.

JEFFERS: I don’t mean to jump ahead if you have any more to say earlier than this, but, I remember seeing–I’ll call it the new product line–introduced at an NCTA show and I was very, very impressed with it.

SHEKEL: The transistor product line.

JEFFERS: The transistor product line because it included, you know, complete new housing and it was really state of the art at that time … at the time of introduction. Did you work on any of that?

SHEKEL: Yes, I did work on that and the chief engineer at that time was Pierre de Bourgknecht, an engineer from Switzerland. He had some very nice ideas which may have been state of the art but I don’t think they were actually state of the market. I think that’s why SKL was not successful in introducing the SKL transistor equipment. The idea was very nice. First of all, the housing was a cylindrical housing about maybe an inch and one-half in diameter. So you could put it into the cable and just make this almost as part of the cable, so that you could have low gain amplifiers and put them very close to each other. And, for the powering, used DC power along the cable. The voltage of the DC power was also used as a gain control. So, you could sample the signal infrequently but then distribute the change of gain along the cable. Theoretically, a very nice idea but I believe that for one thing the idea of DC powering didn’t work out too well. And, also the construction of those cylindrical units, they were not very well suited for mass manufacturing and also not very well suited for maintenance. Of course, the idea maybe was to make this amplifier as inexpensive as possible so they could afford to throw it away, but it didn’t work out this way.

JEFFERS: You know DC powering has been talked about every year since the cable industry started and when all is said and done, no one has had the nerve to go into it because of the corrosion possibility. And, to the best of my knowledge, no one in the industry has really studied it because it does have application in many, many places. Let’s talk about your bosses there.

SHEKEL: Now, let me just say something about DC powering. Like many of the things that SKL did, it was theoretically a very nice idea. It would show all kinds of theoretical advantages. I know I did a couple of talks to show that it was much superior to AC powering. We never observed corrosion problems but you have to see the realities of the market and of the competition and there were quite a few large companies and all of them went AC powering. So, there was quite a lot of customer resistance. It’s very hard to sell something if you have to start explaining to the customers and pitching them and bringing them up to the idea that it is really a good idea. It’s an uphill sale. So as far as the transistor equipment of that type it didn’t work out well.

JEFFERS: Yes, that’s right. You know one further note, of course we reacted exactly the same way. We knew it would be good but the customers were more interested in knowing whether that equipment would be there twenty years from the time they purchased it and that was a tough thing to sell.

SHEKEL: Of course later SKL followed the stream and came out with the transistor amplifiers in the standard configuration in a cast housing with modules but then they were just one of many and there was nothing unique about it anymore.

JEFFERS: Yes, that’s the product line I was thinking of. I do remember the cylindrical ones but I was thinking of the product line they introduced, it seems to me shortly before they went out of business. As a matter of fact, my recollection is they sold that product line to Scientific Atlanta.

SHEKEL: Yes. That’s correct.

JEFFERS: Did you work on that product line?

SHEKEL: Yes. I worked on that product line but that was then just one of the same line like everybody else was doing. And, I think at that time SKL lost the special edge that it may have had, not in the commercial aspect in the innovative design of doing something different, and maybe seeing later other companies following in the same footsteps. Everybody is now going wide band and everybody is now using directional couplers and everybody is using two pilots for slope control. But, when SKL went into making the conventional transistor amplifier, it was just another company doing another product. It didn’t have anything unique to show for it.

JEFFERS: I see. Let’s get back to … can you discuss some of the key people there–Don Spencer and Fitzroy Kennedy? What was your relationship to them? Were they good bosses? Were they heavily involved in the engineering part of it?

SHEKEL: Fitz Kennedy and Spencer were the founders of the company. Fitz was the technical person and Spencer was the financial–the business person. On the business side, he was very conservative and didn’t try to expand the company or to go aggressively after sales. But, the company was growing at a moderate rate. It was a very nice company to work for. So, Spencer was not involved in the technical side but Kennedy was very heavily involved.

JEFFERS: But, what did they do before they started this company? Do you know?

SHEKEL: No, I’m not sure. I know that Fitz later worked at Arthur D. Little. I’m not sure what he did before then. For all I know, they started in 1948 on the basis of two patents–one of them was the distributed amplifier and the other one was a generator for very short pulses which was based on a technique developed during the war in radar … that you charge a transmission line and then you discharge it quickly through a mercury wetted contact and you get a pulse whose width is dictated by the length of the line. And, the line was just a coiled up coaxial cable. So, having these two products, to generate pulses and to amplify them, it was a nice pair of equipment for instrumentation. And, then, of course, the distributed amplifier became the wide band amplifier for cable TV.

JEFFERS: Did those guys get along pretty well?

SHEKEL: As far as I know, yes. I know that Fitz left the company in the middle ’60s … 1965, I think. I don’t know what the reason was. He still stayed as the director of the company but he went to work for Arthur D. Little.

JEFFERS: To the best of your knowledge, are they still living?

SHEKEL: No, none.

JEFFERS: Both are dead.

SHEKEL: Yes, both are dead.

JEFFERS: Oh, that’s a shame.

SHEKEL: Fitz died about four years ago. Spencer was suffering from emphysema and moved to Arizona. He died there.

JEFFERS: How about Pierre? He came in, had this very good theoretical product line that wasn’t too practical. I guess this is the short way of saying it. Where did he go since SKL?

SHEKEL: He was a very ambitious guy and while it wasn’t his skill, he started dealing in real estate and he was buying houses in Boston, buying and selling, and finally found out that that’s where the money is. So, he got up and left SKL.

JEFFERS: How about Bob Brooks? He was a great guy in the cable industry.

SHEKEL: Bob Brooks was on the sales side. When I came to the company, he was a field engineer. A very good field engineer and had a very thorough knowledge of the technical side and worked on the installation of systems, commissioning the systems and troubleshooting. Then, eventually he went into the sales side. But, even then, he was in charge of the field engineering.

JEFFERS: Do you know what he has done since he left SKL? I met him a couple of times but …

SHEKEL: Yeah. He’s now chairman of Cencom Cable in Chesterfield, Missouri.

JEFFERS: I know of them. He’s done well for himself. How about other guys there … Socks Bridgette. Did you know him?

SHEKEL: Yes! Well, if you know Socks, he is about the most colorful guy that I’ve met.

JEFFERS: No, I don’t really know him.

SHEKEL: You never met him?

JEFFERS: No, I don’t think I did.

SHEKEL: He was there before I joined SKL; he was there when I left SKL. Then when SKL went out of existence, he stayed on in the Boston area as a consultant working with a lot of local installations. Only about a year ago he moved to San Diego. He now suffers from ill health and he’s married to a woman whose family lives in San Diego. So, he just moved to a warmer climate.

JEFFERS: I guess the problem with all these gentlemen, and unfortunately us, is we were pioneers in the industry … we are getting pretty old, too.

SHEKEL: But, Socks really, I think, had some of the nicest and most interesting ideas. I really don’t know for a fact but I believe that the idea of adapting the wide band amplifier to cable was his. I know that when I came there first he presented me proudly with a paper that proved that the ideal amplifier would have an 8.7 dB gain. Everybody came to believe it. As far as I know, he was the person who generated it. Of course later it was understood this was something very ideal and not practical conditions.

JEFFERS: That’s right. It’s very theoretical … it can be easily derived.

SHEKEL: But, he did a lot of innovative circuit designs.

JEFFERS: Was he an engineer, totally, or did he have a dual function then?

SHEKEL: No, he was an engineer, totally.

JEFFERS: Okay. How about George Green and Bill O’Neil? Did you know them?

SHEKEL: Bill O’Neil was an engineer. He joined after me, I think somewhere in the mid-’60s. A very good engineer. He worked mainly on the development of the transistor amplifiers … not the cylindrical but conventional amplifiers. Then, when SKL sold that line to Scientific Atlanta and went out of the business, he founded a small company in Waltham that got a license to service these amplifiers. So, for a few years, he was actually working with SKL customers and providing service and maintenance on those systems.

JEFFERS: One question. When you came out with the, let’s call it the conventional amplifier, did SKL produce any of them and for how long?

SHEKEL: Yes. Well, I am trying to recollect. I think for at least two or three years they were a very standard production. They were the standard line of amplifiers. Nobody was buying tube amplifiers anymore.

JEFFERS: I see. Yes, okay. No, that’s right. So, they produced that product line for about two years and eventually, am I correct, as they went out of business, they sold that product line to Scientific Atlanta. How about George Green? Was he an engineer?

SHEKEL: No. George Green … hard to say. George Green joined the company at that time in the late ’60s, when many companies were trying to expand and spin off subsidiaries or acquire subsidiaries. So, he joined the company as vice president for marketing and he started expanding the company … he opened up regional sales offices. He came from Ameco, I believe, before that. So, he was based in Phoenix and the first thing he did was to open a regional sales office in Phoenix, close to home. Then he opened several others and SKL also tried then to acquire some subsidiaries which had nothing to do with CATV. But, in fact, trying to start to build up some kind of a miniature conglomerate, it was over-extended and a couple of years later, George left the company and left quite a few debts behind him. The company then brought in a new management team and the first thing the new management team did was have a massive layoff. It was the first time in the history of the company. Spencer was running the company like a family in a sense.

JEFFERS: When was this last period? Do you know when?

SHEKEL: I’m talking about 1968 or ’69. So, new management came in to try to revive the company–to put it back on its legs. It was now starting to run, not like an engineering company, but more like a business. I don’t know, maybe I used “business” almost in a pejorative way. So, the first thing was a massive layoff. People who had been with the company since its inception were just sent out. Then, workers tried to organize a union and that pitched the workers against the management and it no longer was a nice place to work.

JEFFERS: Were you part of that layoff?

SHEKEL: No, I was not. I left afterwards. But, as I was saying, when Don Spencer was running the company it was really run like a small company … almost like a family. People were cohesive, close together. He was the father figure. And he acted this way, so the company maybe did not make too much money, but everybody had a good time.

JEFFERS: Going back to one thing. This so-called standard product line. Do you remember the model number of that? My recollection is it was a 260 series.

SHEKEL: The cylindrical, DC-powered amplifiers were a 250 and 260 series. The “conventional”, AC-powered amplifiers in cost clam-shell housing were marketed as the 7000 series.

SHEKEL: They were introduced with a big marketing hoopla with a trade name “Colorburst” to emphasize it was for color TV. It did nothing new to color TV; you had color even before that. And with a logo that looks like a peacock … like the marketing people had their hands in it very deeply.

JEFFERS: I’m sure they did.

SHEKEL: Really. The idea was that you have to build an amplifier like everybody else so they can sell it. And, that’s what SKL did. They built an amplifier like everybody else–looks like everybody else’s. When the box was closed, you couldn’t tell the difference.

JEFFERS: Yes! Do you remember if SKL had any association with any of the coaxial cable manufacturers? Did they work closely with them in any way?

SHEKEL: There was no formal relationship. I mean like some agreement that they are going to exclusively with one type of cable or whatever, but maybe they ended up using one or another in preference. And of course SKL, when they were selling a system, were selling all the equipment, including the cable.

JEFFERS: Yes! I seem to recall that they might have used Superior Electric Coax Cable at that time. I do remember that Jerrold had an agreement with Times Wire and Cable and I think Scientific Atlanta had an agreement with another manufacturer. They tied it together as the full sale. It’s possible that’s where I heard the relationship existed between Superior and SKL.

SHEKEL: As far as I know, I do not know of any formal relationship. But it’s a fact, yes, that for several years most of the cables were Superior cables.

End of Tape 1, Side A

Start Tape 1, Side B

JEFFERS: Jake, I’d like to go back over some of the SKL products. Let’s start with the SKL 212 and 222, the vacuum tube distributed amplifiers. You gave us a good run down on those, but I’m not so sure that I caught the time that SKL switched to that cylindrical amplifier. I believe that might have been the first solid state amplifier you people put out?

SHEKEL: Yes. The first solid state amplifier was the model 250 which came in that cylindrical shape. But the tube amplifiers were not phased out. SKL has been offering them all the way up to, I think, 1965 or ’66, while the transistor amplifier, came in in 1960. So, in effect, while SKL was offering transistor equipment. It was only one part of the line. And the transistor amplifier, the Model 250, was something unusual in its shape and mode of operation. It was a cylindrical shape about 1 1/4 inches and it was designed so as if to form a continuous part of the cable that you drop in gain to compensate for the losses. It was powered by DC and the voltage, was also used as a means of gain control. If you increased the voltage you decreased the gain.

JEFFERS: It was a trunk amplifier system?

SHEKEL: It was a trunk amplifier. There was also a series of distribution–a line extender–a Model 253, 252 and so on.

JEFFERS: Okay, good. Now what was the next product line, solid state product line? As I remember it was a 260 or 262?

SHEKEL: Yes. The problem with the 250 line was that it was not acceptable because the idea of DC powering. There was a discussion going on over time whether it would cause harm to the connectors because of polarization. And rather than trying to prove that it doesn’t, SKL then switched to a new line of amplifier that was AC powered. This was the line with the 260 numbers. Now there was the basic trunk amplifier, the Model 265. It was this time in a cast housing with a simple cover and it was a fixed amplifier that was again put into the cable at intervals. And after five of this amplifier, the sixth one that was the powering station, and since there was AC power at this point SKL did put in the tube amplifier at that station, and that was the Model 222–the chain amplifier which was used for AGC. So what you have is modules of six amplifiers, five of them transistor amplifiers with thermal gain control to compensate for the losses. And the sixth one was a tube AGC operated by pilot to mop up the differences. And every second module, that means every twelfth amplifier, there was a two pilot automatic slope control. Also a tube amplifier.

JEFFERS: Okay. On the two, I forget what the trunk was.

SHEKEL: The trunk was a 265.

JEFFERS: Okay. On the 265 was it at that time that SKL switched to the typical hybrid modules that TRW and Motorola made or were they still an individual transistor?

SHEKEL: No. That was about 1962 and it was still individual transistors.


SHEKEL: A single circuit board in a simple box. In fact, it was almost the same size box as was used for the taps. The line also included a high gain, high output model 260 distribution amplifier, that was supposed to cover a large distribution area without need for line extenders.

JEFFERS: Okay. That clears that up. I noticed that pretty late in SKL’s history Bill O’Neil gave a talk at a 1975 NCTA convention and he was apparently working with Jim Grabenstein on a feed forward amplifier for Cumberland. Do you know anything about that?

SHEKEL: Well, I am aware of that but that was way after I did leave SKL. I left SKL in 1970. So I was not directly connected with that.

JEFFERS: Yes. Then there was another product. I believe we discussed it before, but I just want to reiterate this. There was a product that SKL put out that really that was just a drop in to the Jerrold Star Line One product line. What was that model number?

SHEKEL: That was the 7000 Color Burst series, in about 1966. But I want to mention something before that. Even though SKL was producing the various transistor amplifiers, it was also selling tube amplifiers at the same time. And even as late as 1965, tried to come out with another type of amplifier–the Model 215 long line amplifier which was supposed to be the trunk amplifier for long transportation trunks. It was low band affair … only up to 100 MHz but it had a hybrid construction in the sense that the input stage was a low noise transistor amplifier. And the output stage was a chain amplifier of tubes to make use of its low distortion. It was trying to combine the best of both technologies. Again, it didn’t fly much, I’m afraid, in the market. But I think it was an interesting comment for SKL trying all the time to come up with something different and try to stand out. If they could not find quantity of the market share, at least to stand out by some specialized product.

JEFFERS: That is interesting. I am glad you brought that up because I think that is a significant part of the history of SKL.

SHEKEL: As we come to 1966, there was a change of management. The new management team came in and the old Spencer Kennedy was gone. Spencer had left because of health problems. So, Charlie Wright came in as president; Dennis Parks came from IT&T as the chief technical officer; and George Green for marketing. And the whole way of work changed. And the first I remember was that when they brought in all the changes in the engineering department Green said, “It’s very nice to try to be innovative and inventive and so on, but you have to look at the bottom line … you cannot fight with success. So if there is something we see succeed in the market, let us do the same.” And that’s when we came out with the Color Burst line, which as you say was actually, in effect, dropping the modules into the Jerrold Starline housing.

JEFFERS: After that, you came up with what I call the final SKL product line, a very big amplifier that was a full station and all, and eventually it was sold to Scientific Atlanta. Were you involved in that at all or had you left by that time?

SHEKEL: No, I had gone by that time also. And that was after 1978.


SHEKEL: But I know that eventually when SKL went out of the cable TV business, Scientific Atlanta took over the product line.

JEFFERS: Okay. Well, how did Bob Brooks fit in with the picture of SKL?

SHEKEL: Bob Brooks as I remember, started out in field engineering and he was involved in the design, in the sense of bring back information from the field … how the equipment works, the trouble that we’ve seen in the field, how to correct them, and so on. Eventually, he was promoted and he became in charge of marketing and field engineering.

JEFFERS: He was, and by the way still is, a very important man in the cable industry. I believe he is with Cencom right now.

SHEKEL: Yes, with Cencom. He was very important as far as the development is concerned. As I said, in keeping us engineers in touch with the field problems and with the installation problems. And he tried to give us a very good feeling of how the equipment looks to the technician and to the user. And, in that sense, he did affect many of the “design” decisions of the equipment.

JEFFERS: All right. Let me throw out four names that we have discussed briefly … Sox Bridgett, Charlie Wright, George Green and Bill O’Neil. Just give me a brief rundown on how they fit into the SKL picture.

SHEKEL: It’s nice to give them in the historical order. Sox Bridgett is a very unique individual from the beginning … he was there before I came in. I think we can credit him with some of the basic ideas and developments in the cable. Maybe the thing that sticks in my mind first is was when I met him and he tried to explain to me why the 8.7 dB amplifier is the ideal amplifier for cascading lines. We had many discussions about that. He was involved in some of the original designs of the tube amplifiers … the passive networks, the equalizer networks and further on, also transistor amplifiers. He was one of the principal design engineers of the equipment.

JEFFERS: He actually did hardware design?

SHEKEL: Oh yes. He did hardware design and system design.

JEFFERS: Okay, good.

SHEKEL: And also in testing and design of test equipment and developing test methods.

JEFFERS: Good. How about Charlie Wright, George Green and company?

SHEKEL: Charlie Wright and George Green are part of the new management team that came in 1966, after Don Spencer left. And they somehow changed the direction of the company. I don’t know if you remember but the middle sixties was the time everybody was becoming a conglomerate.


SHEKEL: I mean LTV maybe, but also SKL. And they were trying to become a conglomerate by acquiring a couple of other companies that had no relation to cable and also trying to expand the marketing by opening up regional offices. Especially George Green’s since he came from Ameco – opened up an office in Phoenix, Arizona, and for a year or so he grew to like it and expanded the company. But then it seems that the company overextended itself financially and had to pull in. And after a couple of years, George Green left. I don’t think that SKL was ever the same after that.

JEFFERS: Bill O’Neil was an engineer?

SHEKEL: Bill O’Neil was an engineer. He started out as a cooperative student from the Northeastern University and then came in as an engineer and advanced steadily. He is, I would say, a very brilliant engineer, very innovative. His most important contribution, I would say, is what you mentioned before about the development of the feed forward which, I think, is now a standard part of the CATV amplifiers.

JEFFERS: Yes, it is.

SHEKEL: Also, after SKL went out of the CATV business and sold the line of equipment to Scientific Atlanta, Bill O’Neil for a few years had his own small company that took over the service of the SKL systems and it provided maintenance of service to the old SKL customers.

JEFFERS: That’s interesting.

SHEKEL: They were ADS–Amplifier Design and Service. Small company in Waltham.

JEFFERS: Okay. One more question here. I believe you had left at this time. Do you have any background, any feeling, on why SKL went out of business and sold that product line to Scientific Atlanta?

SHEKEL: Well, first of all, in 1966 when the new management came in, the direction of SKL changed. There was less emphasis on trying to come up with innovative designs–the different designs–and much more emphasis on the bottom line … just to follow whatever is successful. And, also, trying to expand it into a large conglomerate and then having to pull back. I think that damaged the financial conditions of the company. The company was then bought and sold a couple of times.

In 1969, George Wayne came in for a short time as president and CEO and he was from a completely different field. He didn’t have much of a feeling for the cable TV and so on. And then sometime, I think, the beginning of 1970, Dick Leghorn acquired the company and tried to put it back on track. But, SKL was a small company … it was actually very different from the other cable companies. Until 1966, as long as it was under the direction of Spencer, it was a small company–going slowly, not trying to expand too much but doing a nice creditable job. And I don’t think it was ready for the kind of expansion they tried to do with the new management.

JEFFERS: How was their business other than cable? In other words, they continued the business particularly with the distributed amplifiers almost as laboratory equipment. Am I correct and did that continue to be a fairly good business?

SHEKEL: That was a fairly good business. They had some special equipment–the Wideband amplifiers for amplification of short pulses, pulse generators and the variable electronic filters, the instrument line. And that was a business which was just steadily bringing in orders. You didn’t have to go out and market it aggressively, everybody knew the name. In fact, many of the users were amazed when they were told that SKL also makes cable TV equipment. They knew this as the instrument company. You just sat back and took the orders as they came over the phone. It was advertised mostly by word of mouth and it seemed it just sold itself.

JEFFERS: Yes, that is a shame. It was a great company. I agree it was small and all, but you’ve already said it … it was very innovative. Tell us about what you did after you left SKL. Where did you go?

SHEKEL: I always knew that I liked to lecture, to teach, to speak to an audience. So, I tried to get into the academic world, into teaching. And I went to the University of Maryland and was there for two years–1970 to 1972. And I did teach some undergraduate courses. I was in charge of the undergraduate office. I was in charge of the computer installation for the college of engineering. It was interesting. However, I found very quickly that the university environment is, or at least at Maryland, somewhat removed from the engineering world … talk about your ivory tower. And I felt that I missed the excitement of actually seeing something which I designed being produced on the line and going out the door and the contact with the users of the equipment. So after my first contract was finished, after two years, I was looking around to get back into engineering. That is when I got in touch with Jerrold.

JEFFERS: Of course I remember that well since I worked with you at Jerrold. Now that you are back in CATV and Jerrold, why don’t you give us a run down on some of the things you did there?

SHEKEL: Well, the first weeks in Jerrold were very exhilarating because here is the company that we were always looking at as number one and trying to catch up with. And here I was part of it. The things I worked on at Jerrold … I don’t know if I have them in order, but if you take no particular order … One thing that always intrigued me in cable TV was the question of the distortion and it was at the time the notion of well behaved and non well behaved amplifiers. An amplifier may have a little distortion at a certain level then, as you went down, the distortion would go up, instead of going down. So, the curve of distortion versus level was not a smooth curve, but it had maybe some dips. And if you tried to design an amplifier to take care of that dip, to have a low distortion output, it was very dangerous. Because it was very easy, by changing the level, to go out of the dip and the distortion would rise dramatically. I was trying to find out the reason … how to explain that behavior. I came up with the idea that actually when we talk about third order distortion, the same frequencies could also appear as a result of higher order–odd orders–like fifth, seventh and ninth. Each of them going up at a different rate with a power level. And if they combined, because of the different phases, the product at this same frequency may add up or subtract. So that really every amplifier, no matter how well behaved it is, will always reach a level where the higher order distortion will catch up and cause this effect. So there is no such thing as a well-behaved or not well-behaved amplifier … they all behave the same way. It only depends at what level it happens. And you have to design it so that the level that you work is still where you have third order without higher order distortion coming in. So, I worked at that. I presented a paper at the 1973 NCTA convention. I wrote about it and that’s it.

JEFFERS: Let me tell you, I remember that well. And to the best of my knowledge, you are the only person in the cable industry that ever ventured into the higher orders to explain some of what we call the poorly behaved amplifiers. So I’d say your 1973 paper remains a classic in the industry.

SHEKEL: Another problem on which I worked extensively was the question of equalization. This is something which really I have been working on for years, because many of the products which I designed at SKL had to do with that. My approach was that actually, what you are doing is you are trying to simulate the length of cable and as the temperature goes up and down, the cable effective length changes. So, the equalizers that you have to use had to simulate a length of cable loss. And as the temperature goes up and the real cable becomes longer, then your equalizer network should become a shorter cable. So, the design of the response should be like a cable loss rather than an inverse of it. And, also, it came out that the best way to control it automatically would be to have the high pilot control the gain and low pilot control the slope. And this is an idea which, I think, had been presented to Jerrold and Jerrold has included it in the design.

JEFFERS: Yes. If I’m not mistaken, I think that you just said that one backwards. I think that you had it that the high pilot controlled … maybe I missed it. Just in case, the high pilot controls the slope, moving in the equivalent cable section, and the low pilot controls the gain.

SHEKEL: I had it wrong?

JEFFERS: I think you did. We will straighten it out. Anyway whatever it was, I think Jerrold, and I think almost every other manufacturer until about that time, has switched to the equalizer. I’ll call it the equalizer … it really isn’t. The cable equivalent way of doing it rather than the equalizer and it also seems to be smoother across the band when you do it that way. So, I would say those studies resulted in something that really is a standard automatic gain, automatic slope control system in the industry. So that lives on beyond your tenure with Jerrold.

SHEKEL: Now as I try and recall another project, it had to do with measurement of reflections, return loss. It was a special design of an impedance bridge that was able to measure very high return loss and eventually I had a patent on this design and I think it is incorporated. It was used extensively by Jerrold and also, as mentioned previously, manufactured by Texscan.

JEFFERS: Yes, that is correct. We licensed them to make that bridge in accordance with your patent. And it really got bridges to be quite accurate–I guess up to a thousand MHz. Certainly I think our spec based on your patent was a thousand MHz, so it was a significant improvement in the accuracy of impedance bridge measurements.

SHEKEL: The design had both wide band and very good balance. That means you can measure very large variance of return loss. Then, something that always fascinated me since the early sixties–using computers. At SKL, I think I was the first user of the time-sharing GE system when it came into Boston in 1965 with a clanking teletype. And at Jerrold I worked with trying to adapt computer and computer methods to cable TV. One project was the test chamber. The test van that Jerrold had to simulate a full cable system with reels of cables and amplifiers and to check out this operation over a temperature range. I adapted a Nova mini computer to be part of that setup and wrote a full program for running the test and reporting the results. Maybe now in 1992, with the ability of the PCs, it looks like a very straight forward project. But back at that time, it had to be programmed from the ground up. I also developed various methods to use in the layout of the system. I mean not a whole system but, for example, how to lay out the distribution part; how to optimize the position of the distribution amplifier and in cable powering; how to design the locations of the AC powering stations.

Ed Note: At Montreux in 1977, Dr. SHEKEL: showed that the design of cable powering requires a recursive program which was not possible with the commercially available programming languages. He managed to construct a recursive program by digging into the GE Timeshare computer operating system. Now, with programming language such as C, it’s a snap.

JEFFERS: I think some of those programs are used today.

SHEKEL: I’m sure they are. And then another project, I think, which I developed into the idea of Play TV which I developed with several other people–including you … I mean you own the patent.


SHEKEL: Which was using the cable system to distribute the games from the central position. Something like a pay TV system but you ask for a specific game and you have it running on your TV. And that was patented, and I think that after I left, Jerrold has tried to put it on the market.

JEFFERS: Yes. There was a major effort on that. If you remember, it worked with Mattel. Intelevision we called it. It was shown in many shows, and it worked beautifully–it really worked well. And we put the product line out and we suffered from exactly the things that Atari and some of the other people suffered from … people got tired of the games. But from the technical standpoint, it was quite an achievement. Is that about it at Jerrold?

SHEKEL: I think of major things. I mean I’ve had a hand in other things here and there.

JEFFERS: The major hand you’ve had when you get right down to it, I mean you’ve said it but not as directly, you really introduced computers to Jerrold. You really did. Because it was just at the time that we started. You were very involved in the pay TV system there, too, I recall. I remember you working on that with Tom O’Brien and some of the people. Which was really the start of … I didn’t say it correctly … an addressable pay TV system. You really were instrumental in the development of the very first addressable pay TV system, too. I mean our system has changed since then, but it was all that business in the early to mid-seventies that we started to go from, I’ll call it, manual operation to computer operation of a lot of the things.

SHEKEL: Yes. I guess I left Jerrold too early.

JEFFERS: You sure did! I wish you were there right now! You are very well remembered at Jerrold. Then, you turn around and left us in early 1978. What have you done since then?

SHEKEL: Yes, I left in 1978 and I joined American Science and Engineering in Cambridge. The product that was being developed by this company was a system of controlling loads on an electric distribution system by using a carrier over the power lines in checking a low frequency signal on the power lines, to open up relays that connect loads. And also, it was a two-way communication system so it could get information back from meters to find out how effective the load shedding is. And the thing that really attracted me to it and was curious, is that the system had many of the basic ideas and the structure of the CATV system. It had a headend, it had distribution lines, it had addressable terminals, it had two-way communication and it was, as I many times jokingly commented, really a cable TV system, except that it has no cable and no TV but it has everything else. I was with the company in the developing of the system until 1989, about eleven years. Then, when I left them, I went into consulting and teaching. I am now teaching at Northeastern University in Boston. I am doing consulting work, both in cable TV and electric load management system because of the two fields I specialized in before.

JEFFERS: I certainly want to thank you for this interview, Jake. It’s been great going over it and particularly in the area of SKL, you are the one thread we have left to the history of SKL and it is greatly appreciated.

Let me ask one other question. As you look back on both your personal experience with CATV and even as you think of CATV as a distribution system to take information, in most cases, it’s entertainment television to all the residential areas of this country. Are there any areas that you think cable could have done something better than just that? Because, so far, that’s about all it’s done. I know, as an example, I always felt myself, that we failed in our ability to do a major education job with the people of this country … go offer that kind of a service. And you, so interested and so involved in education, I was just wondering if you had the same reaction.

SHEKEL: It is interesting because one of the early systems I worked on at SKL, in 1957, was an educational system in Hagerstown, Maryland. And that was a system that had a round robin. I mean it had a round trunk as a closed loop, and branches going out to various groups that could originate from various places. I visited that system once. What I saw, in effect, was that the lectures they had there were just canned lectures. What happened there is that the professor had just taped something, and then had distributed it. So, it was no different than anything coming off an educational station over the air.

Next time I came to teaching by cable TV was when I was at Jerrold, I did part-time teaching at the University of Pennsylvania. For a couple of semesters, I taught as part of their TV distribution network. They would send out the lectures over cable to remote locations, remote classrooms. So I was there and I had the class in front of me. There were also a couple of cameras–one facing me and one overhead. And I knew that what I was talking about was also going out to other students but I think I saw one of the drawbacks of this. I had a class in front of me, which I was talking to, that was fine. But I had no idea of the other students I was talking to, and I had no feedback from them. I mean, even if you have questions back by telephone, it is not the same thing. When you stand and lecture to an audience, you have all kinds of clues from their behavior. They look at you and you sense their response. I mean if they get bored, you know how to pace your lecture … how to change it, how to get deeper into some details, how to gloss over some details. I think visual feedback to the lecturer is very important, otherwise, you might as well have a canned taped lecture. So I think this is one of the things that is missing. No matter how interactive it is, unless you have a big screen, where you can see the whole of the classroom in front of you, it is not the same thing.

JEFFERS: That is very interesting. I think the two of us would agree. The technology is there to achieve some of these things if the industry, as a whole, thought it was worthwhile to develop such a system. I think one of the problems, and I don’t mean to be negative, is that the managers in the American way think of the bottom line. I think when you get right down to it, they don’t see where the income is coming from.


JEFFERS: But hopefully, things like that will eventually come.

SHEKEL: Well, if you feel the development of the teleconferencing now–this is just the beginning. If you have a classroom … the teleconference, but it’s in a much, much larger scale.

JEFFERS: Okay. Very, very nice talking to you and having this interview. I appreciate the time you have taken, Jake.

SHEKEL: My pleasure, Mike. It was really nice to recall these memories.

Skip to content