The K.D. Smith Collection. 
(c)By Edward A. Sharpe Archivist,
 Southwest Museum Of Electricity and Communications (Now SMECC)
Reprinted form SMEC "Vintage Electrics" Volume 2 #1

K.D. Smith, while a member of technical staff of Bell Telephone Laboratories as a staff engineer, had access to what seemed to be an unlimited supply of early experimental examples of solid state technology. Apparently when something was to be disposed of, K.D. would save it. When I asked Jim Early, a colleague of K.D. Smith, if he or anyone else had managed to save any of similar material as K.D. Smith had, he told me no, that K.D. was the only one that had made a systematic effort to collect up some of it.

Although the folks that sorted through the immense collection of old radio tubes, transistors, and assorted items assumed that K.D was merely a pack rat; it has become a proven fact that things were saved for a purpose once you analyze the material at hand and reviewed the reference material published by The Bell System. Within seconds I recognized the artifacts at hand as being historically significant, and within just hours realized why many of the items had been saved.

One reference source that serves as a extremely valuable resource are the lab notebooks full of comments that K.D. Smith kept at home. Many times the information was a duplicate of what he put in the formal notebooks that Bell Labs required employees to keep that would be witnessed to support patent cases. Often though, the thoughts he would jot down were just things that came to mind and he wanted to keep a record of.

Some of the most enjoyable reading in his journals are the records of what K.D. called "PARTLY BAKED IDEAS", which he often referred to in an abbreviated form as "PBI's". They were either brief introductions to a possible invention, or in many cases just a record of a possible way to solve a problem that was at hand.

There were times that were noted in the books that he became rather frustrated in maintaining order in this large collection of artifacts, and at one point on the vacuum tubes, he allowed himself to keep only a maximum of 10 of each type! When it came to early solid-state devices however, `THE MAXIMUM OF TEN RULE' Did not seem to apply! If one was to judge the fondness for a development project, based on the amount of artifacts that were kept, the clear winners would have to be M-1752 junction transistors and Bell Solar Batteries (solar cells).

K.D. made other references in these notebooks that the material needed to be sorted and categorized. Apparently some of this action was carried out, as you would find some of the most profound artifacts in shoe boxes marked `MUSEUM'! Envelopes that were in these shoe boxes had transistors grouped together in them. Many of the envelopes were the original filing envelopes that the devices had lived within all of there lives accompanied by the measurement data on the part. This data was very instrumental when Howard Dicken wanted to see how the parameters had changed in the time since the device's date of manufacture (see the article on this subject by Howard in this copy of VINTAGE ELECTRICS).

In one document that is among K.D.'s notes from the early days, a list provides some great insight as to what K.D. felt were historical or landmark devices. In reviewing this list I whole heartily agree with his selection. At the time the technology was new he had fantastic foresight as to what we would be excited about this many years later!

I wish I had K.D. Smith sitting next to me to explain what some of the items that he had in his collection were, the stories behind them, what had led the developers to the point that the device represented, and to explain to me just what some of the items are! In any collection of artifacts, the person that does the collecting always has the greatest insight on the artifact itself.

K.D. Smith is to be commended for his collecting efforts. Had he not collected in such a large scale manner, the world would be without many examples of the early solid state technology. Although the Bell Patent Department has examples of each M series part, we are not sure that they possess the variations that we have come across here.

Fortunately I have made a number of fine new friends out there that worked with K.D. back during the glory days of transistor development at Bell Laboratories. I can not express enough gratitude for the patience and insight afforded this thankful archivist by Jim Early and Bob Ryder. Without the help of these two associates of K.D. Smith's I would have been traveling uncharted waters without guidance.

Many long hours of discussion and teaching were done by existing friends, namely Morgan McMahon, Jack Saddler and Howard Dicken. You will also see articles by these fine scholars here also in this publication! Yes, I had used transistors since third grade, but had never learned the history of the development, processes involved in manufacture or how the companies were born and died. I have all of these folks to thank!

How the collection came to the museum.

K.D. Smith had passed away and the Smith family contacted Clem Chase, a radio amateur and also at that time president of The Quarter Century Wireless Association, to help the Smith family dispose of some radio equipment.

What Clem thought would be the contents that would fill just a couple of boxes, turned out to be an entire truck load of the wildest assortment of parts and equipment that Clem had seen!

Clem Chase at this point enlisted the help of two other radio amateurs and fellow members of QCWA, Harry Snyder and Gerry Higgins, from Carefree Arizona. Clem drove the truckload of goodies up from Tucson, where they were deposited on Gerry Higgins garage floor to be sorted. The truckload, when spread out took a good part of Gerry's garage space! The sorting process took 3 days, being primarily done in the morning, due to the extreme heat we are endowed with in the summer here in Arizona.

The collection at this point consisted of radio tubes, transistors of what appeared to be of an early nature, books, circuit boards, hardware, scraps of wire, old transformers, odd brass looking objects, scrap metal and amateur equipment. There were also thousands of short lead components suitable for insertion into PC boards that K.D. had kept for future project use.

It seemed most odd that there were only a small grouping of books. Usually in our experience, anyone that has this much
The K.D. Smith Collection, Cont.
equipment and parts also has a vast quality of books magazines and papers! Harry told me that was all that they had seen in the batch, and offered no explanation as to why there were so few.

After I had sat for an hour and read through the books, I noticed that they all contained articles by K.D. Smith. It was clear at that point that K.D. had been one of the pioneers in the early Bell Laboratories transistor efforts.

I then called all of the people that I knew! I wanted to know if they had heard of K.D. Smith, and what these folks knew about early transistor history.

I found that I had an excellent reference library sitting right next to me in the form of BELL SYSTEM TECHNICAL JOURNALS and The Bell Laboratories RECORD. In the pages of these fine journals, the history of the Bell Telephone Laboratories progress is contained!

I also called K.D.'s son Dave Smith, and Dave sent us many papers and notes that K.D. had saved during his time at Bell Laboratories.

Discovery of the Morton tube.

I had seen pictures of the Western Electric 416 tube prior to my encounter with this collection, so when I saw what appeared to be a 416, I was able to recognize it instantly. In my further searches through the collection I found what looked to be a crude 416 tube. It had many of the same aspects as the 416, but instead of having the nicely gold plated pins coming out of the bottom of it, there were wires protruding from the base acting as the connection! The more I inspected the tube, the cruder it looked! Yes! You guessed it! This was one of the early prototypes of the famous 416 triode, or as it is known by Bell Laboratories folks I know, as "The Jack Morton Tube" or as "The Morton Triode".

This tube was the heart of the trans-continental microwave communications network called the TD-2. This system, although not known to all of us by name, nevertheless, has been a part of our lives for a long time. The TD-2 carried , in the days before satellites, all of the cross country TV network programming, as well as long distance phone calls.

At this point I contacted Bob Ryder, a former Bell Laboratories employee, and friend of K.D. Smith. In addition Morgan McMahon introduced me to Jim Early. Both of these fine folks were very helpful in educating me as to what was here in the collection.

I also called John Bardeen, inventor of the transistor. He did not know K.D. Smith very well, as he had left Bell Laboratories in 1951 to teach at the University of Ill. John did, however, send us an early transistor and spec. sheet that he had been sent after the 1952 teachers meeting at the Laboratories (see article "Teachers Taught About Transistors" in this issue).

I finally met Dave Smith in person at the 75 Ave. off-ramp and Interstate 10 in Phoenix. He was going back to Santa Barbara, and had found a batch of interesting papers of K.D.'s for us at the museum. We were actually supposed to meet at 67 Ave. and the interstate near a three story hotel that LeeAnn told us was there. However I guess we both got there and there was no hotel
at 67 Ave. and the freeway!! We both called LeeAnn for help, my call was first and I told LeeAnn that I would be at a Circle K at the intersection of 67 and McDowell, just north of the freeway. I cruised around awhile and called again. The line was busy so I called the other line and she said Dave was on the line and she had passed the info to him as to where to meet! I went on down the road and ended up at the Circle K just as Dave was pulling up.

After a greeting session, Dave showed me a few of the contents of the box he had brought up from Tucson for us. Unknown to either of us, there was a policeman watching both of us, and he came up and asked what we were selling. I guess, looking back on it, that we must have appeared rather odd with cars from two states and our greeting and exchange of old cardboard boxes!

WHAT DOES THE COLLECTION CONSIST OF?

In the future displays of the K.D. Smith Collection at the Southwest Museum of Electricity and Communications you will find many items of interest. Among these but not limited to, are the following list of areas to give you a brief introduction and wet your appetite!

- The K.D. SMITH MEMORIAL -

This display shows pictures of K.D. Smith at various ages. In addition there are photos of him working on various projects at Bell Laboratories. You will also note the listing of all of the projects that he had involvement with during his 40 years at Bell Laboratories. In addition to his ability to collect artifacts from the era that he existed in, K.D. was a very productive engineer and had the ability to work on very diverse projects.

- BOOKS ON SOLID STATE -

Early books published by Bell Laboratories on solid state. These are also supplemented by books given to us by Jim Early, Bob Ryder and Morgan McMahon. In addition to all of this, the semiconductor library is supplemented by the museum's collection of BELL LABORATORIES RECORD and BELL SYSTEM TECHNICAL JOURNALS, that have been here for reference here for quite a while.

- BELL TELEPHONE LABORATORIES NOTES -

There is large collection of preliminary sketches of devices made before they were actually produced. Included also are rough drafts of papers that K.D. presented at conferences. The rough drafts of letters he sent to fellow workers and supervisors show some of the problems that were experienced during device development, and what was done to work out the problems.

One of the more fascinating aspect of this paper collection are the Status Reports, Memoranda For Record, and Technical Memoranda that were issued during the progress of the development of devices. The content of these items cover cost estimates of material and capital equipment for manufacturing and estimates of quality to be produced and the time frame to accomplish it in.
The distribution list on the last page of the above mentioned type of reports reads like a Who's Who of the early semiconductor pioneering effort! Even these distribution lists provide insight, as each project would have certain of the engineers and scientists involved with it. The distribution list tells you which of them was informed of it!

  click for larger view of all the early transistors!

- THE OVERVIEW -

There is also a display showing some of the various types of solid state devices that Bell Laboratories developed that were part of K.D. Smith's preservation efforts. It will give you an overview of diodes, transistors, varistors, thermistors and solar cells.

- INSIDE THE TRANSISTOR -

Besides the devices themselves, there are small displays that were built by Bell Laboratories that show the manufacturing process that the device progressed through, each display is like an exploded view of a component, but implemented in actual parts rather than just a drawing! Feel free to use the magnifier hanging next to the display to examine Point Contact, Grown Junction, Alloy, Diffused Base and other types of transistors that are on display!

- THE BELL SOLAR BATTERY -

Many different forms of solar cells and some historical examples are displayed. These solar cells were called BELL SOLAR BATTERIES, and there are examples as they devel
oped from crude prototypes into the more advanced form that was used on satellites.

Historical samples include one of the arrays that was made up for the first transistorized repeater experiment that took place high a telephone pole in Georgia in 1958. These are the early design P on N Bell Solar Batteries. A variant of the cells that were in this array can be seen encapsulated into a solid block of plastic. There are three cells in this block, and this artifact was used in the late 1950's as a lecture aid by Bell Laboratories staff.

The final historical grouping are examples of Bell solar batteries that were slated for the TELSTAR I project. These were the brothers of the actual cells that went up on the satellite, but alas even though made from some of the same silicon crystals as their brothers, they did not pass the rugged tests that constituted the selection process. Some went up to generate power for the first television relay via satellite, and some remained earthbound to be collected by K.D. Smith and to arrive here at the museum for your viewing enjoyment!

Most of these cells work and output a half a volt each, however, there may be discoloration to the surface, or they did not produce the desired current, or worst case - there are some dead ones also!

We have also included as many pictures in the display as we can, so that you might see what these components actually looked like when their brothers were producing power in examples of amplifying telephone calls to powering TELSTAR I!

These solar cells were quite a bit different from their predecessors. Not only are they rectangular rather than round, but these cells are made with N on P structure to increase power output and lowered radiation damage effects. To armor them up for their cosmic experience, each cell is protected by a window of synthetic sapphire.

There is one of the Bell Solar Batteries out of the TELSTAR batch hooked up to a meter so you will be able to see it functioning. It is rather fun to pass your hand in front of it and watch the deviation of the meter as the light striking it's surface is diminished by the shadow your hand causes.

- DIODES -

Diodes! Some of these date from Before the WW-2 era. This was the solid-state effort that Bell Telephone Laboratories was involved in prior to the invention of the transistor. Even after the invention of the transistor there was much research being done on diodes also. Such items that are on display that came out of that effort are the IMPATT Diode, Varactors, improved Varistors, PIN diodes and more! Those amazing diodes.... not just a crystal detector once the BTL folks started working on them!

- TRANSISTORS -

There is a great type collection of transistors arranged in chronological order by M and A series numbers that Bell Laboratories assigned to projects at their inception. There are transistors here that the only place they were truly seen was inside the lab itself, as many never made it past the experimental stage!

Remember, Bell Telephone Laboratories developed transistors, Western Electric made them, and the Bell operating companies consumed them. Although Bell Laboratories was without a doubt the leader in solid state development, they, nor did their brother companies really sell transistors to the end users. They did, however, license the manufacturing processes and the technology they invented to other companies. These companies Such as TI, RCA, GE, HUGHES and others would build for the end user customer.

There were exceptions to this practice of internal consumption though. Western Electric did have a lot of government contracts. These contracts consisted of radar, microwave relay, missile guidance systems, and communications packages to go into government and NASA satellites.

WHOSE NEEDS DOES THE COLLECTION ADDRESS?

This collection of early Bell solid state devices, outside of visiting the Bell Patent Department, is the most complete type collection of its type in the country. In addition to the devices there are examples of the literature, manufacturing tools, and parts that were used to make up the various solid state devices.

Students who are studying semiconductor manufacture can
actually see how the early devices were assembled. There are samples of the actual germanium and silicon grown crystals that they can study. The process continues with slices from the grown crystal and on to the bar itself that would have leads attached to it. The most complete manufacturing sample file is associated with the M1752 grown junction germanium transistor, the very one that K.D. spent quite a bit of his time helping develop.

The library offers to anyone an outstanding collection of the birth of the era of solid state. It is a relatively small section of the museum's library due to the fact that not much literature was published prior to 1952 on solid state. In era following 1952 the quantity of books almost seems to blossom! We have folks like Morgan McMahon, Jim Early and John Fairfield to thank for their submittal of many of these. we are always looking for more to supplement this section.

The person who is in management may want to study some of the yield figures that we have for the early devices. statistical information is available in the form of Bell Laboratories status reports that outline exactly what state the project was at the time of the report being issued.

The beginning student in the electronics field is treated to artifacts that show solid state in its infancy and simplistic form. The displays in which transistors are shown in their assembly stages serve to de-mystify what exists within the sealed can they are learning to build and design with. Of course, the early literature acquaints them with the historical development of solid state. This is a chance to be exposed to many things that are not possible within a classroom environment!

Diodes - Transistors, the solid state components in integrated circuits. For a student to fully realize the impact of what he will be designing now, it is important to study how the devices that preceded his impacted the world around him. All of this information is at his fingertips.

To the person doing historical research, the K.D. Smith Collection is a vast asset. The researcher not only has actual hardware artifacts but the printed material to draw upon. The museum functions as a centralized reference resource not only covering the early days of solid state, but also embraces electrical and communications technology dating back close to the very earliest inception of the technology itself. - EAS

The Life Of K. D. Smith At Bell Laboratories By Edward A. Sharpe
1930-1940

K.D. Smith was involved with the development of test methods and electronic test equipment relating to carrier systems, coaxial cable terminals and field tests.

We are fortunate to have a large notebook that K. D. Smith saved with some of the memorandums he authored and co-authored. The first of these is dated Oct. 1, 1931, created by K.D. soon after his arrival at Bell Laboratories (remember, he started in 1930), it is entitled "Dynamic Cutoff of Vacuum Tubes". The last in this notebook is dated Mar. 23, 1936; and contains a review of the Boonton Radio Corporation `Q METER'.

This notebook gives some insight as to what K. D. Smith was involved with, but presents only a partial picture by itself. However when you couple it with the Bell Laboratories RECORD magazine, and the BELL SYSTEM TECHNICAL JOURNAL issues that we have in the museum, we will be able to portray a more complete picture... With a bit more research.

1941-1944

America went to war during this segment of K. D. Smith's career. During this epoch he was involved with the development of proximity fuses on behalf of Division 4, National Defense Research Committee. In fact, he was a consultant to the NDRC from 1941 until 1943.

Since this was a extremely classified project, he did not collect much in the way of artifacts or written material to take home during this time.

Seen here in VINTAGE ELECTRICS, along with this article is a picture of K. D. Smith's NRDC ID card. At the end of World War II K.D. Smith was presented with an award from Office of Scientific Research and Development through the NDRC for "Contributing To The Successful Prosecution Of The Second World War". A much reduced copy of this certificate is shown here, as well as a full size version of this document on file in the museum.

1944-1945

Radar - our nation's eyes to protect us against from the unseen enemy forces and to guide our bombs to their precise targets through the darkness of night!

K.D. Smith was working on the development of RADAR at Bell Laboratories during these years, and in 1945. One of his notes references that he was project engineer on the AN/APQ 13 and the AN/APQ 23.

For the person wishing to do research on the World War II RADAR efforts at Bell Laboratories, they will wish to consult the BELL SYSTEM TECHNICAL JOURNAL which in the late 1940's contains many in depth articles and pictures that show and explain the Bell System's involvement with the development and manufacture of RADAR equipment.

1946-1947

K.D. Smith at Bell Laboratories, Cont.
K.D. Smith was project engineer on the TE-1 and TE-2 short haul microwave relay system intended for Television studio to transmitter site service; and for repeatered routes of 2 to 3 links. The TE-1 system operated between 3.7 and 4.2 Gigahertz.

An excellent explanation of this system can be found in a publication entitled "A New Microwave Television System" that K.D. Smith co-authored with J.F. Wentz. This talk was presented at the winter meeting of the AIEE in January 1947, and the paper was printed in the Transactions for the AIEE Volume 66, pages 465-470 in 1947.

For an in depth look at what it was like to set up the first test between Hollywood and Mount Wilson, we have on file K.D. Smith's Field notes of this event. It chronicles the events from unboxing the equipment through the successes and problems that were encountered!

1948-1951

K.D. Smith was the circuit design supervisor on the TD-2 Microwave Radio Relay System. The TD-2 was the backbone trans-continental microwave relay system carrying network television programming as well as long distance telephone traffic. Long before communications satellites were a practical reality, the TD-2 system was what brought us the television shows we so much enjoyed from the network studios in New York, and gave us enough long distance telephone connections to talk to Aunt Martha back on the Eastern seaboard during Christmas day!

K.D. Smith's specific responsibility was the F.M. terminal systems used in the TD-2. The F.M. terminal converted video signals to a 70 MHz frequency modulated signal that modulated the microwave transmitter circuit that generated the output signal of the microwave relay link.

K.D. Smith standing in front of a Radar console during the World
Excellent reference on the TD-2 system can be found in "The TD-2 Microwave Radio Relay System" by A.A. Roetken, K.D. Smith and R.W. Friis. This article was published in the BELL SYSTEM TECHNICAL JOURNAL, Volume 30 (part 2) Pages 1041-1077 on October 1951.

An interesting side light is that this publication was one of the three selected from the BELL SYSTEM TECHNICAL JOURNAL to be preserved until the year 6939 AD, in the Westinghouse TIME CAPSULE II. This time capsule contains a panorama of what was then current human activities. The capsule was buried alongside TIME CAPSULE I. Both capsules reside under ground at the site of the two New York world's fair. TIME CAPSULE I was buried in 1938 and the second was buried in 1965. This historic time capsule is discussed in BELL LABS NEWS, May 15 1965. This newsletter as well as the publication on TD-2 that K.D. Smith co-authored is on file at the museum.

Another excellent reference on the TD-2 system is contained in THE TD-2 STORY, a book that was authored by A.C. Dickieson, and presented to the museum by him. Both publications, as well as the time capsule story in the BELL LABS NEWS present an excellent view of the TD-2 system for the person with the curious mind!

The TD-2 system and its steel and concrete towers was a communications marvel! It deserves a large article here in VINTAGE ELECTRICS in the near future.

Rumor whispers the demise of the TD-2 system, as widespread use of communications satellites is now a reality in our everyday existence. The large "wide bandwidth" fiber optic networks that have been created also supplement the satellites for long distance communication involving television transmission and long distance telephone calls.

TD-2 indeed enriched our lives, and let us take a moment to thank K.D. Smith and all the other developers that made this communications marvel possible.

1951-1952

With experience with vacuum tubes since 1930, K.D. Smith was thrust into the future world of solid state in 1951!

After the invention of the point contact transistor by Bell Laboratories credited to Dr.'s Bardeen, Brattain, and Shockley, one segment of the device development engineering staff set out to perfect the NPN grown junction transistor. In the earliest point in the life of this device, it had been theorized by William Shockley, and a working example built by Morgan Sparks and Gordon Teal. The job left up to the engineering staff was to make it reliable, increase the frequency performance and provide
K.D. Smith at Bell Laboratories, Cont.
K.D. Smith Showing how diodes protect meters. This photo was used in his article in ELECTRONICS in 1957. The month of this
meetings.

K. D. Smith also wrote Chapter 12.2 and Chapter 23.1-23.1 in the Bell Telephone Laboratories series of books entitled TRANSISTOR TECHNOLOGY. These chapters relate to the material evaluation and parameter measurement of transistors. A copy of this is available in the museums research library.

1952-1956

Being a project engineer was nothing new to K.D. Smith, but during these years he was to explore the new domain of silicon semiconductors, such as the Bell Solar Battery, large power rectifiers, voltage limiters and power transistors. The reader will find more information on Bell Solar Batteries by reading further into this issue of VINTAGE ELECTRICS.

During this exploration of the technology he presented or published the following papers:

"Properties and Applications of Diffused Junction Silicon Rectifiers" PGED Washington Conference 1955.

"Economical Diffused Junction Varistors" PGED Washington Conference 1956

"Silicon Diffused Junction Avalanche Diodes" Journal of Electrochemical Society, page 104 April 1957. This paper was also published in the Bell Laboratories TRANSISTOR TECHNOLOGY series, chapter 8b.

Silicon Diodes Protect Meters published in ELECTRONICS (Month not known) 1957.

It appears he was still interested in his old project area involving grown junction transistors, as he published a paper in 1955 relating to improvements in this area. See the 1951-1952 project coverage before this chapter.

1956-Retirement

K.D. Smith continued his work on The Bell Solar Battery, in the form of solar cells that were to ride up into space with both Telstar's I and II communication satellites.

it in a small packaged form. This effort resulted in the creation of a development device that was coded M-1752.

The M-1752 pioneered the way for many other forms of grown junction transistors to follow. K.D and the others that made up the engineering staff created improved versions that were at the same 50 mW power handling level as the M-1752 as well as higher power handling devices. The grown junction triode was to lead to R.L. Wallace's grown junction tetrode, which led to high reliability and bandwidth in reference to the time frame it was created in.

All of these devices, except the Sparks and Teal prototype are on display in the museum for your viewing pleasure! You are able to see how the device was built, as well as seeing grown junction devices from the crude prototype stage to the production models that were used by the Bell System to make our lives more reliable.

During the time that K.D. Smith worked on the development and refinement of the Grown Junction Transistor he published the following works that document the efforts put forth on this device at the Laboratories at that time.

1. Properties of Grown Junction Transistors

National Electronics Conference, where it was presented as a paper and also was published in the proceedings in October 1952. This paper also appeared in print in TELE-TECH magazine January 12, 1953.

2. Surge Limitations of Junction Transistors: This was an unpublished paper presented at the IRE Semiconductor Research Conference June 1953.

3. Grown Junction Transistor Development: Published in the Bell Telephone Laboratories RECORD magazine October 1955. This article is reprinted here in VINTAGE ELECTRICS, and provides a very easy-to-understand explanation of how a grown junction transistor works, and also how one of these devices is fabricated. This is really some great reading, not only for the beginner, but for the seasoned professional as well. The article covers background on the M-1752 as well as later production types used by the Bell System in production style telephone equipment. Although this article is not of the 1951-1952 time period covered in this section, it shows that K.D. Smith continued to keep in touch with the progress of any device or technology that he was once involved with. In 1955 he was currently involved with silicon devices that will be covered in the next section.

Aside from these formal presentations and papers, K.D. Smith enjoyed sharing his knowledge and technology at smaller meetings at colleges and electronics special interest group
K.D. Smith at Bell Laboratories, Cont.
In a letter to J.M Early during this development effort and after Telstar I had been launched, K.D. Smith presented some ideas on why the solar cells output was far more diminished that what had been expected by the proton fluxes in the van Allen radiation belt and the high altitude atomic tests that had preceded the launch of Telstar I. This letter that is on file at the museum, is entitled "Micrometeorites And Damage To Bare Solar Cells In Earth Space Orbits" it is dated April 1963.

This data was forwarded to NASA and the suggestions that K.D. Smith provided in this report are a part of every space borne solar power plant that has been launched since then.

During this period K.D. Smith co-authored a paper along with F.M. Smits and W.L. Brown titled "SOLAR CELLS FOR COMMUNICATION SATELLITES IN THE VAN ALLEN BELT" This paper was presented at the British IRE convention in Oxford England July 1961, and is of course on file at the museum.

The Later Years.

K.D. Smith was to spend much time on the development of diode and transistors that would work at high frequency. We plan to cover this in detail in the next issue of VINTAGE ELECTRICS, as the area is very large.

Some of the publications at this time were:

"Generating Power At Gigahertz With Avalanche Transit Time Diodes" In ELECTRONICS, August 8,1966.

"The IMPATT Diode, A Solid State Microwave Generator" Bell Laboratories RECORD, May 1967, pages 144-148.

K.D.'s time during his later years at the laboratories are not as well documented as the early years were, so research is still underway in this area.

Be sure to read future issues of VINTAGE ELECTRICS to learn more of the work of K.D. Smith.

Picture of K.D. Smith from his retired Bell Telephone Laboratories I.D. card. This is the last photo that we have that was taken of K.D. I would assume it was done in the late 1980's
From Machine Design, January 4, 1962.

Imagine the surprise when K.D. Smith saw the top article in Machine Design (year 1962)! The pictures below are from a 1937 notebook that K.D. kept. (click picture for larger view)

Although he never applied for a patent on this idea, I would imagine that he was happy to see that many years later someone else thought of the same idea!

K.D.'s notebooks are full of ideas such as this one, and you may view them at the museum library.

Photo of K.D. Smith Ca. 1930. This is what he looked like when he joined Bell Telephone Laboratories. (need to scan this)