Chapter Six - Research for Victory

An astonishing degree of precision was added to the crushing weight of Allied military power as World War II pursued its devastating course. A vital bridge on the German supply route in northern Italy, the target of repeated and unsuccessful daylight bombing attacks, erupted one night under the impact of a bomb dropped with mysterious accuracy by an American plane flying in complete darkness. Beneath the waters of the North Atlantic, enemy submarines began vanishing in greater numbers, many of them the victims of a deadly new depth charge using sound waves to hunt down its prey. A Japanese radar station overlooking the harbor of Rabaul, New Britain, was shattered by a pilotless American plane watching its target through a television eye. These were scattered examples of a sweeping revolution in military technology: electronics had become a key factor in Allied superiority.

Many scientists in many laboratories contributed to this radical new trend. The examples here, and a multitude of others, were the fruits of wartime research at the new center which RCA had completed at Princeton just in time for the all-out effort to achieve victory. The roots of these achievements, for the most part, extended back into the prewar years. (p. 129)

The conversion to wartime objectives has a far more subtle effect upon the research laboratory than upon the citizen who is suddenly drafted into military service. In the laboratory, there is a change of emphasis and a new urgency to each project—but these occur within the framework of customary activity. If the research organization has functioned effectively, the flow of results continues without interruption.

There is, however, a drastic change in the conditions under which the scientist works. Military security requirements fall like a blanket over his professional and private life. He is as likely as not to be whisked suddenly from his desk or his laboratory bench to the battlefield or to top-level strategic planning discussions, applying his special talents to the solution of a critical problem. For the director of research, there is a new pressure upon all accustomed activities relating to the establishment of objectives and the allocation of research effort. And there is a new set of problems, beginning with the question of keeping the research staff relatively intact in the face of recruiting forays by draft boards and special governmental agencies.

The new RCA Laboratories organization was amply prepared to discharge a critical responsibility in the war effort. Both the corporation and its research arm had been fully aware during the early and middle 1930s of the revolutionary implications for warfare in the electronic techniques and devices emerging from the laboratory. (p. 130)

Many aspects of RCA research at Camden, Harrison and the Long Island laboratories during the preceding decade had been related directly or indirectly to the needs of the military services. Recognizing the importance of communications to military tactics and strategy, the company had kept the services informed of progress in the development of television and high-frequency radio communication techniques. Scientists and engineers had worked on specific projects under government contract, acquiring familiarity with situations and problems that were to arise on a larger scale for the entire laboratories organization in the total war effort. Typical of these earlier projects were the programs relating to radar and its application to aviation, research in underwater techniques carried out at Camden for the Navy after 1934, and certain military applications of television.

From this standpoint, RCA Laboratories entered the war period with a certain savoir-faire in military research. This was, however, far from being the most important of its assets. The research program of the 1930s had equipped the organization as a whole with two major advantages in meeting the demands of national defense and modern war. The first was a broad range of experience in all essential areas of electronics research. The second was a staff of first-rate scientists and engineers accustomed to working harmoniously together toward a specific objective. The research groups brought together at Princeton in 1942 comprised perhaps the most expert organization in the country in the vital areas of tube design, high-frequency techniques, electron optics, acoustics, and luminescent materials. The advances achieved in (p. 131) all of these were to play a critical role in winning the first major war in which technological supremacy became a deciding factor.

The degree to which past experience bore upon the needs of war is illustrated by the direct contributions of television progress to the development of effective wartime radar systems. [RCA Laboratories director Elmer E.] Engstrom described the connection in the following terms in the book Radar, by Orrin E. Dunlap, Jr.:

As television was growing up, so was radar. Radio engineers and scientists borrowed heavily from television experience to meet heavy demands of war for a wide variety of radar equipment.

Radar needed the techniques developed through experience with shorter and shorter radio waves. Radar also needed cathode-ray tubes and associated time-synchronizing circuits, for presentation of its information, and for this drew much on the techniques, circuits, tubes, and systems developed for television. Radar needed the wide-frequency-band circuits and transmission channels developed for television. Radar required the manufacture of many units of apparatus and the making of large quantities of cathode-ray tubes. Radar required the training of large forces of people to make, install, service, and use complicated equipment, many of the components of which have a counterpart in television.

There were other examples—the application of RCA’s long-distance radio communication experience to the problems of war­time communication over supply and ferry routes; the wealth of background in acoustics, applicable to anti-submarine defense; and practical experience in electron optics for wartime adaptation to reconnaissance.

The conversion from peace to war was not an overnight occurrence, although it demonstrated a commendable amount of forehanded­ness. During the period between the outbreak of war in Europe on September 1, 1939, and the formal entry of the United States (p. 132) on December 7, 1941, the nation as a whole accelerated gradually toward full preparedness. Heavy demands upon industrial research and production were not made until nearly a year after Hitler’s attack upon Poland, with the expansion of the armed forces through the draft in the fall of 1940 and with the enactment of the Lend-Lease program in March 1941.

By June 1941, however, 75 per cent of the RCA research staff was engaged in defense projects either under government contract or supported by RCA with its own funds. At the time of the Pearl Harbor attack, when the nation itself passed over to a complete war footing, 90 per cent of the total RCA research effort had been turned to military ends. During the following year, the percentage rose to virtually 100.

For the next four years, until V-J Day in 1945, the members of the research staff at Princeton worked fruitfully and diligently under the pressures of war, not only in the laboratory but in the many theaters of operation. In January 1945, when the end appeared to be within sight, the results of their work were reviewed in general terms in a report to the executives of the corporation. As a concise summary of the wartime achievement, the review deserves full quotation:

Television: We have made use of our long experience with (p. 133) television by developing several complete television equipments for military use. Our present work includes the development of more sensitive pickup tubes of the Orthicon type and research on lightweight camera equipment for airborne use. Our work on television pickup tubes led to the development of electronic imaging devices and to our present work on military equipment for “seeing” with near infrared invisible radiation. We are also developing a sensitive device for detecting far infrared or heat radiation from distant objects.

Tubes:  Our normal program of developing new types of radio tubes for higher frequencies and for new uses has been continued under government contracts, modified where necessary to meet specific military needs. New operating principles are under investigation, particularly those applicable to frequencies where the transit time of the electrons cannot be neglected. Tubes for pulse operation and also for continuous duty are being developed.

Radar:  Our early work on radio altimeters for aircraft led to our pioneering research in the field of radar. We are continuing our extensive investigations in this field and a large part of our staff are now engaged in work on complete radar systems; on radar components such as tubes, antennas and indicators; and on apparatus using radar signals, such as navigational devices, bomb dropping devices, and gunfire directors. Because of our knowledge of FM principles, we have been able to carry on important developments in applying FM to radar. We continue to be the only laboratory working on this type of equipment. Our work on phosphors for oscilloscopes and kinescope screens has made possible the contributions we are continuing to make toward development of improved radar indicator screens.

Fire Control:  We have developed an automatic electronic gun­fire director for 40-millimeter anti-aircraft guns and are now assisting in preparations for testing it in the European war theatre. We are also working on modifications of this equipment to adapt it for use with larger caliber guns. Another project on which we are engaged requires the application of the principles of the gunfire director in the field of guided missiles.

Antennas:  We are developing antennas for many special military applications requiring operations over broad frequency bands and unusual directional characteristics. These an­tennas are for mounting on all sorts of vehicles, and often the mechanical problems of mounting and streamlining are very severe. We are also making propagation studies in fre­quency ranges which military needs have brought into use for the first time.

Radio:  In the field of communications, our experience has been applied effectively to military problems. We have developed for the Signal Corps a simple, light-weight radio relaying equipment, and we are now working on improved samples of a more elaborate eight-channel time-division pulse multiplex relaying system. We are investigating a number of novel methods for securing secrecy in radio communications, and we are studying methods and apparatus for jamming or interfering with the communications of the enemy. The related problem of avoiding the enemy’s jamming is also receiving attention, and we are studying methods of pulse transmission from that point of view. (p. 134)

Acoustics:  Our normal work with loudspeakers and microphones has been continued with changed emphasis where necessary to meet military objectives. We have been active in the development of sound-powered telephone equipment, and are now engaged in research on anti-noise microphones. We are also busy with research in the related field of underwater sound, including the development of acoustic mines and anti-submarine devices operating at audio and supersonic frequencies.

Personal Participation: Members of our research staff are participating in the administrative planning work of the Office of Scientific Research and Development (OSRD) as committee members, section members, technical aides, and consultants of the National Defense Research Committee (NDRC). Our engineers continue to serve the government as expert consultants and technical observers, in Washington, on proving grounds, and in active war theatres, wherever their services are called upon. By sending our men who have developed a new device into combat areas to assist in the first use of the device, we are able to speed its effective utilization and to acquire experience which is most valuable in developing improvements.

By any standards, this is a proud record. It also is a reasonable summary of the critical role of electronics in World War II. As an achievement by the RCA organization, the program owed a substantial debt to a corporate policy of which only a few hints appear in the 1945 summary we have just reviewed.

Starting during the 1930s with such projects as radar and high-frequency tube development, it had been the practice of RCA to carry out at its own expense the early and basic stages of research in areas of actual or potential military importance. Then, when research had progressed to the point where the results showed sufficient promise of military utility, proposals were made to the military services for development contracts. In this way, the work undertaken for the government was of proven value and was particularly suited to RCA’s abilities, Throughout the war, this procedure guaranteed the most effective use of the research staff and the laboratory facilities. (p. 135)

One result was a rapid and continuous movement of projects from the laboratories to the production lines not only of RCA, but also of many other electronics manufacturers. For RCA alone, it is noteworthy that as early as June 1942, approximately 50 per cent of the war orders on hand at the RCA Manufacturing Company involved equipment resulting from research and development by RCA scientists and engineers. Among the items specifically related to earlier research work at RCA Laboratories were altimeters for the Army and Navy, various types of naval radar, airborne television equipment for both services and for the NDRC, and high-frequency and cathode-ray tubes for the NDRC.

Selecting the most important contribution of RCA’s research staff to the war effort is rather like trying to single out the most important leg on a centipede. Under the circumstances, it is perhaps most profitable to examine a few of the outstanding developments, together with certain unusual situations in which members of the research staff found themselves in the line of wartime duty.

Radar and Associated Matters

A principal field of RCA research activity became the improve­ment and adaptation of radar to a wide variety of military tasks, based upon the pioneering work by Wolff and his associates through the 1930s. In terms of war technology, the development of radar as a basic technique probably ranked second only to the creation of the atomic bomb in its revolutionary importance. (p. 136)

Logically, the advent of war brought intensified effort everywhere to apply the new art of radar to navigation, target detection, identification, and related tasks. In all of these areas, basic contributions came from RCA’s research staff.

From the beginning of the conflict, the pulse altimeter developed by Wolff’s group at Camden had won wide acceptance in the Allied air forces. The virtue of the device, as we have seen, was its ability to determine altitudes from 10,000 to 40,000 feet and higher with an extremely small margin of error. Late in 1938, at just about the time that the pulse altimeter was moving from the testing stage to product design, Wolff and his associates turned to the special problem of low-altitude aircraft operations and instrument landing techniques, in which the margin of error must be close to zero.

Their solution, in 1939, was the first practical FM altimeter. Unlike the pulse radar system, which measured altitude by the reflection of extremely short pulses from the ground, the new type employed a continuous transmission with a timed change in frequency. The measurement was based on the difference in frequency between the outgoing and the returning signal. The development of the new device was carried on as an RCA project until 1941, when the Navy expressed a lively interest in the FM altimeter as a possible solution to numerous problems of instrument landing, dive-bombing, and low-altitude torpedo plane operations. Tests under combat conditions achieved such outstanding results that the new altimeter soon became standard for naval aircraft. Within a short time, it also was adopted for low-altitude operations by the U.S. Army Air Force and by the British Royal Air Force. (p. 137)

Out of the FM altimeter came further advanced applications, many of which heralded certain aspects of today’s “push-button” era of military technology. To a large extent, these developments were carried out by R. C. Sanders and a group of associates who had joined Wolff’s team in 1938 for the FM altimeter project.

The first of these new developments was a special adaptation of the FM altimeter as an adjunct to television bombing equipment installed in a pilotless “drone” aircraft. In this application, the device was used for the automatic maintenance of constant altitude by the “drone.” Sanders and his colleagues then went on to develop four increasingly sophisticated applications: 1) completely automatic bombing, taking account of altitude, speed, and wind velocity; 2) automatic control of the plane, enabling it to head to its target on an intercept course; 3) adaptation to the automatic release of various types of rockets or bombs as chosen by the operator; and 4) automatic compensation for dive or climb, permitting the release mechanism to be used for dive bombing or “toss” bombing as desired.

The first equipment to emerge from this series was the “Sniffer,” for automatic bomb release. Soon afterward came the “Super-sniffer,” which included the means for determining course. By this time, RCA itself was carrying such a heavy burden of manu­facturing that the production of these two items was assigned to another company, whose engineers worked with the RCA research staff at Princeton in the completion of product designs based on laboratory models of the equipment. (p. 138)

The further developments based upon the FM altimeter became available only in time for preliminary tactical use during World War II, but they provided a basis for subsequent important advances in military technology. In concept and in operation, they involved some of the first applications of automatic control to missiles, and many of their principles are in use today in missile operation.

A lapse of five to ten years between research conception and practical application may appear to be long, but there are many cases in which twice as much time has elapsed before actual employment in military tactics. An outstanding example is the airborne ground-speed meter.

In the late 1930s, imaginative officers at the Navy’s Bureau of Aeronautics had conceived the possibility of a completely self-contained airborne navigation instrument that would permit determination of position at all times without reference to the sun, stars, or any external radio signals. Various components of such a system were developed, but a serious limitation appeared in the inability to determine aircraft drift and ground speed both continuously and accurately. The problem was brought to the attention of the RCA research staff at Camden in 1938.

The request produced a proposal from Wolff for a method of ground speed and drift determination, but the project appeared at the time to be of doubtful validity in relation to other products that occupied the research staff at the time, Under the circumstances, Wolff’s proposal was not put to an immediate (p. 139) test. The next step was taken during the early 1940s, when the idea was re-examined and carried forward to a series of flight tests under Navy sponsorship by an RCA group including Stuart W. Seeley, Earl Anderson and Allen A. Barco, whose talents were temporarily available during an interval in the Shoran development program to be described below. With the resumption of Shoran activity and the pressing need for further work on higher-priority problems of an immediate nature, the self-contained navigation system was once more put aside. The preliminary flight tests had shown, however, that high accuracy could be expected with further refinement of the equipment.

At the end of the war, the project was revived and given high priority, with fruitful results. The so-called “Janus” system, fundamental to present-day methods of determining ground speed and drift, is based upon the principles first proposed by Wolff some two decades ago. Until 1958, the development remained classified, preventing an account of the RCA contributions.

The development of airborne radar systems for installation in high-speed aircraft raised certain design problems during the early stage of World War II. One of these was the knotty question of devising antennas that would function effectively without creating aerodynamic difficulties. Wartime fighter planes were pushing the 400-miles-per-hour mark by 1943. At these speeds, even a small dipole antenna projecting from the fuselage created enough drag to slow a plane by 15 to 20 miles per hour. (p. 140)

When the Navy raised this question urgently in 1942, Lindenblad and Carter were sent to Anacostia, Maryland, with instructions from RCA to work out an appropriate solution. According to Lindenblad, both of the engineers were greeted with offers of Navy commissions, which they rejected courteously on the ground that they could be more useful to the war effort if they remained free to work with all of the services. Then, tackling the antenna problem, they produced several solutions for the various types of radio and radar equipment carried in combat planes.

The most familiar of these stemmed from Lindenblad’s radical idea that signals could be radiated from a cavity in the bottom or sides of a plane, with the skin of the aircraft itself pro­viding the path for the current, In this case, the external antenna could be eliminated entirely. In successive visits to Anacostia during 1942 and 1943, Lindenblad worked out the details of such an arrangement and supervised a series of highly effective tests. The end result was the now-familiar “slot” antenna used in high-speed military and commercial aircraft to maintain aero­dynamic efficiency with no loss in antenna performance.

Lindenblad’s contribution was one of several notable radar antenna developments by RCA specialists for wartime use, Another was the narrow-beam antenna developed by George Brown and Donald Peterson for the U.S. Signal Corps SCR 270 search radar. Previous antennas for the Signal Corps system had tended to pick up infor­mation beside and behind the antenna, causing interference with the desired pattern. Brown and Peterson eliminated the difficulty (p. 141) by concentrating the radar signal along a narrow path and elimi­nating any radiation to the sides or the rear. Completed during the early stages of the war, the improved antenna became standard on all of the SCR 270 installations in the various war theaters.

Brightening the Radar Picture

A key to the effectiveness of wartime radar was its ability to present intelligible information about targets and terrain. The most intelligible form for such data was a picture showing the pattern of reflected signals, with sufficient clarity and detail for viewing under a wide variety of circumstances. The requirement was of special concern to Leverenz, who summarized the problem in the following terms:

It was especially desirable to have a panoramic map, completely re-sketched every few seconds, simultaneously showing the locations of distant objects at all points of the com­pass, or sectors thereof, and over a wide range of elevation angles. To provide such a map, it was necessary to devise indicators which would: (1) instantaneously transform mega­cycle-frequency electrical fluctuations into visible image traces (blips), (2) retain the visible blips, which were produced in microseconds, for a number of different fixed scan intervals up to 30 seconds, and (3) dissolve (clear, or “forget”) the previously retained blips at the end of the particular radar scan interval to avoid confusing subsequent images.

The only practical way of doing any of these things was to use the cathode-ray tune that had been developed for television. At the same time, it was apparent that these requirements were exactly the opposite in one important respect from the requirement for television viewing tubes. In television, scanning at a rate (p. 142) of thirty frames per second, the phosphors in the viewing screen must darken instantly when the scanning beam has passed. In radar, scanning as slowly as thirty seconds per frame, the phosphors must retain their luminescence as long as possible. With the advent of radar on a large scale, something new was needed in the way of phosphors.

Mindful of RCA’s unique prewar experience in television, the Office of Scientific Research and Development turned this problem over to the RCA research organization in 1941. It was assigned to Leverenz and his associates, who had been responsible for the bulk of television phosphor development. The group, including Ross E. Shrader and E. J. Wood, began its work at the beginning of 1941 and emerged after two and one-half months of intensive research with the “cascade” phosphor screen—the basis for a major subsequent breakthrough in radar technology.

The cascade screen used a radically new approach by employing two layers, each composed of a different phosphor. The arrangement was designed to increase phosphorescence and at the same time to reduce the initial luminescence, or flash, of radar blips. At the same time, the screen was so contrived that visible persistence could be adjusted to retain blips for many radar scan intervals ranging from 1 to 30 seconds. It seldom happens that a basically complex development is accomplished in so short a time with such lasting results. The cascade phosphor screen went into immediate production, largely at RCA’s Lancaster, Pennsylvania, plant. More than 500,000 tubes employing the screen were manufactured there and at other electronics plants before the end of the war. (p. 143) 

This was a most important advance in radar display techniques, but for Leverenz and his group it was only a beginning. As radar equipment was improved and adapted to a wider variety of appli­cations, the requirements mounted for a family of phosphors capable of varying degrees of luminescence and persistence at scanning rates ranging from hundredths of a second to 2 seconds, for use in navigation, gunfire control, and blind bombing.

A further variation was achieved by Leverenz with develop­ment of a tenebrescent phosphor, or scotophor, which reversed the usual procedure by displaying radar blips as dark spots on a bright screen, This was a linguistic as well as a technical triumph, for both words were new to the language—tenebrescent derived from the Latin “tenebrae,” for dark; scotophor from the Greek “scotos,” meaning dark and “phor,” for bearer, The tenebrescent screen turned out to be especially useful in large-area displays of the type used by controllers in air command centers, since it had an inherently greater legibility.

There was also the metascope phosphor, a top-secret development for use in the metascope, a special infrared viewing device used by American forces on Iwo Jima and Okinawa, but never employed in Europe for fear that it might fall into Nazi hands. The metascope consisted of an optical system which focused an infrared image on a phosphor surface, where it was converted to visible light. The infrared image was obtained by bathing the objective in invisible light from an infrared lamp. While the device it­self was not an RCA development, the most satisfactory phosphor was devised by Leverenz and his associates. (p. 144)

It was in connection with the metascope that Leverenz encountered perhaps the most rigid security measures of the many in effect during the war. On a visit to England, he described the metascope to British military personnel at Teddington. His description of the device was recorded by an official stenographer. The notes were stamped with the British Top Secret classification before distribution to those having “a need to know.” Leverenz himself was not included in the distribution—he had not been cleared for British Top Secret material.

Shoran

Unwanted “ghosts” on a television screen touched off a chain of events that resulted in Shoran, probably the most precise navigational equipment ever devised. Aside from its extreme precision, it is remarkable among modern electronic inventions in three other respects: (1) it was inspired by and capitalized upon an otherwise undesirable electronic effect; (2) it can be almost entirely credited to a single individual, and (3) it was conceived, developed, product-designed and manufactured in quan­tity entirely within one company.

The concept of Shoran was born in 1937 at RCA’s Industry Service Laboratory at 711 Fifth Avenue, New York, during a bout of trouble with “ghosts”—extra images appearing on a television screen as the result of reflection of signals from buildings or other objects. The appearance of ghosts means that the trans­mitted signal is arriving at the receiver not only over a direct path from the transmitter, but from more devious paths as well. Bounced from buildings or other solid objects, the secondary (p. 145) signals arrive small fractions of a second later than the direct signal, causing overlapping “ghost” images on the screen.

Stuart Seeley, of the Industry Service Laboratory staff, set to work on the problem of eliminating the ghosts at 711 Fifth Avenue with the help of the most directive antennas that could be devised. In spite of his best efforts, a few persistent ghosts remained. It is well that they did—for they led Seeley to the deduction that the distance between the main image and the ghost on the screen could provide a means for measuring the extra distance traveled by the secondary signal on its longer reflected path from transmitter to receiver. Moreover, with the position of the transmitter known precisely, the distance measurement could indicate the source of the reflection.

Seeley based his deductions on two known values. One of these was the speed of the scanning beam in the picture tube; the other was the speed of the broadcast signal—equivalent to the speed of light. By measuring the distance between the main image and the ghost image on the screen, he could determine the time elapsing between the arrivals of the primary and secondary signals. This time differential could then be translated into a measure of the extra distance traveled by the secondary signal.

It occurred to Seeley that these deductions might hold the germ of a useful high-speed system for measuring distances. Enlisting the help of Charles Kimball, an associate on the ISL staff, he put the theory to test in early 1938. The experiment involved television receivers at Kimball’s apartment in Jackson Heights, Queens, and at Seeley’s home in Bayside, Long Island, as well as a transmitter at Seeley’s house to pick up and  (p. 146) re-transmit to Jackson Heights the television signals emanating from the Empire State Building in Manhattan. Using this equipment, Seeley and Kimball carefully measured the time difference in reception of the signal at Jackson Heights by its direct path from the Empire State tower and by its indirect route through the transmitter at Seeley’s home. Converting the figure into a measurement of distance, they came invariably within 50 feet of the official surveys of the area by the United States Coast and Geodetic Survey.

“These findings gave rise to the belief that specially designed equipment built primarily for the purpose of path length determination could give an accuracy of plus or minus 50 feet or better,” Seeley wrote at the end of the war. “The considerable thought given to that possibility in the fall of 1938 resulted in the early concept of Shoran as it is today.”

Over the next two years, Seeley and his associates worked intensively to develop a simple and rugged system, operating on radar-like principles. The basic elements were a pulse transmitter and a cathode-ray receiver carried in a plane, and two precisely located ground stations with equipment to receive and send back the pulses from the plane. The receiver in the plane measured the round-trip transmission time and converted the result into distance, producing on the cathode-ray tube screen a visual indication of position in relation to the two stations. The system was named Shoran for “short range,” distinguishing it from the independent and unrelated Loran system for less precise long­range navigation.

Developing the system was one thing: selling it was another. In the summer of 1940, the project was disclosed to the Army Air (p. 147) Force with a proposal that funds be allocated for the development of operating models of a blind bombing device based on Shoran. Nine months later, a development contract was awarded, and the ISL group started work on two complete Shoran units, including two ground stations.

“We had told the Air Force that we could work up a system accurate to within 500 feet because we wanted a substantial margin for error,” Seeley reported later. “When we had the first contract model done, we ran scores of measurements under various conditions and found that it was accurate to within five feet. We did not report this result at the time, because we didn’t think the Air Force would believe it.”

These results were achieved at a time when the military services were understandably far more interested in the development and improvement of existing types of equipment for a rapidly expanding air force than in new and untested systems such as Shoran. Months went by before the original Shoran equipment was given its first military flight tests in August 1942. The results were all but unbelievable. Mounted in a B-17 Flying Fortress flying out of Eglin Field, Florida, the airborne system was put through its paces by Seeley and Earl Anderson with the cooperation of several Air Force officers. Guided only by position readings relative to the two ground stations located 108 and 125 miles away, respectively, the pilot and bombardier took the plane to a 30-foot target and dropped bombs within 100 feet of the mark from an altitude of 20,000 feet. (p. 148)

The results may have been too good to be believed by those who had not seen the tests. In any event, it was the spring of 1944 before the first procurement orders for Shoran were placed with RCA by the Air Force. In the meantime, refined equipment had been designed and tested in a series of flights that disclosed, among other things, the possible usefulness of the system for mapping and survey work. A B-17 crew employing Shoran discovered a 1,000-foot error in Coast and Geodetic Survey charts showing the position of Memory Rock, an islet at the western end of the Bahamas.

During the Shoran development program, Seeley and Van Dyck flew to England to describe the system to leaders of the American Eighth Air Force and the Royal Air Force. They also observed the operation of a rival and more limited British system known as Oboe, in which a ground station tracked bombers out over enemy territory and notified the bombardier precisely when to drop his bombs. This system handled only one place at a time, unlike Shoran, which provided a constant “fix” for any number of aircraft simultaneously. On the return from the discussions in England, the complete file of information on Shoran, including details of equipment and test results, was lost in a plane crash. In the weeks that followed, Seeley laboriously recreated the records from his own memory, with such success that the episode figured in a citation to him by the Air Force for his original conception of Shoran. (p. 149)

The system entered combat for the first time on the night of December 11, 1944. Shoran-equipped American planes, guided by position readings relative to two ground stations in Corsica, flew through darkness to destroy a bridge in northern Italy. The target, a vital link in the German supply line, had escaped damage in repeated earlier daylight attacks. This was the start of a new era in American bombing of enemy targets under all weather conditions and in darkness. As Seeley reported later, by the end of the war in Europe, the amount of tactical bombing being done in any area was predicated almost entirely upon the availability of Shoran equipment.

Shoran was to achieve further success after the war. Starting in 1945, Commander Carl Aslakson, of the Coast and Geodetic Survey, undertook a series of tests with the equipment over a large area of Colorado and Nebraska to determine its potential value as a mapping and surveying technique. The initial results showed the need for some modification of the equipment. With Seeley’s help, Aslakson and his associates turned Shoran into a surveying system of unprecedented accuracy, capable of covering immense areas in a remarkably short time, and producing measure­ments accurate down to one foot in sixty miles, Postwar surveys with Shoran are today producing the first accurate maps of vast areas of jungle, tundra, and ocean, providing a valuable new service in both peacetime navigation and military defense. (p. 150)

Television at War

A most remarkable transformation is the wartime story of RCA television. From the workable but cumbersome equipment which inaugurated public television on the New York World’s Fair Grounds in 1939, it acquired—in one guise—the shape of a compact “eye” screaming through the air in the nose or a guided bomb.

World War II did not last long enough to realize the full potential of television as a military weapon. There was a justifiable tendency in all quarters to concentrate first upon the maximum improvement and use of tried and proven systems, devices and techniques. By the war’s end, however, the future importance of television as a means of extending human sight over the battle­field and beyond had become apparent. Some of this potential had been disclosed in a limited tactical use. And in the course of this development, components and techniques had been advanced to the point of immediate application in postwar commercial television service.

Fittingly enough, it was Zworykin who originated the first RCA proposal for military application of television. In 1934, he had written to David Sarnoff with a proposal for “a flying torpedo with an electric eye”—i.e., a guided missile carrying a television camera and transmitter. At the time, Zworykin was thinking of an airborne system weighing some 140 pounds, including an Iconoscope camera, transmitter, automatic pilot, wind-driven generator, and short-wave radio receiver with associated relays. Mr. Sarnoff promptly took Zworykin to Washington with (p. 151) him to describe the concept to government officials. They met a favorable reaction, but no inclination to commit government funds for development work at the time. But the idea did seem promising enough to warrant some support by RCA on its own within the framework of the large-scale television research and development program already under way.

By 1937, therefore, the trusty Ford trimotor was cruising over the Philadelphia area carrying an airborne television system engineered by Kell and a group of associates including Waldemar Poch, Loren Jones, Merrill Trainer, and Henry Kozanowski. Using standard cameras and scaled-down transmitting equipment, the system picked up and transmitted pictures with fair detail over a range of 35 to 40 miles. Military observers were invited to view the results, but the government's interest still remained largely passive.

By 1939, the television art had made substantial further progress. A new, smaller and improved Iconoscope had been developed by the tube research group at Harrison, permitting the design of commercial field pickup equipment built into suitcase-type units. Using this as the take-off point, a new airborne system was developed during 1939-40—just in time to encounter a new and serious interest by the military services.

The consequence was a series of military contracts extending through the war for a variety of interesting and potentially important television applications in reconnaissance and in missile (p. 152) guidance. In this general program, three distinct lines were discernible:

(1) the BLOCK system, comprising suitcase-size camera and associated units of about 100 pounds for use in drone aircraft and missiles;

(2) the MIMO, a lighter and more compact system of about 50 pounds for use in glide bombs; and

(3) the RING system, a full-scale non-expendable television chain for reconnaissance, employing standard cameras and airborne transmitters broadcasting to ground stations up to 200 miles away.

Basic to all or these systems, and to the progress or postwar television, was another major achievement of RCA research—another of those rare advances that can be identified legitimately as a breakthrough. This time, it was the Image Orthicon pickup tube.

In 1941, the potential military usefulness of television was sufficiently apparent to justify OSRD support for development of a superior camera tube. It happened that work toward this goal already was proceeding under RCA sponsorship at Harrison, where experimental tubes of vastly increased sensitivity had reached the laboratory test stage. The results had, in fact, exceeded in many respects the performance specifications now indicated by the government agency—a tube ten times more sensitive than the Iconoscope, and more compact and more stable in its operation. Supported by the OSRD in its final phase, the project moved to Princeton in 1942 with the opening of the new research center.

The burden of the work was carried by an experienced team com­prising Albert Rose, Paul Weiner and Harold Law, assisted substantially at various times by a long list of talented specialists including Harley lams, Henry DeVore, Leslie Flory, George Morton, John Ruedy, Otto Schade, and I. B. Janes. (p. 153)

The culmination or this effort was the remarkable Image Orthicon tube, with sensitivity up to one thousand times greater than the Iconoscope. In principle, it was extremely simple. The face of the tube was a photosensitive surface, or photo-cathode. Light falling upon this surface through a lens caused the emission or electrons back into the tube. Collected on a thin glass target behind the photo-cathode, these electrons formed an electric charge image or the scene viewed through the lens. From the rear of the tube, an electron gun emitted a beam to scan the rear surface or the target. The beam gave up its electrons to neutralize the charge on the target screen. Where the charge was less, or non­existent—i.e., in areas corresponding to the darker portions of the light image—the electrons in the beam were bounced back to the rear of the tube. Here they were collected and passed through a multiplier which increased the magnitude of the output current by about 1,000 times.

Here, oversimplified for compression within a single paragraph, was a revolution in the television art. Shaped for use with conventional fast photographic lenses, the Image Orthicon endowed television for the first time with the answer to its need for a camera that might see wherever the human eye could see. The Iconoscope had performed commendably at high light levels; the Orthicon had extended electronic vision down to medium light levels with efficiency. The Image Orthicon approached the theoretical limit of pickup tube sensitivity, It could observe with clarity subjects illuminated only by a single candle, a single match, or by infrared radiation invisible to the eye. (p. 154)

The Image Orthicon freed television of its dependence upon the bank of bright lights and permitted completely flexible operation in the studio or in the field. The major effects were to be felt in commercial application after the war—but the new tube provided in wartime a useful and versatile pickup device for use in military television systems. Moreover, it paved the way for further outstanding work by Morton and Ruedy in the post­war years, combining the principles of the Image Orthicon with new multiplier stages and improved materials to achieve a series of pickup devices of astonishing sensitivity and speed for a broad range of scientific and military applications,

On the heels of the Image Orthicon came a logical further step, inspired by the need for the smallest possible pickup equip­ment for airborne use. The task of scaling down the new highly sensitive tube was undertaken by a team including Paul Weimer, Harold Law, and Stanley Forgue. Making certain structural changes in the Image Orthicon design, they devised the MIMO (Miniature Image Orthicon), measuring only 9 inches long and 1½ inches in diameter, in comparison to its parent’s l5-inch length and 3-inch diameter.

The MIMO tube formed the heart of the most unusual of the wartime television systems. This was a miniature camera­transmitter tucked into the nose of the “Roc,” a medium-angle guided-bomb missile developed by the Douglas Aircraft Company and field tested in 1945, just too late to see action in combat. The television system, designed by Kell and George Sziklai, and (p. 155) incorporating special antennas devised by Brown and Jess Epstein, was a masterpiece of miniaturization for its time. It also was extremely simple—for a very good reason. As Kell and Sziklai noted in their technical report on the system, “the object was to get maximum performance for a short time with minimum apparatus, since, in use, the entire unit was expended after a few minutes of service.”

The same was true of the bulkier BLOCK equipment which preceded the MIMO and which did see limited combat service in drone aircraft and glide bombs during the latter months of the war. The BLOCK system, a product of Kell and his associates, employed in its various forms both the Iconoscope and the Image Orthicon. The first type, using the Iconoscope, was built by the hundreds for use in glide bombs, many of which were tested by the Air Force at Eglin Field and in Nevada during 1943-44.

A tendency toward erratic behavior on the part of the early glide bombs, resulting from a temperamental control system, occasionally livened the test period for Kell and his associates as on-the-spot technical advisors in Air Force planes. One of the initial types, for example, sometimes showed a desire to ride along with the plane immediately after its release, bumping gently against the plane’s wing as a result of the lift supplied by its own stubby flying surfaces. Kell has vividly recalled one trial in which a part of the control system failed completely, causing the bomb to zoom erratically about the sky on a course that carried it several times within a few feet of the launching plane. (p. 156)

There were hazards on the ground as well. The signal from the television eye in the nose of the glide bomb was viewed on receivers in an Army trailer for monitoring during practice drops. On one occasion, the trailer had been parked a short distance from the ground target on the Nevada range while Kell and a group of technicians prepared to watch the practice run on the monitor screens. They viewed the image with semi-detached interest until it suddenly became apparent that the object in the center of the picture, toward which the bomb was heading at high speed, was not the target, but the roof of the trailer in which they sat. The premises were cleared hastily, just as the bomb whistled over the trailer to crash harmlessly a short distance away.

The difficulties with the control system were ironed out before the end of the war to an extent that permitted use of glide bombs on a limited scale against German V-1 and V-2 launching sites in, Europe. The BLOCK equipment itself was put to somewhat more extensive use in drone aircraft. In the summer of 1943, for example, the system was loaded into “war-weary” B-17 bombers that were guided by radio from a mother plane to crash into German submarine pens at Heligoland. During the next year, BLOCK equipment was used in Navy drone aircraft for attacks on Japanese shipping in the northern Solomons and for the destruction of a Japanese radar-equipped lighthouse at Rabaul.

There were non-combat applications as well, foreshadowing the postwar extension of television into industrial functions. An outstanding wartime example was the use of the BLOCK system at key stages in the Manhattan Project, which produced the first (p. 157) atomic bombs. Here the television chain permitted surveillance of atomic production processes that could not be approached with safety by human observers.

The third of the wartime television developments, the more elaborate RING system, was designed to meet the need for high-resolution airborne reconnaissance equipment to transmit pictures reliably over ranges of 100 miles or more. RING was developed during 1942 and 1943 by an NBC engineering team headed by O. B. Hanson, Robert E. Shelby, and George M. Nixon. It was equipped with a special transmitter designed by Thomas L. Gottier, of the Princeton staff, and a new type of transmitting antenna developed by Carter at the Rocky Point laboratory.

Unlike the MIMO and BLOCK systems, RING was designed primarily for high definition pictures, with weight and complexity treated as secondary considerations, Initially, the system employed two Orthicon cameras; later versions incorporated the new Image Orthicon pickup tube. The complete system differed substantially from the commercial television system in such basic respects as bandwidth, frame repetition rate, and resolution that was con­siderably higher than in the commercial system.

The NBC group started to work on the project in November 1942, and completed the task in time for flight tests of the equipment in a Navy Catalina patrol plane at Banana River, Florida, in the spring of 1943. A second installation was completed some time later for Navy altitude and acceptance tests in a Martin Marauder. The tests were finally completed in July 1945—again, just too late for combat application. (p. 158)

The three wartime television system developments represented a significant contribution by RCA scientists and engineers in spite of the limited role that these systems played in combat. Coming to fruition late in the conflict, they foreshadowed an important future military role for television and at the same time opened the way to new peacetime applications. David Sarnoff summarized this contribution in a postwar report:

Great praise is due the scientists and engineers whose research and pioneering, technical knowledge and ingenuity, made possible airborne television as a successful weapon of war and opened the way for monumental progress in widening television’s scope of service in peace.

As if to underline the future possibilities, the television equipment, including both ground and airborne systems, was put to extensive use in the atomic bomb tests at Bikini in 1946 to permit close observation of the blasts and their effects.

Seeing in the Dark

Among Zworykin’s varied talents is a good eye with a hunting rifle. He outdid himself one day during the war, however, in a dark room in the basement of the research center at Princeton. Using a standard carbine, he landed repeated shots on a target that was hidden by darkness from everyone in the room. The answer lay in a small cylindrical device fixed to the barrel of the weapon. This was the first “Sniperscope,” incorporating an infrared image tube that could “see” in the dark. (p. 159)

Development of the infrared tube and its associated viewing devices was undertaken by RCA Laboratories at the outset of the war under the sponsorship of the NDRC. Among major problems that required solution were a photosensitive surface with high response to infrared radiation, an electron optical system that would produce maximum brightness and magnification, and a tube design that would lend itself to rapid mass production. Finally, it was essential that the tube itself be sufficiently compact to fit into portable devices as well as fixed units.

Drawing upon their background of prewar experience in electron optics related to television, Norton, Flory and others in Zworykin’s group launched into the project. Within a few months they had achieved success with a rugged and simple tube only 4½ inches long and less than 2 inches in diameter. Within the compact tube were a semi-transparent photo-cathode sensitive to infrared radiation, and an electron lens for imaging the electrons from the photo-cathode onto a small fluorescent screen forming the viewing end of the tube. When the tube was aimed at a target bathed in invisible infrared radiation, a bright visible image appeared on the fluorescent screen.

Having created the appropriate tube, the scientists proceeded to develop a variety of devices around it. All included an objective for forming the image on the photo-cathode, an ocular system for viewing the visible image, and a battery-operated power supply feeding both the tube and the infrared lamp used to light the target. (p. 160)

Mounted on the barrel of a rifle or carbine, as in the version tested by Zworykin, the device became famous as the “Sniperscope” employed by American forces in the Pacific for night combat or sniping. Another version, mounted on a handle for short-range reconnaissance, became known as the “Snooperscope.”

The version which found widest wartime application is, however, probably the least well-known—probably because it was never christened with an equally catchy name. This was an infrared telescope mounted in planes and aboard ships as a night-time detecting and signaling device, In these roles, the equipment played a highly important part in accurate pre-invasion bombardments in both Europe and the Pacific.

Under contracts from the Navy, RCA produced tens of thousands of the infrared tubes at Lancaster, and various types of infrared telescopes at the RCA Indianapolis plant. Engineering teams at both plants played a further important role in turning the laboratory developments into practical production items.

Another approach to infrared detection techniques was made by Kell, John Evans, and others at Camden with interesting results which remained in the laboratory stage when the war ended. In this case, the objective was a method of detecting objects, such as ships, at a distance by means of the infrared radiation emana­ting from exhaust stacks or other heat sources. It was felt that such a system might be a useful adjunct to radar, since it would permit some degree of advance warning at a distance without in turn warning the enemy by sending out radar pulses. (p. 161)

The system developed by Kell’s group consisted of an oscillating mirror, a heat-sensitive cell, and a facsimile-type scanner. In operation, the mirror focused any infrared radiations upon the cell, creating the equivalent of a “pip” on the facsimile recording. Two prototypes were developed, one for use on shipboard, and an airborne version which was tested briefly in a Navy blimp. The shipboard version, placed in a test installation on the shore near the entrance to Delaware Bay, was sensitive enough to pick up the heat in the galley exhaust stack of a lightship several miles away, and for many hours after the galley stove had been turned off for the night. The system appeared promising, but further work was abandoned with the conclusion of the war.

Acoustical Weapons

During the 1930s, the acoustical research group at Camden had contributed major improvements to the Navy’s sonar underwater echo ranging system. In a sense, sonar was an acoustical equivalent to radar, employing the reflection of sound waves, as opposed to high-frequency radio waves, to detect underwater objects. Its effectiveness was based on the excellent sound conduction properties of water, in which sound travels at some 6,000 feet per second—about five times more swiftly than in air.

Sonar was conceived originally during World War I. The system remained largely unchanged until the middle 1930s, when Wolff and his associates at Camden embarked at Navy request upon a search for more effective equipment. At this stage, the project was more a matter of (p. 162) engineering than of research. One phase of the work resulted in a system employing a cathode-ray tube indicator. This was rejected by the officer in charge, on the ground that cathode-ray tubes would be too delicate for use in combat vessels. Returning to the drawing board, the group developed another version employing a light valve and a rotating quartz tube to provide a visual indication of sonar readings.

After 1937, RCA produced a substantial amount of the Navy’s sonar equipment. It was 1939, however, before an appreciable amount of further research was undertaken to achieve basic improvements in the system. Thereafter, and through the war, a series of radical advances flowed from the acoustical research group under Olson to find application in a broad variety of underwater detection and communication devices. This research, and the manufacturing effort which resulted from it, turned sonar into an outstanding RCA contribution of World War II.

Moving to Princeton in 1942, the group acquired a complete underwater sound research facility on the grounds of the new research center. Here the Olson team, including Preston, Hackley and Adolph R. Morgan, carried out the research and development work that gave birth to a new family of “subaqueous transducers”—underwater microphones and speakers—and to radical improvements in sonar systems. The sonar contributions included an echo-ranging variety whose sound impulses radiated in all directions around a ship, and a “searchlight” type that focused the sound impulses along a narrow path to provide both a communications channel and a technique for searching specific areas.   (p. 163)

Perhaps the most novel of these developments was a personalized version of the “searchlight” sonar system, designed and developed for use by Navy frogmen in surveying underwater obstacles lying off the invasion beaches. The apparatus was packaged in a case only 18 inches long and about 2½ inches in diameter. The diver, working under conditions of poor visibility, could sweep the sound beam around in all directions to locate and chart obstacles identified by echoes received in the microphone and fed to him through earphones.

In 1941, the research team began a new development that turned out to be extremely important to the war effort—an acoustical system that would employ echoes from a submarine to explode a depth charge at the point of maximum effectiveness. The fruit of their work was the acoustical depth charge, one of the most closely guarded secrets of the war.

Previously, depth charges were set in advance to explode at a given depth, making success dependent upon the judgment of the launching crew. With the acoustical depth charge, guesswork was eliminated. The operating principle was relatively simple, based upon the so-called Doppler effect. A most familiar illustration of this effect is the rise in pitch, or audio frequency, of an automobile horn as the vehicle approaches, and the decrease in pitch as the vehicle moves away.

In the acoustical depth charge, the difference between the frequency of the signal radiated from the charge and the frequency of the reflected signal from the submarine was measured constantly (p. 164) as the charge sank through the water, The difference decreased as the charge descended toward the reflecting submarine. At the point of nearest approach, the difference became zero—after which it would again rise if the charge were to continue its passage downward. The control system was designed to touch off the blast when the difference in frequencies reached the zero point—at the precise moment to do the most damage. Introduced into combat in the latter stages of the Battle of the Atlantic, the new acoustical depth charge turned out to be a most deadly weapon against Nazi U-boats.

The acoustical group also was responsible for a multitude of less sensational but highly important wartime sound systems and devices. An example was an effective gradient-type noise-suppressing microphone for communications use in noisy environments, such as aircraft and battlefield. Another product of the group was a line of battlefield loudspeaker systems, capable of carrying sound over long distances at sea or on the battlefield.

Acoustical work sometimes involved risks, even at Princeton, far from the combat areas. On a cold winter day in early 1943, Morgan climbed to the top of a ladder with 50 pounds of underwater sound equipment to be lowered into the outdoor pool used for tests. J. Guy Woodward, working on recording instruments in the small building adjacent to the pool, heard a crash and peered from the window to see what had happened. He saw only a broken ladder and a hole in the ice covering the pool—and Morgan’s hat, floating on the small area of open water. In spite of his heavy clothing, (p. 165) Morgan contrived to struggle to the surface and to the edge of the pool, where Woodward waited to give him a hand. Olson drew a moral from the accident.

“I guess it isn’t enough to be a good technical man in this business,” he said. “You have to be a good swimmer, too.”

Pioneering in Computers

The role of electronics was immensely expanded under the pressure of war between 1940 and 1945. As a broad electronic research program, the RCA effort both affected, and was affected by, this broadening of electronic functions. A case in point is the wartime development and growth of electronic computing techniques—a new art which subsequently grew in the postwar era to become one of the most important aspects of electronic technology related to commerce, industry, defense, and space applications.

A notable “first” in the computer field was the development at Camden in the late 1930s of an anti-aircraft fire control system for the Army. This was a pioneering digital computer, created by a research group including Vance, Flory, Rajchman, and R. L. Snyder. The system subsequently was developed into a complete anti-aircraft director system for wartime service under the Army designation M9. During the course of the project, Rajchman developed a new type of storage and switching tube known as the Computron—the first in a long series of outstanding contributions that he would make to the computing art. (p. 166)

The M9 was designed for medium and high altitude anti-aircraft defense. There remained a need for effective measures against low-flying aircraft. The problem was tackled in the early 1940s by Vance and his colleagues, with the objective of developing a high-speed fire control system for 40-millimeter guns. The requirement in this case was a system substantially faster than the M9, but not necessarily as accurate, in view of the high rate of fire and the proximity of the target. The solution worked out by the RCA group was an analogue computer, which has somewhat less accuracy but higher inherent speed than the digital type.

The new system was developed into the T35 high-speed director for 40-millimeter anti-aircraft guns. In early 1945, the first equipment was sent to Europe for combat tests, accompanied by an Army test group that included Vance and Edwin A. Goldberg as technical observers. The mission encountered a series of mishaps, including the non-fatal torpedoing of its ship in the English Channel, and a succession of assignments to areas where no targets were to be found. The equipment was finally put to its first test against German V-l flying bombs in Holland and Belgium just before the war ended.

The tests were too limited to provide useful conclusions, but the experience gained in this and other RCA work on such systems for combat use laid a firm base for continued research in electronic computing techniques.(p. 167)

A related interesting case in point was perhaps the first entirely automatic tracking equipment for shipboard anti-aircraft fire control, developed by Kell’s group at Camden and subsequently at Princeton. When the work was started just before the war, the Navy relied upon a technique that required manual translation of radar information into coded data fed to a fire control computer. The objective of the work undertaken by the RCA research group was an automatic technique that would feed the radar information directly and instantly into the computer, eliminating the time-consuming manual translation process.

The efforts of Kell and his associates—William A. Tolson, Thomas Gottier, Alda Bedford, Henry Rhea and others—were aided by a radar antenna development program carried out by George Brown, Jess Epstein, and Oakley M. Woodward. In about nine months, the equipment had been completed and installed for sea trials aboard the brand-new battleship South Dakota, operating out of the Philadelphia Navy Yard. The RCA system comprised a lobe-switched antenna that automatically followed swiftly moving targets and fed the essential information on range, elevation and bearing directly into the standard computer system for direct control of the five-inch guns. As the big antenna followed the target, so did all of the five-inch batteries on one side or the other of the big warship, directed automatically by the computer. While it would be pleasant to report that the system was put immediately to extensive use, it did not happen this way. RCA was not in a position to produce the radar equipment for the (p. 168) Navy in addition to its other wartime production tasks, and the system did not advance beyond the initial test installation. Nevertheless, it was an outstanding advance in automatic control techniques, demonstrating principles with broad potential application in other automatic control functions.

At the same time, several non-combat requirements for new computing and measuring techniques added further to RCA Laboratories experience in this promising field. In at least two cases, the results found wide subsequent application in commercial use.

The first was the electronic counter, a high-speed precision time measurement and counting device that provided an accurate record of phenomena occurring during time intervals down to millionths of a second. The genesis of this development was the wartime need for a timing instrument that could measure the muzzle velocities of artillery shells as a means of weeding out defective guns and ammunition.

The project was undertaken in 1942 by Igor E. Grosdoff, in C. J. Young’s group. During the following year, the first instruments were turned over to the Army and Navy. The initial types were capable of measuring time intervals of ten thousandths of a second—but this was only a starter for Grosdoff. By 1945, his efforts to increase the speed and reduce the size of the device had resulted in a portable electronic counter capable of measuring frequencies up to 1,000,000 cycles per second with a precision of plus or minus one cycle per second. Employing a crystal­controlled oscillator, a vacuum tube circuit coupling the counter (p. 169) with the signal source, and a neon lamp numerical display, the instrument was completed just in time to enter widespread postwar service as the standard electronic counting device in many research and industrial functions.

The second case is the Antennalyzer, an analogue computer developed at Princeton by Brown and Wendell Morrison as a high-speed instrument for plotting the location and design of antenna towers to achieve any desired directional pattern. Up to this point, the only way of determining such patterns was to work out tedious calculations. The Brown-Morrison Antennalyzer created trial patterns in visible form on a cathode-ray oscilloscope, simply with the adjustment of a series of dials. When the desired pattern appeared on the screen, all of its essential design characteristics could be determined by reading the settings of the dials. With the advent of this device, the plotting of antenna location and design became a matter of a few minutes in the laboratory rather than a few weeks in the field. The device became invaluable in working out the arrangement of more complex directional antenna patterns to accommodate new television and other broadcasting services within the available frequency spectrum.

The Advance in Tubes

The building block of all new electronic systems through the war years remained the electron tube in its various sizes, shapes and forms. The remarkable advances achieved in radar, television, acoustics and other electronic techniques were heavily dependent (p. 170) upon basic advances in tube technology during the prewar decade and in World War II as well. The RCA tube research group, functioning under B. J. Thompson at Harrison had built a solid foundation for widespread electronic progress into higher-frequency operations through the 1930s. The same group, moving to Princeton with the opening of the new research center, continued its work with equal effectiveness under wartime conditions,

Many innovations and improvements emerged from the intensive RCA tube research program for application in wartime radio, radar, television and computing systems. An outstanding development was, as we have seen, the Image Orthicon—but this was perhaps no more outstanding than other tube developments applicable in different areas. Radar technology, for example, was advanced with the help of beam-deflection type amplifying and mixing tubes developed by Edward W. Herold, G. Ross Kilgore, and others, and of improved magnetrons resulting from research by John S. Donal and some of his associates in the tube group. Improved microwave tubes, for application in radar and communications systems were developed by Lloyd Smith, Nergaard, Haeff, and others. In the field of basic research, North and Herold produced fruitful results in the study of signal-to-noise ratio problems in tubes. A major contribution to tube technology in this area was North’s concept of a universally valid measure which he called “noise factor,” Published in 1942, his data have since been used to evaluate every type of radio receiver in terms of its ability to pick up weak signals. (p. 171)

Thanks specifically to these and many other advances in the electron tube art, the systems employed during the war operated with ever greater reliability over an ever increasing range of frequencies. By the end of the war, systems employing frequencies of thousands of megacycles per second were in practical operation, providing entirely new services and opening the way to the general postwar application of microwave techniques. Advances in tube technology also had added a new degree of versatility to elec­tronics through development of new types of storage and cathode ray tubes, both of which are more appropriately discussed within the framework of postwar progress in these fields.

The Personal Touch

The large-scale introduction of electronics into the military tactics of World War II created an urgent demand for the tech­nical guidance that could be supplied only by the scientists and engineers who had helped to develop the complex new devices and systems. The advice that could be offered by the scientist on the spot thus became as vital to the war effort as the invention or improvement of the new electronic weapons.

Large numbers of RCA’s research specialists met this urgent need by splitting their time between the laboratories and govern­ment assignments at home and overseas, Starting with the acceleration of the national defense program in 1939, many were called to service with the National Defense Research Committee and its subsidiary bodies to help muster the nation’s electronic resources (p. 172) and to guide the course of research and developments. Among them were Jolliffe, Engstrom, Zworykin, Beal, Olson, Beverage, and Ralph S. Holmes. Others of the research staff, including Seeley, Van Dyck, Leverenz, Vance, Earl Anderson, and many of their colleagues, accompanied new RCA developments into the field to discuss their application with military commanders or to supervise and observe field and combat tests.

An even greater number of research staff members performed part-time teaching functions at training centers throughout the country, instructing military personnel in the fundamentals of electronics or in the use of radar and other novel systems.

Perhaps the most glamorous of the wartime missions was troubleshooting, typified by the international travels of Beverage and the various members of the communications research staff.

As a leading American authority in problems of long-distance radio communications, Beverage probably holds the RCA Laboratories record for total mileage covered in war service. At one time or another he visited radio installations operated by the armed forces in the North Atlantic area and western Europe, in North Africa and Italy, and in Canada, Alaska, and Florida. Large portions of the same ground were covered as well on associated missions by other members of the group, including Lindenblad, Carter, Usselman, and Murray Crosby.

One of the most critical problems tackled by the group was that of ensuring reliable radio communications along the North (p. 173) Atlantic air ferry route flown by combat planes en route to the European theater. The Army had started by using short-wave communications, but had run into serious trouble as a result of magnetic disturbances and interference during bad weather. A series of on-the-spot studies by Beverage and his associates in Maine, Newfoundland, Greenland, and Iceland led to the substitution of long-wave equipment having far greater reliability under all conditions. The result was an immediate and sharp decrease in plane losses along the route between North America and England.

In 1944, Beverage was recruited by the War Department for a special mission to study problems related to fixed and mobile communications facilities in North Africa, Italy and England. It was a productive mission for the Army and Navy. And for Beverage it provided a variety of experiences that reached a climax of sorts when a V-I flying bomb landed about 300 yards from him in a London street. The productive aspect of the trip was disclosed a short time later in a commendation from General Brereton, commanding the Ninth Air Force in England. It stated, in part:

Dr. Beverage furnished invaluable technical advice and assistance in the establishment of Ninth Air Force radio circuits utilized in the initial stages of the invasion of the Continent, As a result of his work, no technical failures in cross-channel radio circuits were experienced. Such an achievement would not have been possible without his help.

This happens to be one outstanding example of many citations awarded to members of the RCA research staff for wartime service. (p. 174) Moreover, the entire research organization was honored by the Army and Navy with the presentation of the “E” flag in May 1943, for outstanding achievement in the war effort—the first such distinction for an industrial research laboratory. In ceremonies at the Princeton research center on June 17 of that year, Rear Admiral Harold G. Bowen, coordinator of the Navy’s radar program, and Major General Roger B. Colton, Chief, Supply Services, for the U.S. Army Signal Corps, formally presented the award on behalf of the two services, with this citation:

For meritorious and distinguished service to their country in its time of need, the Army-Navy Production Award is presented to the men and women of the Laboratories of the Radio Corporation of America, By their unflagging spirit of patriotism, by their acceptance of high responsibility, by the skill, industry and devotion they are showing on the production front of the greatest war in history, they are making an enduring contribution not only to the pre­servation of the United States of America, but to the im­mortality of human freedom itself.

But the war record of RCA Laboratories was not exclusively a succession of technical achievements, adventures, and awards. In 1944, the research organization suffered a major loss.

Allied bombing of enemy supply lines in Italy had forced the Nazis to move their supplies by highway during darkness. New techniques were required by mid-1944 to interrupt the night­time traffic, either by radar bombing or by some other appropriate new technique. In its search for a possible solution, the War Department consulted B. J. Thompson, who requested that he be sent to Italy to study the problem at first hand. Upon his arrival in Italy, Thompson asked to be taken on a flight (p. 175)

over the enemy lines as the best means of obtaining a complete picture of the conditions and objectives that would have to be met by new equipment.

On the night of July 14, 1944, the plane carrying Thompson took off from an American airstrip in the Florence area. It never returned. The wreckage was found later a short distance from the strip, and Thompson was interred in an American military cemetery.

The loss was reported to Secretary of War Henry L. Stimson, who wrote to RCA President David Sarnoff:

It is with deepest regret and a feeling of personal loss that I have been informed that Browder J. Thompson has been officially reported missing in the Mediterranean Theater of Operations. In the relatively short time that he has served in my office . . . not only has he made an outstanding and invaluable contribution to our war effort but he has engendered a feeling of great personal friendship, respect and confidence on the part of all of us. . .

It is a great tribute to him that, under no other compulsion than his own desire to do all in his power to aid in the solution of a most urgent problem facing our own Army and those of our Allies, and thereby to assist in bringing the war to an early conclusion, he felt it necessary to do as he did. (p. 176)