Harald Friis
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(A scarce pamphlet published in 1957 By J. R. Pierce -   C- From the Arthur Karp Collection at SMECC)




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HARALD TRAP FRIIS was born in Naestved, Denmark, February 22, 1893. He attended the Royal Technical College, Copenhagen, where he received the degree of Electrical Engineer in 1916 and Doctor of Science in 1938.

He began his engineering career in Denmark in 1916 as assistant to Professor P. O. Pedersen. From 1917 to 1918 he worked as Technical Advisor at the Royal Gun Factory in Copenhagen. He received a Fellowship from the American-Scandinavian Foundation in 1919. That same year he moved to the United States and, after a period of study at Columbia University, he joined the Western Electric Company's research department, which was later to become Bell Laboratories.

During his career with the Bell System, Harald Friis contributed substantially to almost every aspect of the radio art. His earliest work was on vacuum tube efficiency. He then worked on ship-to-shore radio reception. In the early twenties he built the very first field measuring set, for the 300 to 400 meter range. He also designed the first commercial double-detection or superheterodyne radio receiver, the Western Electric 4A receiver.

In 1923 he spent several months in England setting up receivers for the long-wave transatlantic telephone link. Later, he worked on short-wave problems. Here his improvements in receiver noise figure made possible Jansky's discovery of interstellar radio signals. The observation of Johnson noise in radio receiver circuits led him to the concept of noise figure. He engaged in many studies of propagation and of antennas; this work culminated in the design of the multiple unit steerable antenna (MUSA).

In 1938 Harald Friis entered the field of microwaves. Here he established accurate measurement techniques which proved invaluable both in the Bell Laboratories' wartime microwave work and in the work of the Radiation Laboratory at M.LT. During the war he was engaged in radar work, particularly in connection with microwave components and antennas. All of this work was characterized by thorough understanding and accurate measurements. In the field of antennas, his invention of the simple rocking horse scanning antenna is particularly noteworthy.

Toward the end of World War II, Harald Friis and his people made extensive and valuable measurements of microwave propagation. He had the responsibility for the basic microwave design of the first large-scale application of microwaves to communication, the TD-X New York-to-Boston microwave relay system. Thereafter he actively pursued forward-looking aspects of microwave communication, including an extensive program aimed at the use of millimeter waves and waveguides for long-route broadband communication systems.

Although Harald Friis has summed up his work in only a modest number of publications and patents, none is trivial; each is a milestone in the art.

Harald Friis was made Director of Radio Research in 1945. In 1952 he became Director of Research in High Frequency and Electronics. He was awarded the Morris Liebmann Memorial Prize for 1939 by the Institute of Radio Engineers, and the I.R.E.'s Medal of Honor for 1955. He was awarded the Danish decoration "Knight of the Order of Dannebrog,"~ presented by King Frederick IX, in 1954, and the Valdemar Poulsen Gold Medal, presented by the Danish Academy of Technical Sciences, in 1954.

He is a Fellow of the Institute of Radio Engineers and of the American Institute of Electrical Engineers. His professional activities also include membership in the American Association for the Advancement of Science; Danish Engineering Society; American Section, International Scientific Radio Union; and Danish Academy of Technical Sciences.

December 13, 1957







Is wisdom wisdom only to the wise? How can we tell wisdom from unwisdom? If deeds are important, then Harald Friis's deeds show he must be wise, and many who have worked for him will testify that he is. He prepared these few notes for a conference at Seaview in September 1957. I have discussed them with him and added comments, sometimes in his words and sometimes in mine. What I have added is indented.





The following brief notes on research jobs may guide the newcomer in the field and serve as a reminder to the experienced research worker.


Except for the triggering action of some basic discovery, a job usually stems from a definite need on a project or a hunch that an advance in the art is possible. The boss is certainly involved in starting a comprehensive project. With a smaller job, it is much better for the initiative to come from the research worker rather than from his boss. It gives the worker a realization of responsibility, and a successful solution is more likely.

Basic discoveries, such as those in solid state which led to transistors, or individual hunches as to possible applications of physical principles, as in non-reciprocal microwave devices using Faraday rotation, provide many jobs for the individual worker in a field. Important research projects, such as ship-to-shore radio, transatlantic radio, and waveguide communication, were suggested to Harald Friis by his bosses. Often a man working on a project finds he has to invent a solution to an unforeseen problem. Thus, while working on an early unattended receiver, Harald Friis had to invent an automatic gain control. One often makes interesting discoveries while working on a project; Harald Friis was the first to observe Johnson noise at radio frequencies. He did this in the course of making a quieter receiver for transatlantic radio. This led him to formulate the concept of noise figure. The receiver was instrumental in the discovery of interstellar radiation by Karl Jansky.

Where possible, it is desirable to split the job into smaller units. It is easier for the individual worker to manage and work efficiently on smaller and well-defined jobs; and remember, that it is always the aggregate of successfully completed small jobs that produces the successful big job.

Harald Friis never searched the literature, but then, he has always been ahead of it. He says, it's good pious advice, though. It is, now that so many people are doing research in so many places. 

A job can be overwhelming when looked at as a whole. But, if it can be divided into parts and each part made to work with maximum efficiency, the over-all problem can be solved. Harald Friis says that when he made radio receivers, he made and tested each part separately, the oscillator, the mixer, the IF amplifier, and so on. The receiver always worked when he put it together. Having the responsibility for a clearly defined part of a project, and one which he can do himself, helps a man in his work and enables him to take satisfaction in an accomplishment that is clearly his. Moreover, a boss should not be a dictator handing out bits of work each morning; he should help a man to do some clearly defined and worth-while thing. 

The research worker should make sure that (a) the job has a well defined objective, (b) there is a real need or a possibility for an advance in the art, and (c) the state of the art is ready for the job. The worth-whileness of the job may be checked by asking oneself the hypothetical question: "Would I do the job if I had to pay for it?"

(a) Without an objective, you can't tell when a job is done. If you go to a man and ask him what he is doing, you expect an answer. 

(b) It would have been possible to transistorize many microwave systems, but no real need arose. Finally a need arose in connection with an economical microwave system for telephony.

(c) The state of the art was not ready for a waveguide system before World War II, but it was afterwards.

The remark about paying means if you owned the Bell System, not out of your own pocket. 

The research worker should become obsessed with the job and it should haunt him day and night if he is the right man for the job. He may believe that scheduled hours of work limit his freedom of activity, but actually he has lost his freedom to the job itself. Excessive amounts of outside activity such as committee work and local affairs may indicate that the research worker is not in the right job. 

A person has to do some chores for professional societies, but when a man starts spending a great deal of time on IRE matters, Harald Friis wonders what's wrong.

A job should be started with a light touch. The research worker should try different approaches and not collect reams of data before he has done some preliminary exploring aimed at a simple solution. He should discuss it with his colleagues and his boss and consider their suggestions with an open mind. The informal "coffee table" conference is unbelievably productive in research. He should also search the literature critically.

Harald Friis never searched the literature, but then, he has always been ahead of it. He says, it's good pious advice, though. It is, now that so many people are doing research in so many places.



When working on a job the research worker should not ask others to solve his problems for him. Certain aspects of the job may require help from experts in a particular field, but the worker should be the real leader of his job.

A man has to understand his problem thoroughly before he can ask intelligent questions about it. If he gets stuck he can seek help, but he should ask for help, not a solution to his problem. It is the man responsible for the job who has the motivation to get it done.

The research worker should not be afraid to tackle work in unfamiliar fields, since he cannot have too broad an experience where his job is involved. The electrical engineer, for example, should not hesitate to enter the fields of chemistry, physics, and structural design.

It is easy for a man at the Bell Laboratories to spend lots of money and suffer endless delays by asking some other department to do something that he could do quickly and cheaply (but not without work) himself. One understands best what he does himself. In the waveguide job, Holmdel men solved problems in electroforming and in thermosetting plastics. Harald Friis had a lot of fun in designing a 6o-foot parabolic antenna. He got competent advice from an expert in structures, but the design was his.

In this age of electronics there is a tendency to use more vacuum tubes, transistors, and circuits than required for satisfactory performance. The research worker should guard against this and simplify his job as much as possible. He should always look for the simplest experimental and theoretical solutions.

This is extremely important if equipment is to be reliable and easily maintained. When he built his house, Harald Friis refused to have an electronic (vacuum tube) thermostat which would hold the temperature to 1/4 degree. The old-fashioned kind, good to 1/2 degree, was plenty good enough, and it was simpler and easier to maintain.

It is wasteful to compromise on the best way of doing a research job. The research worker should always get the special and sometimes expensive equipment needed for the job.

When Harald Friis had 1200 feet of waveguide put up for experimental purposes he designed accurate, if expensive, supports and got the most accurate pipe that could be made. It was scarcely good enough, and anything less accurate would have been useless.

Harald Friis says you must have a good setup. You must do it the best way you can think of. You must make good measurements.

It is foolish to measure errors in equipment rather than the phenomenon you are interested in. On the other hand, one does not use a sledge hammer to kill a fly.

The research worker is responsible for the work, education, and development of the technicians assigned to him. Because of this responsibility, it is annoying to have too much technical help. Overmanning a job by technicians also has a tendency to foster unnecessary work. Technical help is required for construction and maintenance of equipment and for routine measurement, but it is, in general, preferable to minimize technical help and adopt the "do-it yourself" attitude.

Harald Friis says, there should be a rule that whenever something is made for the first time the engineer should make it himself. Any old gimmick-any circuit board, anything. When something is duplicated, use a Technical Assistant. An engineer can tell whether the results make sense while he is making measurements. A TA may not know. But, J. J. Thomson was useless with his hands.

The research worker should not start work on a complicated and costly piece of new equipment in the precision shop before he has had thorough discussions with the shop foreman on the different ways of doing the job. Such a screening process is very desirable, since in many laboratories only a signature on a shop order is required to start a job.

Harald Friis says that one man sent orders to the shop for big pieces of brass which came back all polished and accurate to a mil, which wasn't necessary. Sometimes the foreman will know better than an engineer how to make a thing.

The research worker should stick to his job and get it finished as soon as possible. Delays caused by shop work are unavoidable nowadays and may sometimes justify several jobs to be carried on simultaneously. Those jobs should be closely related, since the worker who flounders from one thing to another because of too many objectives generally does not produce.

One can't do everything, but it sometimes takes a long time to find this out.

It is always advisable to work on more than one particular method of solving a problem. Working on competing methods is stimulating and, like the farmer, the research worker should not carryall his eggs in one basket.

In the waveguide job, both solid and helical waveguides were investigated. In the TD-2 job, the triode, the klystron, and the travelingwave tube were considered.

The research worker should review and re-evaluate his job periodically. In evaluating a new solution of a problem it is desirable to have an old solution in mind for comparison purposes. Such a "standard-of-comparison" solution will naturally change as the art progresses.

Something new has to be better than something old to be useful. Some people seem to like things just because they are different. The research worker should keep his boss informed and make certain that he, the boss, understands the job thoroughly; the boss must be "on board." He should never mislead his boss.


A man should know whether or not he is doing what his boss wants. A man should not go ahead and do something different from what the boss would do unless he knows he is right. He should have the right to, though. I don't think that this should be interpreted to mean that the man should rush to the boss every blue Monday and tell him the job is going terribly. He should weigh the job and try to give the boss a fair picture of it. I believe, however, that he should rush to the boss immediately with all good news. The boss hates to hear such things first from his boss.

Harald Friis likes the word integrity in connection with research, but he didn't know quite where or how to get it into his text.

The research worker should record his results in detail in a notebook. He should also be willing to write an informal quarterly progress report for the benefit of his associates and boss. The quarterly report may also provide a valuable background for a later publication.

A patent is important in getting credit for your work and to the Bell Laboratories. Witnessed notebook entries are invaluable in connection with patents. Harald Friis said, on the other hand, I never kept a notebook.

Contrary to some beliefs, department heads and subdepartment heads read progress reports; from them they get something of their opinions of people and jobs. The report is a good historical record, and if well written it can be incorporated in the text of a published paper. Harald Friis says that people in my department should write better progress reports, which he could understand, and that subdepartment heads should use them to sum up progress on the job from time to time. On the other hand, writing progress reports can be a chore.

When working on a job there is a tendency for the creative research job to turn into the "bread-and-butter" type job that occupies more than 50 per cent of the time of the technical people in a research laboratory. The bread-and-butter job requires competent technical help, but the highly creative worker can now relax and explore new fields.

As a job gets well in hand it can be taken over by less creative people. This takes a bad burden off the creative man.

By-products may change the course of a job. Such changes are natural and permissible in research.

Despite an investment in equipment and an identification with an approach, one should be willing to throw the old away if some other approach is clearly better. Here is one place where integrity is important. Harald Friis had a wooden tower built. He watched it go up. He took a good look at it when it was done and said, that's not the way to build a tower.

One shouldn't be so obsessed with matters at hand as to overlook more important things. If I hadn't been so hypnotized with the idea of an amplifier I would have seen the full importance of backward wave oscillations when Millman produced them. Sometimes byproducts are more important than the job itself.

The research worker should be happy if he was brought a job to a stage where other workers make use of his results. If his job is so successful that great expansion of effort is indicated, he should feel complimented rather than disappointed that he is no longer in complete control of the job.

Some people think they would like to have a sort of patent on a field of work. It is, however, a real accomplishment to sell your work to others.

Excepting long-range jobs, such as advancing the arts of radio, electronics, or waveguides, a job may be stopped before it is finished. This is most difficult, since research jobs have a tendency to go on and on; further improvement is always around the corner. But, if the importance of the job has decreased and if favorable results are too meager, then the job should be stopped. When in doubt, it is better to err by stopping a job, since many jobs may benefit by a period of rest and may readily be resumed if justified later.

In the thirties Harald Friis worked on short waves, rhombic antennas, and MUSA. Ralph Bown told him to stop all this work and go into microwaves. He says, it took me a week to get over this.



In finishing a component or systems type of job, the research worker must have carried his work to the stage where he can demonstrate his results by means of a finished research model or system. He should publish his results in a logical and concise manner, memorandum, paper, or patent, and he should see his job to development. He should then be willing to drop the job and think about the future.

If you insist on perfecting what you are working on, you will never have time to do anything new.

It is important to the morale of the worker and his laboratory that his research job be evaluated correctly. For example, does the job represent a real milestone in the advance of the art or is it just a worth-while improvement? It is unfortunate that the bosses in large laboratories often do not appreciate the value of the work of their people, or at least they do not show that they do.

These are hard words, but there is some truth in them. Bosses should try to get behind public acclaim and popular ideas. Big bosses should show appreciation of fundamental advances. No one is above taking pleasure in appreciation and praise. If they don't get praise for the right things they won't learn right from wrong. It is also important, as noted earlier, for people down the line to tell bosses what is important.

The research worker should realize that he is not to blame if Nature has not permitted favorable results. He is responsible for, and should be satisfied with, accurate quantitative results.

I have seen a good man work for years on something that proved impossible. Knowing what can't be done can be very valuable, as we see in the case of perpetual motion. Harald Friis says that MUSA didn't give as good results as people had expected.

The research worker must accept gracefully the possibility that, ahead of him, someone in another laboratory has found a solution to his problem. With so much effort along broad fronts nowadays, all research workers are exposed to such disappointments.

No one gets anything but patents in struggles for priority. People should take such things gracefully. There is nothing more annoying or pitiable than a man emotionally involved in showing that he was first. Moreover, if you are interested in getting the job done, the origin of the idea is less important than the fact that it is the right one.

The research worker should remember that some credit for a successful job, perhaps more than 50 per cent, belongs to the laboratory employing him. The laboratory supplied a large amount of know-how and gave him many aids and inducements to carryon his work.

Harald Friis says that the percentage varies with the individual, and that in many cases the Laboratories deserves more than 50 per cent credit. He says, the fact that I was planted in the Labs, and all the background, that was everything, John.





Antennas: Theory and Practice (with S. A. Schelkunoff). New York: John Wiley and Sons, 1952.

Radar Systems and Components, Chapter on "Radar Antennas" (with W. D. Lewis), pp. 763-858. New York: D. Van Nostrand Company, 1949.


"The Vacuum Tube as a Generator of Alternating-Current Power" (with John H. Morecroft), Proceedings of the AlEE, Vol. 38, No. 10, October 1919.

"Static Interference as a Function of Wavelength" (with L. J. Sivian), Wireless World and Radio Review, Vol. 10, No. 10, June 3, 1922.

"Radio Transmission Measurements" (with R. Bown and C. R. Englund), Proceedings of the IRE, April 1923, pp. 115-152.

"High-Frequency Amplifiers" (with A. G. Jensen), Bell System Technical Journal, April 1924, pp. 181-205. 

" A New Directional Receiving System," Proceedings of the IRE, December 1925, pp. 685-707.

"A Static Recorder," Bell System Technical Journal, April 1926, pp. 282-291. 

"A Radio Field-Strength Measuring System" (with E. Bruce), Proceedings of the IRE, August 1926, pp. 507-519, 

"Methods for the Measurement of Radio Field Strength" (with C. R. Englund), Transactions of the AIEE, 1927, pp. 492-497.

"Direction of Propagation and Fading of Short Waves," Proceedings of the IRE, May 1928, pp. 658-665. 

"Some Effects of Topography and Ground on Short-Wave Reception," Proceedings of the IRE, April 1932, pp. 699-721.

"Determination of Direction of Arrival of Short Radio Waves" (with C. B. Feldman and W. M. Sharpless), Proceedings of the IRE, January 1934, pp. 47-78. 

"A Multiple-Unit Steerable Antenna for Short-Wave Reception" (with C. B. Feldman), Proceedings of the IRE, July 1937, pp. 303-318. 

"Noise Figures of Radio Receivers" Proceedings of the IRE, Vol. 32, July 1944, PP·419-422.

"Note on a Simple Transmission Formula,"' Proceedings of the IRE, Vol. 34, May 1946, pp. 254-256.

"Radar Reflections from the Lower Atmosphere," Proceedings of the IRE (Letter to the Editor), Vol. 35, No.5, May 1947.

"Microwave Repeater Research," Bell System Technical Journal, Vol. 27, April 1948, pp. 183-246.

"A Reflection Theory for Propagation Beyond the Horizon" (with A. B. Crawford and D.C. Hogg), Bell System Technical Journal, Vol. 36, May 1957, pp. 627-644.




PATENT NUMBER      PATENT DATE                       TITLE

1,586,985      6-1-26       Duplex Carrier Wave Transmitting and Receiving Systems

1,647,349      11-1-27     Radio Signaling Apparatus

1,675,848      7-3-28       Transmission Regulation

1,678,183      7-24-28      Signal Reception

1,727,010      9-3-29       Radio Receiving Circuits (with A. G. Jensen)

1,762,974      6-10-30      Radio Receiving Systems

1,795,648      3-10-31      High Frequency Oscillation Generators

1,8°4,087      5-5-31        Wave Amplifying (with E. Bruce)

1,844,953      2-16-32      Radio Receiving Circuits

1,859,867      5-24-32      Wave Transmission Circuits (with A. G. Jensen)

1,867,356      7-12-32      Electric Wave Translating Systems

1,916,358      7-4-33        Radio Direction Finders (with E. Bruce)

1,947,256      2-13-34      Antenna Counterpoise Systems

2,013,140      9-3-35       Translating Circuit

2,041,600      5-19-36      Radio Systems

2,236,393      3-25-41      Directional Antennas (with A. C. Beck)

2,245,660      6-17-41      Radio System (with C. B. H. Feldman)

2,401,751      6-11-46      Coupling System

2,406,364      8-27-46      Oscillation Generator

2,416,675      3-4-47       Horn Antenna Systems (with A. C. Beck)

2,419,557      4-29-47      Branching Circuits

2,575,804      11-20-51     Microwave Hybrid Junction (with W. D. Lewis and L. C. Tillotson)

2,630,489      3-3-53        Waveguide Joint (with A. C. Beck)

2,773,978      12-11-56     Transmitting and Receiving Circuits for Wave Transmission Systems



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