AM radio, the grandfather of the broadcast industry, has reshaped our view of the world, and of ourselves. "Just a minute! Something's happening.! Ladies and gentlemen, this is terrific. The end of the thing is beginning to flake off! The top is beginning to rotate like a screw! The thing must be metal! ... This is the most terrifying thing I have ever witnessed! Wait a minute. Someone is crawling out of the hollow top. Someone or... something. I can see peering out of that black two luminous discs .. are they eyes? It might be a face. It might be ..."

With that, Orson Welles and his Mercury Theater players unleashed the "War of the Worlds" on October 30, 1938 (the night before Halloween). The play, only an hour long, caused people to dash hysterically into the streets, flock to churches to pray, or fatalistically face death at the hands of Martian invaders. From the CBS Radio Studio One in New York, Welles demonstrated, convincingly and disturbingly, the power of radio.

From 1887, when Heinrich Hertz first sent and received radio waves, to the present, an amazing amount of progress has been made by radio and TV engineers and scientists. We take for granted today what was considered science fiction just a decade or two ago. The route from the primitive spark-gap transmitters to the present state-of-the-art has been charted by the pioneering efforts of many.

Broadcasting (along with telephone technology) has brought the world closer together than the early pioneers of the art could have imagined. Eighty years have passed since Charles D. (Doc) Herrold founded a voice station (as it then was known) at San Jose, CA. Developments between then and now have been marked by many inspired breakthroughs, and many years of plain hard work.
The Roots of Broadcasting
by Jerry Whitaker
In the beginning

In 1895, at age 21, Guglielmo Marconi and his brother Alfonso first transmitted radio signals across the hills behind their home in Bologna, Italy. Unable to interest the Italian government in his invention, Marconi took his crude transmitter and receiver to England, where the British navy quickly realized the maritime potential of radio. Within two years, the Marconi Wireless Telegraph Company had been founded.

The invention of the vacuum tube diode by J. Ambrose Fleming in 1904 and the triode vacuum tube amplifier by Lee DeForest in 1906 launched broadcasting as we know it. Early experimental stations took this new technology and began developing their own tubes using in-house capabilities, including glass blowing. As the young electronics industry began to grow, vacuum tubes were produced in great quantity and standardized (to a point), making it possible to share new developments and applications.

It is difficult to answer the question, "Who was the first broadcaster?" Much depends on what is defined as broadcasting . As far as AM radio is concerned, the grandfather of the broadcast industry, there were five stations that exhibited a rich tradition of being first in broadcasting:

     KDKA, Pittsburgh . Dr. Frank Conrad conducted the experimental work that led to the establishment of KDKA, which made its formal debut on November 2, 1920. Conrad was apparently the first to use the term "broadcast" to describe a radio service.

     WWJ, Detroit . The birthplace of broadcasting at WWJ was the Detroit News. The station signed on the air August 20, 1920. It was the first station to be operated by a newspaper, and the first commercial station to broadcast regularly scheduled daily programs.

     KCBS, San Jose . Doc Herrold's station at San Jose (which eventually became KCBS, San Francisco) began as an experimental operation with the first documented transmissions occurring in 1909. It is said of Herrold that he conceived the idea of broadcasting information and entertainment programs to the public.

      WHA, the University of Wisconsin . 9XM-WHA achieved its first successful transmission of voice and music in 1917 from the University of Wisconsin campus in Madison. Pioneers in the establishment of the station were Malcolm Hansen and Professor Earle Terry.

      WGY, Schnectady, NY . Operated by the General Electric Company, WGY served as the test bed for many experiments in AM radio. Later efforts at the facility were directed toward perfecting FM and television transmission.

Each of these stations was first in its own way, and each played a significant role in establishing the foundation for broadcasting. Contributions included both equipment and technology.

Most stations in the 1910s and '20s built their own gear. For example, at the University of Wisconsin, Madison, special transmitting tubes were built by hand as needed to keep radio station 9XM, which later became WHA, on the air. The tubes were designed, constructed and tested by Professor E. M. Terry and a group of his students in the University laboratories. Some of the tubes were also used in wireless telephonic experiments carried on with the Great Lakes Naval Training Station during 1918, when a war-time ban was imposed on wireless broadcasts.

It took many hours to make each tube. The air was extracted by means of a mercury vapor vacuum pump while the filaments were lighted and the plate voltage was on. As the vacuum increased, the plate current was raised until the plate became red hot. This out-gassing process was primitive, but it worked. The students frequently worked through the night to get a tube ready for the next day's broadcasting. When completed, the device might last only a few minutes before burning out.

Plate dissipation on the early tubes, designated #1, #2 and so on, was about 25W. Tube #5 had a power output of about 50W. Tubes #6-8 were capable of approximately 75W. Tube #8 was one of the earliest hand-made commercial products.

Sarnoff: the visionary

The "broadcasters" of the 1920s and early 30s were experimenters, not businessmen. Some businesses did, however, spring from the makeshift laboratories of the early scientists. David Sarnoff, general manager of RCA was quick to capitalize on the new medium.

Sarnoff was a powerful figure in the development of radio broadcasting in the 1920s and '30s, and a key mover in the development of television from its beginning in the late 1920s through maturity in the '50s and beyond. Sarnoff was born in Russia in 1891, and came to the United States at the age of 9. After completing his schooling, Sarnoff secured a job as a telegraph operator with the Marconi Wireless Company and quickly proceeded to make a name for himself. In 1912, at the age of 21, he intercepted the first distress signals from the doomed ship Titanic . Legend has it that Sarnoff stayed at his post for 72 straight hours to keep the world apprised of the rescue attempts, and the names of survivors. As the story goes, when the disaster was over, Sarnoff was a household word.

Four years later Sarnoff, then a contracts manager at the Marconi Company, sent a memo to his boss suggesting the use of radio for entertainment: "I have in mind a plan of development which would make radio a household utility in the same sense as the piano or phonograph... The receiver can be designed in the form of a simple 'Radio Music Box'...(which) can be placed in the parlor or living room."

Sarnoff's marketing vision and appetite for hard work led him in 1919 to join the Radio Corporation of America (RCA) as general manager. RCA was created by General Electric when the American Marconi Company was returned to private control by the U.S. government following wartime operations. RCA's function was principally to handle the nation's overseas communications. RCA later became a stand-alone company, independent of GE. Sarnoff was best known at RCA in the years following World War II as "The General." (In 1944 he was awarded the rank of Brigadier General.)

Radio Central

Sarnoff and RCA's first major project was the construction of a huge radio transmitting station at Rocky Point, NY. The facility, completed in 1921, was hailed by President Harding as a milestone in wireless progress. The President, in fact, put the station into operation by throwing a switch that had been rigged-up at the White House. Wireless stations around the globe had been alerted to tune in for a congratulatory statement by the President.

For a decade, Radio Central , as it was known, was the only means of direct communications with Europe. It was also the "hopping off" point for messages transmitted by RCA to Central and South America.

The Rocky Point site was not only famous for its role in communications, but also for the pioneers of the radio age who regularly visited there. The guest book lists such men as Guglielmo Marconi, Lee DeForest, Charles Steinmetz, Nikola Tesla, David Sarnoff and many others. Radio Central was a milestone in transatlantic communications.

There were originally two antenna structures at the Rocky Point site, each with six 410 foot towers. The towers stretched over a 3-mile area on the eastern end of Long Island.

The facility long outlived its usefulness. RCA demolished one group of 6 towers in the 1950s; five more were destroyed in early 1960. The last tower of the once mighty Radio Central was taken down on December 13, 1977.

Radio City at Rockefeller Center

NBC was created in 1926 through the acquisition of two early experimental radio stations that had been founded by Westinghouse and AT&T. The network's commercial broadcast operations began in October 1927 at 711 Fifth Avenue in New York. The facilities, then viewed as spacious, were designed by venerated chief engineer O. B. Hanson, who would later go on to design the network's 30 Rockefeller Center headquarters.

The first station, WJZ, had been established in 1921 by Westinghouse Electric and Manufacturing Company. A Newark, NJ, factory cloakroom was the original studio, equipped with a rented piano and an acoustic phonograph. After the station was purchased by RCA, the studios and transmitter were moved to Aeolian Hall in New York.

The second station, WEAF, on New York's Walker Street, was put on the air by the American Telephone and Telegraph Company, which was, in the words of the company,"anxious to study the possibilities of radio broadcasting."

In just six years, the pioneer network outgrew the Fifth Avenue quarters. On November 11, 1933, NBC began network operations at "30 Rock". The 11-story building, just to the west of the 70-story RCA Building Tower, simultaneously fed two networks and the two local stations. The building contained 22 studios and five audition rooms, with associated client and observation rooms, switching booths, a master control center and other technical facilities. The new radio complex occupied almost 280,000 square feet.

Hanson's vision

Hanson's master plan for radio broadcasting from 30 Rock evolved from his radio communication experience, which began in 1912 with his education in "wireless" at the Marconi Company (later the RCA Institute). He went to sea twice, and between voyages, worked for Marconi's testing department. Hanson eventually became chief engineer of the department and helped put WAAM radio in Newark on the air. Hanson moved to WEAF in 1922, becoming the assistant to the plant engineer. When NBC bought the station in 1926, he became the chief engineer.

Hanson's vision in broadcast facilities design is implicit in the radio network's 55-year occupancy of 30 Rock, with the continually expanding TV network as a co-occupant since the late 1930s. His accomplishments lend credence to the old saw that experience is the best teacher. His design knowledge was the amalgamation of lessons learned at sea, at Marconi, at the experimental facilities of WAAM and WEAF and, later, in the installation and operation of the network's Fifth Avenue facilities.

It is particularly interesting that Hanson designed 30 Rock for both radio network broadcasting, and for what he described as "elementary visual broadcasting, or television, as it is more popularly known."

His foresight was evident. "Anticipating the advent of television," he wrote, "the entire lighting system in the studio section was designed to operate on direct current to obviate the possibility of stroboscopic interference from alternating current lighting. Five 750kW motor generator sets in the basement (have) a considerable portion of capacity intended for flood lighting, a requirement for television."

The design of a ninth floor, 4-studio group anticipated special needs for complex live radio production as well as live television, as shown in Figure 2-1. The four 30-foot, almost-square studios were arranged around a single central control room. Hanson installed sound-insulated windows from this control room into each of the four studios. The floor of the control room was designed so that it could be converted into a turntable that revolved via an electric motor.

"One purpose of this studio group is to allow, in sound broadcasting, for the separation of various performers," Hanson wrote. "For example, the orchestra might be in one studio, the principal players in another and the remainder of the cast in still another. The outputs from the three studios would then be electrically combined or 'mixed.' The arrangement allows the producer a more accurate control over the 'balances' of the units involved.

"Another purpose of these studios is to allow for rapid scene shifts in television. This would be accomplished by simply revolving the control-room floor so that the scanning equipment, which would be mounted thereon, would face the desired studio," he said. (What was Hanson's 1930 vision as to the form and size of the TV camera?) "Thus, four scene changes could be effected, if necessary, within a very short time."

According to Hanson, "The maximum practicable degree of centralization (is needed) to simplify the problem of routine inspection and maintenance, and to facilitate the location or correction of trouble in the minimum possible time."

All of the centralized switching, master control and input/output equipment was situated originally on the fifth floor, along with a power room and battery room (providing 14Vdc filament power at 250A, and 400Vdc plate B+ voltage at 2.5A), and a main equipment room filled with 330 racks including 300 audio amplifiers. On the periphery of this floor (one of two with windows) were operating staff offices, recording rooms (for electrical transcriptions), a laboratory (specific capabilities or purposes not identified) and operating and maintenance shops. Table 1 provides and equipment roster and materials list for the 30 Rock project.

With the sale of NBC radio in 1988, the 11-story studio core was transformed into an all-TV plant.

WLW: The nation's station

Radio station WLW has a history as colorful and varied as any in the United States. It is unique in that it was the only station ever granted authority to broadcast with 500kW.

The station actually began with 20 watts of power as a hobby of Powel Crosley, Jr. The first license for WLW was granted by the Department of Commerce in 1922. Crosley was authorized to broadcast on a wavelength of 360 meters with a power of 50W, three evenings a week.

Growth of the station was continuous. It operated at various frequencies and power levels until, in 1927, WLW was assigned to 700kHz at 50kW and remained there. Operation at 50kW commenced on October 4, 1928. The transmitter was located in Mason, OH. The station could be heard as far away as Jacksonville, FL and Washington, D.C.

The super-power era of WLW began in 1934. The contract for construction of the enormous transmitter was awarded to RCA in February 1933. Tests on the unit began on January 15, 1934. The cost of the transmitter and associated equipment was approximately $400,000, not much today, but a staggering sum in the middle of the Great Depression.

At 9:02 p.m. on May second, programming was commenced with full 500kW of power. The super-power operation was designed to be experimental, but Crosley managed to renew the license every 6 months until 1939. The call sign W8XO was occasionally used during test periods, but the regular call sign of WLW was used for programming.

"Immense" is the only way to describe the WLW facility. The antenna reached a height (including the flagpole at the top) of 831-feet. The antenna rested on a single ceramic insulator that supported the combined force of 135 tons of steel and 400 tons exerted by the guys. The tower was guyed with eight 1 7/8-inch cables anchored 375-feet from the base of the antenna.

The main antenna was augmented by a directional tower designed to protect CFRB, Toronto, when the station was using 500kW at night. The directional system was unique in that it was the first designed to achieve both horizontal directivity and vertical-angle suppression.

A spray pond in front of the building provided cooling for the system, moving 512 gallons of water per minute. Through a heat exchanger, the water then cooled 200 gallons of distilled water in a closed system that cooled the transmitting tubes.

The transmitter consumed an entire building. Modulation transformers weighing 37,000 pounds each were installed in the basement. Three plate transformers, a rectifier filter reactor, and a modulation reactor were installed outside the building. The "exciter" for the transmitter produced 50kW of RF power! A motor-generator was used to provide 125V dc for control circuits.

The station had its own power substation. While operating at 500kW, the transmitter consumed 15,450,000 kWh per year. The facility was equipped with a complete machine shop because station personnel had to build much of the ancillary hardware they needed. Equipment included gas, arc and spot welders, a metal lathe, milling machine, engraving machine, sander, drill press, metal brake, table saw and other equipment. A wide variety of electrical components were also on hand.

WLW operated at 500kW until March 1, 1939, when the FCC ordered the station to reduce power to 50kW. The station returned to super-power operation a few times during World War II for government research. The days when WLW could boast to being "the nation's station," were, however, in the past.

The FCC enters the picture

As broadcasting began to develop, it became obvious to lawmakers that some type of regulation was needed to provide for orderly use of the airwaves. To fill this need, the Federal Communications Commission was formed in 1934, the end result of the Communications Act of the same year. The FCC, now observing its 55th year, was officially established on June 19, 1934, when President Franklin Roosevelt signed the enabling legislation. Some noteworthy actions during the first year of operation included:

      First broadcast license denied (KGIX, Las Vegas) for failure to complete its construction as required.

      Current ownership information required from broadcast stations.

      Hearings held on non-profit educa|ion broadcasting allocations.

      Allocations for clear and other channels (with several stations operating simultaneously at night) to be surveyed.

      First amateur license revoked.

The "golden era" of radio

Radio of the pre-World War II days was more than an entertainment and information medium. It was a friend; a connection with the rest of the world; an escape from the hardships of the Great Depression. Radio was special. People involved in it were special. This, legend has it, was the "golden age" of radio.

If you were to step back 50 years into the studios of a local station you would find a much different world than the broadcast station of today: different equipment, different types of people and different business goals. Broadcasting of this era was more than just a business or a job. It was the profession of magic.

Radio had a distinctly formal air about it. Announcers and musicians dressed in tuxedos. Female performers were elegantly attired as well, even when there was no studio audience. Announcing was formal. Broadcasting was regarded as a grand production, almost theatrical in nature. Enunciation and vocal clarity were essential, partly due to limitations of the equipment, but also because of the tradition of the theater. This formality of attitude and style would remain a part of radio well into the 1940s.

Many local stations had a staff orchestra, some for playing jazz, others for symphonic programs. A few stations had their own dramatic groups. Each station had its following of loyal fans who would structure their days around their favorite radio programs. Those were the days that brought radio to its peak of popularity and influence.

Nearly every station had several studios of varying sizes. In New York and Hollywood, the networks used theaters for programs presented before audiences. Because audio consoles of stock design did not appear until the late 1930s, each station assembled its own facilities. Mixers were put together from individual faders. Amplifiers were stock items consisting of several basic types. Monitor loudspeakers were usually electro-dynamics mounted in a baffle of no particular design. Performance left a lot to be desired.

The standard volume unit indicator (VU meter) was adopted by the industry in 1939. Prior to that time many different instruments were used to adjust program levels. Ballistic characteristics were far from standard, and the rectifier configurations inside the meters varied from model to model.

The mainstay of the studio was the venerable RCA 44 series ribbon. The microphone provided fairly good directional characteristics, but its size and vulnerability to wind noise limited its use mainly to inside pickups. Condenser microphones were used to some extent in the '30s. Compared with today's versions, the early condensers were large, heavy and prone to produce noise under humid conditions. Dynamic microphones also enjoyed popularity, chiefly for remotes because of their ruggedness.

For many years, phonograph records were frowned upon for actual broadcast use, due in part to questions regarding license and royalty matters. The main source of recorded music was transcription libraries. These libraries were leased to stations for use on the air. The 16-inch discs utilized various forms of modulation. Some used a vertical, or "hill and dale", cut while others used a laterally modulated groove similar to modern discs. Turntables had to be large to accommodate the 16-inch discs; the machines were heavy for speed stability.

Remote amplifiers were back-breakers in the literal sense. These "portable" units weighed in at 35 to 40 pounds. Add to this several microphones, stands, cables and headphones, and you can see why only the bravest souls liked to do remotes.

The use of radio relay equipment was limited to frequencies between 1.6 and 3MHz. This required relatively long antennas, even when loaded with an inductance. Skywave effects were also a problem, and frequently caused interference. Because AM was the only method available, the systems were highly susceptible to noise.

The origins of the networks

The formation and growth of the national radio networks is an exciting chapter in the history of broadcasting. The growth and prosperity of networks was linked tightly with the number of potential affiliates.

The giant RCA organization was the first company to recognize that the development of broadcast technology and management of broadcast services could best be performed by an independent organization. Accordingly, RCA under the guidance of David Sarnoff set the trend in network formation by creating the National Broadcasting Company in 1926. By the following year it had two divisions, the Red  and Blue  networks.

The origins of the Columbia Broadcasting System (CBS) can be traced back to 1926 and a company called United Independent Broadcasters (UIB). The firm came close to bankruptcy several times during its first year or so of operation. One of the organizations that kept UIB afloat for awhile was the Columbia Phonograph Company. When the record company sold back to the original investors their interest, they retained the name Columbia Broadcasting System. In 1927 William Paley became interested in the fledgling company, and decided to invest in it and help run it. The rest, as they say, is history. Incidentally, in 1938 CBS brought the Columbia Phonograph company (now Columbia Records) and held it until recently.

In 1934, the Mutual Broadcasting System was created to serve the increasing number of radio stations on the air at that time. During the 1940s, two additional radio networks were founded, the DuMont Network (1946) and the Liberty Broadcasting System (1949). They played an important role in the broadcast industry of their time, but later bowed to the giant networks and their well-established affiliates.

In 1943, Edward J. Nobel bought the NBC Blue Network (operated by NBC) and renamed it the American Broadcasting Company. The sale to Nobel was prompted by a federal antitrust ruling. The sale price to the Lifesaver manufacturer was $8-million. In 1953, the company was merged with Paramount, providing a valuable entry for the network into the telefilm business.

FM grows up

FM radio was the forgotten stepchild of broadcasting until the early 1960s. The awakening came as the result of FM license allocation changes and stereo transmission. In 1962 the FCC revised its commercial FM rules to divide the United States into 3 zones (instead of the previous 2). Three classes of commercial FM stations were also created. Until the '62 decision, FM stations were authorized on the basis of protecting the predicted service contours of existing stations. The new rules, however, changed the FM assignment scheme to one requiring minimum mileage separations between stations.

In 1963 the table of assignments  for commercial FM stations was created, and nearly 3,000 assignments were made to nearly 2,000 mainland communities. Assignments in Alaska, Hawaii, Puerto Rico and the Virgin Islands were added in 1964.

The new scheme enacted by the commission was not universally popular, however. Some FM stations on the air at the time were faced with having to reduce their power level and/or antenna height to meet the new guidelines. Stations operating at high powers, 125kW ERP was not uncommon, protested and sought to gain public support. In Northern California, for example, stations that were to be impacted by the new rules organized an appeal to listeners, broadcast simultaneously on the stations. All of the stations to be affected reduced their power during the broadcast to show the public the negative impact such a reduction would have on service.

The effort was copied in Los Angeles and other markets. Finally, in 1963, the grandfather rights of stations that had power in excess of Class B limits were granted.

The second spark that made FM come alive was stereo. Although stereo audio dates back to experiments performed over wire lines by telephone engineers in the 1880s, real development came only with post-World War II technology. In 1959, the National Stereophonic Radio Committee was created to examine the many proposed systems of transmitting FM stereo and submit a final recommendation to the FCC. In the summer of 1960, 6 systems were field tested over KDKA-FM in Pittsburgh, with receivers set up at Uniontown, PA. The system proposed by General Electric and Zenith was adopted, with broadcasting authorized to start on June 1, 1961.

The first stations to begin stereophonic programing under the new rules were, quite appropriately, WGHM, Schenectady, NY (owned by General Electric), and WEFM, Chicago (owned by Zenith).

Circular polarization of the transmitted signal was another major step for FM radio. One of the early proponents was KPEN-FM, Atherton (on the San Francisco Peninsula), which later would become KIOI (better known as K-101), San Francisco. KPEN received a special temporary authorization from the FCC in the later part of 1963 to start testing the effects of adding a vertical component to the existing horizontal signal.

A second Western Electric 10kW transmitter was purchased and modified to provide the needed power. Separate vertical dipoles were manufactured and installed on the station's tower. With this setup, engineers were able to vary the phase relationship and amplitude so that the station could switch from a horizontally polarized signal to a circular pattern. Monitoring points were established in rugged areas of San Francisco to observe the results. It was found that as the vertical component of the transmitted signal was increased, reception of stereo signals improved significantly.

At the same time, Lew Wetzel of WFIL-FM was proving to the commission that the vertical component of a circularly polarized transmission did not extend the 1mV contour. With these two reports, the FCC decided that it would indeed be in the public interest for FM stations to transmit with circular polarization.


"Radio Pioneers," Broadcast Engineering , Intertec Publishing, Overland Park, KS, May 1979.

Nelson, Cindy, " RCA Demolishes Last Antenna Tower at Historic Radio Central," Broadcast Engineering ,
Intertec Publishing, Overland Park, KS, February 1978.

Burke, William, "WLW: The Nation's Station," Broadcast Engineering , Intertec Publishing, Overland Park, KS,
November 1967.

Riggins, George, "The Real Story on WLW's Long History," Radio World , March 8, 1989.

"The Last 20 Years at the FCC," Broadcast Engineering , Intertec Publishing, Overland Park, KS, May 1979.

Gabbert, Jim, "Case Study: K101, an FM Pioneer," Broadcast Engineering , Intertec Publishing,
Overland Park, KS, May 1979.

Dorschug, Harold, "The Good Old Days of Radio," Broadcast Engineering , Intertec Publishing,
Overland Park, KS, May 1971.

Wallechinsky and Wallace, The People's Almanac , #2, 1978 Bantam Books.

WTIC: Radio to Remember , WTIC 60th anniversary publication.

Schubin, Mark, "From Tiny Tubes to Giant Screens," Video Review , April 1989.

Paulson, Robert, "The House that Radio Built," Broadcast Engineering , Intertec Publishing,
Overland Park, KS, April 1989.

Table 1. The equipment and materials used in the construction of NBC's Red and Blue radio networks and
two local stations at 30 Rockefeller Center in the early 1930.

Equipment installation time: 9 months
Audio cable, miscellaneous sizes: 470,000 feet

Other miscellaneous wire: 250,000 feet

Largest cable used: 1,800 conductor

Synchronous clocks (220Vac/60Hz): 275

Conduit, miscellaneous sizes: 660,000 feet

Trench for cable: 2,500 feet

Sound-insulated doors: 296

Microphone outlets in studios: 250

Loudspeakers: 175

Radio receivers: 110

Equipment racks: 330

Audio amplifiers: 300

Vacuum tubes: 2,000

Remote monitoring stations: 120

Reprinted with permission and the courtesy of Dr. Russell Naughton