A VIRTUAL TOUR OF WEAF IN 1927
By John Schneider, W9FGH
(Click on photos to enlarge)
The AT&T building at 463 West Street was the original home of WEAF. This photo was taken in the late teens, before the station’s antenna was constructed on the roof of the building.
The floor plan of the WEAF studios in 1923, showing the locations of the large and small studios, the announcer’s booth (1), and the control room (19).
This was the WEAF audio control room at 195 Broadway in 1924. The program was fed from this panel to the transmitter on West Street over an AT&T phone line.
This view shows the WEAF antenna, supported by two 300 ft. towers. The transmitter building was located midway between the towers.
This was the WEAF antenna tuning house, 1927. The inductors and capacitors inside matched the balanced feed line from the transmitter building to the unbalanced antenna’s impedance. The vertical downlead from the antenna can be seen at the center of the photo.
This view of the WEAF RT-150A transmitter shows the power amplifier frame in the foreground, the modulator frame in the center, and the rectifier frame in the background.
This is a general view of the main transmitter room at WEAF in Bellmore. The modulator frame is seen to the left, the rectifier frame is in the background, and the power control panel is on the right. The operator’s desk is located in the center of the room.
This view shows the main transmitter room as seen from the operator’s desk, looking to the left of the previous image. The crystal oscillator cabinet is at the left, and the intermediate power amplifier cabinet is to its immediate right. The output condenser and coupling transformer are located at the corner of the room, with the power amplifier assembly at the far right. The connection to the antenna is made through the two glass bowl insulators in the corner of the room near the ceiling.
This was the WEAF operator’s desk. The switch panel could switch individual tubes out of the circuit in case of a failure, and substitute standby tubes. The two RCA Radiola 20 receivers were used to monitor the station off-air, and to listen for maritime distress calls on 600 meters.
This was the main power control panel for the transmitter. From here, the operator started the transmitter by engaging each system sequentially - the cooling system and all of the high voltages and motor generator circuits.
The output coupling condenser was a large air capacitor consisting of many variable plates. A motor controlled the vertical position of the top plate to adjust the resonance.
This was the output coupling transformer that fed the antenna. The primary and secondary windings were separated by an electrostatic shield. The wooden base of the cabinet contained a rectifier that fed a signal sample to an oscillograph for viewing the modulation.
These three filament motor generators provided the filament voltage for the 32 large water-cooled tubes in the transmitter.
This was the generator control panel in the basement of the building. It selected which one of several motor-generators would go on line. Behind him are the bias voltage generators and intermediate plate voltage generators. The transformers for the high voltage rectifier tubes are seen in the background. The battery charging control panel is seen at the base of the stairs, just outside the entrance to the battery room.
The GE RT-150A transmitter was only in operation for four years at WEAF before it was replaced with this new RCA 50B transmitter in 1931, at a cost of $300,000. A new wing was added to the Bellmore building to house the new transmitter, which was elaborately adorned with aluminum decorative panels to showcase its modern technology. The rear of the transmitter was surrounded by glass observation windows. The old transmitter was modernized and was kept in place as an emergency backup system.
WEAF was initially conceived by AT&T as a “toll broadcaster” – a radio-station-for-hire, with blocks of program time that would be leased to anyone that wanted to broadcast. On August 28, 1922, WEAF broadcast what is widely considered to be the first radio commercial, promoting a new apartment building. But the toll concept did not attract many paying users, and so WEAF out of necessity reverted to creating its own programs. It quickly became one of the country’s most important station, presenting high quality talent like singer Vaughn De Leath, Will Rogers, the Happiness Boys, the Silver Masked Tenor, the Ipana Troubadours, and a number of renowned artists from the Metropolitan Opera Company. One of WEAF’s first announcers, Graham McNamee, was to become radio’s most famous announcer in the 1930s.
On the technical side, Western Electric was using WEAF as a laboratory for the development of its commercial broadcasting equipment. WEAF began with 500 watts, but by 1925 it was using the country’s first 5,000 watt transmitter, a Western Electric prototype. WEAF was also a pioneer in the early development of radio networks, as it regularly linked up with its sister station WCAP in Washington as well as other stations around the Northeast to create the first “chain broadcasts”. These early WEAF experiments, coordinated with sister company AT&T, led to the construction of an elaborate national network of broadcast-quality telephone lines which would become a major source of revenue for AT&T.
In 1919, AT&T was one of the original partners in the formation of RCA (the Radio Corporation of America), along with General Electric, Westinghouse and the United Fruit Company. However, the marriage of these companies did not go smoothly, and RCA suffered a great deal of internal friction between its partner companies. For one thing, Westinghouse and G.E. had been fierce competitors since the AC-vs-DC current wars of the 1880s. Additionally, AT&T felt its patent holdings gave it a monopoly on transmitter technology and radio broadcasting – a point strongly contested by both GE and Westinghouse, who were also operating their own pioneering stations. All of this turmoil finally came to a head in 1926 during a serious of contentious meetings between the partners that resulted in AT&T exiting the business of radio broadcasting, and the purchase of WEAF by RCA for $1 million. The partners also agreed that AT&T would provide broadcast transmission lines to RCA for the creation of a proposed national radio network.
RCA made good on that plan in September of 1926, in a powerful move that reinforced its dominion over radio broadcasting - it formed the National Broadcasting Company (NBC) as an RCA subsidiary, and created two new national radio networks – the NBC Red and Blue Networks. WEAF became the key station for the Red network and WJZ headed the Blue Network. The new networks quickly signed up many of the most important radio stations in major cities around the country as, and AT&T settled comfortably into its lucrative new role of supplying NBC with all of the network lines it needed to feed affiliate stations around the country. In 1927, all studio operations of NBC, WEAF, and WJZ were consolidated in beautiful new art deco studios at 711 Fifth Avenue. (They would move again in 1933 to even more opulent surroundings – Radio City in the new Rockefeller Center building.)
Within a few short months, RCA and NBC had become the kings of the radio hill, and they now turned their attention to improving their two key New York outlets.
RCA now wanted to lead the nation in the development of “super power” transmitter facilities for its two stations. The first high power station in the country was General Electric’s WGY in Schenectady, New York, which began operating regularly at 50 kW in 1926 and even experimented with 100 kW in 1927. However, the Federal Radio Commission would not allow any station having more than 5 kW to broadcast from inside its city limits for fear of overloading the public’s still-primitive radio sets. If RCA was going to increase its stations’ power beyond 5 kW, it would have to transmit from outside of New York. The company obtained two rural tracts of land for its stations and contracted with its partners Westinghouse and General Electric. Westinghouse would build a 50,000 watt transmitter for WJZ, and GE. would build one for WEAF.
WJZ was the first station to throw the big switch, which began operating experimentally with a Westinghouse open-frame transmitter from Bound Brook, NJ, in late 1925. However, the station immediately received 1,500 interference complaints from nearby neighbors, and as a result was not allowed to operate with more than 30 kW until 1933.
WEAF was the second station to increase power, broadcasting from a new transmitter site located in more rural surroundings on Maple Avenue in Bellmore, Long Island, 28 miles East of New York. Construction began in the summer of 1927, and the new site formally debuted on October 10. Let’s take a virtual tour of that facility.
A VIRTUAL TOUR:
The WEAF transmitter
was housed in a two-story 30x70 ft. stucco building decorated in a colonial
style to blend in with its rural surroundings. Two 300 foot towers supported a single 3/8”
wire antenna, instead of the multi-wire T-type configuration that was typical
of that era. A center downlead wire
connected the antenna to the tuning house. As an aircraft hazard marking, the towers
were painted in alternating 12 foot bands of black and yellow and illuminated
by floodlights. (This was before orange and white colors we see today were
Even though it was constructed by GE, all the top electronics minds of Westinghouse, GE and RCA participated in the planning of the new RT-150A transmitter, representing the apex of radio science in the day. Dr. Alfred N. Goldsmith of RCA, Dr. E.F.W. Alexanderson of General Electric, and Frank Conrad of Westinghouse, all participated in its design.
RT-150A TRANSMITTER DESCRIPTION:
The new transmitter incorporated several major design enhancements that were “firsts” for their era. While most transmitters were basically high-powered free-running oscillators, the RTA-150’s carrier frequency was generated by a quartz crystal housed in a temperature-controlled oven. It used a MOPA (Master Oscillator-Power Amplifier) configuration, where the crystal oscillator’s signal was amplified in a series of successive stages until it reached the final 50 kW Class A amplifier.
The transmitter was a “Rube Goldberg” design compared to the sleek transmitters of just a few years later. It consisted of separate assemblies for each major operating function, which were installed at different locations in the building. The major sections were:
At the time, the highest-power vacuum tube available was GE’s UV-207, rated for 10 kW input power, so to reach 50 kW it was necessary to combine many tubes in parallel. In all, the transmitter contained 32 tubes– eight RF tubes plus two spares, six pairs of modulator tubes with two pairs of spare tubes, and six UV-214 Kenotron rectifier tubes. The power amplifier, modulator and rectifier sections were each enclosed in separate open-frame chassis with exposed tubes. The high voltage connection points were also exposed, and the only protection for the operators against contact with high voltage was a wooden railing that ran in front of the transmitter.
Each of the 32 tubes was housed in its own porcelain socket and cooled with distilled water, and there were rubber hoses coiled around each tube base to deliver the flowing water. The cost of each tube was $10,000 (in 1927 dollars), and so a relay at each tube prevented accidental damage to the tube by not allowing its operation unless the water was flowing. 65 gallons of water per minute circulated through the tubes in a closed-circuit system, and it was pumped to an outdoor heat exchanger to extract the waste heat before returning it to the transmitter.
AC power for the power amplifier and modulator cabinets was supplied from the rectifier cabinet. The 2,300 volt AC mains voltage was stepped up through large transformers and fed to the six Kenotron water cooled rectifier tubes, connected in a double-Y configuration to provide 15,000 DC volts at 12 Amperes.
The operator’s control desk sat in the middle of the main transmitter room, and contained two radio receivers and a transmitter control switch panel. One of the RCA receivers was tuned to the station’s 610 kHz frequency (later changed to 660 kHz), while the other one was tuned to the 600 meter maritime distress frequency. Regulations required the station to leave the air immediately in the event of an SOS distress call. The operator’s control panel selected the tubes that would operate in the transmitter, and allowed the operator to shut down a defective tube and switch in a replacement without taking the transmitter off the air.
The basement of the building was the power house. It housed three 25 kW filament voltage motor-generators, four 3 kW intermediate plate voltage motor-generators, two 0.55 kW bias voltage generators, plus assorted power transformers, rectifiers and switching equipment. There was also a storage battery room and a storage vault for spare tubes.
All told, the entire WEAF transmitter facility represented an investment for NBC of $500,000 - or$6.8 million in today’s dollars. It represented the pinnacle of radio science in 1927, and received great amounts of publicity when it opened.
Despite NBC’s huge investment, the installation was not a great success. The transmitter was at the leading edge of technology, and as a result was never very stable in its operation. There were just too many devices in parallel, and it was difficult to keep them all functioning and in balance. The transmitter also was not capable of 100% modulation because of its use of the Heising modulation method. The result was that only one other 50A was built to fulfill the RCA contract. It went to WEAF’s sister NBC station WENR in Chicago.
Before two more years had passed, GE had developed the new 100 kW UV-862 power tube, which eliminated the need to parallel so many smaller tubes. Using this new tube, GE and Westinghouse collaborated on a new transmitter called the RCA 50-B. Unlike the RT-150A, this unit proved to be a successful product, and it entered the marketplace just as dozens of stations were being authorized for 50 kW operation. The transmitter found its way into dozens of the country’s high powered stations over the next decade, and many of them were still operating into the 1950s.
At WEAF, the old RT-150A was replaced with a new 50B in 1931. A new wing was added to the building to house new transmitter, and the old RT-150A was kept in place as standby rig.
But there was another, more fundamental problem with the Bellmore site - its signals were never very strong in New York City – it was just too far away. Initial reports in 1927 showed that WEAF in many parts of the city was weaker than from its old 5 kW rig on West Street. Finally, in August 1941, WEAF moved again – this time to Port Washington, NY – ten miles closer to the city. A new two-tower directional array was put into operation, and the station’s signal in New York City was finally strong again. The 50B was moved from Bellmore to Port Washington, and so the old RT-150A probably sang its swan song by keeping WEAF on the air during the move.
In November, 1946, NBC changed the station’s call sign from WEAF to WNBC. In 1988, NBC sold the station, and it became WFAN, which is operated today by CBS Radio. Since the 1960s, it has broadcast from its present transmitter location on High Island in the Long Island Sound.
NOTE: This article appeared in the Spectrum Monitor Magazine, December, 2015.
John F. Schneider & Associates, LLC