October 30, 1931…NBC Begins Work On Empire State Tower
October 30, 1931…NBC Begins Work On Empire State Tower
On this day in 1931, NBC began putting a TV transmitter on top of the Empire State Building. The first experimental TV broadcast from the building was on December 22, 1931.
I don’t think the broadcast tower atop the building’s dirigible mooring mast was added till after 1936. At this point, antenna elements were simply attached to the existing mast.
RCA’s first experimental television transmissions began in 1928 by station W2XBS in Van Cortland Park and then moved to the New Amsterdam Theater Building, transmitting 60 line pictures in the new 2-3 mHz band allocated to television. A 13 inch Felix the Cat figure made of paper mache was placed on a record player turntable and was broadcast using a mechanical scanning disk to a scanning disk receiver. The image received was only 2 inches tall, and the broadcasts lasted about 2 hours per day. By 1931 the station became part of NBC and began to transmit from 42nd St.
The Empire State Building was completed in May of 1931, and RCA leased the 85th floor for a studio and transmitter location for experimental television broadcasts. RCA, through its broadcasting division NBC, applied to the Federal Radio Commission on July 1, 1931 for construction permits for the sight and sound channels of a television station, which were issued on July 24, 1931. The call sign W2XF was issued in December 1931 for the “sight” channel of that station on an assigned frequency of 44Mc. The RCA transmitter had an input power to the final stage of about 5Kw, giving an estimated power output to the antenna of about 2Kw.
The sound channel of the TV station was separately licensed as W2XK for a 2.5Kw transmitter to operate on 61Mc. Both transmitters were located on the 85th floor and used separate vertical dipole antennas.
Below are some shots of the Empire State mooring mast built as a dirigible docking station, but aside from King Kong and Fay Wray, no one ever went up there. The winds proved to be too strong and there were several near accidents in mooring tests, but a bag of mail was once delivered via the mast. The last photo is I think from the late ’50s and shows the assigned areas of the tower. Enjoy and share! -Bobby Ellerbee
Here’s an article about the signals from the Empires State Building that I wrote a few years ago that I hope you will enjoy: https://blogs.telosalliance.com/the-empire-state-building-where-it-all-began
Kong was facing northeast during his “last stand” as evidenced by the Chrysler Building to his lower right, the world’s tallest before the ESB.
It looks to me that you have the power numbers backwards, Bobby. If the “input power to the final stage {was} about 5Kw”, the antenna power would have been higher than that, not 2Kw. Perhaps the input power to the final stage was actually about 2Kw and the power to the antenna was 5Kw? Speaking as an engineer, of course . . . . 😉
Great history lesson.
It was RF killed the beast.