Monday, March 23, 2015
You're on the Air!
by Carol A. Westbrook
The excitement of a live TV broadcast...a breaking news story...a presidential announcement...an appearance of the Beatles on Ed Sullivan. These words conjure up a time when all America would tune in to the same show, and families would gather round their TV set to watch it together.
This is not how we watch TV anymore. It is watched at different times and on different devices, from mobile phones, computers, mobile devices, from previously recorded shows on you DVR, or via streaming service such as Netflix and, soon, Apple. Live news can be viewed on the web, via cell phone apps, or as tweets. An increasing number of people are foregoing TV completely to get news and entertainment from other sources, with content that is never "on the air." (see the chart,below, from the Nov 24, 2013 Business Insider). Many Americans don't even own a television set!
We take it for granted that we will have instant access to video content--whether digital or analog, television, cell phone or iPad. But video itself has its roots in television; the word itself means, "to view over a distance." The story of TV broadcasting is a fascinating one about technology development, entrepreneurship, engineering, and even space exploration. It is an American story, and it is a story worth telling.
At first, America was tuned in to radio. From the early 20's through the 1940s, people would gather around their radios to listen to music and variety shows, serial dramas, news, and special announcements. Yet they dreamed of seeing moving pictures over the airwaves, like they did in newsreels and movies. A series of technical breakthroughs were needed to make this happen.
The first important breakthrough was the invention in 1938 of a way to send and view moving images electronically--Farnsworth's "television." Thus followed a series of patent wars, but at the end of the day, we had television sets which could be used to view moving pictures transmitted by the airwaves. In 1939, RCA televised the opening of the New York Worlds Fair, including a speech by the first President to appear on TV, President Franklin D. Roosevelt. There were few televisions to watch it on, though, until after the end of World War II, when America's demand for commercial television rapidly increased.
This led to the next big advance in television--network broadcasting. The big radio broadcast companies such as RCA (Radio Corporation of America) and CBS (Columbia Broadcasting System) naturally expanded into this media, but their infrastructure was limited. Though the frequencies used for AM radio transmission, from 540 to 1780 kHz (kHz means cycles per second) can travel long distances from their transmitting stations, each wavelength can only carry a limited amount of signal energy; in other words, it has a narrow bandwidth. Much higher frequency wavelengths, in the megahertz range (million cycles per second) are required for television so they can carry the additional information needed for picture as well as sound. As a result there was a scramble for higher frequency wavelengths, which was mediated by the FCC (Federal Communications Commission), the entity that regulates broadcasting. In 1948 the FCC allocated the higher frequency bands, designating which ones would be reserved for radio, and which ones for television, and and assigned channel numbers to the TV bands. The VHF television channels were designated 2 - 13. Channel 1 was reallocated to public and emergency communications, which explains why your TV starts with Channel 2! Several higher frequencies, designated as UHF, were reserved for later TV use, including channels 32 to 70. The FCC also froze the number of station licenses at 108 in 1948.
Because the number of broadcast stations was limited, TV was available only if you lived within range of a broadcast network, primarily CBS, NBC or ABC. In other words, if you lived a large city--New York, Chicago, Washington, Philadelphia, Boston, Los Angeles, Seattle or Salt Lake City. Outside of these areas, you might have a chance if you lived on a hill, put up a very high antenna, and prayed for a thermal inversion or a charged ionosphere to propagate the short signal to your television. My husband Rick, an electrical engineer and amateur radio buff, recounts that he watched the coronation of Queen Elizabeth in 1952 from his TV set in a small town in Pennsylvania, due to an environmental quirk (sunspots?), but everyone else had to wait for the films to cross the Atlantic and be shown on their local station.
Yet, for those of us who lived in a prime location, there was an ever-expanding number of programs to watch, such as the Texaco Star Theater, the Milton Bearle Show, and a variety of news shows. Many of us grew up on Howdy Doody, or shows created locally and televised live. I recall walking home from grade school for lunch as a child in Chicago, spending an hour watching "Lunchtime Little Theater," before returning to school to finish the afternoon's lessons! Many of these early shows have been lost, as they were never recorded, and video had not yet been invented.
Television broadcasting eventually went nationwide, thanks to microwave transmission, which developed out of WWII radar. This technology was used to relay television broadcasts to local affiliate stations, which could then broadcast them on their regular channels in the local area. Microwaves use point-to-point transmission, from one microwave tower to the next, and microwave towers were constructed to span the continent. The FCC increased the number of television station licenses, and the broadcast companies truly became "networks." Finally, everyone could watch the same shows at the same time.
But TV was still limited geographically--it could not cross the ocean. This problem was not solved until the third important technology was developed, that of satellite broadcasting. Sputnik, the first space satellite, was launched in 1957. Five years later, July 23, 1962, the first satellite-based transatlantic broadcast took place using the Telstar satellite to relay TV signals from the US ground station in Andover, Maine, to the receiving stations in Goonhilly Downs, England and Pleumeur-Bodou, France.
It's fun to watch this broadcast, which was introduced by Walter Cronkite, and began with a split screen showing the Statue of Liberty on the left and the Eiffel tower on the Right. The satellite transmission was followed a live broadcast of an ongoing baseball game in Chicago's Wrigley Field between the Philadelphia Phillies and the Chicago Cubs, and also included live remarks from President Kennedy, as well as footage from Cape Canaveral, Florida, Seattle, and Canada. I've included a short clip of the Kennedy broadcast.
If you looked up at the night in 1962, you might see the Telstar satellite zoom across your backyard sky. It took about 20 minutes to traverse, passing every 2.5 hours. Broadcast signals could only be transmitted to Telstar and back to land stations on either side of the Atlantic only during this 20-minute transit time, so the tracking satellite dishes had to be fast-moving; they also had to be very large to capture such a weak signal. It is impressive to see the massive size of the dishes in these satellite ground stations, and, and to imagine how quickly they had to move to sweep the sky. This picture of Goonhilly Downs gives you an idea of their size.
Although Telstar demonstrated that satellite transmission was possible for long-range broadcasting, the equipment and precision needed for tracking a rapidly-moving low-earth satellite was onerous. So the space scientists at NASA and Bell Labs launched the next generation of satellites, named "Syncom," into high earth orbit at just the right distance from the earth so that their speed matched the speed of the earth's rotation. When orbiting directly above the equator, the Syncom satellites appeared to be stationery over a single geographic location. Thus, the geostationary (or geosynchronous) satellite was born.
Stationery satellites paved the way for a tremendous expansion in telecommunications, and are still in widespread use. Satellites enabled the rise of cable TV networks such as HBO and CNN in the 1970s, which broadcast without having to go through FCC-regulated television transmitting stations. Instead, their programming was sent via satellite to the cable service, and from there selected programs went by cable to the TV of paid subscribers. These stations could also be accessed through Satellite TV subscription, such as Galaxy, which broadcast them directly to their customers' satellite dishes. Because early satellites could only carry a limited number of cable channels, multiple satellites had to be accessed to provide the purchased programming. Moveable satellite dishes of about four to twelve feet in diameter were positioned in the subscriber's yards or on their roof. Satellite TV further expanded American's access to television, reaching rural communities that had limited (or no) cable service and poor antenna reception; they also provided special paid programming, such as sports events watched at bars. This picture shows a 10-foot moveable dish in my yard in Indiana.
Stationery TV dishes--such as Direct TV antennas--were not feasible until satellites were able to carry more programming, so the dish could stay parked on only one geosynchronous satellite. The technical advance which allowed this was the development of digital video, in the late 1990's. Digital video would eventually displace analog-- remember when the DVD was introduced, which rendered VCRs obsolete in just a few years' time? Each genosynchronous satellites could now carry many more simultaneous channels than before, since each channel takes up only a small fraction of the bandwidth when compared to analog signals. Digital signals also increased the capacity of traditional TV, broadcast from ground towers, which eventually transferred to the HDTV standards, which broadcast at the high capacity UHF frequencies. The transition to HDTV was completed in June 2009, and the TV networks abandoned analog transmission on the old VHF channels, though many of the newer stations carry the old numbers (2 - 13). TV viewers are surprised to learn that they can watch their favorite channels on the newer HDTV sets using only a simple indoor antenna, and many are giving up their pricey cable services. Digital video signals were ready for growth in other media, as they theoretically be transmitted over the internet or by cell phone, and could be stored easily for re-broadcast.
Yet one more step was needed before widespread internet and cellular-based video could occur, allowing us to watch television programs as we do now. This was not a technical advance but an economic one--the sharp drop in the price of computer memory, which happened about 2009. Prior to that, computers had a lot less memory and storage capacity. Perhaps you remember the agony of trying to watch a YouTube video in its early years? Or of waiting for your browser to load? Now we take it for granted that we can view digitized images, create them, share them, watch pre-recorded programs, and record on our TIVO from multiple sources. There seems to be no limit to the ways that we can enjoy television, truly viewing "pictures at a distance." It is a far cry from the early years of television that many of us still remember, when we all watched a small, black-and-white screen with poor sound, to watch John, Paul, George and Ringo sing "I Love You." Now those were the days!
Thanks to my husband Rick Rikoski, for his patient and helpful explanations of the technology of television and its early development.
Posted by Carol A Westbrook at 01:10 AM | Permalink