Scott Morrison

The Evolution of Television Delivery
By Scott Morrison

According to Nielsen, the average American watches 34 hours of TV a week, nearly as much time as one would dedicate to a full-time job. To find out how TV has become a major part of American life, this blog will take a look at the history of television, specifically its delivery methods as they’ve progressed from analog over the air (OTA) to Internet delivery.

In 1950 only 9 percent of U.S. households owned a TV, but by 1960 that number skyrocketed to 87 percent. At that time, the delivery method for television was a method known as over the air or terrestrial television. As the name suggests, OTA delivered content through the air using radio frequency (RF) signals which were received by antennas on each television.

This early delivery method had its advantages but some of those advantages also created limitations. With analog OTA broadcasting, television was easily accessible for the public. Using the antennas on the television, viewers would literally pull the signal out of the air. However, because the content was delivered over the air, there were distance limitations. An antenna could only transmit a signal so far, and if you were not within that range, you could not get the signal. Another limitation was the inability to utilize the subscription model of today. With the signal being transmitted freely over the air, anyone with a reception antenna could view the signal. Advertising and public funding were viable income sources for the stations, but with this technology, there was no way to institute a pay for access model.

Television’s next step in its delivery method evolution was cable television or community antenna television (CATV) which came about in the mid 1950s. This system used the same RF signals but delivered the video content to individual homes using coaxial cable. Large “community antennas” were erected near communities that could not receive OTA signals due to distance or challenging/mountainous terrain, and coaxial cable was run from the community antenna to individual homes, hence the name community antenna television.


In coaxial cable transport, quality does not significantly deteriorate over distance, so with this new system, terrain and distance were eliminated as a limitation. This delivery method also offered the ability for broadcasters and cable companies to create a subscription based model, a model accepted as the norm in today’s world.

The next delivery method introduced to the world of television was analog satellite television. While this technology saw its beginnings in the early 1960s, the first North American satellite to carry a TV signal did not come about until 1972.

In an analog satellite TV setup, there is a transmitting antenna located at the uplink facility, or origination point. The uplink dishes are about 30-40 feet in diameter (larger dishes have greater accuracy) and direct the signal to the satellite. The satellite then transmits the signal back to earth at a different frequency to be picked up by the reception antenna. After traveling such great distances, the received signal is very weak, so the reception antennas are parabolic in shape to reflect the signal to the dish’s focal point where a “feedhorn” amplifies the weak signal and blocks out the “noise.” The signal is then fed from the reception dish inside the home through a coaxial cable.

While this method also sends the broadcast signal over the air, a subscription based model was still a possibility as the satellites could distribute a scrambled or unscrambled signal to allow for conditional access.

The next development came in the early 1990s and was not necessarily a development in delivery method, but in the utilization of delivery methods. Next, digital cable television and digital satellite television came on the scene. With digital cable technology, broadcasters and cable companies were able to compress the video signal to allow many television channels to occupy the same frequency space of just one analog channel, allowing them to provide more channels.

With the digital advancements came digital over the air television, also known as digital terrestrial television (DTT). Like OTA, DTT uses RF frequencies to deliver television through the air. Digital transport technology has allowed providers to compress video channels so that they take up less frequency space and to offer various two-way communication capabilities.

You may have noticed while flipping through the channels that you may have access to an irregular channel number like 7.2. This is a direct result of the introduction of digital channels. The term channel was used to notate a specific frequency range, but with multiple channels occupying the space that used to be allocated to one channel, the channel notation was compromised, so sub-channels were developed as a solution. The 7 in this instance is the physical channel and represents the specific frequency range, and the 2 is the sub-channel or the spectrum of data used within the physical channel. This actually happens with the other digital delivery methods but, to make things easier on viewers, providers have created virtual channels. Simply put, the provider will take a channel like 7.2 and change the notation for the viewer to an unused channel number like channel 155. While the physical channel is actually 7.2, the viewer only ever knows it as channel 155.

(Since June of 2009, all full power U.S. television broadcasts are required to be exclusively digital under the Digital Television and Public Safety Act of 2005.)

The most recent developments, of course, are using Internet Protocol or IPTV for the delivery of television programming. This involves using hardware or software to encode the video and audio signals into an acceptable IP format such as H.264 (MPEG-4) or MPEG-2. That signal can then be streamed over a LAN/WAN one direction or Point-to-Point (as in the LEIGHTRONIX IncodeX One Point-to-Point solution) or in a two way scenario which can then provide users with interactive television (as in the LEIGHTRONIX LuxeVision IPTV solution). The advent of IPTV has also enabled cable and content providers to allow users access to TV stations and other video content over the Internet using personal home networks (wirelessly and/or via Ethernet cables).

A big advantage of Internet delivery for television is the interactive ability. The Internet allows for bidirectional communication and as a result viewers can determine exactly what content they want to view and when. Another advantage is convenience. With wireless Internet and streaming capabilities, viewers can watch video content from their TV, laptops, tablets, and even their phones.

With the introduction of this technology, the line between Internet and TV was blurred. Because of this, many fear that the introduction of Internet delivery may be the beginning of the end for television. In 2011, 98 percent of American homes had a television, and in 2012 that number fell to 97 percent, marking the first ever decline in this statistic. However, as you can see, the face of television has changed many times and each time for the better. While we may not know what television will look like tomorrow, I think it’s safe to say it will continue to evolve and that television is a technology that is here to stay.

Scott has been managing sales at the national level for over seven years at LEIGHTRONIX. With 25-plus years of experience in the professional video market, Scott’s primary responsibilities include establishing and maintaining dealer distribution channels.

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