"Everything old is new again." That saying couldn't be more accurate when it comes to over-the-air television broadcasting. The first commercial TV broadcasts took place in the 1930s and color television was in development toward the end of World War II, finally making its way into a commercial (and expensive) product for the home in 1952 – long before color television broadcasts were practical!
Yet, younger generations seem surprised that such an option even exists for viewing television today. Even though the demise of free, OTA television has been predicted time and time again, it's still here – and even more important in the midst of the coronavirus pandemic. Network news program viewership is at an all-time high, as are local news programs in the early and late evening. More and more people are cutting the cable cord and installing antennas to take advantage of free, advertiser-supported TV.
How, exactly, does broadcast television differ from streaming video? For one thing, it is a 'one serving many' model. It doesn't matter whether one viewer or one million viewers are tuned in - image and sound quality will remain consistent. For another, TV stations operate independently from each other, with their own infrastructure and back-up power. A severe storm might knock out your Internet and cable connection, but the local television station(s) will still be on the air, providing news, weather, and public safety information.
Television stations around the world transmit on groups of frequencies allocated exclusively for their use. In the United States, those frequencies are 54 to 88 megahertz (MHz), 174 to 216 MHz, and 470 to 608 MHz. The first group consists of TV channels 2 through 6, which are known as "low band, very high frequency (VHF) channels." The second group consists of TV channels 7 through 13, which are called "high band VHF channels." Finally, the last group consists of channels 14 through 36 and is referred to as "ultra-high frequency (UHF) channels."
TV stations set up powerful transmitters on tall towers, buildings, and hills to cover wide geographic areas with their signals. All you need is some sort of antenna to pull in these signals – your existing television or external DVR already has a tuner built into it for TV channel reception. But there are some helpful things to know about how those signals radiate from the TV station and travel to your home.
A television station transmitting on TV channel 6 has a center frequency at about 85 megahertz (MHz). We can't see it, but the waves of energy pulsing out from the transmitting tower actually have a physical and measurable size. We describe that measurement as the signal's wavelength, and a channel 6 TV signal has a wavelength of about 3.5 meters, or 11.6 feet.
A high-band VHF TV station transmitting on channel 10 (center frequency of 195 MHz) has a wavelength of about 1.5 meters and a wavelength of 5 feet, while a UHF TV station transmitting on channel 30 (center frequency 569 MHz) has a wavelength of .53 meters or 1.7 feet. As the frequency of the station increases, the wavelength of its signal decreases in size. That's why UHF TV antennas are much smaller than VHF TV antennas.
To make sure the signals have a good chance of reaching your home, TV stations typically operate with high power levels for a large coverage area. There are also smaller, low-power TV stations that serve limited geographic areas. The right antenna, installed indoors or outdoors as required, can receive them all. And you'll find that the size of the antenna and its number of elements increase as the distance to the TV stations increases.
So why is any of this information important? For the best reception of any broadcast TV signal, our antenna should have a physical length equal to or close to the wavelength of that station's signal. We can compromise somewhat and get away with smaller antenna elements if the signal from the TV station is strong enough at our house, particularly for indoor TV reception.
Your grandparents' TVs often used long, telescoping whip indoor antennas back in the early days of broadcast TV, as these "rabbit ears" were required to pull in the TV stations on channels 2-6 and 7-13. And yes, those "rabbit ears" still work today!
Now, let's take a look at a rooftop TV antenna. Its elements are pretty long and there are many of them, sometimes arranged in an arrow pattern. But there are also smaller outdoor TV antennas, with some resembling a bow tie and others shaped in a loop. There are also flexible plastic panel antennas, antennas that look like large books, and combinations of straight metal elements and loops – even small bow ties mounted to a screen.
Despite their differences in appearance, each of these antennas are designed for optimal reception over a specific range of TV channel frequencies. If you live near a city with stations transmitting on low-band and high-band VHF frequencies, a small indoor panel antenna may not be sufficient. Conversely, if your local TV stations are all broadcasting on UHF frequencies and are strong enough, that same panel antenna will do the job nicely.
To get started with free TV reception, go to Channel Master's Antenna Selection tool and enter your zip code. This page will provide plenty of useful information, including TV channels available in your area, the distance from your home and compass direction to each TV station's transmitter site, and recommendations for TV antennas. Next month, we'll go into more detail on the different antenna types, how they work, and how to choose the right one for you.