VHF and UHF refers to the signal frequency in use by the broadcasting TV station. TV signals are broadcast in waves referred to as wavelengths. Every TV channel is assigned a channel frequency. The frequency assigned to the TV station determines the size and shape of the wavelength pattern. These wavelength patterns are flying through the air at the speed of light and every wavelength has a little different shape and size. The various shapes and sizes of these wavelength patterns is how your TV tuner understands which TV channel to receive and display. A proper TV antennareceives all available TV wavelengths all of the time. When you change the channel on your TV what you’re really doing is telling the TV tuner which TV channel wavelength/pattern you want the TV tuner to display. A wavelength can be thought of as a code that the TV tuner understands.
Simply put, Signal Frequency is the time/space between the signal waves. Wavelength is the size and shape of the frequency pattern.
VHF UHF TV Antenna Signals
Every TV station is assigned a broadcast channel frequency governed by the FCC. The FCC is responsible to make certain each TV station in a region is assigned a different channel frequency (wavelength pattern) so one TV station doesn’t interfere with another. If two TV stations wavelength patterns are the same and both are in range of the TV antenna in use the TV tuner would attempt to receive both channels causing bad reception on both TV channels.
VHF refers to TV channel frequencies of channels 2 through 13. The VHF signal band is broken down into two frequency bands. VHF low band refers to channels 2 through 6 and VHF high band refers to channels 7 through 13. UHF refers to TV channel frequencies of of channels 14 – 51. Since the digital transition in 2009 most VHF low band TV stations are now assigned to digitally broadcast on VHF high band or UHF signal frequencies. Even though the TV tuner may display a low band channel number such as 2.1 on the TV screen chances are the channel is no longer a low band VHF channel. The TV tuner is showing you the old analog channel number so you can recognize the channel number the TV station has used for years when they were an analog TV station.
Prior to the transition from analog to digital TV signals in 2009 the UHF frequency band was channels 14 through 69. The new digital UHF frequency band is now channels 14 through 51. The TV tuner may still display channels above 51 but again this is only for recognition purposes.
To determine the actual channel frequencies in use in your region you must determine the “Real Channel Number” or the “RF Channel Number” of the stations to be received. You can no longer depend on the channel number displayed by the TV tuner as being the actual channel frequency in use.
VHF low band = 2 – 6
VHF high band = 7 – 13
UHF band = 14 – 51
VHF UHF Antennas
We know that every channel in a region uses a different wavelength pattern. The receiving TV antenna in use must be capable of receiving all of the different wavelength patterns. If the antenna in use doesn’t receive all of the wavelength patterns there will be some channels it can’t receive.
In most areas of the United States a VHF UHF TV antenna is required in order to receive all of the available channels. There are few exceptions. VHF TV signal wavelengths are longer and wider than those used for UHF. UHF TV signals wavelengths are shorter and narrower. There are 50 wavelength patterns in the TV signal band and each one is a little different shape and size. The TV antenna you choose must be designed to receive all of the frequency patterns in use by the TV stations in your particular TV viewing region.
No matter where you live chances are you will need a VHF UHF antenna to receive all available channels.
TV antennas can be designed to receive a single channel frequency or they can be designed to receive all available channel frequencies. The more channel frequency patterns the antenna is designed to receive the larger the antenna must be. TV antennas designed to receive the larger VHF signal pattern must be larger than those designed to receive the smaller UHF signal pattern.
In recent years the TV antenna market has been flooded with tiny TV antennas designed to go unnoticed by the user. Some of these antennas are housed in plastic, others are thin and many make exaggerated claims that the user only finds out after they purchase and connect the antenna. These antennas are very appealing do to their size and their ability to blend in with the surroundings. For users and strong signal areas that only require UHF TV signal reception these antennas may work. However, to achieve reliable reception on both the VHF and UHF signals most areas require an antenna that looks like a real TV antenna.
Currently there are no regulations on the TV antenna performance claims made by the retailer or manufacturer. A manufacturer or retailer can say just about anything they want in reference to antenna performance. The following are some examples.
“HDTV antenna“ There’s no such thing as an HDTV antenna.
“VHF UHF TV antenna” Even if the TV antenna can barely receive a VHF signal or a UHF signal it may still be called a VHF UHF antenna. Remember small antennas perform poorly on VHF signals and larger antennas designed properly increase the range the TV antenna can receive a signal. Antenna performance is in direct relationship to signal receiving surface area of the antenna and proper design.
“150 mile Range antenna“ Under normal conditions no antenna of any reasonable size or reasonable elevation above ground can receive a reliable TV signal at a distance of 150 miles.
My advice is to get educated. Learn the difference between hype and fact. If you have VHF and UHF signals in your area make certain the TV antenna you choose is equally capable of receiving VHF and UHF TV signals.
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