Can an Amplifier Boost My Cable TV?by Jacob Andrew
Determining whether to amplify your cable TV can depend on a lot of changing factors. The way in which your cable is delivered -- digital or analog -- the level of service you're receiving and the quality of the amplifier are all important considerations that affect how an amplifier helps your signal. A boost in quality is possible with an amplifier.
Digital vs. Analog Amplification
A big factor affecting the cable industry is the transition from analog to digital signals. Simply put, analog signals worked like radio in that your television tuned into a certain frequency to get a different channel. In this way, the delivery of each individual channel is dependent upon the quality of the frequency your home or business is receiving. Digital works in a more two-way method. In a digital system, information is encoded into a series of 1's and 0's at the cable company, transmitted through the wire and then reinterpreted by cable box or a tuner within your television. Your TV requests that a certain channel be delivered to the TV and the cable company honors that request by activating that stream of digital bits. This way, only your overall ability to receive any transmission can be affected by signal quality, not any one channel. Therefore, an amplifier on a digital signal is only important if you're unable to get any television signal. Adding an amplifier to a working signal won't make it better.
Like a radio signal, cable signals can degrade the further they get from the original transmission point. This phenomenon is called attenuation, and analog frequencies can quickly become unreadable. To get the signal into homes and businesses, cable companies employ many amplifiers. Once the cable connection reaches your home, the cable company may no longer be concerned with assuring that the signal doesn't attenuate. However, in-house coaxial wiring might be the proverbial straw that breaks the camel's back, extending the length of the cable run to a point where it attenuates. Amplifiers take the fading signal and use electricity to regenerate the signal, which mitigates that attenuation. Generally the amplifier has an inbound connection where the line from the cable company comes in and then an outgoing connection which connects to your other devices. Amplifiers need access to a power outlet to work.
Low quality amplifiers can actually hinder your cable performance by failing to boost the right frequencies. Most amplifiers are sold according to what frequency range they accommodate. While analog signals can go as high as 2 gigahertz, some amplifiers work only on signals up to 1 GHz, effectively ignoring half of the available spectrum.
If higher channels are being lost to attenuation, then an amplifier can help recover these. This applies only to an analog environment; digital systems limit the channels based on access control systems at the cable's central office. High channels in analog systems, however, utilize higher frequencies. The higher frequencies attenuate faster than low frequencies, making it possible for lower channels to work while higher channels degrade too much to be seen. This matters only when your cable company has already authorized you to receive those channels. For analog systems, cable companies typically employ a frequency filter in their closest distribution box. These filters stop those higher frequencies from reaching your home. No amplifier will make those frequencies appear, no matter how powerful.
It's tempting to think that an amplified cable signal might lead to high-definition transmission. However, HD transmissions come only from digital delivery mechanisms. Though an amplified signal can result in a less-snowy picture, analog systems rarely deliver images higher than 600 pixels wide and more often only 480 pixels. By contrast, most HD standards provide 720 or 1,080 horizontal pixels. The broadcast system limits the maximum bandwidth that a channel can use, so these higher resolutions are only possible through signal compression technologies offered by digital.