Can an amplified antenna actually be worse than a non-amped one?

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In the last several years, we’ve seen a lot of new antennas come on the market with built-in preamplifiers. They tend to be smaller than non-amplified antennas, and in the antenna world smaller generally means more popular. Generally, amplified antennas are sold as a way to get more channels and a better signal. But is that really true?

There are some folks, myself included, who will tell you that it’s possible that an amplified antenna is worse than a non-amplified antenna. So what’s the deal? Should you avoid an amplified antenna?

Not usually… 

but that doesn’t mean that an amplifier “couldn’t hurt.” An amplified antenna was “the way to go” in the days before HDTV but the reasons they worked with those old signals have almost all disappeared. It’s important to know when to use an amplifier and when using one can actually hurt you. In order to understand that, you’ll need to understand why TV signals today are different from the TV signals back in the 20th century.

Today’s television signals are digital, and digital signals behave differently than analog ones. Amplifiers make the difference important. When you amplify a signal, you’re amplifying the whole signal… and that means you’re also amplifying things that you don’t want. With digital signals, the only thing that matters is whether a tuner can tell the difference between a 1 and a 0. It doesn’t matter what the overall signal level is as long as you can do that. The tuner’s ability to tell a 1 from a 0 generally has more to do with the amount of noise than anything else.

The way amplifiers used to work

With analog signals, even if the signal was “noisy” you could usually get something from it by amplifying it. Analog TV tuners work like your ears… turning up the volume makes it easier for you to pick out tiny details. Without an amplifier a signal might be very “snowy.” Add an amplifier and you’d get a picture that might be less snowy.

Digital tuners don’t work like that. With a digital signal you either see that “1” or you don’t. Amplifying a very weak signal doesn’t bring you any more results. On the other hand, a proper low-noise amplifier will help you with “marginal” signals, those signals that come in and out, by bringing in more signal without adding more noise. Those amplified antennas you buy today are designed to try to hit that “sweet spot” where they’re just a little too weak to get good reception. Adding a powerful amplifier kicks them over to the point where they work great.

Putting this another way…

Here’s the part you need to know… all amplifiers not only amplify noise, they also add it. You can use complicated digital filters to reduce the noise and try to make up more signal where you can, but it only works so well. So, if you amplify a very weak digital signal, you could actually be making it worse. The best time to use an antenna amplifier is when the signal is strong but occasionally fades, such as on rainy days. An amplifier will also help you take a strong signal and distribute it to multiple rooms.

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About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 10,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.