Should you buy a variable gain amplifier?

Amplified antennas aren’t without their controversy. I’ve gone through the reasons you might want one, and I’ve also explained that a poor-quality amp is worse than none at all. In fact I’ve written a lot of articles on the subject if you’re interested. Read them all and you’ll get a really mixed view about antenna amplifiers. There’s a reason for that.

Antenna amplifiers don’t do what you think they do.

You would think an amplifier just takes a weak signal and makes it stronger. It does do this, but digital signals don’t respond to that kind of amplification the way analog ones do. Once you’ve locked onto a digital signal it doesn’t actually matter how strong it is.  I explain more in this video:

Variable gain

Most amplifiers don’t have variable gain. This one from Skywalker does. It lets you adjust the gain from a low of 15dB to a high of 25dB. Those numbers make sense because 15dB is the right number for compensating for an 8-way splitter. 25dB is typical for most preamplifiers.

When you choose a variable gain amplifier, you really have to be careful about the manufacturer. All mechanical parts are going to add noise to an amplifier, and noise is the one thing you can’t ever remove. Once it’s there, it’s there forever. A “knob” adds more noise than virtually any component, and a badly-designed one can overpower the amplifier and make the signal worse than it was when it started.

A brand like Skywalker is a good bet, though. They aren’t well known to most home DIYers, but their splitters and combiners are used an awful lot in commercials installs. I’d trust them.

No matter which variable amplifier you choose, look for one where it’s clear that the attenuator knob is connected straight to the circuit board. Ideally it should be a small screw head mounted on the surface, but a small knob like this one is essentially the same thing.

You want to avoid one with a big knob that’s mounted above everything else, like this one we used to sell.

That’s a sign of an inferior and noisy component most of the time.

Why would you choose a variable amplifier?

Using a variable amplifier is best when your TV stations come from many different directions. If one channel is much closer than others you may have problems. The closer channel may be overamplified, and that means you’ll get worse reception than you did before. Turning down the amplification so it’s “just enough” to help those distant stations and “not enough” to cause problems with closer ones. It’s a delicate dance, but you shouldn’t have to do it more than once. After that the amplifier can be safely tucked away to do its job in peace.

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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 8,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.