What is an FM trap and why would you need one?

“It’s a trap!” (No, not that kind of trap)

If you are looking around the Solid Signal web site, you find a lot of pieces of equipment you didn’t know you needed? Perhaps you’ve noticed this one:

THAT kind of trap.

Let’s explain.

This is a distribution amplifier with a built in FM trap. An FM trap may sound like the sort of thing your local DJ may spring on you, but an FM trap can be an important part of your antenna system. It can help you get the best reception not just with radio, but with television as well.

Understanding broadcast signals (a little)

If you have a large over-the-air antenna with an amplifier, you may find that some stations are not as clear as you feel they should be. Often times this is due to the fact that the amplifier is not only boosting the signals you need, but also the signals you don’t. Not only that, it may be boosting signals that don’t need boosting.

Understanding amplification is really much harder than it was in the past. Today’s television signals are digital. This means that they respond to amplification far differently that you would expect. Digital television signals are made up of ones and zeroes. So, the only thing to really worry about is if they are detected at all. Think of a TV signal as someone tapping on a table with a distinct pattern. If the room is quiet, you can hear the tapping. If the room gets louder, you might still hear it. Or, you might need the “tapper” to tap louder. But, it doesn’t matter how loud they tap, as long as you can hear the tapping. Louder tapping doesn’t make it better.

That’s the way amplification works with digital signals. All it needs to do is make the signal strong enough so that your TV can receive it over the surrounding noise.

Why an FM trap can help you

Let’s say you live 60 miles from the television towers. However, your town has a local FM station. The signals from that FM station don’t need boosting at all. In fact they may be so strong that they may cause interference on those distant television stations. Amplifying the signal just makes it worse.

The solution is to use an FM trap. An FM trap stops radio signals before they leave your antenna, and before they get amplified. Some FM traps just filter out all FM signals while the one shown above can also be tuned to filter out specific frequencies. This can come in handy if you’re trying to amplify distant radio signals as well as TV ones.

Do you need an amplifier with an FM trap?

Don’t be afraid of falling in an FM trap… it’s just another tool you can use to make the most out of your home theater system. You’ll need one if you think that close FM stations could be affecting your very distant TV stations. And, if you need one, you’ll find antenna accessories and everything you need to live your best digital life when you shop at the all-new Solid Signal.

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.