“It’s a trap!” (No, not that kind of trap)
This is an FM trap. That 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.
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.
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.
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.