ARRL

Indoor Antennas

So you say that you can’t put up an outdoor HF antenna of any kind? There’s hope for you yet. Antennas generally perform best when they’re out in the clear, but there is no law that says you can’t use an outdoor antenna indoors. 

If you have some sort of attic in your home, apartment or condo, you’re in luck. Attics are great locations for indoor antennas. For example, you can install a wire dipole in almost any attic space. Don’t worry if you lack the room to run the dipole in a straight line. Bend the wires as much as necessary to make the dipole fit into the available space. 

Of course, this unorthodox installation will probably require you to spend some time trimming and tweaking the length of the antenna to achieve the lowest SWR (anything below 2:1 is fine). Not only will the antenna behave oddly because of the folding, it will probably interact with nearby electrical wiring. 

Ladder-line fed dipoles are ideal for attic use—assuming that you can route the ladder line to your radio without too much metal contact. In the case of the ladder-line dipole, just make it as long as possible and stuff it into your attic any way you can. Let your antenna tuner worry about getting the best SWR out of this system. 

The same dipoles and loops that you use in your attic can also be used in any other room in your home. The same techniques apply. Keep the antenna as high off the floor as possible. (As with most antennas, the more height, the better.) For indoor operating, however, most hams recommend using low output power. You’ll avoid RF “bites” as well as interference to VCRs, TVs and so on. Many hams have been successful operating indoor antennas with just a few watts output.