Tips for ham radio antennas in an attic

If you are a radio amateur or wish to become one, and local regulations do not allow you to place antennas outside your home, don’t panic, because there are several solutions. There are stealth antennas, of which the flagpole and metal gutter are perhaps the best known. But even if those are not possible, there’s also the attic antenna.

In online groups, people often ask what the best antenna is for use in an attic. The answers sometimes contradict each other. It’s often impossible to just give advice without knowing on which frequencies someone wants to transmit and/or receive, what the space available in the attic is, how high the floor of the attic is above street level. But also what materials are used in the roof and walls of the attic. Therefore, in this article, we will go through the factors step by step that help you make a choice.

Materials in the roof

Most attics have a wooden roof, often covered with tiles, bitumen, slate, zinc, steel, or other materials. Then, there’s often insulation applied, usually glass wool, rock wool, or polyurethane. Radio waves can penetrate these materials to some extent. It’s important to know that the higher the frequency, the greater the damping by the roof materials.

Metal roof materials reflect a significant part of the radio waves. Same goeds for insulation covered with aluminium foil. In many cases, the antenna can then not or only difficultly be tuned. In addition, only a small part of the radio waves will actually reach the outside world, or will be mostly scattered around.

Frequency and damping

As the frequency increases, so does damping by roof materials. You won’t notice much of this on the lower HF bands, but for example, on the 10-meter band, this damping is already noticeable. On 2 meters (VHF) and especially 70 centimeters (UHF), it becomes problematic.


Try to use all the space (height, length, and width) you have, because the less you have to shorten your antenna, the more efficient the radiation. Especially on HF like the 20 meter band, an antenna is already quite large.

Height above the street

How high you can place your antenna in the attic relative to street level can determine the choice between a vertically or horizontally polarized antenna. A horizontal dipole more than 3/4 wavelength above the street, generally has a more favorable radiation pattern for DX than a vertical antenna. If you have a high pitched roof, then there might be room for a vertical antenna. If you have a long pitched roof, then there might be room to place a wire antenna or dipole.

Antenna suggestions

Here are some suggestions for antennas that could fit into your attic.

The wire antenna

This is perhaps the easiest antenna to place in an attic. For example, place in an L-shape or diagonally. For most bands, you will need a tuner. Tuning at the antenna itself is the best way, for example with an automatic tuner. Such wire antennas need a good counterpoise. A piece of wire or a large piece of metal. Preferably not existing piping, as they can actually pick up interference in your reception. Often a 9:1 impedance transformer is used to be able to tune the antenna well on many frequencies. The higher the wire hangs, the better. This antenna does have some directionality.

The vertical antenna

The advantage of a vertical antenna is that height does not influence the radiation for DX as much as a horizontal antenna. The disadvantage is that for efficient operation, this antenna needs to be 1/4 of the wavelength long. A shorter vertical antenna is a possibility, but then it must be electrically extended with an extension coil. Or here is also the possibility to make the antenna resonant with an autotuner directly at the antenna. The vertical is not direction-sensitive but needs at least two 1/4 wavelength radials as a counterpoise (which you may zigzag to safe space). The combination of 1/4 wave radiating element with 1/4 wave radials usually means a good SWR between 1 and 1.5.

The horizontal dipole

The dipole antenna has a number of properties in common with the dipole. This antenna is also direction-sensitive and wants to hang as high as possible for DX. You can hang the legs of the dipole horizontally, but also diagonally in an inverted V shape. In the V shape, the antenna is a lot less direction-sensitive. Each leg is a 1/4 wave in length. The impedance is close to 50 Ohm, so great in terms of SWR. If you feed the dipole via a coaxial cable, then it’s necessary to place a 1:1 balun where the coax connects to the dipole. Here too, it’s possible with an automatic tuner to tune the dipole onto various frequencies.

The horizontal sky loop

If your attic has an almost square surface, a horizontal loop is also a serious option. Simply a wire in square shape with a circumference of one wavelength. The limitation of this antenna is that the radiation angle is high, so not so suitable for DX. The impedance lies between 100 and 150 Ohm, which means you need a 2:1 impedance transformer or a (automatic) tuner.

The Cobweb or Classic Halo

This square antenna is essentially a horizontal dipole (Cobweb) or folded dipole (Classic Halo) with the ends close together. The advantage of this antenna is that the sides on, for example, the 20-meter band, are only 2.8 m (9 ft) long. There’s no direction sensitivity. The Cobweb needs a 1:4 impedance transformer, the Classic Halo can be fed directly with coax via a 1:1 balun.

A Classic Halo with elements for 10 and 20 meters could fit into an attic.

The magnetic loop

A special antenna is the magnetic loop. A very compact antenna that fits on almost all attic floors. The downside is the somewhat less efficient radiation and the very narrow bandwidth. Most commercial magnetic loops have the possibility to tune automatically. This compact antenna is direction-sensitive with a deep null, so you must have the possibility to rotate it. Magnetic loops to transmit on are significantly more expensive than the earlier mentioned antennas.

Interference and your health

What you seriously need to take into account with indoor antennas is interference. On one hand, on your reception by electrical appliances in the house and at neighboring houses. On the other hand, interference on the same devices by transmitting with an antenna in the house. Standing very close to antennas when transmitting with high powers can be harmful to your health.