How Do I Get a FM Signal in a Steel Building?

By Erik Johnson

Steel buildings are increasingly common due to their low cost of construction and easy maintenance. One drawback for those who live or work within is their tendency to interfere with radio waves, especially those in the FM band. Some listeners will be able to adjust the position of their radio, while others may resort to installing an external antenna or using the Internet to hear their FM broadcasts.

Position Your Radio

Steel siding and metal framing in a building acts as a Faraday cage to block electromagnetic radiation, such as radio waves. If you’re near the exterior of the building, try moving your radio toward a window to maximize the FM signal you receive. Even deeper into a large steel building, simply adjusting the position of your radio can sometimes boost your reception. If your radio has an external antenna, experiment with positioning to catch any signal that makes its way past the steel exterior. A single strand antenna works best when it’s fully extended and stretched to a high location. A T-shaped dipole antenna should be placed perpendicular to the direction of the transmitter. Many radios have a connector for an external antenna. Try a “rabbit ears” style antenna. They’re inexpensive and frequently work as well as more expensive FM antennas. Faint signals can sometimes be amplified by FM boosters to an acceptable strength, though in most cases amplification increases interference as well.

Outside Antennas

Sometimes a steel building blocks too much signal to get a good FM reception. If possible, mount an FM antenna on the roof of the building. Install the antenna as high as local regulations will allow and point ti toward the desired broadcast transmitter. In a smaller metal building, connect the outside antenna directly to the radio. Larger buildings or in settings where a radio must be mobile within a building require a repeater. A passive repeater is an antenna inside the building connected to the outside antenna with a shielded wire. A huge structure would require a powered repeater, which amplifies the radio signal before rebroadcasting it within the building.

Internet Broadcast

In an office setting, you may not be able to receive signal through the walls, nor are able to install equipment on the roof of the building. Many FM stations stream their broadcasts through the Internet and can be played through your computer speakers. Check the website of your favorite station to see if they offer this service. In a corporate environment, verify that Internet radio is approved by the company.