Engineering:Helix building

Helix building of the backup tower for Blosenbergturm in Beromünster.

Helix building under the backup tower in Beromünster.

A helix building is a small structure at the base of a longwave or mediumwave radio transmitter. Within, there are capacitors and coils for coupling the signal from the feed cable to the antenna. The building may also contain lightning protection devices. Active components such as amplifiers are usually not housed in a helix building.

The interior of the helix building is typically covered with copper or aluminum, in order to control stray radiation.

In operation the components can have a voltage of several hundred thousand volts. The electromagnetic fields can heat up animals and humans like a diathermy device.

The helix building, which may be a simple switchbox for small transmitters, is usually next to the transmitting antenna array, but in some cases it can be the base of a mast radiator.

See also

• Radio Frequency Power Transmission