Cage aerial

A cage antenna is an antenna which consists of a plurality of wires, the so called reuse ropes, which are generally radially symmetric.

Construction

In the simplest case, it is in a cage antenna to a parallel and radially symmetrical arrangement of wires, which are supported at their ends by a ring and are summarized way behind these rings to the outer sides and tense. The Reuse ropes then describe between the rings, the surface of a cylinder. This arrangement is also referred to as a cage trap. Alternatively, the wires may be radially symmetrically fixed to rings of different diameter, whereby the wires to describe the lateral surface of a truncated cone. Both antenna structures reminiscent of fish traps. From cage traps to dipole antennas can be put together with a large bandwidth. Examples include the quadrant antenna, a steep omnidirectional shortwave transmitting antenna in the form of an L- dipole of two identical cage traps, and the curtain antenna ( a judicial radiant short-wave transmitting antenna ) with a plurality of cage traps constructed Faltdipolen.

A special type of cage antenna is the flat trap. Here, the antenna wires are arranged in a plane next to each other and are accordingly not worn with rings, but rods and summarized.

Another design of the cage antenna is the radially symmetric vertical arrangement of wires around a radio tower or transmitter mast. Reuse the ropes are hereby fixed to two horizontal support ring disposed concentrically around the upper and lower part of the mast or tower and electrically combined. Instead of a linearly - vertical arrangement, the ropes can be arranged Reuse tapered or by means of additional bracings or boom in a bent shape around the supporting pole or tower around. If one uses mast or tower supported Reuse antenna as a transmitting antenna, so they act as omnidirectional. By combining Reuse ropes with separate high-frequency power supply, it is possible to operate such antennas Reuse as a directional spotlight. The ARRT - antenna is a mast- supported cage antenna, which can be interpreted as a shrinkage -reducing transmit antenna. One advantage of the reuse antennas is that the supporting tower or support pole may be grounded and its use for other wireless services, for example in the VHF range, facilitated the static benefit due to the lack of Fußpunktisolation and also facilitates the supply of aviation safety lighting.

Reuse antennas were built in the past few decades in different versions for radio stations in the long, medium and short wave range. In Germany and Austria mast or tower supported Reuse antennas at the long-wave transmitter Zehlendorf, on the medium wave transmitters Zehlendorf and Langenberg and on shortwave transmitter Moosbrunn be used. They were used until their decline even at the long-wave transmitter castle, on the medium wave transmitters Bremen Oberneuland ( folded flat Reuse ) and Wolfsheim ( as a reserve antenna ) and on shortwave transmitter tube village ( as a reserve antenna).

Foot of the transmitting tower where the eight vertical Reuse ropes are fed.

Shortwave antenna quadrant of two horizontal cage traps

Shortwave cage antenna of the transmitter Bodensee

Kinked flat Reuse on the left side of the transmission mast