Antenna French ham-shortwave described in the magazine "CQ". According to the author of the design, the antenna gives good results when working on all short wave Amateur bands - 10 m, 15 m, 20 m, 40 m and 80 m. It does not require particularly careful calculation (except for the calculation of the length of the dipoles), no fine tuning. To install it immediately so that the maximum of the directivity was oriented in the direction of preferential relations.
The feeder of the antenna can be either two-wire, with a characteristic impedance of 72 Ohm coaxial, with the same characteristic impedance. For each range, except in the range of 40 meters, the antenna has a separate half-wave dipole. 40-foot range works well in such a dipole antenna range 15 m.
All the dipoles are configured to average the frequency corresponding to the Amateur bands and connected at its center parallel to the two short copper wires. These same wires podpisyvaetsya bottom feeder. For isolation of the Central wires from each other are used three plates of dielectric material. At the ends of the plates to make the holes for fastening wire dipoles. All the junction of wires in the antenna propaedeuse, and the attachment point of the wrapped tape feeder made of plastic, to prevent the cable from moisture. Calculation of length L (in m) of each dipole is calculated by the formula
L=152/fcp,
where favg is the average frequency range, MHz.
The dipoles are made of copper or bimetal wire, guy wire - a wire or cord. The height of the antenna - any, but not less than 8.5 m.
Literature
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