The Amateurs often have difficulties with the installation of a full-sized antenna for operation at low frequency LW bands. One of the possible embodiments of shortened (about two times) dipole band 160 m shown in the figure. The total length of each half of the radiator is about 60 m. They are composed of three times, as is schematically shown in the figure (a) and held in this position, the two leaf (b), and several intermediate (b) insulators. These insulators and similar Central made from nephroscopes dielectric material with a thickness of about 5 mm., the Distance between adjacent conductors of the leaf antenna is 250 mm.
As the feeder use coaxial cable with a characteristic impedance of 50 Ohms. On average Amateur frequency band (or required of its areas - such as the Telegraph) tune the antenna by moving the two jumpers connecting the two conductors (in the figure they are shown in dashed lines), and observing the symmetry of the dipole. Jumpers should not have electrical contact with the Central conductor of the antenna.
Referred to on the drawing the dimensions of the resonant frequency 1835 kHz was achieved by installing jumpers at a distance of 1.8 m from the ends of the cloth of the standing wave Ratio at resonance frequency is 1.1.
Data based on frequency (i.e. the bandwidth of the antenna) article no.
Author: Di Rocco; Publication: N. Bolshakov, rf.atnn.ru