Dual band dipole for 3.5 and 7 MHz
The basis of this design is taken ideology like w3dzz antenna, but the barrage circuit (ladder) at 7 MHz is made of coaxial cable. The drawing of the antenna shown in Fig.1, a coaxial design of the ramp in Fig.2. Vertical end pieces 40-foot canvases of the dipole have a size 5...10 cm and are used to tune the antenna to the required area of the range.
Ladders made from 50 or 75 Ohm cable length of 1.8 m, laid in a twisted Bay with a diameter of 10 cm, as shown in Fig.2. The antenna is supplied coaxial cable through the balun device of the six ferrite rings pulled on the cable near the feed point.
Author: Regis Necklace (F3BE); Publication: N. Bolshakov, rf.atnn.ru