Proposed bunk antenna operating at 10, 12, 15, 17, 20, 40 80 metres SW-band. The upper tier (In) works on 10, 15, 20, 40 and 80 metres, the lower tier (H), 12 and 17 metres (figure 1).
Input resistance (B) is 180 220 Ω (N) 45 50 Ohms. Antenna power is carried out by two coaxial cables, separately for each tier (figure 2). Transformer TR1 with a ratio of 1:4 wound on a ferrite ring with a diameter of 60 mm and height of 10 mm, a permeability of 400 to 600. Wrap at the same time the two wires with a diameter of 1.5 mm or line with a characteristic impedance of 100 Ohm - uniformly around the ring 10 turns. Can use transformers from the antenna RV-12.
The antenna you can feed one cable by installing a relay on the lower tier. Switch must braid cable and Central wire at the same time.
Author: V. A. Fursenko (UA6CA); Publication: www.cxem.net