Construction Details

2-El.-10m-50Ohm

2-El.-12m-12Ohm

2-El-12m-28Ohm

Dualband 12/17m

2-El.-15m-50Ohm

2-El.-17m-28Ohm

2-El.-20m-28Ohm

2-El.-30m-28Ohm

Dualband 10/15m

DK7ZB-Dualband-Beam 10/15 m

The beam has only one feedpoint with 50 Ohm and has an open-sleeve element for 10 m

The bandwidth on 10 m is narrow, the designed part of the 10-m-Band is for SSB

10 m: 4,7 dBd     10 dB F/B

15 m: 4,2 dBd    10 dB F/B

The Duoband-Yagi built by Franz, DL6EBH

The scheme of the beam with the currents for 28,5 MHz

Number Tube Length
1 25x2 mm 200 cm
2,4, 7, 9 20x2 mm 150 cm (+15 cm overlap)
3,5 16x1,5 mm 108 cm (+ 15 cm overlap)
6 25x2 mm 2x 99 cm (2 cm gap in the center)
8, 10 16x1,5 mm 85,5 cm (+15 cm overlap)
11, 14 20x2 mm 100 cm
12, 13 16x1,5 mm 208,5 cm (+15 cm overlap)
15, 16 16x1,5 mm 200 cm (+15 cm overlap)

Element lengths for the two bands, keep the outer tubes 15 cm longer for the overlap. The open-sleeve-element for 10 m and the reflectors can be mounted direct above the boom (metallic connection), but do not use big metallic brackets! This can detune the beam!

Feeding with a current balun