Open-sleeve principles VHF-Duoband principles Duoband-Yagi 6m/10m 10m-Dipole+ 3-El.- 6 m Triband-Yagi 6m/4m/2m   Duoband-Dipol 2m/70cm 2m/70cm 2+2/3 El. 2m/70cm 4+5 El. 2m/70cm 5+8 El.

DK7ZB-Duoband-Yagi for 10m and 6 m

This Duoband-Yagi has a boom of 3,60 m and 3 elements for 10 m, 4 elements for 6 m and one feedpoint with 50 Ω

The Yagi left was built by  Olli, DH8BQA
10 m   4,8 dBd    F/B 25 dB

 6 m   6,7 dBd    F/B 14 dB

The diagram of the elements

The currents in the Yagi system on 50,150 MHz show the action of the open-sleeve radiator

The elements for 10 m are tapered with 20/16-mm-tubes, the elements for 6 m are made with 12 mm tubes. Element 3 is the radiator of the system and must be constructed with two halves and an insulated part in the middle of the element. Feeding with a 50-Ω-coax-choke (length about 1,5 m, uncritical). The table has the lengths for one element half, the 16-mm-tubes must be 150 mm longer as the real length in the table!

Element-No. Assignment 20x1,5 mm 16x1,5 mm 12 mm Position
1 Ref  10 m 1000 mm 1740 mm - 0 mm
2 Ref  6 m - - 1430 mm 800 mm
3 Rad  10 m 1000 mm 1645 mm - 2000 mm
4 op.-sl.-6 m - - 1430 mm 2093 mm
5 Dir 1  6 m - - 1350 mm 2600 mm
6 Dir  10 m 1000 mm 1395 mm - 3300 mm
7 Dir 2  6 m - - 1360 mm 3600 mm

Tuning for best SWR on 6 m with the distance of element 4 to the radiator.