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.

Triband-DK7ZB-VHF-Yagi for 6 m, 4 m and 2 m with one Feedpoint

This Yagi was developed with EZNEC +5 and has only one feeding point of 50 Ω and a boomlength of 1,25 m. With this length a log-periodic would not give satisfying results on 50 MHz.

It has 2 elements on 6 m and 4 m and 3 elements on 2 m.

The boom is made from 20x20x1,5 mm Aluminium, the elements are all made with 10x1 mm-Aluminium tubes. No other diameters allowed for this design, do not scale for other tubes without a NEC-program!




Bandwidth SWR 1,5


4,49 dBd

8,6 dB

1,75 MHz


4,29 dBd

10,8 dB

1 MHz


5,43 dBd

10,6 dB

> 2 MHz

Only a finetuning of the 2-m-open-sleeve radiator was necessary, the other elements have exact the predicted lengths!

The Triband-Yagi

built by

Jaap, PA0O






Reflector 6 m

0 mm

2914 mm


Reflector 4 m

300 mm

2080 mm


Reflector 2 m

600 mm

1044 mm


Open-sleeve-Radiator 2 m

1000 mm

981 mm


Radiator 6 m, fed

1065 mm

2764 mm


Open-sleeve-Radiator 4 m

1148 mm

2006 mm


Director 2 m

1200 mm

970 mm

Measured data with a Vector-Analyzer:

The  SWR between 40 MHz and 150 MHz  shows SWR <1,1 in the bands with 6 m low-loss-cable Ecoflex-10.

The antenna is fed with a choke-balun. I used 11 turns of Aircell-5 on a PVC-tube with 25 mm diameter. The length of the cable is about 1,00 m.

The coax socket is mounted on the bottom of the radiator-box ang grounded to the boom. For better mechanical stability the box has an epoxy-plate.

The 2-m-open-sleeve-radiator is not yet fixed with a screw for finetuning. In practise the choke has an influence on the 2-m-element which leads to a length correction. In this case element 4 was cut 3 mm and was shifted + 10 mm away from the 6-m-radiator. In the table are the corrected length and position of element 4.

The complex currents in the coupled system when fed with 144,3 MHz

The measured SWR between 50 and 51 MHz

The measured SWR between 70 and 70,5 MHz

The measured SWR between 144 and 146 MHz