The DK7ZB-Reflector-Hentenna

Descriptions for 144-MHz- , 70 MHz- and 50-MHz-Reflector-Hentennas below!

The original Hentenna as a special kind of a single loop was described first in the 1970ies by Japanese Hams, an English article by JF6DEA/KE1EO about the Antenna ("The Hentenna – The Japanese 'Miracle' Wire")  was in the QST 1982 and in the ARRL-Antenna- Compendium, Vol. 5. The basic function of the  Hentenna structure is the 1,50-λ-Extended-Quad. This antenna with the figure of an "Oblong" has a gain of 3,6 dBd, but a feedpoint impedance of 73 + j 470 Ω.

The Hentenna has nearly the same gain, but a clever feeding with an impedance at XX of 50-70  +/- j 0 Ω .

The parts have the following lengths:

W - 1, 6, 7: 0,15 λ

S - 2, 4: 0,1 λ

H - (3+2), (5+4): 0,5 λ

The data of the Hentenna-Loop:

Gain 3,05 dBd

3-dB-Azimuth-angle 88,2°, 3-dB-Elevation-angle 69,5°
Введите частоту : (МГц)
Длина элементов W (λ/6) (мм)
Длина элементов S (λ/10) (мм)
Длина элементов H (λ/2) (мм)
On-Line calculator from RA3TOX http://rfanat.ru

Left: Azimuth-plot

 

Right: Elevation plot

The 144-MHz-Reflector- Hentenna by DK7ZB

With two reflector elements the Hentenna can be changed from a bidirectional antenna to an interesting directional antenna.

50-Ω-Impedance, fed with a 50-Ω-coax-choke (look for the pictures). A vertical metallic support through the antenna system has no influence to the feedpoint impedance and the resonant frequency!

 

Gain 7 dBd, F/B 15 dB

Dimensions for a 2-m-Reflector-Hentenna wit 10-mm- and 12-mm-elements

Segments Lengths 12 mm Lengths 10 mm
1, 6, 7 (hor) 314 mm 314 mm
3,5 (ver) 824 mm 822 mm
2,4 (ver) 219 mm 218 mm
8,9 (Ref) 1006 mm 1003 mm
Dist. Rad-Ref 320 mm 325 m


The mechanical details of the construction. The loop edges and the connections are made of copper-fittings for 10-mm-tubes

The 50-MHz-Reflector-Hentenna by DK7ZB

With two reflector elements the Hentenna can be changed from a bidirectional antenna to an interesting directional DX-antenna.

The data of the Hentenna with two reflectors by DK7ZB:

Gain 7,05 dBd, F/B 12,5 dB

Impedance 50 +/- j 0 Ω

3-dB-Azimuth-angle 71,4°, 3-dB-Elevation-angle 59°

The vertical pattern is a little bit asymmetric with a 3° upward lobe (see down).

Segments

Length

1, 6, 7 (hor)  

900 mm

3, 5 (ver)  

2343 mm

2, 4 (ver)

625 mm

8, 9 (Ref)

2900 mm

Distance Ref-Loop 975 mm, all elements 12 mm diameter

The 70-MHz-Reflector-Hentenna by DK7ZB

Pattern and gain are the same as with the 50-MHz-antenna, dimensions for 12-mm-elements in the table below

Home Page of DK7ZBwww.qsl.net/dk7zb/Quadlong/Hentenna.htm