Theory of the Quadlongs 4/6-m-Quadlongs 2-m-Quadlong 2-m-4x-Quadlong 2-m-4x-Oblong The Hentenna (2 m, 4m, 6 m)
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The 50-MHz- DK7ZB- Quadlong


Gain 6,4 dBd, F/B 21 dB


The 70-MHz-Quadlong see down


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The 50-MHz-Quadlong has a little bit reduced gain of 6,4 dBd and was designed for a better F/B of 21 dB. The antenna has a medium bandwidth with an SWR <= 1,5 from 49,5-50,5 MHz.

The feedpoint impedance is 28 . Use the DK7ZB-choke for feeding .

(2x λ/4-75-Ω-coax-cable wound to a choke)


The dimensions of the 50-MHz-Quadlong

Diameter for the loop and the reflector 12 mm or 12/6 mm


Ref.-Length 3000 mm (12 mm) 2992 mm (12 mm)
D (Ref-Loop) 855 mm 855 mm
A (hor) 880 mm (12 mm) 890 mm (12 mm)
B (ver) 2280 mm (12 mm) 2230 mm (6 mm)

The 37,5-Ω-Choke with 2x 1,00 m 75-Ω-cable parallel

Here 5-mm-full-PE CATV-cable, handles 500 Wtts RF

Impedance transformation 28 Ω to 50 Ω

For the four edges I use 12-mm-Cu-fittings which are used for heating purposes. After possible changes for tuning the Aluminium-tubes are fixed with screws.

The 70-MHz-DK7ZB-Quadlong

Gain 6,49 dBd

F/B 18 dB

Feedpoint Impedance 28 Ohm

The dimensions of the 70-MHz-Quadlong

Element-Diameter for the Loop and the Reflector 12 mm 



Ref.- length

2126 mm (12 mm)

 D (Ref-Loop)

620 mm

A (hor)

644 mm (12 mm)

B (ver)

1624 mm (12 mm)

Feeding 28/50- with a λ/4-choke of two coax-cables 75 parallel

The 70-MHz-DK7ZB-Double-Quadlong

The Quadlong can be built up with a double frame. The gain increases only 1 dB, but this antenna has a greater bandwidth than the single Quadlong. Feeding with the DK7ZB-choke, the same as for the Quadlong.


Data of the DK7ZB-Double-Quadlong:

Impedance 28 Ohm

Gain 7,5 dBd       F/B 19 dB

3-dB-angles      71,6 hor     54,8 ver

The gain is 0,7 dB higher than the well known "Double-Quad" by DL7KM and DJ9HO. The mechanical construction is much easier!

The lengths ot the elements, distance center to center of the tubes

Ref.-Length 2140 mm (12 mm)
D (Ref-Loop) 595 mm
3,4,6 (hor) 618 mm (12 mm)
1,2,5,7 (ver) 1475 mm (12 mm)