DG7YBN / 144 MHz / YBN 2-2w
  Last Update Feb 28th 2018


Performance Data and Geometry
Pattern and VSWR
Download as File
Stacking                 =>   4 x 2 elem. vertical produce 13.5 dBi at a HPBW of 71 degr.

YBN 2-2w Yagi   with Conventional Driven Element

This little Yagi is as much bandwidth as can be. A forgiving and easy to build alternative to the HB9CV.

It does not have the HB9CV's famous F/B ratio but is much easier to build, no phasing lines, no capacitor ...
Nothing to protect from rain and snow. When you ar portable with a little antenna and little rig anyway
a high F/B does not help much. And note that the HB9CV's true gain is around 4.15 ... 4.2 dBD. No more then that.

The photo shows a build on 15 x 15 mm boom and symmetrising
Quarterwave Line grounded with an N-cable-flange bushing.

A YBN 2-2w built by Thomas, M0ABA
Thomas reports to work into GW and DK over 480 k easily using the FT8 digital
mode with this small Yagi. Record so far is a FT8 rx report over 648 k by DK0IZ in JO43sx.

Performance Data

Gain vs. isotr. Rad.   6.4 dBi
Gain vs. Dipole        4.3 dBD
-3 dB H-plane        133.2 deg.
-3 dB E-plane         69.6 deg.
F/B                   -9.0 dB
F/R                   -6.5 dB
Impedance               50 ohms
Mechan. Length         410 mm
Electr. Length        0.20 λ

Stacking Dist. h-pol.
top-to-bottom         1.30 m
side-by-side           n.a

Table revised Oct. 2017

        Pos.   1/2 Length  BC 20x20   BC 25x25     BC 1x1"  
                 in NEC     = 3.9      = 7.6        = 7.9
Refl.     0      506.0     1015.9      1019.6      1019.9
DE      410      463.0      929.9       933.6       933.9
                          ele. 8 mm   ele. 8 mm   ele. 3/8"
Note: element lengths for Ø 8 mm fit 5/16" too

The Dipoles diameter is 10 mm for all examples.
Use EZNEC's Auto-Segmentation at 144.3 MHz.

Pattern and VSWR Plots

Elevation and Azimuth plot


Simulated Return Loss and VSWR plot


EZNEC file of this Yagi with Straight Split DE  

EZNEC file of 2 x vertical stack

EZNEC file of 4 x vertical stack

Stacking 2 over 2

Elevation plot at 1.3 m distance

Note: the dipoles must be prolonged to 474 mm in NEC or plus 11 mm for
all ready to use measures due to impedance interaction at that close distance.

Gain vs. isotr. Rad.  10.2 dBi
Gain vs. Dipole        8.1 dBD
-3 dB H-plane         45.8 deg.
-3 dB E-plane         72.2 deg.
F/B                  -14.7 dB
F/R                  -14.7 dB

Stacking 4 x 2 vertically

Elevation plot at 1.3 m distance each

Note the different element positions and lengths of the inner Yagis - see drawing below.

Simulation at 4 m above perfect ground

Free Space Simulation

Elevation and Azimuth Plot and Data


Gain vs. isotr. Rad.  13.5 dBi
Gain vs. Dipole       11.4 dBD
-3 dB H-plane         21.2 deg.
-3 dB E-plane         71.0 deg.
F/B                  -17.7 dB
F/R                  -17.7 dB

These numbers are almost equal to the DJ9HO 4 x Quad. Gain is approx. similar,
HBW is a little wider, F/B almost similar. But as 4 x 2 ele. probably more handy for portable use.

The DK7ZB 4 x Quadlong is less high, just 2.85 m compared to the 3.9 m of the 4 x 2 element.
The 4 x Quadlongs gain is 2.1 dB less while F/B of the 4 x Quadlong is 2.2 dB higher.

73, Hartmut, DG7YBN

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