DG7YBN / 144 MHz / YBN 2-2w
  Last Update Sept. 14th 2014




.......


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.


2 Element Yagi

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.




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
Geometry

        Pos.   1/2 Length  BC 20x20   BC 25x25   BC 1"x1"  
                 in NEC     = 3.9      = 7.6      = 7.9
				 
Refl.     0      506.0     1023.9      1036.6     1032.9
DE      410      463.0      995.9       999.6      999.9
                           ele. 8 mm  ele. 8 mm  ele. 3/8"
						   
Note: element lengths for Ø 8 mm fit 5/16" too

The Driver 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

 


RL and SWR plot










Downloads

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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