Gain vs. isotr. Rad.  14.4 dBi
Gain vs. Dipole       12.3 dBD
-3 dB E-plane         36.4 deg.
-3 dB H-plane         40.2 deg.
F/B                  -25.0 dB
F/R                  -25.0 dB
Impedance             12.5 ohms
Mechan. Length        5074 mm
Electr. Length        2.44 λ

Stacking Dist. h-pol.    DL6WU     max. G/T
top-to-bottom           3.03 m      3.45 m
side-by-side            3.35 m      3.75 m

For building ...
SegmentationBC = +2.3 mm = (144.8 MHz - 144.4 MHz) * 5.85 mm/MHz

Geometry

8 mm Elements:

5 mm Elements:

Use EZNEC's Auto-Segmentation at 380 MHz to derive shown segmentation.

Building Plan

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Pattern and VSWR Plots

Elevation and Azimuth plot at 144.1 MHz

 

SWR and Return Loss plots - simulated with 4nec2

Gain and F/B, F/R - simulated with 4nec2

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Folded Dipole 12.5 to 50 ohms Version

The Folded Dipole is made from 10 mm aluminuim tube: 959 mm outside / outside, with a bending diameter of 54 mm inside the bends.

Unfortunately non of the WiMo stock Folded Dipoles is fitting this span width. They can deliver 940, 990, 1007, 1010, 1016 mm ready bent tubing.


It would be practicable to buy a larger one, cut it left/right side,
insert pieces of 8 x 1 mm tubes and use tiny hose clamps or screws to fasten the pieces when adjusted to length.
As an alternative one could use just the bent ends and push these into 12.0 x 1 mm tubes as arms of the DE.

BUT: making a Folded DE is not that difficult, here is the link to G3SEK's good website on making one: www.ifwtech.co.uk/g3sek/diy-yagi/dipoles.htm


SWR and Return Loss Plot

This is modeled with typical offset to element plain caused by on-boom mounting of elements. D1 is 1 mm longer here!

Impedance at feedpoint is 50 ohms then, add a grounded Quarterwave Line and / or ferrite core

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Downloads

EZNEC file of this Yagi  

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Stacking

Stacking Dist.    DL6WU Formula    max. G/T
H-plane               3.03 m        3.45 m
E-plane               3.35 m        3.75 m

Gain vs. isotr. Rad.  20.31 dBi
Gain vs. Dipole       18.16 dBD
-3 dB H-plane         16.3 deg.
-3 dB E-plane         18.2 deg.
F/B                  -26.4 dB
F/R                  -26.4 dB
T_ant                228.6 K*
G/T                  -3.29 dB*

Gain vs. isotr. Rad.  20.48 dBi
Gain vs. Dipole       18.33 dBD
T_ant                236.8 K*
G/T                  -3.26 dB*

Theoretical numbers, no phasing line losses
nor imperfections caused by H-frame included
*) T_sky = 200 K, T_earth = 1000 K as in VE7BQH G/T table

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Matching 12.5 to 50 ohms

Coax line transformer principle and applied concept = the ferrite improved DK7ZB - Match

   

  Attenzione!     Take care when lengthening the cables, measure the right length instead of refering to given v-factors only.
                                      A good choice may be the diam. 5 mm PTFE coax RG-142 B/U: real resonate length (144.1 Mhz) shield-shield is around 345 mm


  Find more information on my Phasing & Matching Lines page

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Detailed Building Plans

Scaled Drawing of Boom Parts 1, 2, 3

Scaled Drawing of on half of the symmetrical Boom Strut

  Find more information on bending the strut on the Yagi Booms and Struts page






73, Hartmut, DG7YBN