Gain vs. isotr. Rad.  11.9 dBi
Gain vs. Dipole        9.8 dBD
-3 dB E-plane         46.4 deg.
-3 dB H-plane         56.2 deg.
F/B                  -30.3 dB
F/R                  -22.8 dB
Impedance               50 ohms
Mechan. Length        866 mm incl. 2 x 40 mm stand off
Electr. Length        1.13 λ

Stacking dist. h-pol. (100 percent per DL6WU)
top-to-bottom         0.737 m or 2.42 ft
side-by-side          0.881 m or 2.89 ft

How many OMs have been looking up this design since Oct. 2025?



Geometry

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Bent Dipole: DE(a) is the inner straight length and pos. on boom, DE(b) is position of tips and span width when bent

• Drawing of the blade dipole as PDF, • The Dipole of the GTV 70-9w fits the GTV 70-10w nicely (tnx Thomas, M0ABA for measuring this!)

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The model uses EZNEC's Auto-Segmentation at 1050 MHz.
The DE's is 10 mm for all examples.
Using a 'Blade Dipole' is recommended with elements through boom

A simple symmetrising section may be made from a 3 x 1/4 Lambda line grounded at the far end with
N-flange-bushing and an aluminium plate and ferrite core added as close as possible to the DE,
see below.

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This Yagi with 8 mm elements on a 15 x 15 mm boom with standard insulators

Ele. 8.0 mm DE 10.0 mm Boom 15 x 15 mm

"Ready to saw and drill" data for mounting elements on boom with BC according DG7YBN for standard insulators
as sold by WiMo, Tino's Funkshop, HF-Kits NL, 7arrays:

You may alter the rear offset as long as you keep a minimum of 40 mm, it will not influence an 'on boom' BC.

Building hints:

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For building hints see the GTV 70-19
For fastening elements through boom
For making of a 'Blade Dipole' which I recommend for elements through boom builds

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Radiation Pattern and VSWR Plots

Elevation and Azimuth plot at 432.1 MHz (Elements 8 mm)

   

VSWR and Return Loss (S11)

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Downloads

none so far

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Stacking

Stacking Dist.    DL6WU Formula
H-plane               0.737 m
E-plane               0.881 m

Gain vs. isotr. Rad.  17.91 dBi
Gain vs. Dipole       15.76 dBD
-3 dB H-plane         25.0 deg.
-3 dB E-plane         20.6 deg.
F/B                  -32.4 dB
F/R                  -23.4 dB
T_ant                 110.7 K*
G/T                  -2.54 dB*

Theoretical numbers - these do not include phasing line losses
nor imperfections caused by H-frames or mast poles etc.
*) T_sky = 27 K, T_earth = 1800 K as in newer VE7BQH G/T table

Screenshot of the Excel VBA AGTC-2lite for this 4 Yagi stack

A vertical 4 Yagi stack

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stacked at 733 mm: 17.9 dBi at a HPBW of 46 degr. on just 2.2 m of height on pole

A vertical 8 Yagi stack

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stacked at 733 mm: 20.9 dBi at a HPBW of 46 degr. on just 5.13 m of height on pole

A 2 x 180 deg. vertical 4 Yagi stack

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stacked at 733 mm: increased F/B by optimised distance Refl. to Refl. of 725 mm

A brief description of this array of 2 x 180 deg. 4 x vert. GTV 70-6m  

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Symmetrising 50 to 50 ohms feedline to 432 MHz Bent DE

The principle is similar to the 1/4 Lambda coax. Adding 2 x 1/4 Lambda or a half wave line does not change anything but allows
to form a gentle bow below the boom or until behind the Reflector. Follow practical construction hints on "Building a Yagi" page.

    

  Attenzione!     Take care when lengthening the coax, measure the actual electrical length instead of considering v-factors specified in a catalogue only.
                                      A good choice may be the diam. 5 mm PTFE coax RG-142 B/U: real resonate length (432.2 MHz as 3/4 Lambda) shield-shield is around 348 mm


  Find more information on Phasing & Matching Lines page






73, Hartmut, DG7YBN