Gain vs. isotr. Rad.   8.99 dBi
Gain vs. Dipole        6.8 dBD
-3 dB E-plane         59.9 deg.
-3 dB H-plane         89.2 deg.
F/B                  -25.2 dB
F/R                  -20.3 dB
Impedance               50 ohms
VSWR Band Width       1.02:1*
Mechan. Length         995 mm plus offsets
Electr. Length        0.48 λ

Stacking Dist. h-pol. (144.3 MHz)
top-to-bottom         1.481 m or 4.8 ft
side-by-side          2.084 m or 6.8 ft

*) as in VE7BQH G/T table = at 145.00 MHz

How many VHF operators have been looking up this design since Febr. 2025?

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Geometry

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This Yagi with 8 mm elements on a 20 x 20 mm boom with standard insulators

Ele. 8.0 mm DE 10 mm Boom 20 x 20 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:


Includes an SBC of 2.05 mm

Foremast mount version, 400 mm rear offset (remember, with elements mounted on boom you may alter the rear offset)

The Drivers diameter is 10 mm.
The EZNEC model is done with Auto-Segmentation at 380 MHz

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Ø 3/16 inch Elements, 3/8 inch Dipole - Through Boom - Dimensions (BC acc. SM5BSZ's BC.exe)

Imperial Boom 1"

This table is only valid for: Boom shape: square Boom dim: 1 x 1 inch Wall thickn.: 1.6 mm Holes in boom: 7.7 mm Offset rear: 40 mm Offset front: 40 mm

Note: All the above include a "Segmentation Density Correction" (SBC) of 2.93 mm per element.


Note: with through Boom BC it is important to stick to the boom end offsets given below!

Read abt. the SBC here .

Imperial Boom 1"

This table is only valid for: Boom shape: square Boom dim: 1 x 1 inch Wall thickn.: 1.6 mm Holes in boom: 7.7 mm Offset rear: 500 mm for foremast mounting Offset front: 40 mm

Note: All the above include a "Segmentation Density Correction" (SBC) of 2.93 mm per element.


Note: with through Boom BC it is important to stick to the boom end offsets given below!

Read abt. the SBC here .

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Sketch of Bent Dipole

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Pattern and VSWR Plots

Elevation and Azimuth plot at 144.3 MHz, 4.76 mm element version:

 

RL and SWR plots - simulated

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Satellite xpol. Version

With this xpol version the distance between v- and h-plane is a full 1/4 wavelength. So that feeding is uncomplicated via 2 same length 50 ohms coax cables and a power splitter for instance. When bulding this, mind that the down planes differ slightly, see buiding table and sketch of bent dipole for v- and h-plane.

Circular polarised 3D pattern

Circular polarised pattern with data, 145.8 MHz, elements 4.763 mm = 3/16 inch

VSWR and Return Loss (S11) with a bit of overhead when wet

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Ø 3/16 inch Elements, 3/8 inch Dipole - Through Boom - Dimensions (BC acc. SM5BSZ's BC.exe),
offset element planes 514 mm = 1/4 wl on 145.9 MHz (Mind this refers to the two exiters, the dipoles distance).

Imperial Boom 1"

This table is only valid for: Boom shape: square Boom dim: 1 x 1 inch Wall thickn.: 1.6 mm Holes in boom: 7.7 mm Offset rear: 500 mm Offset front: 40 mm

Note: All the above include a "Segmentation Density Correction" (SBC) of 2.93 mm per element.


Note: with through Boom BC it is important to stick to the boom end offsets given below!

Read abt. the SBC here .

Sketches of Bent Dipoles

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Downloads

None so far.

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Stacking

Stacking at 1.80 m e, h for circular polarisation
which is slight understacking against distances per DL6WU formula.

Plot and data of 4 stacked in H-configuration GTV 2-5m sat xpol

Antenna View & Elevation Pattern

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73, Hartmut, DG7YBN