Gain vs. isotr. Rad.  10.5 dBi
Gain vs. Dipole        8.4 dBD
-3 dB E-plane         44.6 deg.
-3 dB H-plane         52.8 deg.
F/B                  -32.2 dB
F/R                  -25.5 dB
Impedance               50 ohms
VSWR Band Width       1.06:1*
Mechan. Length        1617 mm plus offsets
Electr. Length        0.78 λ

Stacking Dist. h-pol. (144.3 MHz)
top-to-bottom         1.804 m or 5.9 ft
side-by-side          2.344 m or 7.7 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 2.93 mm

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