DG7YBN / 144 MHz / GTV 2-7w   Last Update June 14th, 2024
.......

Performance Data and Geometry
Pattern and VSWR
Stacking

GTV 2-7w  Yagi with bent Driven Element

For the given bandwidth this Yagi shows quite a low Antenna Temperature and a moderate gain for its length. The bent DE (K6STI style) transforms to 50 ohms at feed point for direct feed. Design date of issue: 2020.09.18

GTV 2-7w xpol built by_ZS6JON

GTV 2-7w 3D pattern plot at 144,3 MHz

Performance Data

Specs: with 8 mm elements @ 144.1 MHz
```
Gain vs. isotr. Rad.  12.3 dBi
Gain vs. Dipole       10.1 dBD
-3 dB E-plane         44.6 deg.
-3 dB H-plane         52.8 deg.
F/B                  -25.0 dB
F/R                  -22.1 dB
Impedance               50 ohms
VSWR Band Width       1.01:1 *
Mechan. Length        2691 mm
Electr. Length        1.29 λ

Stacking Dist. h-pol. (144.1 MHz)
top-to-bottom         2.34 m or 7.7 ft
side-by-side          2.74 m or 9.0 ft

Stacking Dist. h-pol. (145.5 MHz)
top-to-bottom         2.32 m or 7.6 ft
side-by-side          2.71 m or 8.9 ft

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

How many VHF operators have been looking up this design since Sept 2020?

Geometry

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 1.17 mm

```
SegmentationBC = +1.17 mm = (144.3 MHz - 144.5 MHz) * 5.85 mm/MHz
BaseBC (20x20) = +3.90 mm for semi-insulated on boom
Total          = +5.07 mm
Note: element lengths for Ø 8 mm fit 5/16" too
```

The Drivers diameter is 10 mm for all examples.
The EZNEC model is done with Auto-Segmentation at 400 MHz

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 1.17 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 .

Sketch of Bent Dipole

Pattern and VSWR Plots

Elevation and Azimuth plot at 144.1 MHz

Elevation and Azimuth plot at 144.5 MHz

Elevation and Azimuth plot at 145.0 MHz

Elevation and Azimuth plot at 146.0 MHz

Finally: A comparison between elevation patterns DK7ZB "7-El.-Ultra-Wideband-Yagi 50 Ohm, 6 MHz SWR < 1,15" and shorter GTV 2-7w.

RL and SWR plots - simulated

Gain and F/B, F/R

Return Loss (dB) plotted on the full xpol, both planed combined by ZS6JON, span 120 - 171 MHz:

None so far.

Stacking

```
Stacking Dist.    DL6WU Formula (144.1 MHz)
E-plane               2.74 m or 9.0 ft
H-plane               2.34 m or 7.7 ft

```

Plot and data of 2 vertically stacked GTV 2-7w using DL6WU stacking distances

Antenna View & Elevation Pattern

Plot and data of 3 vertically stacked GTV 2-7w using DL6WU stacking distances

Antenna View & Elevation Pattern

Plot and data of 4 vertically stacked GTV 2-7w using DL6WU stacking distances

Antenna View & Elevation Pattern

Plot and data of 4 in H-config stacked GTV 2-7w using DL6WU stacking distances

Elevation & Azimuth Pattern

Excel version of AGTC_lite screenshot (Tsky = 290 K, Tearth = 5400 K)

Mind that this Yagi covers the whole 2 m band with a Return Loss better -35 dB or VSWR 1:03 in theory.
So the Antenna G/T will not be as low as you might be used to from comparaing a GTV Yagi to others in
the VE7BQH Antenna Tables.

73, Hartmut, DG7YBN