DG7YBN / 144 MHz / GTV 2-7w
  Last Update Sep. 29th, 2020




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Performance Data and Geometry
Pattern and VSWR
Download as File
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 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


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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

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










Downloads

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



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