DG7YBN / 28 MHz / GTV 28-5m
  Last Update Dec. 22th 2025


.......




Performance Data and Geometry
Pattern and VSWR
With Ground Gain
Stacking


GTV 28-5m   with bent Dipole

28.1 to 28.7 MHz with VSWR < 1:1.2 (Return Loss better -20 dB)


On 28 MHz we should less look for gain but for a very clean pattern, because if the band is open, successful DX more or less comes down to fade out unwanted signals. If we can easily produce a signal that enables us to ping our own echo when twice (!) around the globe with less than 100 watts of output, we may pass on 0.5 dB of gain. And when band is closed that little bit would not help at all. The bent dipole (K6STI style) transforms to 50 ohms at feed point for direct feed.

Design date of issue: 2025.12.07

This Yagi built by BG5TOX at all - BY5HB, Xiaoshan Radio Amateur Club
during 2025 ARRL 10 m contest (claimed score 477,996 points).

BG5ABL is raising the antenna:



Current distribution





Performance Data (28.5 MHz, 16 mm el.)
 

Gain vs. isotr. Rad.  10.5 dBi
Gain vs. Dipole        8.4 dBD
-3 dB E-plane         52.6 deg.
-3 dB H-plane         70.2 deg.
F/B                  -32.2 dB
F/R                  -19.8 dB
Impedance               50 ohms
Mechan. Length        8202 mm + 2 x 50 mm offset
Electr. Length        0.78 λ

Stacking Distance
top-to-bottom (vert.)  9.1 m

Geometry

On Request ...


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Pattern and VSWR Plots, free space simulation

Elevation and Azimuth plot at 28.5 MHz

 


SWR and Return Loss plots - simulated with 4nec2









Sketch of Bent Dipole




Radiation pattern with Ground Gain (28.5 MHz)

• At 12 m above perfect ground 


Gain vs. isotr. Rad.  16.2 dBi  at  12 deg.
Gain vs. Dipole       14.1 dBD
F/B                  -30.2 dB   at 140 deg.

• At 16 m above perfect ground 


Gain vs. isotr. Rad.  16.4 dBi  at   9 deg.
Gain vs. Dipole       14.2 dBD
F/B                  -27.0 dB   at 149 deg.








Stacking

• 2 x vertical GTV 28-5m, lower Yagi 12m agl, upper + 9.1 m: 


Gain vs. isotr. Rad.  18.6 dBi  at   8 deg.
Gain vs. Dipole       16.5 dBD
F/B                  -29.0 dB   at 172 deg.








73, Hartmut, DG7YBN



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