YBN 28-8m

Performance Data and Geometry

Pattern and VSWR

With Ground Gain

Stacking

YBN 28-8m with straight split Dipole

Digi Modes + SSB band 28.1 to 28.6 MHz

On 28 MHz we should less look for gain but very clean directivity, 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 gain. And when band is closed that little bit would not help at all.

The patterns scattering factor (dt.: Streufaktor) as ratio of all rear and side lobes against the beam lobe is what we should look for in first place.

Design date of issue: 2022.10.18

Current distribution

Performance Data (28.5 MHz, 16 mm el.)


Gain vs. isotr. Rad.  13.06 dBi
Gain vs. Dipole       10.9 dBD
-3 dB E-plane         40.7 deg.
-3 dB H-plane         46.2 deg.
F/B                  -29.1 dB
F/R                  -19.1 dB
Impedance               50 ohms
Mechan. Length       17100 mm plus 2 x 70 mm rear and front offset
Electr. Length        1.63 λ

Stacking Dist. h-pol. (28.5 MHz)
top-to-bottom          13.5 m
side-by-side           15.1 m

Geometry

For building on a 40-50 mm boom, 16 mm elements insulated with hydraulic clamps like from co. Stauff:

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Pattern and VSWR Plots

Elevation and Azimuth plot at 28.5 MHz

SWR and Return Loss plots - simulated with 4nec2

3D pattern

Radiation pattern with Ground Gain

At 20 m above perfect ground


Gain vs. isotr. Rad.  18.8 dBi  at   7 deg.
Gain vs. Dipole       16.6 dBD
F/B                  -29.31 dB   at 173 deg.

Stacking

Elevation plot and data of 8 over 8 array at 13.5 m stacking distance
Free Space

Elevation plot and data of 8 over 8 array at 13.5 m stacking distance
Lower Yagi 15 m, upper Yagi 28.5 m above perfect gnd


Gain vs. isotr. Rad.  20.86 dBi
Gain vs. Dipole       18.7 dBD
F/B                  -31.1 dB

73, Hartmut, DG7YBN