Gain vs. isotr. Rad.  10.0 dBi
Gain vs. Dipole        7.9 dBD
-3 dB E-plane         55.6 deg.
-3 dB H-plane         75.0 deg.
F/B                  -25.9 dB
F/R                  -19.6 dB
Impedance               50 ohms
Mechan. Length       10375 mm plus boom offsets
Electr. Length        0.73 λ

Stacking Dist. h-pol. (21.20 MHz)
top-to-bottom         11.6 m

Geometry

For building on a 50-60 mm boom, 25 mm mid-element tubes insulated with hydraulic clamps like from co. Stauff:

How many pageviews did this design get since Juni 2026?

---

Pattern and VSWR Plots

Elevation and Azimuth plot at 21.20 MHz

 

SWR and Return Loss plots - simulated with 4nec2

---

Radiation pattern with Ground Gain

At 14 m above perfect ground

At 14 m above perfect ground

Gain vs. isotr. Rad.  15.7 dBi  at  14 deg.
Gain vs. Dipole       13.5 dBD
F/B                  -27.5 dB   at 163 deg.

---

Stacking

---

73, Hartmut, DG7YBN