50 MHz HDA

After lunch we had to wait for our boat safari and I thought it was a nice idea
to calculate a 50 MHz Horizontal Dipole Array (HDA) aka 2 elements to be
easily and quickly built when we arrive in Thondwe on Monday.

Within the boundary conditions (Z = 50 + j0 Ohm) the contrapsion converged to an
acceptable radiation pattern and impedance. I tried some other model solutions
(there are many ways to Rome) but that didn’t make much difference.

Of course more elements will improve vertical/horizontal radiation patterns,
but this antenna may be a nice (mechanical) substitute for a HB9CV.

Bear in mind, most Yagi’s are presented in free space with nice radiation patterns.
However, when you put them in the air above real ground,
(vertical)radiation patterns deteriorate significantly!

Left: radiation pattern in free space, right: radiation pattern @6m above average ground.
Right some ground gain is introduced. A real nice to have : -)
(click on image  to enlarge)

Below the VSWR50 response  (Click on image to enlarge):

For co-calculators, here’s the NEC-file.

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