Very easy
to build antenna, the figures are for a 1,5mm2 wire.
If
one uses insulated wire, shorten the length of the wires with 3-4%
(depends
on the insulation material of the wire).
On 20m
height this will be very good DX antenna. Bi-directional.
Azimuth plot -----------------------------------------
Elevation plot on 12 meters height
The SWR
can be changed by changing the length of the dipoles.