If a second horizontal arm
is added at 180° opposite
and both are tuned by length to the desired frequency, the radiation
field balances. The radiation
pattern becomes circular and the antenna becomes a tall ground
The MFJ-1790 10 meter antenna (Reference 7) is an example. It has an 11-foot vertical and two 6-foot
radials to give “Low Radiation Angle for outstanding DX”.
The Wide L-Antenna
vertical arm is short, the length of a 90° side arm can be adjusted to resonate the antenna to the desired
frequency. The SWR match
can be better than the Equal-L Antenna.
Depending on elevation, ground and diameter of the wires
or tubes used, there will some ratio between the length of the
vertical and horizontal arms that will give a nearly perfect match
to a 50 ohm coaxial cable.
configuration has the characteristic of being shorter than a halfwave
dipole with nearly the same gain.
both horizontal and vertical polarization, it is less effected
by undulations in DX skip reflections (QSB) than a conventional
Antenna modeling software can optimize a vertical dipole
for the best wide
OFC ratio at 1/2-wavelength feedpoint elevation over ground. Using
that capability, Figure
6 below shows what happens with a 2/3-1/3 ratio as
the longer lower arm is
swung upwards in 15° increments.
Note that the best SWR and
Gain combination occurs at around 105,
or 15° above horizontal.
compares favorably with the gain of a center-fed dipole using
the same wire and fed at the same elevation over the same ground.