It is clear that an L-Antenna
is easy to tune at any up-bend ratio between about 0.35 and 0.65;
and with effort, out to a 0.25 or 0.75 ratio.
For hams wishing to fine-tune
their L-Antennas, 0.40 and 0.60 are the magic points.
Note that there is an impedance
effect caused by ground coupling as the horizontal arm gets longer.
The Wide L-Antenna cannot quite get to a 1:1 SWR.
Of particular interest is
that L-antennas have both vertical and horizontal polarization. The ARRL Antenna Book says: “Some immunity
from fading during reception can be had by using two receivers
on separate antenna, preferably with different polarizations” (Reference 9).
In this case there are different
polarizations on one antenna.
The resulting effect of reduced fading can be heard on
DX signals by switching between an L-Antenna and a conventional
dipole. For nearby communications, an L-Antenna makes
all the difference in hitting repeaters and talking to hams with
verticals, dipoles or yagis.
The Tall-L Antenna
vertical arm is tall, the length of a 90° side arm can be adjusted to resonate the antenna to the desired
frequency. The SWR match
of a Tall-L antenns can be better than the Equal-L Antenna. Depending on elevation, ground and diameter
of the wires or tubes used, there will be some ratio between the
length of the vertical and horizontal arms that will give the
best match to a 50 ohm coaxial cable.
Anywhere up to a 2/3 up-bend ratio works.
Understanding this you can easily tune any vertical radiator.
The total length will always be about ½ wavelength.
L-configuration has the distinct functions of a vertical in that
it is generally quieter than a dipole and performs well for DX. It can be a good choice when listening around