Vladimir Polyakov, RA3AAE,
HF- magazine, 1998, pp.: 27- 31
in Russian in Moscow).
I would like
to make a simple directional
I had observed lots
stopped at ZL- beam with two
active feeding. The
very attractive for me.
This one at
its small sizes (only
lambda/10 in length) was
the same parameters as 3-
1 shows a simple design of the ZL- beam. Points X-X
is the feeding terminal of the antenna. ZL- beam consists of two
dipoles (simple or folded) that connected together by crossed
wires. Depending on the length of the fires the dipoles fed by
some phase shift that helps form the diagram of directivity. (Note by I.G.:
More about ZL-Beam see References 1 and 2)
phase shift between the antenna's elements
are obtained by two ways. At first, it needs change the length of
the crossed line. The second, (it is fine tuning) by changing of
the length of the dipoles. If the tuning may be made then no matter
at which points at the crossed line would be connected feeder of
Usually ZL-beam is used as antenna with horizontal
polarization i.e. the dipoles are placed in parallel to ground.
That is because of the simplicity of that antenna design.
I decided to make antenna with vertical placement of
the dipoles to ground. For the antenna's element should be suitable
J- Antenna. (Note by I.G.: More about J- Antenna see References
3 and 4). Figure 2 shows two version of that J- Antenna.
Version of the antenna with the grounded stub (right at the Figure 2)
is mostly suitable for my design. It is possible to connect the
lower point of the grounded stub with any ground- roof of the
car, metal mast and so on. It is possible to match the antenna
with any coaxial cable by choosing the feeding points.