antenna works on the 10- and 2- meter Bands. Antenna does not
require any switching in ATU when the band is changed. Antenna
radiates radio wave with vertical polarisation. Antenna is fed
by 75- Ohm coaxial cable. The cable is very chip compare to 50-
Ohm coaxial cable. It is possible to buy 30- meters good 75- Ohm
cable intended for underground placement for 10… 20 dollars. Practically
any transceiver (designed for 50- Ohm antenna) could work with
75- Ohm antenna. Figure 1 shows design of the antenna.
the2- meter Band the radiated part of the antenna is a Vertical
Dipole (item 1). Physically the dipole is simulated by two
tubes (item 1). Vertical radiator (that serves at the 10- meter
Band) (item 2) is going through
the upper tube. The vertical is connected with the upper tube
at the bottom of the tube. Coaxial cable (item
4) is going through the lower tube. Central core of the
coaxial cable is connected to the upper tube. Braid of the coaxial
cable is connected to the lower tube. Radials (item
3) for the 10- meter band antenna are connected to the
braid of the coaxial cable a little lower of the lower tube. The
tube (item 1) is quarter-wave
sleeve (serve like an RF choke) for the 2- meter Band. The choke
does not allow the leaking of the RF current of the 2- meter Band
to the others parts of the antenna.
5, 1971. Front Cover
the vertical (item 2) and coaxial
cable (item 4) going through the vertical and lower tube
(item 1) is insulated on RF at the 2- meter Band from
the Dipole Vertical antenna (item 1).
The Dipole Vertical antenna (item 1)
has input impedance close to 75- Ohm at the 2- meter Band.
the 10- meter Band the antenna is a Vertical antenna with 3 slope
downward radials. All parts of the antenna from the top of the
vertical (item 2) to the ends of the radials (item 3) are radiated.
antenna with 3 slope downward radials (as it is shown on the Figure 1) has input impedance near 40… 60-
Ohm when the antenna is fed at the terminals “Vertical- Radials.”
The input impedance is less the 75- Ohm. To match the antenna
input impedance with the 75- Ohm coaxial cable the feeding terminals
are risen up. It is going to increasing of the antenna input impedance
in proportional with: