h is the height from the radials to the feeding
terminals. The resonance frequency of the 10- meter Band antenna
does not change at the shift of the feeding terminals. Moreover,
at the antenna design the shift of the feeding terminals (for
the 10- meter Band) allows to place the vertical antenna for the
2- meter band higher on to the antenna design. It has sense at
the limited (on to high) installation of the antenna.
Dipole Antenna for 2- meter band influences to resonance frequency
of the 10- meter Band antenna. The influence is lowered the resonance
frequency of the antenna. So it is possible compensate the influence
by the shortening of the vertical (item
2). This influence may be calculated theoretically but
the simple way is practically find it. For the described here
antenna it needs to be shortened the vertical on to 100- mm while
the antenna would be tuned to the resonance.
Table 1 shows SWR of the RA3AAE Antenna for the
10- and 2- meter Band.
Vertical of the antenna (item 2) made of aluminum wire in diameter of 8- mm
(0- AWG). Vertical Dipole Antenna (item
1) made of duralumin tube in diameter of 30- mm (diameter
1-1/2- inch). Antenna radials (item 3)
made of antenna wire in diameter 1...2- mm (12- 18 AWG). Vertical
(item 2) is fixed on to wooden
mast with help of insulators. Each radial (item 3) has two insulators at the end.
The antenna needs
lighting protection. Closed Stub (item 5)
does this function. The stub has electrical length ¼ lambda at
10- meter Band and 5/4 lambda at 2- meter Band. The stub has high
impedance at the bands and this one does not affect to the antenna-