In the summer 2011, UA6AGW persistently have been working
on improvement of his antennas (see Reference 1). Article below is just a digest of the hard work.
Figure 1 shows parameters of the Antenna UA6AGW V.40.0 that is
obtained from the test with help of an Antenna Analyser AA- 330M.
As it seen from Figure 1, the antenna
has too much reactance at the working frequency. Next version
of the antenna, Antenna UA6AGW V.40.1, has no the lack.
At the new version of the antenna
the diameter of the loop was decreased. There were shortened the
horizontal wires. Capacity of the capacitor C2 was increased.
Figure 2 shows the design of the new antenna- Antenna UA6AGW V.40.01.
The modification is caused increasing
of the RF-voltage across the capacitor C2. If you remember, in
the previously version (Antenna UA6AGW V.40.0) it was used an
air- gap capacitor for C2.
At the new version (Antenna UA6AGW V.40.01) there were
used a fixed High- Voltage RF-Capacitors (Russian brand K-15U-1)
for C1 and C2. Antenna was tuned in to resonance by changing
of the length of the horizontal wires. Figure 3 shows the box with the capacitors.
4 shows parameters of the Antenna
UA6AGW V.40.01 that were obtained from the test with help of an
Antenna Analyser AA- 330M. Antenna UA6AGW V.40.1 was demonstrated
at annual South Russia