ANTENTOP- 01- 2013 # 017

Antennas UA6AGW. Modification and Development

Aleksandr Grachev, UA6AGW

Credit Line: CQ-QRP # 39, pp.: 22- 27.

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.

Introduction

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.

Antenna UA6AGW V.40.01

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.

Figure 1 Parameters of the Antenna UA6AGW V.40.0

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.

Figure 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 Maykop- Hamfest- 2011.

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