Experimental Helical Antenna

for the 40- meter Band

Ends of the antenna were hanged up to the rope on the balcony. Figure 2 shows end of the antenna. Figure 3 shows antenna installed on the balcony. Balcony was at the four floor of the building and the main direction for antenna radiation was closed by nearest 5 store building.

Antenna parameters were taken with antenna analyzer. Figure 4 shows antenna impedance/SWR at the 40 meter band. Antenna bandwidth is 100- kHz at the 40- meter band. Resonance may be shifted with changing of the length of the antenna wire. Antenna has additional resonance at 27 MHz band.

Figure 5 shows antenna impedance/SWR at the 27- MHz band. Figure 6 shows antenna impedance/SWR from 2 to 32- MHz.

Antenna was tested in the Air. Antenna worked fine on the receiving. However the antenna worked moderate on the transmission. Anyway at 40- W power going to the antenna I made QSOs up to 1000- km.

73! UN7FGO

Figure 2 End of the Antenna

Figure 3 Antenna Installed on the Balcony

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