ANTENTOP- 01- 2005, # 007

Window Dipole Antennas with Capacitive Loads

Figure 11 A window dipole antenna with capacitive loads of central installation

Adjustment of the both antennas is simple. A SWR- meter or HF- bridge (see References [1]) is connected to feed points of the tuned antenna. Gradually shorten moustaches (symmetrically each moustache) of the antenna to minimum SWR or when antenna input impedance is just active (have no reactance) at needed frequency. At shortening moustaches the moustache wires roll up to a little coil.

Input Impedance of 10-meters Band Window Dipole Antennas with Capacitive Loads

Theoretical parameters of the antennas (copper, wire in 1-mm (18- AWG) diameter) were simulated with the help of MMANA. Figure 13 shows input impedance of the antenna shown in Figure 11. Theoretical input impedance of the antenna is 22- Ohms. Practically measured input impedance of the antenna was 30- Ohms. Losses in neighbor objects add the 8 Ohms. Theoretical gain for the antennas is near 1,5- 1,7 dBi.

Figure 12 A window dipole antenna with capacitive loads of up or down installation

Figure 13 Input impedance of the antenna shown in Figure 11

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