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ANTENTOP- 01- 2005, # 007  

Window Dipole Antennas with Capacitive Loads

 

 

Figure 6 SWR at 50- Ohm coaxial for ‘wide’ antenna

 

A ‘narrow’ antenna of central installation has theoretical pass band 1300 kHz at SWR 1,5:1 at 50- Ohm coaxial cable, and pass band 2744 kHz at SWR 2:1 at 50- Ohm coaxial cable. A ‘wide’ antenna of central installation has theoretical pass band 1480 kHz at SWR 1,5:1 at 50- Ohm coaxial cable, and pass band 2979 kHz at SWR 2:1 at 50- Ohm coaxial cable. It is quite enough for working at 6- meters band especially since the real antenna has pass band wider the theoretical.

 

Parameters of the 6- meters Band Window Dipole Antenna with Capacitive Loads of Up and Bottom Installation

 

Theoretical parameters of the antennas (copper, wire in 1-mm (18- AWG) diameter) were simulated with the help of MMANA. Figure 7 shows input impedance of the antenna installed at window 150 cm wide. Figure 8 shows input impedance of the antenna installed at window 210 cm wide.  Theoretical input impedance for ‘narrow’ antenna is 43- Ohms, for ‘wide’ antenna- 60- Ohms. The data are very good matched with my practical measurement of the antennas.

 

A 50- Ohm coaxial cable should be used for feeding of the antennas. This one can be connected directly to antenna feed points, as it is shown at Figure 2. A 75- Ohm coaxial cable is possible to use for an antenna installed at wide (210 cm) window.

Figure 9 shows a SWR at 50- Ohm coaxial for ‘narrow’ antenna shown at Figure 2. Figure 10 shows a SWR at 50- Ohm coaxial for ‘wide’ antenna shown at Figure 2. Theoretical gain for the antennas is near 1,5- 1,7 dBi.

 

A ‘narrow’ antenna with capacitive loads of up or down installation has theoretical pass band 1377 kHz at SWR 1,5:1 at 50- Ohm coaxial cable, and pass band 2697 kHz at SWR 2:1 at 50- Ohm coaxial cable. A ‘wide’ antenna with capacitive loads of central installation has theoretical pass band 1393 kHz at SWR 1,5:1 at 50- Ohm coaxial cable, and pass band 2876 kHz at SWR 2:1 at 50- Ohm coaxial cable. It is quite enough for working at 6- meters band especially since the real antenna has pass band wider the theoretical.

 

Window Dipole Antennas with Capacitive Loads for 10-meters Band

 

Figure 11 shows schematic a window dipole antenna with capacitive loads of central installation. Figure 12 shows schematic a window dipole antenna with capacitive loads of up or down installation. Antenna central installation can be installed at window 210-cm wide. Antenna up or down installation can be installed at window 150 or 210-cm wide.

 

The design of the both antennas is similar to design shown at Figure 1b. Two ropes are installed at two ends of the window. Capacitive loads fastened to the ropes by thin wires or ropes. Diagonal capacitive loads are spread by thin ropes. Third rope is installed at the center of the window. Antenna central insulator (made from a piece of any plastic or PC board) is fastened to the rope.

 

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