ANTENTOP- 01- 2005, # 007

Window Dipole Antennas with Capacitive Loads

Figure 19 shows a SWR at 50- Ohm coaxial connected through matching device (see Figure 14) to 'wide' antenna (see Figure 12). SWR was simulated by MMANA. Theoretical gain for the antennas is near 1,1- 1,3 dBi

A 'narrow antenna with capacitive loads of up or down installation has theoretical pass band 157 kHz at SWR 1,5:1 at 50- Ohm coaxial cable, and pass band 314 kHz at SWR 2:1 at 50- Ohm coaxial cable. A 'wide' antenna has theoretical pass band 425 kHz at SWR 1,5:1 at 50- Ohm coaxial cable, and pass band 733 kHz at SWR 2:1 at 50- Ohm coaxial cable.

So those antennas can work only at a part of the 10 meters band. For working at all 10- meters band matching device can be retuned for needed frequency. However, the 'wide' antenna often works at all 10 meters band without retuning the matching device due losses at neighbor subjects.

References:

1. Igor Grigorov. Antennas. Matching and Adjustment.- Moscow. RadioSoft, 2002. ISBN 5-93037- 087-7

Figure 18 SWR at 50- Ohm coaxial connected through matching device to 'narrow' antenna

Figure 19 SWR at 50- Ohm coaxial connected through matching device to 'wide' antenna

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