ANTENTOP- 01- 2015 # 019

Modified Dipole Antenna DL1BA for 40- and 20- meter Bands

By: Igor Vakhreev, RW4HFN

In my opinion the explanation how the DL1BA Antenna (Antentop 01- 2015, pp: 53-55, Dipole Antenna for 40- and 20- meter Bands) is working at the 20- meter Band is very simple. Parts of the antenna- there are long wire (5.6-meter length) before inductor, inductor and short wire (1.5- meter length) after inductor- make 1.5- lambda dipole at the 20- meter Band. Figure 1 shows current distribution in the DL1BA Antenna at the 20- meter Band. The current distribution proves my suggestion.

As you can see from the Figure 1 the minimal current (current node) is placed at half meter up from the inductor. It allows find another approach for tuning of the DL1BA Antenna. It is possible make one side of the antenna a little short- say to 30- 50- cm.

Figure 1 Current Distribution in the DL1BA Antenna at the 20- meter Band

Figure 2 Modified Dipole Antenna DL1BA for 40- and 20- meter Bands

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