At the current node
at the short side it is added wire in length (what the antenna
is shortened) 30- 50- cm. At this case the adjusting of the antenna
would be simple. At the 20- meter band the antenna is tuned by
shortening the added wire. At the 40- meter Band the antenna is
tuned by shortening of the one short wire after inductor that
laid at non modification (that is without added wire) side. Both
tuning practically do not influenced to each other. Figure
2 shows the modified antenna.
The MMANA file of the Modified Dipole Antenna DL1BA for 40- and 20-
meter Bands may be loaded: http: // www.antentop.org/019/rw4hfn_dipole_019.htm
Simulation the Antenna in MMANA shows that it is possible to tune the antenna for both Bands by
playing the lengths of the added wire (part C see Figure 2) and the short wire after
inductor (part B at right side antenna shown on Figure 2).
Figure 3 shows SWR of the modified antenna at the 40- meter
4 shows SWR of the modified antenna at the 20- meter