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Antentop is FREE e-magazine devoted to Antennas and Amateur Radio an
Special page devoted to
Helical Antenna for the 20- meter Band
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ANTENTOP- 01- 2013 # 017 |
Helical Antenna for the 20- meter
Band |
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Figure
1 Schematic (A) and
Design (B) of the Helical Antenna for the 20- meter Band |
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The
input impedance of the helical antenna is strongly depends on
the quality of the antenna grounding. With good antenna grounding
the antenna should have input impedance around 8- 12- Ohm. For
example, when I disconnected the antenna grounding system (www.antentop.org/017wires_017.html) and the antenna
ground was only metal base of the microphone stand connected with
the earth the antenna had input impedance 70- Ohm. |
The
low input impedance of the helical antenna is matched with 50-
Ohm- coaxial cable with help of a simple ATU. Figure 2 shows the schematic (A) and the design
(B) of the ATU. Parameters of parts of the ATU are calculated
by me with the help of the free antenna simulator MMANA. |
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Last Updated:
February 18, 2018 19:45
