ANTENTOP- 01- 2013 # 017

Vertical Antenna for the 20-, 15-, 10- meter Bands (Antenna UW4HW)

Yuri Matiychenko, UW4HW

Credit Line: Radio # 12, 1968, p.:21.

Classical Vertical Antenna (aka Ground Plane Antenna) without additional tuning works satisfactory only at one amateur band. However, so called "thick" antennas (looks like three-dimensional geometrical figure) could work with good SWR in the frequencies range F1/F2= 3, where, F1- high working frequency, F2- lower working frequency. Common use those ones is a Conical Antenna (Figure 1) and Exponential Antenna (Figure 2).

For Conical Antenna the pass- band is increased with the increasing of the Alfa at the antenna base. Antenna has optimum parameters at Alfa = 60-70- degree. At the Alfa = 60- 70- degree the Conical Antenna has impedance near 70- 80- Ohm. The same thing is for Exponential Antenna. However, the maximum diameter of the Exponential Antenna is almost in three times less compared to the Conical Antenna.

As usual the antennas shown on Figure 1 and Figure 2 made from wires or tubes to simulate the Conical or Exponential shape.

Radio # 12, 1968. Cover.

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