[TowerTalk] Re; vertical base impedance

[ARTHUR BERNSTEIN]

Before my tower came down I used a type of T on 160. Approx.  55 ft. Vertical with 2 sloping top loading wires about 35 ft each. Fed on ground with inferior radial system. Had a resonance (SWR wise) below the 160 meter band. It needed capacitance. For a capacitor I used a long length of Teflon, thin coax @ 39 pf/ft (?)Actually coiled it up on a 1” form. Total capacitance was about 1000pf +/-. It made the Z very close to 0 at lower band edge. It had a 2/1 SWR bandwidth of about 100 kHz, which meant there was ground loss, though the VSWR curve was beautiful. It worked fair, only because radial system needed to be improved. Before I could do more, the tower came down after two wind events. The coaxial capacitor held up under my 500 watts. It might have been  RG-302 or similar 50 ohm? Very thin, 1/8”?

Art., N2KA
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