Why do you want to make it short and base load it? The top loading wire are
more efficient and if anything I would just put a hairpin coil at the base
to match it to 50 ohms.
John KK9A
To: towertalk@contesting.com,topband@contesting.com
Subject: [TowerTalk] Antenna Modeling needed 160 vertical
From: Ed Stallman
Date: Sat, 29 Aug 2009 16:32:26 -0500
Hello Towertalkers
My plan is to construct a 160m vertical using 4 inch irrigation
tubing 90 ft tall, with 4 top loading wires spaced 90 degree and
sloping down at 45 degrees . My target freq is 1.830 but would like
to make the top-loading a bit short so that the antenna was resonant
about 2 MHz. Then put a small (a few uH) loading coil at the base to
bring the antenna to resonance at the desired frequency. I am
placing the antenna 300ft away from any other structure , hoping for
no interaction . I'll start with 32 ground radials and add more
later, not sure on the length ? 90ft or 130ft ?
two questions
how long will the top-loading wires be for resonant at about 2 MHz
using # 14 copper insulated wire?
how long should I make the ground radials ?
Thanks Ed N5DG
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