On 2/3/2018 12:45 AM, John Randall via Topband wrote:
What about a helically wound vertical Inv L
73John
Digitally signed mail - John M0ELS
Glad you asked this FAQ:
Helical winding is a concept that intuitively makes
sense. Unfortunately, if you rigorously analyze it,
it makes no sense. A lumped loading coil is
always better. I didn't say a helically wound
vertical won't work at all; it just will be
inferior to a vertical using a conventional loading
coil, which is much easier to build as a bonus.
The length of wire in a helically loaded vertical
is much greater than the length of wire in an
equivalent loading coil. Therefore, the resistive
loss is much greater in the helical case.
For a multi band design, the helically wound antenna
is even more of a non starter.
73
Rick N6RK
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