On 4/28/16 6:09 AM, Patrick Greenlee wrote:
George, I can't say one way or the other, could be the antenna in
question or something similar. I never personally touched one but saw
plenty of them atop tuna boat masts and crow's nests as well as some at
residences. It seems to me to be an easy way to get on the air with
something with some directivity and "aimability", at least with useful
steerable nulls. I like solutions sans traps when available.
Patrick NJ5G
On 4/28/2016 7:52 AM, George Dubovsky wrote:
Patrick,
Back in the day, a company called Kirk made a series of what they called
"helicoidal" beams. The elements were tapered fiberglass with approx 1/4"
wide, thin copper strap wrapped around in a spiral, and the whole
thing was
covered with something like spar varnish. Ring any bells?
This idea of a spiraled element has been around for decades. From an
electrical standpoint, it's not a whole lot different than a loading
coil at the base: the radiator being "physically short compared to a
half wavelength" means that it's going to have a lot of capacitive
reactance which you have to tune out in some way.
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