On 1/29/2014 6:25 PM, Jon Zaimes AA1K wrote:
I've read of the 36-foot-high base-loaded elements ON4UN described in
his book, and understand these would have a slightly narrower bandwidth
than an element with top-hat wires.
But what about an element loaded with a coil at the center or at the
top? Would there be advantages to that approach that would come close to
the short verticals with top-hat wires, or any serious disadvantages?
73/Jon
AA1K
I once built a 4x2 fixed array using 30 foot verticals, the height
chosen because I had a bunch of 30 foot long irrigation pipes. I not
only did not use top loading, but I didn't resonate them with a
coil either. Thus the signal was low, but usable. This array
worked perfectly, with directivity as per theory. So I think you
will be fine w/o top loading wires, especially if you use a resonator
coil. The reason not to use a resonator coil is if you want to use the
array on more than one band. My array had quarter wave end fire
spacing on 80, and eighth wave spacing on 160. It even worked on
the broadcast band with a little gain, but a lot of F/B ratio.
Rick N6RK
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