On 4/20/18 8:59 AM, Brian Beezley wrote:
Is anywhere the information how the bent driver works?
I don't know how it works, Maximo.
I have been using bent elements to design antennas for the 88-108 FM
broadcast band for about ten years. Bent elements can really benefit
designs that must have good patterns over a 20% bandwidth.
It might be because it's more like a fan or bicone - both of which have
wider SWR bandwidth.
One might compare with a tophat loaded slightly short vertical, as far
as percentage BW.. I don't have numbers in front of me, and generally
"short" relative to wavelength means narrower bandwidth, but in this
case, you're talking about "slightly short"
I got the
idea from the original Moxon 2-element Yagi, the one that bends driven
element and reflector tips at right angles toward each other. I figured
the bends just increased the coupling between the two elements without
decreasing the distance between their central high-current regions. So I
experimented with other coupling methods I thought might be easier to
construct. A bent driven element is particularly easy since the element
usually is already split in the middle and all you need to do is angle
the mount on each side. Some builders preserve an existing mount with
the element straight in the center and bend it a short distance out with
a tubing bender. That seems not to degrade the benefit.
http://ham-radio.com/k6sti/five.htm
http://ham-radio.com/k6sti/ly.htm
Brian
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