Henry,
That is very interesting, and I would like to identify the antenna you are
remembering.
I did some searching and found a few possibilities. One is the KinStar
low-profile AM broadcast antenna made by Kintronic Laboratories. It was
specifically designed to reduce the height required for an AM transmitting
antenna in locations with zoning restrictions. It uses several short
vertical conductors with horizontal top loading, however, so its actual
geometry is different from the trumpet coil I am proposing.
There are also "flared skirt" AM antennas and folded-monopole designs. Some
of those have a conductor cage that widens outward and can look quite
trumpet-like. There have been versions capable of handling 50 kW and
considerably more.
If you remember anything else about the antenna - the manufacturer's name,
an article where you saw it, a photograph, trade name, or even roughly what
the structure looked like - please send it along.
I am particularly interested in whether the radius of the antenna changes
continuously with height. If somebody has already developed a high-power RF
antenna with a genuinely flared or trumpet-shaped conductor geometry, its
dimensions, impedance measurements, current distribution, and design
literature could be extremely useful for our experiment.
Our trumpet-coil experiment is somewhat different in purpose. We are
deliberately specifying the radial profile mathematically and testing
whether the accumulated phase depends upon:
ln(r_w / r_n)
with the predicted fine-structure coefficient.
Still, an existing commercial broadcast antenna using similar geometry
could give us valuable information about fabrication, distributed
capacitance, current distribution, impedance, and unexpected RF behavior
before we build our experimental resonator.
So I would very much like to track down the antenna you have in mind.
David W. Thomson
On Thu, Aug 27, 2026 at 2:25 PM Henry Hurrass <audioteslallc@xxxxxxxxx>
wrote:
> There's an a.m. antenna that was just came on the production last couple of
> years that sounds exactly like what you're saying a trumpet design. It's
> primary purpose was the cut down on the height of any Tower so it would fit
> in a residential area. I don't recall the name of the manufacturer but it's
> an AM broadcast antenna rated at 50 KW
>
> On Thu, Aug 27, 2026, 11:19 AM Ken <pupman.com@xxxxxxxxxxxxxxxxxxx> wrote:
>
> > So what size trumpet coil do you want? Diameter of trumpet part vs what
> > length? Feet or inches work. What form materials or shapes are a go or
> > no-go? The weird shape will require some sort of adhesives or epoxies to
> > hold the windows into place so they don't slip. It sounds like you want
> to
> > instrument the whole thing. How many breaks in the insulation are
> allowed?
> > How will connections be made?
> >
> > Making a form isn't an impossible task, if you can draw up specs.
> >
> > Ken
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