The HEBA/CFA for MF AM broadcasting (there was one planned for an LF BC
station on the Isle of Man) has been commercially tested only for ground
wave coverage as one would for a full size BC monopole antenna. I am going
on the assumption that there is no "crossed-field" radiation occurring and
that the HEBA is just a short, fat monopole. As such it has the elevation
radiation characteristics just like any other monopole 90 degrees or less
in height. Maximum radiation depends on the far-field ground
characteristics.
Dave KH6AQ (formerly WX7G)
On Fri, Apr 19, 2024 at 9:58 AM Mike Fatchett W0MU <w0mu@w0mu.com> wrote:
> What is the desired coverage area for the antenna? I would expect it to
> be very small, local area coverage of 50 miles or so. What is the take
> off angle etc.
>
> W0MU Mike
>
> On 4/19/2024 1:41 PM, Dave Cuthbert wrote:
> > The HEBA appears to be the same animal as the CFA (Crossed Field Antenna)
> > patented by Dr. Kabbary and M.C. Hately in the late 1980s. As the HEBA
> > Model 103 Performance Analysis says, *" WWAS accomplished this feat of
> > engineering through the development of a two-element antenna that
> generates
> > the electric field and the magnetic field separately."* This is the idea
> of
> > the CFA where separately generated E and H fields combine in space to
> > overcome one or more limitations of conventional antennas.
> >
> > I thought the CFA was debunked by the time the last one was sold by Dr.
> > Kabbary's Egyptian antenna company in 2003. Up to that time there were
> > several articles in AntenneX magazine about the antenna along with
> attempts
> > to build and test it. Dr. Kirk McDonald, a regular author for AntenneX,
> > goes into the math in his paper *“Crossed-Field” and “EH” Antennas
> > Including Radiation from the Feed Lines and Reflection from the Earth’s
> > Surface.*
> >
> > My NEC models at the time for a CFA driven as a standard monopole against
> > the Kabbary-recommended 2-story, copper strapped building showed it
> > operating well enough as a standard monopole. The CFA on top of the
> > two-story building formed a center-loaded monopole. I can build that
> model
> > again and report back here if anyone is interested. I will compare them
> to
> > the HEBA performance analysis.
> >
> > Sometime around 2002 an Australian ham/BC engineer worked with Dr.
> Kabbary
> > to tune up a CFA at an AM broadcast station in Australia. After Kabbary
> > give up and returned to Egypt the amateur retuned the antenna as a
> standard
> > monopole that exceeded the measured field strength of the CFA tuning. To
> me
> > and others the promise of the CFA for topband was a heady time which
> helped
> > propel me more deeply into antenna design and analysis. The CFA turned
> out
> > to be both a disappointment and a good lesson.
> >
> > *Wikipedia CFA article*
> > https://en.wikipedia.org/wiki/Crossed_field_antenna
> >
> > * “Crossed-Field” and “EH” Antennas Including Radiation from the Feed
> Lines
> > and Reflection from the Earth’s Surface*, Kirk McDonald, Princeton
> > University
> > http://kirkmcd.princeton.edu/examples/crossedfield.pdf
> >
> > *HEBA Model 103 Performance Analysis*
> >
> https://www.thebdr.net/wp-content/uploads/2020/06/high-efficiency-broadband-plain-english.pdf
> >
> > Dave KH6AQ
> >
> > On Fri, Apr 19, 2024 at 6:01 AM Radio KH6O <radio.kh6o@gmail.com> wrote:
> >
> >> I'd like to see a version of this for 160M:
> >>
> >>
> >>
> https://www.radioworld.com/news-and-business/headlines/wqvram-is-granted-cp-to-use-heba-antenna-at-night
> >>
> >> --
> >> 73,
> >> Jeff KH6O / 6
> >> _________________
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> >>
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