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INTRODUCTION TO EH ANTENNAS
By Ted Hart CEO
www.eh-antenna.com
75 Meter EH Antenna on an Emergency Van
20 Meter Ham Antenna
AM Broadcast Antenna
1200 to 1700 KHz
AM Broadcast Antenna – 500 to 1700 KHz
ABOUT THE AUTHOR
AM Broadcast antenna
The Author
- Ted Hart got his license (W5QJR) in 1948 and has been continuously active.
Because of an early interest in Ham Radio, Ted had a very long and enjoyable career as an
Electronics Engineer before retiring in 1996. Incidentally, other items Ted developed for Ham
Radio include the Antenna Noise Bridge, the Small Loop Antenna, and many other items and
concepts printed in Ham and Professional Magazine articles.
INTRODUCTION
This book takes the reader through the basic EH-Antenna concept and guides the reader
through the detailed design and construction of a working Ham EH-Antenna, and provides the tools to design an EH Antenna for any
specific applications.
The EH-Antenna provides a unique combination of improved efficiency and real estate conserving features to make the antenna
attractive to old and new Hams alike. It is one of the only alternatives for the space stricken Hams in the urban areas. EH Antennas
have repeatedly given good and consistent results when built, tuned, and used the way they are designed. As the aerial is very small
and inexpensive to build with commonly found materials, it’s an aerial I warmly recommend for confined spaces or stealth
applications even in the developing countries. As an added feature, the EH-Antenna is easily hidden and very stealthy compared to a
dipole or any vertical aerial. I have a couple of homebrew EH-Antennas in my attic and I have no complaints from my neighbors.
Although the EH-Antenna was conceived a few years ago (1996), it has not yet gained wide acceptance. New ideas sometimes take
time to grow, but there has been a great deal of confusion about this technology as a result of new principles that must be incorporated.
The purpose of this book is to clarify the theory and to provide information to the public that will allow any ham to build an EH
antenna to suit his own specifications (frequency, bandwidth, etc.) and correctly employ it. It is through this knowledge and use of the
aerial that the reader (and user) can discover for themselves the many features the EH-Antenna has over conventional aerials.
The EH-Antenna concept is covered by three (3) patents. Because it does not conform to classic theory as printed in the textbooks, the
scientific community has also been slow to embrace the material. Controversy isn’t always a bad thing, especially if it leads to mature
and responsible debate. Furthermore, this book will provide the technical and application data to dispel all of the negative comments.
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It is my hope that all individuals, especially critics, will take the time to simply build the device and see for themselves that sometimes
new ideas actually DO work!!!
This aerial concept is proven in various applications including AM Broadcast, Ham, and commercial systems. Two companies, one in
Europe and one in Japan, manufacture and sell EH-Antennas for Hams under license of the patents. To date there is no company in the
USA manufacturing Ham aerials. A company in Italy uses EH-Antennas to communicate with miniature transponders that are the new
method of reading bar codes at a distance, known as RF Identification (RFID). The EH-Antenna provides a large improvement over
other types of aerials in this application.
The target audience of this book is the Radio Amateur, but the information will be an eye opener for the practicing Aerial Engineer.
To ensure an understanding, concepts and theory are presented in an overly simplified manner so that ideas are easy to follow. The
less experienced Ham may choose to gloss over some technical information, but he will gain a sufficient understanding of the EH-
Antenna to build and use one. For those who want more detailed technical information, it is available at the web site, including
documents and references to other web sites. There is also a discussion group on the Internet for the EH-Antenna.
Because the book is written for Hams, I feel it is important to make it open and free to every one. Send a copy to a friend and tell
others in your Ham club about it. It will be a great item for discussion on the air. The gift of a great aerial will be appreciated by any
Ham, especially those apartment dwellers that have gone silent because they could not install a large aerial. For those who wish to
make a presentation to their Ham club, there is a Power Point presentation on the web site that includes both the video and text to be
read along with the video for a complete presentation. That presentation is out of date as are others on the web site. This book should
be considered the updated version for all EH Antenna concepts and implementation.
Health and Safety
The EH-Antenna is, when in use, emitting a very strong RF field, often very much stronger than with a conventional aerial. Besides,
when did you have a full size dipole for the 80m band inside your shack for test? I want to remind you all about the information about
RF safety rules you once had to learn before you were first granted your Radio Amateur Certificate! Use low power when you are
testing and tuning the aerial inside your shack or if anyone is in close vicinity to the active aerial. Remember the symptoms of
excessive RF radiation!!!!! It’s almost like getting sunstroke and it is dangerous with excessive RF exposure!
Do not touch any parts
of the aerial while transmitting!!!
Any resulting nerve damage could take time to manifest symptoms and they are
not
reversible!
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The most common cause of RF radiation accidents are generated by the Ham testing and tuning in the shack. If unsure about RF
radiation, take time to freshen up your knowledge by reading the ARRL Handbook’s chapter on the subject!
Most of the RF outdoor accidents end with a fall. Never work alone, especially if you use a harness to prevent you from a fall. Many
falls where a harness was used resulted in fatal injuries unless discovered and taken care of within 8 to 15 minutes after the fall! Again,
never work alone.
All RF accidents are avoidable! And unnecessary!
The introduction and health warning was written by Dan Anderson of England.
@ copyright August 2005
To My Dearest Helen
You are my inspiration and my rock. Without your patience and encouragement, I don't think I would have had the strength to
complete this document.
Ted
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FORWARD
This is an unusual book that discloses unusual characteristics of an unusual and new concept in antenna theory. Therefore, I am taking
liberty with conventional book formats and also want to present a preview of coming distractions. The following list covers the major
differences in performance parameters between EH and conventional (Hertz) Antennas. The name of this new concept, and the logo,
implies that the E and H fields are in phase and efficiently integrated at the source, thus bringing the far field to the antenna. A total of
16 unique parameters associated with the EH Antenna are pointed out. Therefore, prior knowledge of antennas and antenna theory
must not be allowed to override these new concepts in the readers mind if the reader desires an understanding of the EH Antenna. For
reference, the new parameters are listed below. Corresponding parameters for a Hertz antenna are included for comparison.
PARAMETERS OF AN EH ANTENNA
Maximum radiation is a function of proper phasing, not resonance
The E and H fields are in phase at the antenna.
Size of an EH Antenna is typically less than 2% of a wavelength.
EH Antennas are typically vertical dipoles – no land required for radials
Length-to-diameter ratio of EH Antenna cylinders set the radiation pattern.
Bandwidth is a function of the capacity between cylinders.
Radiation Resistance is a constant 120 ohms.
Efficiency of the EH Antenna approaches 100%.
For receiving, it produces the same signal level as a full-size Hertz antenna.
Signal to noise ratio is significantly better than a Hertz antenna.
Electromagnetic interference (EMI) is virtually eliminated.
Harmonic radiation is virtually eliminated.
Bi-cone and disc-cone shapes can be used to enhance the radiation pattern.
Radiation pattern of a small loop EH Antenna is flipped orthogonal.
An active array can have close-spaced elements with limited interaction.
The EH antenna produces both conventional and Kor radiation.
PARAMETERS OF A HERTZ ANTENNA
Radiation Resistance is almost constant over a wide range
Radiation begins when the fields are in phase at the far field
Hertz antennas are 50% of a wavelength or loaded for resonance
AM Broadcast verticals require 120 ¼ wavelength radials
Multiple elements are used to control the radiation pattern
The bandwidth is a fixed entity of Hertz antennas
Radiation Resistance is a function of antenna size
Efficiency is a function of size
Received signal level is a function of size
Hertz antennas respond to independent E or H fields
Large E and H fields cause EMI
Hertz antennas are resonant and have related harmonic resonance
Single element wire antennas have fixed patterns
Radiation is in the plane of the small loop
Coupling between elements causes very difficult matching problems
Hertz antennas produce conventional radiation.
The EH Antenna concept is the most significant change in antenna theory in more than 120 years.
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