ALE (I'll drink to that)

Many receive advice, only the wise profit by it.
—Publilius Syrus (1st C. B.C.)

stands for Automatic Link Establishment. It is the method developed over the last 10 years or so to improve HF communications and make it more usable by untrained operators. It has two main benefits:

2) it takes advantage of short-term ionospheric conditions that can improve connectivity by as much as 20 dB with respect to conventional HF predictions.

The ALE methodology is possible due to the great power of computer chips that may now be packaged even into hand-held transceivers. The system works like this: A "sounding list" or "scan list" is established for the net. A receiver then operates in the scan mode, sequentially listening for a call on a list of perhaps 10 or 20 frequencies. The CPUs are "smart" in that they can detect calls made to their particular address, or a general call can be sent to many receivers.

When an operator at, say Station A, wishes to call, say, Station B, “A” pushes just one button, and very short test signals are sent on all frequencies of the scan list. If one or more are received at “B”, the computer there performs a link quality analysis (LQA) by computing the relative "score" on each channel, usually bit error rate. The “B” radio then answers on the channel with the highest LQA score, the “A” radio then acknowledges the "link-up" and begins to send the message. All this is done with push-to-talk techniques as usual, although some protocols are now available for automatic data transmissions. But most of the applications are for SSB Voice.

ALE (originally called "adaptive HF") evolved to the second generation, which is now fielded throughout the military. A most interesting set of developments includes the expansion of ALE techniques to amateur radio operations and to various Homeland Security participants, such as the Civil Air Patrol. The FAA is also interested, especially in locations like Alaska, where downed aircraft needing location and rescue are common.

The different vendors have their own proprietary protocols, so even though there are ALE military standards, some radios work better than others. "3G" radios — the third generation — are now out, but they cost an arm and a leg and are not yet found everywhere. The 3G radios have very accurate frequency standards and may thus be synchronized, so the receiving station that may be in a covert situation need not engage in the LQA handshaking. In that case, the receiver simply answers on the best frequency, having performed its own LQA, and the distant transmitter, having reverted to its own scanning mode, receives the message, which is usually a short burst. Most of these radios work in the data mode and send e-mail-like traffic.

ALE places high demands on the radio equipment itself. However, successful ALE operations are equally dependent upon antennas that can support this mode. ALE places a high emphasis on NVIS techniques, since much of the communication is within a radius of 500 miles. Hence, there are needs for special antennas having a broad operating bandwidth and a very high radiation angle. Among the most popular field antennas are terminated folded dipoles and related antennas.

Besides the venerable B&W antennas, there are a number of offerings emerging from Australia. Terminated antennas achieve the requisite broad SWR passband via the terminating resistance, but, of course, suffer considerable loss relative to a similar antenna with no termination. Among the unterminated antenna types available commercially are fan dipoles, vertically oriented LPDAs and vertically oriented LP loops. In general, the unterminated antenna types are far more complicated—and expensive—than the simpler terminated antennas.

There is considerable room in this region of rising HF interest (actually upper MF and HF interest) for the development of new or revised older antennas to make them serviceable for ALE. Hence, the general parameters of ALE suggest a broad area for antenna experimentation, one that we have not delved into very far in the history of antenneX.

It is not clear at this point that everyone who toys with the idea of ALE has the same needs in terms of radiation patterns. Military and government services have both long-range and short-range needs. However, many of the civilian needs for ALE are short range. In the HF region, this generally means NVIS communications. NVIS tends to fizzle out above about 8 MHz, although government specifications tend to call for coverage from 2 to 30 MHz. As well, many civilian needs—such as emergency beacon reception—may not need the ultra-high-speed capabilities of the present conception of ALE. For this reason, it may be possible to employ pre-tuned matching devices for each scanned channel and switch them in milliseconds rather than in microseconds. Whether user services would buy into a slower-speed form of ALE that might also simplify antenna needs is an open question at this stage of development.

Nevertheless, the field of antennas for ALE service is wide open to the experimenter and developer. I hope we see some developments from our readers so we may share them with our other readers.

LIFE AFTER THE PATENT
As I have mentioned in my previous column, I would like to share some experiences for the benefit of our readers about what happens after a device patent is secured. What steps were taken to make it to market, or what steps (or lack of) may have caused nothing more than disappointment. In fact, it would be great to have both stories—those that made it and those that didn’t. Here is one of those stories:

miron.jpg (21606 bytes) After the Patent: A Volume Loading Antenna
By
Doug Miron KC0NKY

Prologue
In the early 1990s, I discovered that an electrically-small dipole which is end-loaded with volumes that are similar to thick plates has much more capacitance than the same size wire-radial loading. This effect allows circuit resonance to be achieved with a practical-sized radiator wire. The mechanism and early experimental results are described in [1], and a recent multi-band HF prototype is described in [2].

By 1995, I had persuaded South Dakota State U. (Brookings, SD, USA) to enter into a contract with me whereby they would finance further development and pursuit of a patent. The Dean of Research hired a big-name Minneapolis law firm because they allegedly have experts in all technical fields. However, the one assigned to my case was a refugee from Motorola who didn’t know anything about electromagnetics, let alone antennas. Furthermore, the Patent Office Examiner also seemed to know nothing about antennas, and was fixated on the resemblance between a two-dimensional shape in my application and that in an earlier patent patent describing a Yagi with shortened elements.

After several rewrites and denials at about $25,000, the University decided to abandon the effort. They signed the intellectual property back over to me. I found a lawyer in Sioux Falls, SD and we started almost all over again. For another $2,500, I was granted a patent in 1999[3].

Epilogue
I am not an entrepreneur. I like solving technical problems, and sometimes it is necessary to sell an idea to management, but I’m fundamentally neither a salesman nor a manager. So I wanted to sell the idea and make some money from it.

When we first started pursuing the patent, I wrote up an advertising letter and mailed it to all the antenna manufacturers listed in a product directory. I got a few expressions of interest, but essentially they said “Let us know when you get the patent.” After I got the patent, I wrote another advertising letter, mailed it out and got no responses. Also, after the patent I received a number of solicitations from companies that would market it for some up-front money from me. I felt suspicious about that. My feeling is that they would be more sincere if they worked for a percentage of the sale. So I didn’t try them.

My last attempt was an e-Bay auction. I didn’t want to sell for peanuts, so I set a minimum bid of $1 million. I posted a notice of the auction on NEC-LIST (Numerical Electromagnetic Computation List), the only antenna list I was on at the time. Some people said I was crazy and I guess they were right. I didn’t get any bids.

To this point then, I haven’t made a nickel directly from the patent although I did earn an antenneX subscription by writing about the antenna [2].

When I first did a patent search, I found a number of ideas that seemed improbable as antennas. Since I’ve seen the claims for the CFA, the CTHA and some similar exotic antennas, I can understand now why people would be skeptical of the modest claims made for volume-loading. As far as handsets go, I’ve been told low cost beats better performance.

So, I gave up...for now. -30-

References
[1] “Volume Loading—A New Principle for Small Antennas”, ACES Journal, Vol. 14, No. 2, July 1999.
[2] “The HF Short Fat Dipole: A Progress Report”, www.antenneX.com , September 2004.
[3] U.S. Patent 5,986,610, “Volume-Loaded Short Dipole Antenna”, issued 16 November 1999.

BRIEF BIOGRAPHY OF AUTHOR
Douglas B. Miron - KCØNKY
Siouxland Scientific Computing
19298 Thoren Drive NW
Solway, MN 56678

Douglas B. Miron received B.E. and M.E. degrees in Electrical Engineering from Yale in 1962 and 1963. Doug then received a Ph.D. in Electrical Engineering/Control and Communications from University of Connecticut in 1977. He worked in industry from 1963 through 1967, and 1970 through 1979 and 1996—1997.
Doug was an educator at South Dakota State University from 1979 through 1996 and has been consulting since 1998. He has worked, taught, and published in nearly every major area of electrical engineering. Current interests are in small antennas and RF circuits.

Kudos to Douglas for having the intestinal fortitude (guts!) to share his story with this large audience of his peers about a failed attempt to bring his "new" device to the market. That takes plenty of character and self-assurance. Moreover, he is to be applauded for his success in convincing the University to provide the substantial cost financing and legal help needed on the front-end "load" of his endeavor—and he says he is not a salesman!

What his experience shows is that one is subject to all kinds of pitfalls that can either work for or against the would-be inventor. From his story, his bad luck initially was from having his project assigned to unqualified people. There is no way to predict that kind of snag ahead of time and thus, right away after such a good start with the backing secured from the University, up jumps a new unexpected deal-killer! While one might be able to argue for a more qualified "legalman," there is not much one can do about the selection of the "examinerman" drawn to review the application. So, Doug has an novice legalman arguing his "case" to an examinerman who doesn't understand "Greek."

I sincerely hope we get more of these "stories" to share with our readers, especially those who may be considering the Patent Application Process—read and learn from the experience of those who went before you. The more you learn about the potential pitfalls, the better your chances of success.

HAIRPINS AND FOLDED MONOPOLES
Of special note in this month's issue is taken of Claudio Re's (of Italy) Hairpin antenna article and Valentin Trainotti's (of Argentina) folded monopole antenna article, since essentially, they are about the same antenna type approached from different directions. It is noted in one illustration (Fig. 8) in Claudio's piece and one of the photos at the end of Tino's piece to see the caged folded monopole versions as very much alike. The difference is that Tino is concerned with AM BC use as a resonant or near-resonant antenna with a 50-Ohm feedpoint impedance. Claudio concerns mostly for the characteristics of the antenna when it is quite short and exhibits the inductive reactance that is inherent to its nature as both an antenna and as a shorted length of parallel transmission line.

The above two articles are then followed by another fine article on this subject of folded monopoles by L.B. Cebik, W4RNL about "Modeling Folded Monopoles." See more about these articles below.

As a result of this new programming, you will be able to obtain your own login, change it to update your info, change your password and delete membership if & when you desire without our help. Of course, the bottom link on the new page provides help if you still need it.

AN INVITATION TO CONTRIBUTORS
wpe2B.jpg (5748 bytes)

antenneX thrives on the contributions of antenna experimenters, ranging from the informal home shop construction project to the theoretical investigation of basic antenna, feedline, and propagation phenomena. Over the years, we have published articles on the use of new or newly adapted materials, known antennas adapted to new circumstances, modifications of antenna structures, basic explorations of both common and unusual antennas, antenna modeling exercises, design improvements, antenna matching techniques from both a physical and mathematical perspective, evaluations of mini-antennas and their underlying theory of operation, new and patentable designs, propagation tutorials, and.... The list goes on, since no antenna-related topic is irrelevant to the readers of antenneX.

At the same time, antenneX has experienced continuous growth in its readership—for which we are appreciative. However, all readers can help us do even better. How? By submitting an article every now and then based on your current antenna work that may be useful at any level to other readers.

Among the engineering and researching readers, there are undoubtedly a number of unclassified and non-proprietary findings that antenneX readers would like to know. Among the practical antenna designers, there are ideas, tests, and numerous other practical findings to benefit our readers. Antenna builders very likely have some techniques to share with other readers. Besides the regular articles, we always have the home work shop column for shorter practical ideas and we always have the invited news and editorial column for information about new technologies, future advances, lost old but good ideas, and personal views on the good to bad things that are happening in the world of antennas and propagation.

If you are uncertain about whether your ideas merit an article, please feel free to send an outline to the general editor/publishers at submissions@antennex.com . Do not feel that you must be ready to be a regular submitter to write for antenneX, because we welcome the individual contribution as much as monthly articles. As well, do not believe that the slots in each issue are already spoken for—we shall always make room for a worthy article.

Modeling Yagis by Equation
Part 2. High-Gain and Wide-Band Yagis
By L.B. Cebik, W4RNL

In the first episode of this short series, we examined some of the properties of Yagi arrays that make the task of automated design somewhat tentative. At the bottom line, for any given performance parameter--and often for sets of parameters--there is no single set of dimensions that will achieve the goal. Despite this limitation and others pertaining to the use of algorithms as a basis for antenna construction, we did put together enough data points for a 4th-order regression polynomial set that is reliable with respect to the maximum front-to-back version of the 3-element Yagi. The emergent calculated models have 180-degree front-to-back ratios in excess of 50 dB and resonant feedpoint impedances very close to 29 Ohms throughout the range of calibration (that is, element diameters between 3E-4 and 1E-2 wavelength).

This episode will complete the work--so far as it has gone--by examining high gain and wide-band versions of the 3-element Yagi. As well, before closing the book on the project, we shall look again at the limitations of the effort and what they mean for the builder.

The H-Cube Antenna
By Claudio Re, I1RFQ

This article describes of the H-Cube, one of the first designs of Claudio Re not yet revealed. The H-Cube, Helix Cube (first erroneously called Elix Cube and E-Cube from Re), was one of the first Re designs developed during the search for the “Holy Grail” of Compact Antennas. The goal is to develop an economical compact monoband antenna which could be tuned over a Ham band and which had a real gain of around -3 dBd.

The main idea was to reduce the losses on the coils and trying to avoid baluns and transformers used in the early Cube prototype. This was accomplished using bigger coils, with bigger wire diameters and bigger coil diameters. While filling the cubic space with this big coils the performance improved. In the end, there was no more need of both vertical radiators and top plates. This Cube became a large Helix and the setup was called H-Cube.

Triangular & Rectangular Loop Wire Antenna
Characteristic Versus a Simple Inverted Vee Antenna: Part II
By Fred M. Griffee, N4FG (EE Retired)

In the first part of this 2-part series of articles, brief coverage is provided for comparison of the subject antennas. Part II provides a more detailed comparison. Other data are also provided as a review and are included at the bottom of each elevation radiation pattern where the “take-off” (TO) angle for maximum gain occurs. For the inverted vee antenna (IV), the gain point for comparison to the others, is set to equal the TO where their maximum gain occurs. This enables a fair comparison to see whether, in fact, the IV antenna is a better or worse performer.

The Hairpin Antenna
By Claudio Re, I1RFQ

This article describes the investigations on how to convert the common use of loading a short vertical radiator with a coil to its dual and use for this a mast that can continue with no effect to support other antennas and cables. The end configuration is similar to the Hairpin Antenna described in several articles, now in the antenneX Archives. And the antenna could be tuned over an extremely wide range of frequencies, only with the use of two capacitors. This set-up could be very interesting in a lot of cases and we will explore the reasons why.

MF AM Folded Monopole Characteristics
By Valentin Trainotti, Buenos Aires, Argentina

The folded monopole antenna has been used for a long time in medium frequency amplitude modulation broadcast applications, in order to have a grounded radiating structure and with a height close to a quarter wavelength. It was primarily introduced in order to obtain a high efficiency, simple and grounded radiator for several applications but especially for MF AM stations. Nevertheless, almost no technical information is available for this antenna in the specialized literature. This article shows a folded monopole sketch used in this project.

In general the monopole height was chosen close to a quarter-wave to consider in the cage effect. Tower and cage constitute a kind of quasi-coaxial line, short circuited at the antenna top. If its length is close to a quarter wave produces an almost infinite input impedance between the cage and ground, because tower is generally connected to ground.

Measurements have been made on a real scale 72 meter height model with a 6-wire cage in order to validate the antenna input impedance and directivity calculations. Cage and supporting mast structure makes up a kind of transmission line and for this reason different standard triangular tower were analyzed in order to determine their effect on the input impedance.

Modeling Folded Monopoles
By L.B. Cebik, W4RNL

The folded monopole is an interesting variation on the standard linear monopole. Essentially, the folded monopole is one-half of a folded dipole. As such it retains two important properties. First, the act of folding results in an increase in the feedpoint resistance relative to the linear or open-ended monopole. The exact ratio of impedance transformation depends on the relative diameters of the fed and the "other" wire. The transformation ratio answers to the same equation that we have often seen for the folded dipole. Although the ratio of wire diameters provides the key variable in the equation, the spacing between the wires plays a significant role in two ways. The terms of the ratio itself are each ratios of diameter to spacing. For reference, the following equation appears in many texts, where R is the ratio of impedance compared to the open-ended linear antenna, s is the center-to-center spacing of the wires, and d1 and d2 are the 2 diameters, with d1 representing the fed wire. As well, the wires must be close enough to each other to ensure that the pair forms a transmission line and not a simple wide-spaced half loop. The fact that the folded monopole is itself a transmission line comprises the second major property of the folded monopole.

Well, there you have it, folks—thanks for listening and remember, the reading lamp is always on for you in the reading rooms. If I can be of further help, I'm just a Stone's Throw! away.-30-

Best reGARDS, Jack L. Stone, Publisher
jack@antennex.com
December 2005 antenneX Online Issue #104