By Association

he antenneX discussion list provides a unique forum for conversations on virtually any topic related to any part of the antenna system. List members come from around the world and enter the discussions from many different levels of expertise, from a relative novice level to scientists and engineers with long experience. The association among members is purely voluntary, without cost, and without long-term commitment other than the individual member’s own interest in the subject area. As in many associations, the discussion list contains as many readers as it does active participants.

Despite the uniqueness of the antenneX discussion list, it is only one of many associations, groups, institutes, and other organizations that devote all or some significant part of their effort to the subject of antennas and antenna systems. National amateur radio associations are among the groups with the largest and most diverse membership. The logos only record three such groups with sufficient interest in antennas to create significant antenna publications. The ARRL Antenna Book, edited by Dean Straw, N6BV, and the DARC publication, Rothammels Antennenbuch, edited by Alois Krischke, DJ0TR, are two premier antenna publications, while the RSGB antenna publications appear in many volumes by various member authors. This note mentions only three of the groups, but might have as easily added the Belgian, French, South African, and Australian associations to the list.

Professional associations are equally an important part of the web of development and communication among those interested in antennas. In the United States, the key organization is the IEEE (Institute for Electrical and Electronic Engineering), with antenna work focused in the Antennas and Propagation Society (APS) subdivision. Their focus is defined in a Field of Interest statement: “Experimental and theoretical advances in antennas including design and development, and in the propagation of electromagnetic waves including scattering, diffraction and interaction with continuous media; and applications pertinent to antennas and propagation, such as remote sensing, applied optics, and millimeter and submillimeter wave techniques.” For further information, see http://www.ieeeaps.org/. The Society holds an annual symposium with proceedings; the most recent gathering was mid-June of this year.

Besides IEEE, there are a number of specialized associations, such as AMTA (Antenna Measurements and Techniques Association), largely sponsored by industries affected by developments in the field of study. Their featured meeting will be in St Louis, MO, November 4-9, 2007. For further information, go to http://www.ieeeaps.org/.

Europe also sponsors major antenna and propagation conference, of which the 2007 EuCAP conference in November may be the major event for the year. For additional information on the Edinburgh (UK) meeting, see http://www.eucap2007.org/. EuCAP is sponsored or supported by a considerable number of other European research associations. Among them is the IET (The Institution of Engineering and Technology) at http://theiet.org/.

(The IET web site is under construction.) IET also sponsors ACE, the Antenna Centre of Excellence, at http://www.ist-ace.org/. The Centre sponsors courses in antenna technology, and its web pages make interesting reading. In a related ACE-sponsored effort, we can find the Virtual Center of Excellence (VCE) and the European School of Antennas at http://www.antennasvce.org/Community/Education/Courses.

In France, you may wish to look at http://www.see.asso.fr/?alt=french, the SEE (in English, Society of Electricity, Electronics, and Information and Communications Technologies). Like other national organizations, SEE sponsors publications and conferences.

Do not neglect the growing number of specialized professional magazines and journals as sponsors of conferences. For example, Antenna Systems and Technology is sponsoring a combined conference in Denver, CO, on September 26 and 27, 2007. Antenna Systems 2007 is a two-day international conference focused on the latest and most important advancements in antenna systems and technology. Short-Range Wireless 2007 is a two-day technical conference focused on the most recent advancements in short-range wireless standards and technology for industrial, commercial and residential applications. For further information, see http://www.antennasonline.com/ast07_index.html.

Appearances to the contrary, we have not presented this list of associations and both recent and up-coming conferences just to show how far ahead of the US that most of the world is in graphic logos—although that may well be true in its own right. Rather, with thanks to Alois Krischke for the web links, the point has been to illustrate the wide variety of other associations of those interested in antennas and antenna systems. This list is just a starter. We hope readers will supply antenneX with web links to other societies and associations having similar interests. Also, if you receive advanced information on forthcoming conferences, please also convey the information to the publisher of this journal. We would like to provide advanced notice of such conferences whenever possible.

There is one other message: at worldwide conferences, some papers may be of direct interest to both the readers of antenneX and the members of the discussion list. If you encounter any such presentation or paper in the proceedings, you can serve our group very well by summarizing it and placing the information on the list—or supplying the publisher with a brief summary. Please do not violate any copyrights, but giving a summary and a source for readers to pursue to find the original will be highly useful. There are both cutting-edge technologies of which we should be aware. As well, there are practical techniques that might be useful to many. Your alertness and willingness to provide antenneX readers with some information will be highly appreciated by all.

Just send your submissions to <submissions_at_antennex.com> Replace the "_at_" with an @ sign.

DX & Antenna Seminar Coming Up in Ohio
The ARRL Great Lakes Division Convention is being held on Saturday, September 22, 2007 at the Sheraton Independence
Hotel at 5300 Rockside Rd., Independence, Ohio. Sponsor tables and the sign-in table open at 9:00 a.m. Opening
ceremonies begin at 11:30 a.m. Prices for this event have been kept low due to the terrific support from sponsors
like: Yaesu, Heil Sound, Stepp IR, DX Engineering, Coaxial Dynamics, Universal Radio, Solder It, Bulldog Battery,
Finger Dimple, American Tower Company, The Daily DX and VE3SUN Dx Monitor.

Seminar only tickets are $25 for advance sale and $30 the day of the event. A full ticket including seminars, buffet,
a free ticket for the prize drawing and Wouff Hong is only $50. Tickets can be purchased online at www.2007gldc.org
You can pay by check or credit card online or follow directions for mailing your payment in.

The featured banquet speaker is Joel Harrison W5ZN, President of the ARRL. Bob Heil K9EID and Chip Margelli K7JA will
host a Heil Sound Workshop to the entire audience. Then the rooms will split and go into double seminar modes. Salon
1-2 will feature a extended seminar about DX and DXpeditions with speakers like Bob Allphin K4UEE, Bernie McClenny
W3UR, Don Karvonen K8MFO, John Papay K8YSE and a Q/A panel moderated by Tedd Mirgliotta KB8NW that has the DX speakers
about plus others. Salon Three's first seminar will feature a EmComm manager from the ARRL Headquarters. Next will
be Bob Frey WA6EZV and Dick Arnett WB4SUV about Amateur Radio Direction Finding and last, but not least, Jim Sanford
WB4GCS Eagle Project Manager from AMSAT. Salons will be rejoined again for a antenna seminar by Tim Duffy K3LR. As
the seminars close Jim Weaver K8JE will present the Great Lakes Division Awards. Currently nominations are being
accepted for Division Awards at www.2007gldc.org. Following the banquet a Wouff Hong ceremony will be held.

Many great door prizes will also be given away. Yaesu donated a FT-857D valued at $750, Heil Sound donated a
top-of-the-line Microphone Package valued at $642, Coaxial Dynamics donated a meter and element valued at $380 and Bob
Check W8GC donated a VX-150HT valued at $110.

A hospitality room courtesy of CARS, LEARA and NODXA will be open Friday evenings from 7:00 p.m. until midnight.
Saturday it will re-open at 10:00 a.m. until 6:00 p.m. Card checking will be available for DXCC, WAS, VUCC Low Bands
and VHF. Jim Weaver K8JE can check 160 meter cards Saturday between 10:00 - 11:00 a.m. by reservation at
www.2007gldc.org.

Even if you are not a ARRL member, please attend the convention to see what ARRL has to offer. Discount coupons will be
available to attendees for use at the Cleveland Hamfest being held Sunday, September 23rd.

MORE VISTA
In last month's column for June 2007, I described our experiences here with upgrading to Windows VISTA. I hope the readers found some useful tips in that piece. We have experienced upgrades here from Win2000 Pro and XP Pro.

There is not much more to add to that segment except that FrontPage still crashes. At least though, we know when it will crash now—whenever we go to install or edit a hyperlink online. This means we can do everything using FrontPage on VISTA except edit hyperlinks directly on the server. If the edits are performed on the local workstation, it doesn't crash. If anyone else has this same experience and found a solution, please let me know.

In the last piece, I mentioned that MSIE-7.0 would not run but FireFox would. That issue was solved during the writing of that column and I described the solution. Now, MSIE-7.0 is blinding fast.

Moreover, I did receive one very useful tip from a reader of last month's column about how to upgrade from XP and not lose the license activation. Although we weren't concerned about that issue ourselves, this tip may prove useful to others planning an upgrade from XP to VISTA. Here's the tip, thanks to James Jones, WA7POS:

Indeed, I did recommend that one use the newest machine possible or purchase a machine bundled with VISTA. We build all of our machines here from scratch and select suitable quality components for the type of work we do and without all those extra but useless apps or components usually aimed at gamers.

For example, my new workstation machine which must handle lots of graphics, was designed and created with the following specs (assembled March 27, 2007):

VISTA can analyze your computer's performance with tips on how to improve it. Here's a screenshot of the above machine's rating by component:

As one can see readily, a machine is rated by its slowest component. In my case above, it's the CPU at a 4.8 score (drats! may have to buy a faster CPU). By comparison, another machine running an AMD 64-bit Processor with 2.40GHz CPU is rated at 4.2. The other machine is an older one upgraded from Win2000 Pro. It doesn't have some of the later tech stuff, but 4.2 is fine for our needs. Plus, the CPU, at 2.4GHz is a bit slower than the 3.0GHz of this machine.

In summary, our experiences here have been very positive using VISTA and the performance is excellent. The above is a very fast machine. Just click on something and there it is! I like it.

NOTE: If you have other experiences to share besides the ones here and described in my June 2007 column, just send them to "jack_at_antennex.com." Of course, replace the "_at_" with the @ sign. I will be glad to publish any useful tips for the benefit of those anticipating a move to VISTA.

VISTA USAGE DOUBLES
Our server is able to gather interesting stats about visits to our web site. One that relates to the above discussion shows that, although still a low percentile overall, those using VISTA has nearly doubled in the month of June 2007 versus May 2007. Here are the stats for your information:

THE PURPOSE OF THIS JOURNAL
In my column for September 2006, “The antenneX Mission,” I wrote about a subject close to my heart — the purpose of this journal. It had been quite some time since I had reminded our readers of our original purpose when we set out some 20 years ago.

More than anything else, this journal has always been a “labor of love” for me. It is the reason I founded the antenneX magazine almost 20 years ago, knowing that running a magazine is a tough business and especially so since I planned to do it without the traditional revenue support from advertisers or outside investors. I wanted this magazine to always be able to write about any issue without concerns of losing the support from any of those type revenues. I am pleased to say, we have never steered from that course one iota. And, as a consequence, we have covered some very controversial developments throughout the past two decades. In the process, we have provided valuable factual information to more than 200 countries, even to the most remote regions of the globe. Hence, our readers are much more informed about the truth about all of the “new” devices as their stories unfolded in the antenna and antenna-related field. For more details, you are encouraged to read my column from September 2006.

Additionally, we were pleased to receive and publish in the October 2006 issue, a very special editorial reaction to my column written by one of our long-term readers and contributors, Dr. Jef Verborgt. Those two articles are located by the following links below:

VISIT THE GUEST ROOMS
The relentless attacks on our web site by pirates and the like has made it necessary to add more security to protect our material against such piracy. It's only fair that we know who enters the House of antenneX, so our guests will need to provide some minimal information in the process of obtaining a login. This includes using your real active email address without which a login cannot be received. Do not confuse this login with a paid subscription login. They are not the same and your subscriber login will NOT work in the Guest Room areas. Of course, you may choose to create your own login to the Guest Rooms using the same login as your subscription, if the system will accept it.

Along with the continuing fight against spam/virii junk, protecting our material and valuable bandwidth against piracy takes up a great amount of our time—time we can't really spare. The Internet is simply not the friendly neighborhood it used to be in the "old days" and more and more security must be installed to counteract these intruders. Thus, we have made the access to the Guest Rooms as automatic as possible for you to manage your own login.

In view of the above, we have overhauled the numerous free and open-access sections that have always been wide open to all of our friends throughout the many years antenneX has been online. But, we must change with the times as the need dictates. I don't think the Internet will become more friendly in the near future and protected sites with logins are fast becoming the rule rather than the exception. To repeat, most would like to know who they invite into their house. The same applies at the House of antenneX. It's really worth the effort!

We have activated a new login system for access to the above guest rooms — and, the login can be totally managed by our guests. Above is a graphic of what you see as a login page to the new consolidated area, "antenneX Guest Rooms." This new page for logins is at this location now and available for your use:

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
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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 manuscripts at 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.

Notes on the Extended Aperture Log-Periodic Array
Part 2: The Extended Aperture LPDA
By L. B. Cebik, W4RNL

In Part 1 of this exploration, we examined the extended element, which lies at the heart of the extended aperture LPDA (EALPDA). A center-fed element about twice as long as a normal resonant dipole with a capacitance equi-spaced about 30% of the distance from the feedpoint outward along each half element will show about 1.1 dB additional gain and a narrower E-plane beamwidth than the dipole. The resonant impedance of the extended element is about 200 Ω or roughly 3 times the impedance of a resonant dipole. We may construct such elements as monopoles or as extended dipoles. Longer elements with additional capacitances and higher gain values are possible, but the simplest extended element is all that we need for the basic EALPDA.

We also took a long look at optimized wide-band standard-design LPDAs for the 5-30 MHz range, the frequency span covered by the basic EALPDA shown in the Tanner 1973 patent submission. To replicate the somewhat vague reference to a long-boom LPDA, I modeled a 56-element LPDA using a τ of 0.96 and a σ of 0.18. Because LPDAs are subject to somewhat dated understandings based on literature from the 1960s and 1970s, we explored the antenna’s performance in several modeling contexts. We looked at the antenna in free space and as a horizontal array 100’ over perfect ground and over various grades of real ground. We rotated the antenna 90° to examine its properties in monopole form over perfect ground. Finally, we created a sloping LPDA with each element terminated 4’ above perfect ground and above several qualities of real ground. The exercise familiarized us with the types of performance values that we see in each orientation so that we can apply the correct set for comparison with the EALPDA in its many possible configurations.

With these prerequisites, we are in a position to examine—within the limits of the available design information and the ability of modeling software to capture the design—the extended aperture log-periodic dipole array.

An Electrostatic Wave
By Kirk T. McDonald, PhD
Joseph Henry Laboratories, Princeton University

All electrostatic fields E (i.e., ones with no time dependence) can be derived from a scalar potential V(E = -ÑV) and hence obey Ñ x E = 0. The latter condition is sometimes considered to be a requirement for electrostatic fields. Show, however, that there can exist time-dependent electric fields for which Ñ x E = 0, which have been given the name “electrostatic waves.”

Baluns: Which One to Choose
for Wide Ranging Complex Terminations?
By Fred M. Griffee, N4FG (EE Retired)

After building and testing many variations of a balun to be used with a single wire antenna for all HF Amateur Radio bands, I find it is difficult to select an overall best choice characteristic. Eight variations out of 14 are tested and measured so comparisons can be made. The remaining six are similar to the eight choices and therefore considered redundant.

It is important to mention that previous tests of the stick R33 ferrite type (permeability of 125) 4:1 balun experienced high losses evidenced by getting very hot when used on the 80-meter band with my antenna system. Therefore, for my application, it is considered a poor choice but is included regarding comparison with other balun choice characteristics.

I include line current measurement data found when using the MFJ -835 balanced line current meter. The baluns examined are the Ruthroff and Guanella types with varying core and winding variations. A balanced matching network is constructed with the assumption it will be the most efficient. Common mode current isolation is provided by using a coaxial bead 1:1 type balun using the well-known Amidon FB-73-2401 ferrite bead in quantities covering the final 5.3-foot length.

EZNEC for Windows, Version 5: A Review
By L. B. Cebik, W4RNL

TAt the Dayton Hamvention for 2007, Roy Lewallen, W7EL, introduced the latest version of his well-known program, EZNEC. Version 5 elevates the program from a simple implementation of NEC to what Roy calls an antenna system analysis program. The aim of this review is to see what justifies the expanded view of the program. The latest version is still true to its roots, all the way back to Roy’s initial offering, ELNEC, a DOS implementation of MININEC 3.13. EZNEC in DOS format followed, with EZNEC for Windows (version 3) occurring next. Version 4 added a number of refinements at all levels and introduced the Plus version with an expanded segment capability and other features. Roy had already introduced EZNEC/M and EZNEC Pro/4, the latter including NEC-4 cores, although version 5 now standardizes the labels to Pro/2 and Pro/4 to distinguish the core levels included with the software.

My Review of the PF4 Test Results
By Bill Graham, VE3ETK

In last month’s issue (June 2007) Dave Cuthbert, WX7G performed and presented a review of my PF4-20 antenna. It is well written and has probably taken up a lot of his time. From the pictures it appears that he has constructed a good working model. He chose to use ‘conventional antenna theory’ for his analysis, which in turn allowed him to use existing modeling software to come up with some conclusions. Alas, that choice meant that he had to leave out certain key factors that I believe contribute to the success of the PF4 and therefore make a couple of his conclusions erroneous in my opinion.

"Balanced feed" and feedline radiation - Part 1
By Jan Gunmar SM0AQW

Antenna balance and baluns are popular discussion subjects among radio amateurs. Questions pop up in many discussion lists and many seem to worry about the consequences of “antenna unbalance.” There are also many conflicting views on what the “balance problem” actually is, what should be ”balanced” and how it should be done. It could be instructive to look a little closer at the term” balance” because there are a number of myths and misunderstandings circulating and perhaps some controversies around ”balance” are quite unnecessary!

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
July 2007 antenneX Online Issue #123

	May 07	June 07
Windows XP	79.0%	78.4%
Windows 2000	7.3%	6.1%
Windows Vista	2.6%	4.7%
Windows 98	2.3%	2.6%
Windows 2003	0.5%	0.4%
Windows others	8.3%	7.8%