The Cube Family Grows!

Further tests and measurements by both inventors showed some departures from the modeling results of the C-Cube. At the present time, work is underway to remedy this problem and the results will be presented in a future article. In the meantime, it has been decided to present the L-Cube and, subsequently, the H-Cube designs.

The basic idea came from a short balanced dipole inductively loaded and with capacitive hats, filling the target WL/20 cubic space. This design is similar to the ANTAP, which is to be found in the third article of that series in this month’s issue of antenneX. The ANTAP is an antenna designed for used in tight places like apartments, etc.

So, now we have the C-Cube and the L-Cube, which basically takes up the same amount of space, except one acts like a dipole and the other like a loop! Looks like we have the right size for most needs and is now just a question of learning about the test results. The Dan and Re team are to be congratulated on their tireless efforts and apparent positive results on the Cube Family designs. Perhaps with the H-Cube also in the works, another “child” is on the way!

Claudio is not satisfied with just building antennas. He really enjoys analyzing and testing them too. During the past month, we introduced some new software by Claudio and his partner, Oscar Steila, IK1XPV, both of Italy. In case you missed the new product announcement, below is a copy:

*** Unique New Radio/Antenna Software Release ***

CIAOradio, or Computer Interface Audio Out Radio, is a program for using a Personal Computer equipped with a full duplex audio card as a demodulator receiver plus signal level analyzer for Radio Amateur application.

Before, few radio amateurs could afford access to the sophisticated and costly equipment needed to make these tests with reasonable precision now provided by this very affordable software:

With a Personal Computer running Windows, you can:
- digitally filter and demodulate signals from 0-24 kHz
- digitally filter, demodulate, measure and record signals in the HF range
- measure the gain of the antennas in Line of Sight mode or in Ionosferic mode, with an electronically switch driven from the PC's standard serial port.

This exciting new software is developed by Claudio Re, I1RFQ and Oscar Steila, IK1XPV of Italy and was introduced in their co-authored article published by antenneX in the December 2003 issue. The article is entitled: A New Digital World: The "CIAO Radio Project."

A link to the article, plus details about the software is provided in the URL below:
http://www.antennex.com/Sshack/ciaoradio/ciaoradio.html

antenneX is pleased to bring another great product to its shelves in the Shopping Shack. Be sure to check the main menu for more great stuff:
http://www.antennex.com/shopping.htm

ANTENNA DISCUSSION LIST
In my last couple of columns, I have chosen "A Likeable Thread" from our antenna discussion mail list. Moreover, I have always stated that it was my personal choice and not necessarily one other may choose as being "most likeable."

This past month's discussion activities have made it too difficult to make my usual choice, mainly because the discussions covered a very wide variety of subjects primarily about the basic aspects of antennas and its components. Not that they were simple subjects, but more about the application of the basics and how to use them in different ways. Following is a summary of some of the subjects covered in the 244 messages in January 2004 discussions:

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 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.

THE SPAM-VIRUS UPDATES
I have made a habit of passing along anything of interest regarding the Internet and e-mail services. In previous columns, I have discussed at great lengths the issue of SPAM and virus/worm emails as and when they appear as a new threat to our readership. By doing so, I feel antenneX can help make a difference in the war against those intruders. Hopefully, if we inform 60,000+ readers, and those readers tell two other people, that would be almost 300,000 people who would be armed with early information and help prevent the infection and further spread of these little devils. Since we run several mail servers, we see those intruders right from the start. By the time you hear it in the TV news, your computer may already be infected.

After a couple of months of relief from the Sobig virus attack, up jumped some new viruses this past month. As soon as we saw them in our computer logs, we tracked down the necessary background info from our sources and notified those on our announcement mail list. For those who may have missed that warning, here is a copy:

**** Dangerous Virri on the Prowl ****

This is a public service announcement by antenneX Online Magazine.

Over the past week, we have seen two more mass-mailing viruses, W32/Bagle and W32/Novarg, impact a significant number of home users and sites.

-- Systems Affected
Any system running Microsoft Windows (all versions from Windows 95 and up) and used for reading email or accessing peer-to-peer file sharing services.

-- Overview
In recent weeks there have been several mass-mailing viruses released on the Internet. It is important for users to understand the risks posed by these pieces of malicious code and the steps necessary to protect their systems from virus infection.

-- Description
The technology used in these viruses is not significantly different from prior mass-mailing viruses such as W32/Sobig and W32/Mimail. Unsolicited email messages containing attachments are sent to unsuspecting recipients. They may contain a return address, a provocative envelope, or something else that encourages its receiver to open it. This technique is called social engineering.

Because we are trusting and curious, social engineering is often effective. The widespread impact of these latest viruses, which rely on human intervention to help propagate the spread, demonstrates the effectiveness of social engineering.

-- Safe Look at the Actual Virus Example
Once again, we have dissected one of these dangerous little monsters and taken screenshots for examination for those who would like to see one.

If you are reading this, then you ARE involved and a target of this or some future flood of similar attacks. Knowledge is powerful. By informing the thousands on our mail lists will help to thwart and reduce the damage of similar attacks.

For a look at an example of one we call MyDoom, please go here:
http://download.antennex.com/lab/safe_mydoom.htm

We will continue this policy of disseminating information and dangers that we learn about via the Internet. —Jack L. Stone

FEEDBACK
By the way, I was a bit amused by one reader feedback to my virus alert above (who shall remain anonymous) that took me to task over the use of the term "social engineering." I thought I would also include that feedback message and my public response to it here today, just in case anyone else was scratching their heads over the use of that terminology because I may use it again in the future.

To my anonymous friend: Actually, I "borrowed" the term "social engineering" from one of our long-standing professional sources of research about this specific threat. Internet Security issues is their primary business. Presenting such issues using the proper terminology to present alerts is very important to them and their reputation. They are specialized engineers and careful wordsmiths in their own right, so I felt safe in repeating the term. Admittedly, I don't use the term every day but it seemed to fit this particular event. Thus, the term is most certainly used outside the confines of your employer, my anonymous friend.

Now, if I were to pick nits, these are not "email scams" either by definition. A scam is defined as:

As applied to the viruses in question here, it is not a business scheme or business swindle because the creator(s) want to hide their identity and thus, never receive any direct benefit from the propagation, except perhaps some sort of anti-social satisfaction. In other words, to deceive and knowingly gain at the expense of others. Whereas, an email virus is not unlike the activities of a terrorist who might employ the use of a deadly virus such as anthrax, etc. — to destroy.

I think we can agree on the main thing: Email virus attacks of any description are certainly annoying if not a bad thing!

Notes on the Batwing
Part 2: Uni-Directional & Omni-Directional Batwings
By L.B. Cebik, W4RNL

In Part 1 of this short series of notes on the batwing antenna, we examined the basic dipole-like properties of the antenna. We found it to have about 3 dB gain over a conventional dipole, along with a very wide bandwidth. The gain is a function of the compression of higher angle radiation due to the antenna's vertically symmetrical structure. The wide bandwidth results essentially from having very closely coupled dipoles of different lengths.

Lab Notes: The Litz Loop
By Joel C. Hungerford, KB1EGI

During the past three months Joel investigated the effect of changing the surface area of a magnetic loop, while holding all other parameters constant and investigated the effect of changing the circumference of one or more parallel connected loops without changing the planes or tuning capacitance. This month Joel continues the look at surface area this time using a “Litz wire” configuration -– a bundle of smaller enamel coated wires that add up to the desired surface area. This configuration is found to add a new parameter to the loop: the mutual inductance between the wires.

Transformer Magnetic Coupling & Matching
with One Variable: Part II
By Fred M. Griffee, N4FG (EE Retired)

In Fred's previous article, he included examples related to various areas of a toroid type transformer design. This month's article is a continuation and has become Part II. Some of the areas mentioned in Part I related to the coefficient of coupling being assumed to safely equal unity when using a bifilar winding. Some past measurements used in Part II indicated that the coefficient of coupling did not equal or approach unity too closely. These data are included showing predicted values for the coefficient of coupling.

THE "ANTAP" Apartment Antenna: Part III
By Claudio Re, I1RFQ

There is a big demand in the USA for an HF Apartment-sized Antenna that could continuously tune in the range of frequencies from 3-30 MHz. Local and regional regulations often prohibit the use of exterior antennas. Many of the dwellings are built with wood, which is a not a bad insulating material when dry. Many homes have in the highest part of the house as an apartment or an attic where Hams want to put their antennas. However attic apartment space is often limited. This article describes the development of an antenna suitable for this purposes called ANTAP (ANTenna for APartments).

A Half-Sloper, a Tower and RFI
By Tom Cox, KT9OM

This winter, Tom wanted to re-acquaint himself with life on the HF bands, especially on 160M, where he had had limited success in the past, due in part to the lack of a good antenna. Since he had the new tower to attach more things to, Tom decided to hang a half-sloper for 160M at the 80-foot level and see what developed. His new half-sloper was the unexpected cause of some consternation. While it worked well on 160M transmit, which is approximately what it's cut for, but it also works TOO well on the AM band, and there's the rub now that Tom must find a solution for an elusive problem in the realm of RFI so familiar to many.

Historical Overview
of the “Cube Family “of Antennas
By Claudio Re, I1RFQ and Dan Handelsman, N2DT

We have the C-Cube and this month the new L-Cube, which basically takes up the same amount of physical space, except one acts like a dipole and the other like a loop! Looks like we have the right size for most needs and just a question of learning more from the test results. The Dan and Re team are to be congratulated on their tireless efforts and apparent positive results on the Cube Family designs. Moreover, an H-Cube is being developed for its own uniqueness. Perhaps with the H-Cube also in the works, another “child” is on the way!

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. February 2004 antenneX Online Issue #82
reGARDS, Jack L. Stone, Publisher jack@antennex.com