The New Cube-C Antenna Arrives!By Jack L. Stone, Publisher
The New Cube-C Antenna Arrives!
By Jack L. Stone, Publisher
s I had mentioned in previous columns of recent
months, a very interesting new antenna device was in the works and we would be writing
about it as soon as it was tested. That time has finally arrived and perhaps we have
something special here.
We were aware of this project in progress by the developers for an efficient compact based
on conventional science. Several of our independent antenna experts have been observing
the developments and based on their belief that this one has very high promise, I am also
encouraged enough to announce it to our readers in 185 countries.
In this month’s issue of antenneX we reveal this new design for a compact
antenna developed jointly by Dan Handelsman, N2DT (USA) and Claudio Re, I1RFQ (Italy). It
is one of three compacts developed by this team and is a “Compact Cube” or
“Cube-C” as I believe it will be called. This first of three new compact
antennas by these co-developers is protected by the Patent Office therefore allowing us to
publicize the design.
Just how compact is it? As shown by the front cover this month, 50cmX50cmX50cm for 40
meters isn't bad! Doing the quick conversion, that's about 20 inches per side! Small
enough to carry through the doorway and up the stairs.
It is encouraging to hear that it is not based on any exotic theory or hype, but proven
antenna techniques. Most importantly, the design was not to be released until it had been
extensively tested and proven to perform as predicted. Depending on the size and frequency
of use, the gain is claimed to be anywhere from 5 to 20 dB higher than a compact loop's
according to the co-developers.
It certainly looks like a good compact prospect and material for experimenting. A number
of experiments are already under way and I hope we’ll hear about them. Our series of
articles about these new “Cube-type” antennas begin this month and will continue
over the next several months. There will be plenty of details provided about performance
and how to construct one for the band(s) of choice.
AN INVITATION TO CONTRIBUTORS
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
onward, 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. We must be doing something right. 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 reasoned views on the good to bad things that are happening in
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If you are uncertain about whether your ideas merit an article, please feel free to send
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ANTENNA DISCUSSION LIST
Since the new antenna-discussion list was established by antenneX a
couple of months ago, it has grown to more than 330 subscribers.
It is also a pleasure to see the variety of subjects covered from theory, involving high
math, to modeling, to antenna components, to projects under way and new concepts being
introduced. Indeed, the list is a great “watering hole” to get questions
answered expertly and to exchange ideas.
The list is so successful that the Forums have been very quiet as a result. It appears
that most prefer the new list method of communicating. As a consequence, we expect to cap
off the Forums and use the new list format entirely. However, there is an incredible
amount of valuable information that has been accumulated by the 26 Forums over the years
since early 1997. There are thousands of posts there for the reading. A very fast Search
function is available for quick location of a list of links to the messages that contain a
keyword of interest.
Thus, we intend to continue to make the Forum postings available for read-only and focus
on building the new antenna-discussion list for new active exchanges. We hope you will
make use of the facilities provided and enjoy the new services.
EASIER TO SUBSCRIBE TOO
The standard “out of the box” Majordomo mail list program that we use can be
difficult when a an open+confirm policy is used and a random key must be sent back to
confirm the subscription. The confirmation method is utilized primarily to help discourage
spammers trying to harvest the email addresses on mail lists. Like everyone else, the
spammer must send back a valid email address before the subscription is complete and
access is given to the list. Of course a valid email address means they could be
identified.
Within the past few days, a “patch” was located that modifies the program and
this patch now provides more robust handling for open+confirm un/subscription policies.
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This should be more secure than the old auth cookie method and easier for users. It also
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ONE MORE COUNTRY JOINED LAST MONTH!
Country number 185 just joined the listing of "Where in the World is antenneX?"
As is our custom, we welcome the latest newcomers and try to tell a little about the
countries, some of the history and any other things our research discovers that might be
of interest. The US CIA's World Factbook is most helpful in this research. A warm welcome
to these latest newcomers!
WELCOME ZAMBIA, COUNTRY #185
The
territory of Northern Rhodesia was administered by the South Africa Company from 1891
until it was taken over by the UK in 1923. During the 1920s and 1930s, advances in mining
spurred development and immigration. The name was changed to Zambia upon independence in
1964.
Air pollution and resulting acid rain in the mineral extraction and refining region;
chemical runoff into watersheds; poaching seriously threatens rhinoceros, elephant,
antelope, and large cat populations; deforestation; soil erosion; desertification; lack of
adequate water treatment presents human health risks.
The population is estimated to be just fewer than 10 million. Estimates for this country
explicitly take into account the effects of excess mortality due to AIDS; this can result
in lower life expectancy, higher infant mortality and death rates, lower population and
growth rates, and changes in the distribution of population by age and sex than would
otherwise be expected. Life expectancy is at about 37 years for both sexes.
Despite progress in privatization and budgetary reform, Zambia's economy has a long way to
go. Privatization of government-owned copper mines relieved the government from covering
mammoth losses generated by the industry and greatly improved the chances for copper
mining to return to profitability and spur economic growth. However, low mineral prices
have slowed the benefits from privatizing the mines and reduced incentives for further
private investment in the sector. In late 2000, Zambia was determined to be eligible for
debt relief under the Heavily Indebted Poor Countries (HIPC) initiative, but Zambia has
not yet finalized its Poverty Reduction Strategy paper. Unemployment rates averaging 50%
remain high, but GDP growth should continue at about 4%. Inflation should remain close to
a whopping 20%.
COMMUNICATIONS
Telephones - main lines in use: 130,000 (including more than 40,000 fixed telephones in
wireless local loop connections) (1997)
Telephones - mobile cellular: 75,000 (2001)
Telephone system: Facilities are aging but still among the best in Sub-Saharan Africa.
High-capacity microwave radio relay connects most larger towns and cities; several
cellular telephone services in operation; Internet service is widely available; very small
aperture terminal (VSAT) networks are operated by private firms.
Radio broadcast stations: AM 19, FM 5, short-wave 4 (2001)
Radios: 1.2 million (2001)
Television broadcast stations: 9 (2002)
Televisions: 277,000 (1997)
Internet country code: .zm
Internet Service Providers (ISPs): 5 (2001)
Internet users: 25,000 (2002)
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IN THIS ISSUE
This month is our 76th online issue! We again include many fine articles by our great writing team. Now, allow me now to introduce this month's line-up of content:
THE AUGUST 2003 ONLINE ISSUE NO. 76 CONTENTS:
OUR MONTHLY COLUMNS (plus this one by yours truly):
FEATURE ARTICLES IN THE LIBRARY:
Notes
on Reversible Yagi Arrays |
| The reversible wire Yagi array has been around for a long time. There are many ways to construct such arrays, including fancy switching systems in the wire elements, reflector and director loading stubs, and even reflector and director loading using lumped components. These techniques all use the minimum number of wires and electrically or electro- mechanically alter their electrical lengths within the array. We can either change directions using these methods or we can change the properties to peak performance within a given band. |
LAB NOTES: Multiband Antennas |
| Joel got a new perspective on the loaded dipole from this month's exercise. He had not realized that he could put multiple sets of coil/capacity hat combinations in parallel on the end of a dipole cut for the highest desired frequency. Previous experiments showed that a loading coil with a reactance above about 1500 ohms at the frequency set by the center wire section of the dipole blocked any effects of anything beyond the coil. This implied a large coil, which could be tuned over a wide frequency range with a small capacitor made by an extended wire end. It is a Tesla coil antenna! |
Antenna
Tuner and Filter Analysis |
| In many discussions concerning antenna system impedance matching or tuning, reference is made to low or highpass filter configurations. For the lowpass filter itself (or other type filters), it must always be terminated in its designed termination or else its overall characteristic will be far from the desired characteristic. Regarding the antenna tuner, it is recognized as an impedance matching network but also includes some filtering. The low or highpass filter configuration is addressed towards the antenna tuner since there have been many who feel a lowpass configuration is more desirable than a high pass configuration. It will be shown that it makes little difference whether the filter characteristic of an antenna tuner is of the low or highpass configuration when considering harmonic attenuation. In fact, as has been mentioned many times by many including myself, if a harmonic filter is needed, then it should be added to the impedance matching network or external to it at its input where the lowpass filter will be properly terminated at both input and output. |
THE
MICROVERT ANALYZED: Part 1 |
| After Claudio had investigated the performance of the SuperC antenna, he was asked to do the same with the MicroVert. The analysis is presented in two parts: In the first article, we shall investigate the use of modeling software to theoretically predict the performance of the MicroVert. In the second part, we shall discuss measurements of a MicroVert that was built and tested at 50 MHz in various conditions. |
Notes
on HF General Coverage LPDAs |
| The most popular range for LPDAs among radio amateurs is 14-30 MHz. Within that range, boom lengths of 30-35' hold considerable interest, since these booms are similar to the ones used for advanced multi-element, multi-band Yagis. In fact, it is quite possible to construct an LPDA with a 30' boom that provides better than 7 dBi free-space gain and better than 20 dB front-to-back ratio across all of the amateur bands included in the passband. |
The
Compact Cube |
| During the past year, Dan and Claudio have been engaged in designing and testing three different classes of compact antennas. Publication has been held back to satisfy two conditions: the first is testing the designs to make sure that they perform as predicted and the second is protection of the designs by patent filing. Dan has filed for US patents on two designs and Claudio is in the process of patenting his design. All three designs have been built and tested and the designers/authors are satisfied that they perform as expected. This is the beginning of a series of articles about these new cube designs. |
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. August
2003 antenneX Online Issue #76
reGARDS, Jack L. Stone, Publisher jack@antennex.com
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December 31, 2010