Existence: Man is the only animal for whom his own existenceis a problem which he has to solve.
—Erich Fromm (1900–1980), U.S. psychologist
Existence: Man is the only animal for whom his own existence
is a problem which he has to solve.
—Erich Fromm (1900–1980), U.S. psychologist
LF, VLF, and ELF
(But no LS MFT)
By Jack L. Stone, Publisher
s most new antenna work progresses upward in frequency to the microwave
regions, lower Frequencies fail to attract much interest. I am not here thinking of the
well used MF, HF, and VHF regions of the spectrum. These regions attract considerable
interest both to refine older technologies and to develop answer to changing needs. The
region that I have in mind is lower still: the regions called LF, VLF, and ELF. They
extend from less than 3 kHz through 300 kHz. As of 1990, international allocations had not
extended below 9 kHz.
However, these very long-wave regions of RF activity have been drawing increasing attention, some of it serious and some out of curiosity. A popular pastime has evolved in the detection of ELF signals, and some physics departments have devoted time, energy, and other resources to investigating these signals and their origins. What are we listening to and why does the signal have the particular properties that we experience. The raw curiosity that drives physics often leads to new and improved—and sometimes esoteric—understandings of the universe in which we live.
The lowest regions of the RF spectrum also interest the power industry. Low frequency alternating current power generation yields many phenomena that best appear in the lowest frequency ranges. Of course, we have the harmonics of the basic AC frequency (60 Hz in the US, 50 Hz in much of the rest of the world). These signals tend to be hindrances to most of the interesting potentials of the lowest frequencies, although monitoring the harmonic level can be an important diagnostic tool to discover faults in the system.
Now consider the very large collection of devices that go into power generation and transmission. The number of these devices—relays, insulators, etc.—increase as the power generation and transmission web becomes ever more tightly interlocked. For long transmission lines over remote terrain, there is only one basic diagnostic tool: visual inspection from low, slow aircraft by a trained observer.
However, the industry is discovering that many devices have characteristic emissions as they move from standard service to the verge of failure. Cracked insulators have emissions that appear on certain frequencies according to the maker's materials and typical failure modes. Many of these frequencies appear below 20 kHz. They show up in waterfall patterns that scan large sections of the spectrum in question.
The power industry is largely untrained in the techniques of RF reception in the lower frequency region. Most receivers are primitive direct conversion sets that translate audio into computer signal via a simple audio card. Therefore, most reception consists of signal detection at a given frequency, but with no information on the wave shape of the signal. Such information is highly useful in diagnosing signal problems at higher frequencies. But currently available equipment is not up to the task of wave shape analysis in this region. The problem is not the output tool, such as a relatively rudimentary oscilloscope. Rather, the problem lies in the region of filtering the desired signal and separating it from the mass of noise. One can easily create laboratory arrangements to achieve these ends, but the industry currently lacks a compact and portable instrument that can aid diagnostics during a fly-by or drive-by inspection.
More relevant to antenneX readers is the primitive state of antennas used to detect signals in the lowest frequency regions of the spectrum. Simple short whips and relatively small loops comprise the main antennas in current use. Waves are so long that we seldom get out of the near fields of their sources. Therefore, detection of either electrical or magnetic fields is possible.
What is the best antenna to use in conjunction with appropriate detection instruments for finding, recording, and analyzing diagnostically interesting signals from the lowest frequencies? antenneX contributors have both created and analyzed many interesting designs for very small antennas, but most of these antennas have been aimed at higher frequencies and the chief interest has been in the far field characteristics. At the very lowest frequencies, virtually any antenna except for the power grid itself is very short. And the chief interest of diagnosticians is the near field.
Antenna modeling software offers some utility in the expanded understanding of the ELF-LF region. It offers near field as well as far field analysis. However, it also has limits in terms of the shortest antenna or loop length that it can accurately analyze when we measure antenna length as a function of a wavelength.
Practical problems also abound. We are a long way from LF equivalents of FCC vans that bristle with antennas that can detect illegal and out-of-specification signals. Most experimental antennas that may offer improved reception may have to stick out car windows or rest in a sling below an inspection aircraft.
The entire field of ELF to LF antennas is open to new investigation and new
developments. Indeed, once we separate out all of the signals in which physics takes and
interest and all of the signals applicable to the power industry, there likely will be a
lot left over. Someone will want to know both what it is and why it is. What think you?
Coincidentally, our regular contributor, Claudio Re has covered the "other" side of the coin on the topic of receiving distant phenomena with his fine article contribution this month “In Search of the Schumann Resonances.” This screenshot shows the practical tests made by Claudio with the Marconi L Long Wire connected to ground, the passive RC filter, the amplifier and the Sound Card of the PC using the CIAORadio software.
For quite a while, antenneX has been distributing the
CIAORadio Software in most parts of the globe. Claudio and his partner that own and
operate CIAORadio in Italy have made continuous improvements to the software over time.
Just today, we have a brand new demo available for download at:
http://www.antennex.com/Sshack/ciaoradio/ciaoradio.html
Moreover, CIAORadio has been developing an interesting piece of hardware the "CIAORadio MultiMode Receiver Test Set" as shown in the photo below.It is to be used with the above software which drives the unit.
A sample unit of the above Test Set is winging its way from Italy to be tested by Dave Cuthbert who will review the performance of the unit and provide a review article of his findings. If all goes well, antenneX plans to distribute the unit as a companion to the software. We expect to produce the results in the next issue of antenneX for February 2006. So, keep an eye out for this one!
BTW: “LS MFT” in the title of this piece is the very old classic radio commercial acronym meaning “Lucky Strike Means Fine Tobacco” back when smoking cigarettes was more in vogue. (Sorry, I just couldn’t resist!) On the other hand, sadly, my own father’s life was cut short (59) from that very brand of addiction. I tried smoking once....but, didn't inhale.J
THE NEW PATENT SECTION
At the risk of being repetitive, I have mentioned the new patent section under
construction in the open access Guest Rooms. This new section is in addition to the many
other “rooms” or sections already full of useful content as listed further
below:
• Antenna Science • Preview Articles • Software Download • Antenna Modeling
• From the Shack • Propagation • Ham WorkShop • Stone's Throw! • Discussion Forums
• NEW Patent Section (Under Construction)
If you haven’t yet visited the Guest Rooms, it is a worthwhile visit:
http://www.antennex.com/guests.html
Alois Krischke, DJ0TR/OE8AK has taken on the huge job of building this new
section, seeding it with his own large private collection of patents spanning many years.
Since 1956 he is an active radio amateur with the callsign OE8AK and since 1968 also with DJ0TR. For many years he regularly made radio contacts using the special event callsign DL0DM from Deutsches Museum (German Museum). He is a member of the radio amateur team there and also of Förderverein Amateurfunkmuseum (Amateur Radio Museum). Alois has successfully taken part in "radio fox-hunting" activities (Amateur Radio Direction Finding) for many years and was Austrian, Bavarian and German Champion. He has published numerous publications on antennas, antenna novelties and antenna patents and also owns a big private collection of antenna patents, reaching from the first antenna patents of Edison (USA 1885), Marconi (England 1896) and Braun (Germany 1898) until the present time. He is continuing author of "Rothammels Antennenbuch" (Rothammel's Antenna Book) and was co-author of the book "Antennen-Lexikon" (Antenna Encyclopedia). |
THE 2-FOR-2 ANTENNA
Dave has done it
again! Over the years, one of our writers, Dave Cuthbert, WX7G has come up with some very
interesting designs for shrinking antennas that work. No black magic—they just work!
In this month Dave
describes his latest brainstorm. If you looking for a fun antenna project that you can
build inside the warmth of your home during a cold winter’s day, here it is: the
“2-for-2 Coffee Can Antenna.“ Why is it called the 2-for-2? Because it’s
made of two coffee cans and it’s for both the 2-meter and the 3/4-meter bands.
In just an hour or
two, you can build this unique antenna that not only performs well but is also quite the
conversation start, as described by the photo to the right.
If you want to have
some fun and the rewards of a working antenna, you are encouraged to read this article by
Dave. The first step is to remove the coffee from the cansJ
An NEC-2 modeling file accompanies the article to review and play with.
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 nine 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 logins are 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!
This list pertains to those sections with free access now in our new Guest Rooms we have built and fully operating:
• Antenna Science
• Preview Articles
• Software Download
• Antenna Modeling
• From the Shack
• Propagation
• Ham WorkShop
• Stone's Throw!
• Discussion Forums
• Patents (new room under construction)
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:
Get you login all setup now at this URL:
http://www.antennex.com/guests.html
We've really tried to make it easy while still fending off the bad guys, i.e., pirates!
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.
If you still need help or have questions about
our login areas, check this page first:
.....and, you can always get help here if you still have further
questions:
The new Antenna Discussion List is a infinite fountain of ideas making it a great "watering hole" for exchange of ideas, questions and answers on a wide range of antenna-related subjects. You will be in good company along with some of the brightest minds available. Were else would you have such free access to this level of expert advice? To participate or just read along on some very interesting subjects each month with 2000+ members from all around the globe, you are welcome to join us:
You are encouraged to contribute your thoughts on various subjects to a worldwide audience.
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 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.
To see details of our writing guidelines, please look at: Writing for antenneX
Subscribe for the Premium Feature Articles!
Enjoy these new concepts with our readership: Be sure your subscription is active so you don't miss these new and exciting concepts and more to follow. If you are thinking about subscribing or renewing, save 20% with a 2-year subscription. Just go to this URL and check on the Subscription option of your choice.
http://www.antennex.com/signup.htm
Keep the issues coming and stay on the leading edge of antenna technology!
~ BE SURE TO VISIT THE SHOPPING SHACK ~
Shipments worldwide ~ plus instant downloads
| Subscription | Books | Software | Antennas | Components |
IN THIS ISSUE
This month is our 105th issue online! We again include many fine articles by our great writing team. Now, allow me to introduce this month's line-up of content:
OUR MONTHLY COLUMNS (plus this one you are reading by yours truly):
FEATURE ARTICLES IN THE LIBRARY:
Wide-Band
40-Meter Yagis |
| In my Notes on Wide-Band Yagis, I discussed several 40-meter designs for full-band coverage (Volume 2, Chapter 7). Since the appearance of those notes, QEX has published an interesting new design by J. V. Evans, N3HBX. It promises (and delivers) the performance of a full-size wide-band 3-element Yagi in about 2/3 the boom length (31' vs. 45'). The key feature is the absence of a reflector element. Some years back, I noted in converting a 2-element pair of phased elements into a beam that a reflector was unnecessary, since the directors control both the gain and the front-to-back ratio. N3HBX provides further confirmation of this fact with his beam. |
(Antenna)
The Patent Section |
| Alois built up a big private collection of many thousands of antenna and antenna related patents at his home in Germany. This collection reaches from the first antenna patent (1885) up to the patents of the present time. Jack Stone plans to establish a spcial antenna-related Patent Section at antenneX in 2006 that will be located in the Guest Rooms. Alois is building this rather large new section to be opened soon. |
Triangular
& Rectangular Loop Wire Antenna |
| This Part III of this series of articles includes a revisit to the antenna design. The loop antennas described are of similar configuration as illustrated in Part I but will include different dimensions and a resonant frequency of 4.3 MHz. For some HF frequencies, it is shown that the loop antenna configurations will surpass the inverted vee (to be describe in Part IV) design. |
In
Search of the Schumann Resonances |
| For some months now, my interest has been captured to the challenge of receiving some “exotic” signals in the range of ELF – SLF – ULF – VLF frequencies. By connecting an antenna to a PC with a Sound Card and Software like CiaoRadio, it is possible to receive, analyze, and demodulate any ELF – SLF – ULF – VLF signal up to 24 kHz. These new tools make it easy to gain a better grasp over these interesting challenges. |
Broadband
by Balloon |
| To
aspiring Hams, location (QTH) is everything. Ideally, in order to get out into the wide
world one needs to live on the top of a hill, and also far from neighbours who might
invoke the local planning regulations to restrict the kind of antenna that can be
deployed. Similar problems afflict cell phone providers and WiFi Internet providers, who
are increasingly restricted by public antipathy towards transmitting masts. They too,
search for the high ground in life. On the other hand, those folk (hams or cellphone users or WiFi users) who happen to live in shaded valleys in hilly regions have severe problems in getting connected, unless they happen to be overlooked by a base station. No matter, there IS a solution to these problems. |
Two
for Coffee, or the 2-for-2 Antenna |
| Are
you looking for a fun antenna project that you can build inside of your warm home during a
cold winter’s day? Well here it is, the 2-for-2 Coffee Can Antenna. Why is it called
the 2-for-2? Because it’s made of two coffee cans and it’s for both the 2-meter
and the 3/4-meter bands. In just an hour or two, you can build this unique antenna that not only performs well but is also quite the conversation starter! |
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
January 2006 antenneX Online Issue #105
Send mail to webmaster@antennex.com
with questions or comments.
Copyright © 1988-2011 All rights reserved - antenneX©
Last modified:
December 31, 2010
Alois Krischke was born in Austria in
1936. During his studies at the Technical University of Vienna he was already specialized
on antennas. For many years he was active in the development of antennas and later in the
fields of radiomonitoring and radiolocation at Rohde & Schwarz in Munich until 1996
when he retired. 
