PROPAGATE THIS!

…and… Are You Losing Emails?
By Jack L. Stone, Publisher

st0402_t.jpg (1082 bytes)his month is a special month—it is our 60th issue of antenneX online—and five years of success and dynamic growth. Some 60,000 read antenneX each month now as we continue to grow with reasonable expectations that level will continue to grow and reach 100,000 by our tenth anniversary! Thank you, readers!

bio-marcel.jpg (30136 bytes)In celebration of this big anniversary, we wanted to make it a BIG issue. As a consequence, we have a lot in store for you this month. This is a bonus issue with 12 new articles rather than our usual 10.

NEW PROPAGATION COLUMN
One of those 12 fresh articles represents our launch of a brand new monthly column “Propagation” which begins this month and is written by our newest writing team member, Marcel H. De Canck, ON5AU of Belgium. Signal propagation is a subject that is one of the most basic ingredients of radio and is something everyone in radio should know about in order to maximize communications in the most effective way. It’s not enough to have the best equipment and the best antenna if you are trying to send out a signal against a brick wall. Conversely, one may possess a very crude rig, running low power, but yet transmit/receive a signal to great distances with ease, simply by making use of a thorough knowledge about how signal propagation works within the environment.

Marcel’s presentation on this subject is excellent. The articles are well presented with good content and he explains things with clarity. We are very pleased to add this column as it now covers another yet another important subject to help round out the content of our magazine that is focused on the very subject of signals, since that is one of the primary functions of the antenna and antenna-related system. We think you will enjoy this new monthly column by Marcel—another dimension and another reader service by antenneX!


WAVE POCKETS INVESTIGATED
The subject of propagation is quite timely considering the stir created by the article last month by Dr. Fathi Kabbary about his findings on a phenomenon called “wave pockets” observed from signal measurements of the MW mast antennas in Egypt and monitored over more than two years. That article was entitled “Daytime Wave Pockets Medium Wave Mast Antennas” and appeared in our March 2002, issue of antenneX.

One of our writers and members of the GARDS, Ralph Holland, VK1BRH of Australia has spent the past month on a exhaustive study of Dr. Kabbary’s findings. Ralph, who is very capable technically, did quite an impressive study that includes an in-depth review to analyze and attempt to determine the reason for such wave pockets, a similar phenomenon that has been observed and written about as far back as the 1950s. Further, Ralph discovered that some of his broadcast colleagues in Australia had observed wave pockets, but as with others, the reason wasn’t pursued.

An intense investigation was made into the Kabbary findings to see what might be the cause, interference by surrounding objects, the terrain, ground wave, sky wave, water table, the Nile delta, and so forth. Also, some of this may explain why some Egyptian CFAs are supposed to be working while nowhere else. It has not gone unnoticed that the site conditions are critical for a CFA installation.

Take a good look at the great job Ralph did, and afterwards, no doubt you also will wonder with a desire to know more about wave pockets. The more we know about propagation, the better we understand signal behavior and the antenna's ability to deal with it. Other members of the GARDS cooperated in this effort as well including a great map drawn by Håkan Widenstedt of Sweden with careful plots of Dr. Kabbary's measurements along the road from Tanta. Yes, there will be more to come on this subject to reach a better understanding of this propagation phenomenon. Computer simulations are planned and more physical measurements to see if we can duplicate the wave pockets at different parts of the globe. Those additional findings will be reported here as well as any more follow-up reports by Dr. Kabbary, who continues to monitor the signals in Egypt.

Click here to read Ralph’s article


ISLE OF MAN CFA VIEW REVEALED
On February 13, 2002, we received a message from Paul Rusling, CEO of Isle of Man International Broadcasting, plc along with a News Release about the granting of the much sought-after license to broadcast at Isle of Man. I announced this in my column for March 2002.

Then, on March 29, 2002, I received the following new announcement from Paul Rusling about his IoM MusicMann279 Long Wave radio station planned for placement offshore near Isle of Man  (original European spelling retained).

"We had our nicest possible Valentine's gift in mid February from the Communications Commission - our Full Broadcast License. We are now engaged in the hard work of finalizing our financial requirements prior to the final negotiations of the terms and conditions for the major funding.   It's comforting that there are more willing funders than we need investment and that investors share our view -  that the advertising markets are coming out of a deep trough and that there will be a big market for our station.

We've spent quite some time recently looking very closely at our requirements for the offshore platform where the transmission facility will be housed. Our naval architects, Burness Corlett, have come up with a superb design which will look quite spectacular close up, although the use of grey-blue coatings will tend to make the structure blend into the surrounding seascape (and, on many days, the sea fret).

iom_cfa.jpg (5233 bytes)The octagonal structure is bound to become quite an attraction, however its location four kilometres offshore at the northern end of Ramsey Bay will mandate use of binoculars or a telescope to get a good look at it as it will be about 9 kilometres from Ramsey harbour. While the closest land is high cliffs, it is privately owned and there is no way for the public to get really close for a good look; even walking several miles of the coastal footpath along the beach will not be very helpful as visibility over a flat surface needs elevation either at the subject or the receptor. The best views are likely to be at low water.

As so many people do wish to come and take a look at the platform, we are helping several boat owners organise trips to look at the platform. These will depart from Ramsey and we shall give fuller details on the web site when details have been agreed.  The Douglas to Belfast sailings operated by the Steam Packet company will pass approximately a mile inland of the platform while Heysham to Belfast sailings will usually pass about two miles to seaward of it.

To whet your appetite, here is an artist's impression of the platform which should give you some idea of how slender and elegant it will look. At high water, the sea will (usually) be at a level below the small platform on the fore leg. At low water, around half of the legs will still be beneath the waves.

 Easter is a time when we Christians look for a new beginning; the Resurrection. That is indicative of what we hope our new radio station will bring. Not just for the Isle of Man, which will get a new voice heard far and wide to publicize its excellent facilities and natural beauty, but a fresh new feel to radio that will help invigorate other radio stations too. It was Easter 1964 when Radio Caroline first broadcast to the British Isles and that historic weekend certainly shook up radio in these islands. This is a time when the days are at last longer than the nights, and we are all looking forward to a better world, a better life and some great times. We hope you will enjoy them with us. — Paul Rusling, Founder"

In a further discussion today (April 1, 2002) with Paul, he stated:

I stress that it isn't the absolute final design, but the one we are currently working on. It's octagonal in shape, and has three two internal decks (storage, generators, transmitters). It is built to the same construction and use regulations as apply in the offshore energy exploration and production industry, is to be classified by Lloyds of London, but follows ABS (American Bureau of Shipping) 'designs' and rules. - Paul


THE RUSSIAN WOODPECKER
During this past month, I received a picture of the “Russian Woodpecker Antenna”. It was obtained by our writer from Russia, Igor Grigorov, RK3ZK and he wished to share it with us. Some of you may be familiar with this antenna which was used as jammer….

woodpeck.jpg (42600 bytes)

Richard Morrow, K5CNF, who has operated for over 40 years, tells me he remembers the Woodpecker and this is how he described it:

The over the horizon radar (OTR) that many hams had to endure for years was used to track aircraft over the horizon at great ranges, often thousands of miles away.

It was characterized by a pulsed type of signal that sounded like a single cylinder engine at a low idle speed. Because of this it was called the Russian Woodpecker. It was often found on the 14-MHz band and when it was there it tore up communications, jamming all of the normal ham communications beyond belief. But after a while the hams found out that if you sent a string of dits at the same repetition rate of the transmitted signal coming from the OTR for a minute or so, the operators would have to shift frequency. In this case we jammed them!
No one ever got in trouble for doing this I might add. Many times this signal could be moved completely out of the ham bands by this method. The many signals that showed up to do this would render the radar useless as the weak reflected signals from the radar targets would be totally obliterated by the much more powerful ham transmissions. On occasion it would show up as low as the 40 meter band in the winter, but for the most part, the operators kept it in the higher frequency ranges above 12 MHz. The output power from this radar must have been in the megawatt range and covered anywhere from 100 kHz to half a Megahertz bandwidth at times.

It was a total nuisance as it jammed any communications that were unfortunate enough to be in the signal covered by the radar. Impulse type noise limiters were not much use against it as it managed to overpower them and cause ringing in the IF strips of some rigs. It was an extremely powerful signal if the antenna was pointed in your direction. The antenna pattern was capable of being aimed in many directions, but even if the major lobe was aimed away from you, propagation would often cause the signal to show up on your doorstep via long path propagation. The receivers were not at the same location from all indications.

The USA also had these radars, and they were moderately successful from all indications, but the true story on this is still classified. The Woodpecker is gone now and that is one thing not missed by most.


ARE YOU LOSING EMAILS?
A few of days ago, I sent out an alert to the antenneX announcement list about a new trend I had noticed within the past month or so. I thought I should let our readers know about it because some folks may be losing important emails and not be aware of it. Within the past month or so, following a broadcast mailing to  the several thousand on our announcement list, I noticed a substantial surge in a certain type of bounced emails. The bounces were returned from the intended recipient’s mail server with the error message that the email could not be delivered because user has exceeded quota.

Now, it's a fact we always get bounces and that is to be expected, but for the usual reasons of bad or stale addresses because we weren’t notified of a change, or the user’s mail server was temporarily down, etc. However, up until a couple of months ago, I don’t recall receiving any bounces for the “over quota” problem out of several thousand on our list. Certainly not enough to notice as being a problem. Now, with each send to our list, the percentage has grown in quantum jumps. We usually only send one or two announcements per month. Because we don’t send announcements very often, we figured by the next send, the trend would have reversed itself and returned to normal. Instead the trend had worsened!

At first, even though the quantity of bounces attributed to the “over quota” problem had jumped, it didn’t trouble me because our message for an announcement certainly wasn’t of “life or death” importance. I further surmised that this was only a temporary glitch and even if the user had allowed the email box to overfill, the next time we sent out a message, it would most likely go through. But, when we sent out a second and a third announcement over the past month, the surge of these type of bounces didn’t decrease—they increased with each mailing. This indicated that something must have changed in the way ISPs were administrating their email system—after all, it was unlikely that so many recipients on our list of readers had just suddenly changed habits all at the same time in the way they downloaded and read their mails. So, this caught my attention enough to want to investigate further. Since I administrate some mail servers myself, I had a pretty good idea where to look and I also understand about quotas and the way emails are processed over the Internet and through the servers.

INQUIRING MINDS WANT TO KNOW
I wanted to find a possible correlation for this sudden surge in “over quota” email bounces. It wasn’t that I needed to do so for any other particular reason than I felt compelled to let alert our readers to this issue because it was obvious that emails were being rejected outright and I suspected that those recipients didn’t know they might be losing valuable emails into the ether—forever! Besides, only a very small percentage of the total emails bounce for any reason and thus, most get through to the intended recipient. But, on the other hand, several hundred of our list may or may not know their emails are being rejected and lost for the unexplained quota problem. While our announcements may not be of great importance, other email may be. As examples, here are examples of those bounce errors typically received from the ISP servers:

One example (most often-too bad)
=================================================
“I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

Disk Quota Exceeded.
Sorry, your message cannot be delivered because the recipient has
exceeded their disk space limit for email.”
=================================================

Another example (pretty short-too bad)
=================================================
Sorry, your message to auser@xxxxx cannot be delivered.
This account is over quota. (ED: real username edited out)
=================================================

Another example (longer and nicer at least-but contact how?)
=================================================
One or more of the recipients of your message did not receive it
because they would have exceeded their mailbox size limit.  It
may be possible for you to successfully send your message again
at a later time; however, if it is large, it is recommended that
you first contact the recipients to confirm that the space will be
available for your message when you send it.

User quota exceeded: SMTP
=================================================

Another example (The sender is supposed to fix it-not ISP-HOW?)
=================================================
This e-mail message was undeliverable due to the
following reason:

.net 012: The recipient(s) account is temporarily over quota.

Solution:
1. Contact the recipient by alternate means to inform them that their
mailbox is full.
2. Ask the recipient to pop/delete their e-mail before additional e-mail
can be received.
=================================================

A POSSIBLE REASON FOR SUDDEN QUOTA REJECTIONS
Before sending out my recent alert to the list, I had received a hint as to the possible cause from a few of the fellows that had bounced because of quota rejection. In each case, they had noticed that the amount of spam (unsolicited emails) received had jumped by a huge factor of as much as 10-15 times the ordinary rate. Thus, instead of receiving 10 spams, their box was filled with more than 100!! Ahah! A direction to look!

It didn’t take long to track down a good reason for what may have caused the surge of over-filled mailboxes. It was related to the “blackhole” system that had changed. Most ISPs (Internet Service Providers) subscribe to a “blackhole” service which is a company that specializes in maintaining a “blacklist” of known spammers and/or networks that have open mail server relays that enables spammers to sneak through with their thousands or millions of spam messages. These blacklist companies continually track down these offending spam outlets and add the domains to the blacklist. The ISPs subscribe to this service because it’s less expensive and easier to subscribe to the service than every ISP doing this for themselves. I do not know the price of a subscription to the service, but understand it's not cheap and beyond the reach of some of the smaller ISPs on tight budgets.

It seems things were working out pretty well with the subscription method, until the economic downturn and the blacklist subscription rates increased to a point that some ISPs just could no longer afford to subscribe. Unfortunately, the problem of spam didn’t go away though and the loss of this valuable tool opened the floodgates for spam through those smaller ISPs who did not have an alternative method or a list to block and/or filter the offending domains.

BUT BATTLE CREEK MAKES IT WORSE
To make matters worse, the City of Battle Creek, Michigan, USA managed to cause a shutdown of one of these important services because they didn’t understand the business of ORBZ, an important blacklist used by many ISPs throughout the country and perhaps around the globe.

ORBZ is one of many blacklist organizations on the Internet today: a controversial, though legal, method of blocking open relay servers that route spam and unsolicited commercial e-mails (UCE). By publishing a list of known IP addresses using open relays Internet service providers (ISPs) are able to block e-mails from that domain to its customers.

But, according to Internet Business and ISP News reports of March 20 and 22, 2002 through the Internet Business News – and ISP News and excerpts taken from those reports written by Jim Wagner says (see links below to articles) an information systems “expert” and a local “detective” in the City of Battle Creek, Michigan, USA were responsible for convincing a judge to issue a search warrant and seek to seize ORBZ's business documentation. Instead of simply calling up the owner of the blacklist company to ask what they did, these “experts” for the City just assumed ORBZ was conducting some sort of illegal business—a purely snap judgment with unfortunate consequences to numerous ISPs and untold millions of email users!

Well, owner Ian Gulliver’s reaction to the legal action was that of defiance—he was not about to release such delicate information to the public domain. So, on March 20, 2002, and fearing jail time, Gulliver pulled the plug on his business instead and moved his valuable blacklist out of reach from prying eyes. In an e-mail notice to members of his open relay blackhole zone (ORBZ) discussion list, Ian Gulliver told his flock he was shutting down immediately rather than turn over documents to the 10th Judicial District Court in Michigan.

Then on March 22, the City of Battle Creek found out they made a mistake… but, too late, the damage was done!

Forbes Mercy, owner of NWInfo.Net, an ISP in Yakima, Wash., was one of many people around the U.S. who fired off an angry letter to city officials for shutting down a service that kept spam, porn and e-mail viruses off computers.

The fact the courts are dropping charges means nothing, he said in his e-mail addressed to the city's mayor, attorney general and IT specialist, if it means ORBZ doesn't come back online.

"In one step your city has grid-locked the entire Internet, as all the servers that subscribe to ORBZ are now rejecting nearly all mail," he said in an e-mail sent Thursday evening. "...your city IT person can brag that he gave you such bad advice that he caused you both negative national attention for his incompetence in not recognizing the good service ORBZ gave to the rest of the world."

"As a city manager you can now say "I upheld the rights of citizens to be excessively spammed and receive pornography," he added.

"How hard is it to call the guy and question him before forcing him to shut down?" one member queried. "It could've been blown over with a 20 minute phone call, now it's probably too late (for ORBZ)."

The whole stories are found at:
http://www.internetnews.com/bus-news/article/0,,3_995251,00.html
http://www.internetnews.com/isp-news/article/0,,8_996341,00.html

The above shutdown of a major blackhole operator has resulted in opening the floodgates of spam even wider—and it’s now filling up your mailboxes at a much faster rate—without notice most likely. Since I haven’t peered into each and every email box situation, I cannot say with absolute certainty that the above has caused the sudden jump in “over quota” bounces, but the evidence is pretty strong and I strongly suggest that everyone takes some preventative measures to reduce the chances of losing emails from the over-quota syndrome no matter what the reason—that is if you care about your emails. As you can see from the above bounce messages, the ISPs are not going to worry too much about your rejected emails.

The events of my findings above seems to be overwhelming evidence behind this recent sudden surge in “over quota” bounces. Suspecting that many of our readers were not aware of the current state of the email system, I sent out the alert about ISPs rejecting emails. Based on the many replies I have received, with the exception of one, the readers did not know they might be losing emails, or that they were over quota—or even had a quota.

WHAT CAN YOU DO TO PROTECT YOUR EMAILS?
Now what can you do to avoid being over quota? Well, there are several things you should consider doing. First, what IS your email quota…? Did you know you had one? Of course you do—there are limits to everything, but I doubt that many know what it is. Is it based on a quantity of messages? Or is it the set to a byte size limit? These can vary widely from small sizes to several megabytes depending on your ISP’s policy. I imagine when you signed up for the email account the agreement mentioned your quota (probably somewhere in the fine print). But, again with all due respect to the ISPs, there must be limits—it’s just unfortunate they have not all established a better method of notifying the user when the quota is hit, which could be at any moment within a 24-hour period—even while you sleep!

Finding out what your quota limit is would be a good first step, then HOW to manage your emails within that limit is the next problem to solve, made even more critical with the event of a recent increase in spam. Control is definately within the user's control—bascially a simple matter of checking your emails more often and cleaning out the box to make more room for new emails.

e_account.jpg (32657 bytes)Consider these steps:

To the right is a screenshot of MS Outlook’s settings for emails found in \Tools\Accounts\Advanced tab. The red arrow is pointing to a check box. If the box is unchecked, emails will download and delete. If the box is checked, it will leave the mail on the server for the number of days you designate.

Eudora has settings in the “Options” menus for this too and I imagine other brands of email clients do too, but I only use Outlook and Eudora for a Windows workstation.

As some have said, they travel all week and cannot check the emails during a week at a stretch. Regardless of this reason, those folks are running a high risk of losing emails especially during this period of unbridled spamming. More precautions should be taken in such case, perhaps having some one else download the emails during an absence, or forwarding the emails, or using another computer at your travel destination if possible, ....or???.

HELP YOUR ISP FIGHT SPAM AND HACKERS
Now, with all of the above said, I don’t want to give any sort of impression to suggest the ISPs are the culprits. Quite the contrary, I don’t know of any “bad” ISPs and they do indeed make it possible for us all to communicate in a way that would otherwise not be nearly as efficient. We would have a difficult time publishing articles written by our writers that are spread over more than 22 countries. Thanks to the ISPs for email and email attachments! (oh,oh, watch out for those attachements—they really fill up the mailbox fast) No, I’m simply describing what I suspect is probably a temporary problem and then things are likely return to normal. How soon is the question. In the meantime, perhaps I have shed a little more light on this business of the Internet that is somewhat mysterious to many (not all of course)—and, as another beneficial result, perhaps we’ve helped the ISPs by notifying and explaining to a few of their subscribers to clean out those email boxes more often—and how to better manage emails while minimizing possible losses!

The ISPs are literally at war with spammers, malicious hackers, viruses, worms and the like. It's a never-ending battle after battle and I for one, do not envy them their job in this respect. I hasten to add, there are some really smart computer engineers/technicians running these systems. The intruders keep devising ways to attack and the ISP must keep coming up with counter-defenses. Quite frankly, aside from filling up the mailboxes, I'm more concerned about the malicious hackers, viruses and worms as they are more destructive. With spam, it may be annoying, but at least you can punch the delete button or set up filters of your own on your emails clients. So, let's help the ISPs and ourselves at the same time by better managing our mailboxes so the ISPs have more time to fight the really bad guys!


ANOTHER COUNTRY JOINED LAST MONTH!
Country number 179 just joined the listing of "Where in the World is antenneX?" As is our custom, we welcome the latest newcomer and try to tell a little about the country, some of the history and any other things our research discovers that might be of interest. A warm welcome to this latest newcomer!


WELCOME MALAWI, COUNTRY #179
malawi.jpg (14305 bytes)Malawi is located in Southern Africa, east of Zambia at 13 30 S, 34 00 E and contains an area of 118,000 sq km. It borders on Mozambique, Tanzania and Zambia.

It was established in 1891 as the British protectorate of Nyasaland which became the independent nation of Malawi in 1964. After three decades of one-party rule, the country held multiparty elections in 1994 under a provisional constitution, which took full effect the following year. National multiparty elections were held again in 1999.

Ethnic groups are made up of Chewa, Nyanja, Tumbuko, Yao, Lomwe, Sena, Tonga, Ngoni, Ngonde, Asian, European with English and Chichewa as the official languages.

Malawi has a population of just over 10.5 million and (ouch!) life expectancy is only about 37 years! Malawi is landlocked and ranks among the world's least developed countries. The economy is predominately agricultural, with about 90% of the population living in rural areas. Agriculture accounts for 37% of GDP and 85% of export revenues. The economy depends on substantial inflows of economic assistance from the IMF, the World Bank, and individual donor nations. In late 2000, Malawi was approved for relief under the Heavily Indebted Poor Countries (HIPC) program. The government faces strong challenges, e.g., to fully develop a market economy, to improve educational facilities, to face up to environmental problems, and to deal with the rapidly growing problem of HIV/AIDS. More than half live below the poverty line.

COMMUNICATIONS:
Telephones - main lines in use: 37,000
Telephones - mobile cellular: 7,000
Radio broadcast stations: AM 9, FM 4 (plus 15 repeater stations), short-wave 3
Radios: 2.6 million
Television broadcast stations: 1
Televisions: ZERO!
Internet Service Providers (ISPs): 8 as of year 2001
Internet users: 10,000 as of year 2000


NOW WHAT'S THE ISSUE?
This month is our 60th online issue! We again include many fine articles by our great writing team. Allow me now to introduce this month's line-up of content:


THE APRIL 2002 ONLINE ISSUE NO. 60 CONTENTS:

OUR MONTHLY COLUMNS (plus this one by yours truly):

FEATURE ARTICLES IN THE LIBRARY:

An 80-Meter LPMA: A Design Idea and a Modeling Dilemma
Part 1. Designing the LPMA with a MININEC Ground

By: L.B. Cebik, W4RNL

Although many amateurs are familiar with the log periodic dipole array (LPDA), fewer are familiar with the log periodic monopole array (LPMA). The LPMA has been around almost as long as its bigger brother, but not many amateur applications have emerged from the basic design. These notes will focus on a 3.5-4.0 MHz limited passband LPMA in a design exercise that will highlight some of the main electrical and physical characteristics of the antenna type. As well, we shall look at some of the stumbling blocks to the design of an LPMA that might actually be implemented with confidence.

LAB NOTES: The Panadapter
By Joel C. Hungerford, KB1EGI

Joel found a real treasure at a HamFest last month—an old W.W.II “panadapter”! The panadapter is the precursor of all the fancy spectrum analyzers used today in the HF and microwave bands, and is a very different animal from the DSP spectrum analyzers used to tune psk and similar audio signals. A panadapter is the short name for a panoramic receiver. It is used with a communication receiver and is connected to the receiver’s IF amplifier. It has a little oscilloscope as an output display, which shows all the signals in a small frequency region above and below the frequency that the receiver is tuned to. It was used to help locate signals that are either mis-tuned, or deliberately trying to avoid being heard. Joel puts this old instrument through its traces this month as he analyses its many unique features.

QRP Expedition Above the Clouds - Part 3
By Igor Grigorov, RK3ZK

The UR-QRP Club is made up of members from Russia and the Ukraine. The idea to go to Ancient Crimea for a QRP-expedition has been considered by the members of this QRP-club for quite some time. Finally in May of 2001, the QRP-expedition became a reality. They set other things aside, collected their backpacks, stuffed them with QRP gear and other tourist gear into them and left for the Crimean mountains. This expedition gave them a good chance to visit with the other members of the QRP club, visit ancient places in Crimea and to go to the beautiful, but rugged AI-Petri Mountain in the locale. This is the third part in a series of articles by Igor about this exciting QRP-expedition we originally announced in May 2001. This is an interesting story whether you are planning a QRP-expedition or not.

PLATE DIPOLES AND PRISMATICS
By Dan Handelsman and David Jefferies

A plate dipole is similar to a rod dipole, with the rods replaced by plane sheets of metal, which can be of any shape, but in this example they are assumed to be rectangular, with a small spacing between the parallel edges. Dan's new Prismatic P2 is like a rectangular plate dipole with the inside missing, so that the P2 is delineated by wires of appropriate thickness running along the perimeter of the plate dipole. The spacing and thickness of the wires in the parallel edges of a P2 are carefully chosen to form a transmission line of the necessary characteristic impedance.

A Ready-Use Portable Antenna
By Richard Morrow, K5CNF

While prowling one of the local Radio Shack stores Richard noticed a package labeled as a portable short wave listening antenna (RS 278-1374). Examining the label I saw that it had a length of 23 feet was on a small plastic reel. Immediately I began to see the possibilities of using this antenna for portable QRP operations, so I bought two of them to convert and use them with his SW radios. Check out another clever idea of Richard's that is inexpensive, but very effective.

A Water Resistant Enclosure for the LDG Z11 QRP Tuner
By Richard Morrow, K5CNF

After purchasing the LDG AT-11 auto tuner Richard began to think about using it for portable with his SGC-2020. After a lengthy and detailed analysis he finally decided to spend some more money and order the Z-11 QRP auto tuner. Since Richard anticipated emergency operations in case of a hurricane and other disasters which visit the Corpus Christi, Texas USA area where commercial power failure is a fact of life, I was interested in long battery life and a way to best protect the equipment from the fierce elements during such a a disaster. In this article, Richard explains his solution to both.

 MultiNEC Antenna Modeling Software - A Review
By Dan Handelsman, N2DT

Recently, Dan Maguire, AC6LA asked Dan Handelsman to try out MultiNEC, a program he developed to allow users to "program by variable" with NEC programs that do not allow that feature. In helping to beta test it, Dan found that it had a host of useful features that would enable beginners to work with NEC more easily and would enable "experts" to extract useful information at a glance. Dan concludes that, in its present form, it is an outstanding program! Moreover, Dan is an extremely helpful and cooperative guy who will do anything to add to its features-if feasible. It is FAST AND EASY TO USE!  And - It's FREE!
 

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. April 2002 antenneX Online Issue #60
reGARDS, Jack L. Stone, Publisher
jack@antennex.com


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