DXERS UNLIMITED
MID-WEEK EDITION
TUESDAY, JUNE 19, 2001
By Arnie Coro CO2KK
Send your comments, questions and ideas to: arnie@radiohc.org
Hi amigos! You are listening to the mid-week edition of your favorite, listener oriented, radio hobby program, now available on the air, on our Dxers Unlimited website, and via our exclusive free e-mail distribution list! I am Arnie Coro, radio amateur CO2KK, your friend here in Havana and host of this twice-weekly program devoted to our wonderful, fascinating, hobby, yours and mine: RADIO!!!
 The Aurora Monitor software is available for download at http://www.spacew.com/aurora
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And now our headlines: G2 class geomagnetic storm sent the A index, geomagnetic disturbance indicator past the 30 units mark even at lower latitudes....BUT, the high-speed solar wind made those charged particles from the solar corona continue their path into outer space... something interesting, the solar wind's proton count early morning Tuesday was extremely low.... maybe an indication of the clean sweep done by the coronal mass ejection!!!
Headline number two: the number of sunspots
continues to be remarkably high for this phase of the solar cycle... more
than 220 sunspots average for the past several days! 
Headline number three: Tubepad 5.0, a freeware drawing program for making radio schematics is free, thanks to the courtesy of Gary Johanson, WD4NKA, long-time Dxers Unlimited's listener... Tubepad 5.0 works with the standard run of the mill PAINT program or any other similar software, and the schematics produced are really nice... Have paper and pencil or pen handy as I am going to tell you where to download Tubepad 5.0 radio and electronics drawing freeware...
Headline four: ART-ANTENNAS, yes amigos, the ART-ANTENNAS feature presented here at Dxers Unlimited's weekend edition, attracted a lot of attention from listeners all around the world... It seems like ART-ANTENNAS could become extremely popular among apartment building dwellers and others facing strict covenant and zoning law external antenna restrictions... More about ART-ANTENNAS later in today's edition of your favorite radio hobby program, the one and only providing YOU with the most up to date HF plus 50 megaHertz propagation updates and forecasts, and Arnie Coro's exclusive YOU HAVE QUESTIONS section... Stay tuned for more radio hobby related information coming to you from Havana... I'll be back with you in just a few seconds.
My wife Olga is a cultural promoter; she is also a gifted artist, so when I showed her the latest DUAL TETRAHEDRAL PYRAMID antenna for the upper end of the HF spectrum, I wasn't surprised when she said that this was truly a work of art! "Arnie," she said... "This antenna could be forming part of any modern arts museum collection!" Then, I showed her the DUAL CROSSED LOOPS ARRAY, another of my ART-ANTENNAS, and Olga was also very enthusiastic about its looks... but she said that it was not as pretty as the DUAL TETRAHEDRAL PYRAMID.... Then, I showed her the BIRDCAGE SPECIAL, the third ART-ANTENNA design, and she said that it could be fitted nicely near a water fountain, or in our own backyard! So amigos, after having the opportunity of discussing ART-ANTENNAS not from the radio engineering point of view, but from an artistic one, there is no doubt that many people could benefit from those three designs and the many more that may come in the near future when radio engineers and artists continue to work together searching for antennas that are efficient and at the same time can be disguised as a piece of art work!!!
I am now finishing the tests of the DUAL TETRAHEDRAL PYRAMID antenna, and here are some of the preliminary results... First of all, it is a free-standing antenna, needs no guy wires. It is broadbanded, and in the first test prototype, which is still in the works, I was able to work the 15 and 10 meter bands and compare results with a full-size horizontal dual-band dipole.... The DTP Stealth ART-ANTENNA performed very well -- so well, in fact, that I decided to run a similar comparative test on the ever-popular 20 meter or 14 megaHertz amateur band.... On 20 meters the DTP Stealth Antenna was about one full S unit or 6 dB down from the standard half-wave dipole, something to be expected.
But, as my good friend Professor Jose Amador, radio amateur CO2JA, likes to say, when your amateur radio signal at the other end of the QSO is running 20 dB over S9 due to good propagation, a minus 6 dB loss will still keep your signal at the other fellow's transceiver or receiver 14 dB above S9.... In other words, the DUAL TETRAHEDRAL PYRAMID has so far demonstrated that it can be used from 14 all the way up to 29.7 megaHertz, and that frequency range, amigos, includes no less than the following amateur radio HF bands: 20 meters, 17 meters, 15 meters, 12 meters and 10 meters...that's FIVE BANDS, plus the 27 megaHertz Citizens Band.... Then the antenna will provide reception of the 19, 16, 13 and 11 meters international shortwave broadcast bands too!!!
The DTP Stealth DUAL TETRAHEDRAL PYRAMID antenna can be easily built by someone with average mechanical abilities, and you can make it in such a way that it can be easily assembled and disassembled....The prototype DTP is made from several 3-meter, or about 10-feet long, lengths of 12 millimeters or half-inch aluminum or copper tubing, a center section to which they are attached, and three insulating support pods. The antenna is fed using 75 ohm coaxial cable, and you can add ground radials to increase its efficiency if you wish to do so, although they are not really required for regular everyday use.... The DTP prototype has so far handled the 100 watts output power of my HF transceiver very well, and as I said a while ago, tests on the 20, 15 and 10 meter bands have shown excellent performance in comparison with a standard tri-band half wave dipole....
The complete step by step building instructions for the DTP DUAL TETRAHEDRAL PYRAMID antenna will soon be made available here at our website for downloading, amigos! So soon you may be able to build your first ART-ANTENNA and enjoy our wonderful hobby without anyone realizing that the modern art sculpture in your garden or backyard is also a short wave antenna!!!
You are listening to the mid-week edition of Dxers Unlimited, coming to you from Havana.... our e-mail address is very easy to remember, send mail to arnie@radiohc.org, and if you happen to have any radio hobby-related question, feel free to send it to me, I'll answer back direct to you via e-mail and also on the air, as other Dxers Unlimited's listeners may want to learn from your question, too.
And here is today's question, sent in by a listener in Florida, USA:
Arnie, Florida is the thunderstorm capital of the world, according to a webpage I visited recently... I want to install a tower for my antennas, but I am really afraid of being struck by lightning! Any advice?
Well amigo, right now we are in the middle of the thunderstorm season, and this is a good opportunity to remind all listeners of the importance of disconnecting all radio and TV equipment from antennas, power lines and ground every time that you finish using them....That's the safest way to go, no doubt!!! Disconnect from the power lines, the antennas, and the ground system... As regards to a tall tower or mast, my advice is NOT TO INSTALL ONE, unless you can afford a professional ground system installation, and even then, at locations like Florida and the Caribbean, towers and masts should be kept as low-profile as possible. As a matter of fact, one of the safest approaches is to use a collapsible tower or telescopic mast that is kept at the lowest possible height when not in use... There are several easy-to-homebrew mast designs that are ideal for those locations... BUT, do remember that every mast or tower installed should be provided with an appropriate grounding system, something that may prove to be very expensive indeed!!! For most short wave bands applications. amigo from Florida, a mast or tower of no more than 20 meters or about 60 to 70 feet above the average terrain will provide you with excellent results when supporting a multi band beam antenna and holding the upper ends of slopers for different bands!!! And even at half that height, you will have a lot of fun working DX!!!
And now... http://www.qsl.net/wd4nka/ is the URL of the webpage kept by Gary Johanson, WD4NKA, where you can download the freeware Tube Pad 5.0 radio schematics drawing program amigos... I can tell you that it works great!!! As a matter of fact, my friend Gary developed it over almost two years, kindly sending to me each and every upgrade he has made to Tube Pad, which originally was a program to draw vacuum tube circuit schematics, but which later developed into a very complete library of electronic symbols, including beautiful -- I must say outstanding -- drawings of electronic parts, so that you can make your own pictorials of radio equipment. You have to use Tube Pad to realize how easy it is to go from the drawing board to an actual schematic diagram, like the one that I am including below ... One of the more popular REGENERODYNE receivers, the Super Squared 3 VHF Regenerodyne with Superregenerative Detector!
 The Super Squared 3 VHF Regenerodyne
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And now amigos, as always at the end of the show, here is Arnie Coro's Dxers Unlimited's not copyrighted, in the public domain, for the enjoyment of our radio hobby... HF plus 6 meters propagation update and forecast... Solar activity now seems to be stable, and possibly going down gradually after this rare upsurge in the number of sunspots that was so unexpected.
But let me tell you that Doppler measurements show there are very few sunspots on the other side of the SUN, the one we don't see from Earth, an indication that next week will bring in less activity. Due to the great number of sunpsots, solar flux has stayed at rather high figures, but the effects of this enhancement is only seen after local SUNSET in the Northern Hemisphere, where the nighttime Maximum Useable Frequencies have shown an increase of up to 30 and even 40 percent from those expected... Sporadic E openings have gone down in frequency, once again reminding scientists of the subtle interaction between higher solar activity and Sporadic E layer events... Best band for ham radio DXing nowadays is 15 meters, with 17 meters running a close second. For daytime short wave broadcast listening 13 and 16 meters offer the best reception, with 19 meters a close second for shorter paths...
See you at the weekend edition of the show, and don't forget to send your signal reports, comments QSL requests and radio hobby-related questions to arnie@radiohc.org or Via Air Mail to Arnie Coro, Radio Havana Cuba, Havana, Cuba...
Arnie Coro CO2KK
Havana, Cuba
June 19, 2001
Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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