RADIO HABANA CUBA
DXERS UNLIMITED
WEEKEND EDITION
SATURDAY, JULY 7, 2001
By Arnie Coro CO2KKSend your comments, questions and ideas to: arnie@radiohc.org
Hi, amigos! Welcome to the weekend edition of Dxers Unlimited, coming to you from Havana. I am Arnie Coro, radio amateur CO2KK, and here are our headlines for today:
TRANSATLANTIC signals on the 50 megaHertz, the 6 meter band, was mother nature's weekend present for radio amateurs... Many reports of two-way ham contacts on 50 megaHertz from the Caribbean to Europe Saturday morning.
TRANSPACIFIC signals, spanning more than eleven thousand kilometers, but this time at the other end of the radio spectrum, long waves, also made headlines this week, when several New Zealand radio amateurs testing on the low frequency band from 130 to 190 Kilohertz had the thrill of their lifetimes when they received via INTERNET e-mail signal reports from Canada... And here we see again the INTERNET not interfering or stopping amateur radio, but actually helping to promote this wonderful hobby, amigos!!!
Our third headline for today, an e-mail received from NA5N, my good friend and homebrew equipment guru, telling Dxers Unlimited's listeners that there is an upgrade for Paul's famous Desert Rat solid state easy-to-build regenerative receiver, and he adds that this one comes with full construction details for the tuning coils, something that is going to help newcomers to enjoy this wonderful circuit a lot more. I can describe it as wonderful, as I have already built three of them here, one for me, and two for the younger generation of future radio amateurs here in my neighborhood. And by the way... the Desert Rat solid state regenerative receiver must be an ideal tail end for a REGENERODYNE, too!!!
I will answer several listener's questions and at the end of the show, as always, our exclusive and not copyrighted, in the public domain HF plus 6 meter propagation update and forecast will tell you about the most recent bottoming of solar activity during this solar rotation.
Stay tuned for more radio hobby related information coming to you from Havana... My sound engineer and producer is Jose Costa Pupo at studio 6, I am Arnie Coro, back with you in a few seconds...
Saturday morning those monitoring the 6 meter band for the typical run-of-the-mill summertime single hop sporadic E contact were rewarded by TRASATLANTIC signals via multiple hop or perhaps whispering gallery type 50 megaHertz propagation. Hams in Puerto Rico worked lots of Europeans!!!! There is great interest among scientists concerning the way 6 meter band signals span the Atlantic Ocean via sporadic E, and two theories are trying to explain this long range propagation... One calls for multiple reflections up and down from several properly located Sporadic E highly ionized clouds, while the other theory says that tilted Sporadic E clouds at both ends of the path allow a very low-loss transmission of signals within the ionosphere, without it bouncing back and forth from the upper atmosphere to the sea surface and back up and down again several times.
My own theoretical research paper published in 1966, and still considered one of the landmarks regarding Sporadic E layer propagation, described the more than three hops paths as practically impossible with the radio frequency energy provided by the typical amateur radio equipment's power output, which very rarely exceeds 10 kilowatts of effective radiated power, that is the transmitter power, minus the feedline loss, plus the antenna gain... See, a one kilowatt input ham 6 meter band rig may generate about 700 watts of radio frequency output, you may subtract about 50 watts of line loss for a typical run to the tower and antenna, then add something like 10 decibels if you use a really nice long Yagi... ending up with about 6.5 kilowatts of Effective Radiated Power or ERP... Now, tell me how in the world is it possible that my 65 watt ERP station may allow me to make a nice two-way 6 meter band contact with Spain located some seven thousand kilometers away??? The only logical answer, in my humble opinion, is the tilted Sporadic E clouds at both ends of the contact!!!!
If you have already joined those of us who have a nice time chasing DX on 6 meters, keep those radios ON ALL THE TIME Sunday from as early as your local sunrise, as we may see yet another day of superb DX condition on 6 meters on July 8th, too!!!
You have questions, and YES, you can be sure that they will be answered here at Dxers Unlimited... you can send your radio hobby related questions via e-mail to arnie@radiohc.org, and via AIR MAIL, a postcard will do, to Arnie Coro, Radio Havana Cuba, Havana, Cuba...
Here is today's first question to be answered, as there are several waiting in line. This was sent by a listener in Mexico, and yes, this show is heard very well in Northern Mexico via our 9820 kiloHertz frequency on the air from 05 to 07 hours UTC with the Pacific Coast of North America 4 by 4 curtain array... Well amigo from Mexico, I already answered to you via e-mail in Spanish, but the question was so interesting that I thought many Dxers Unlimited listeners would like to listen to the answer, too... Here is the question:
Arnie, you talked recently about ART-ANTENNAS, in other words, antennas that could be built to such a physical design that they may be disguised as art work... GOOD, but isn't it possible to use other let's say, unconventional structures as stealth antennas in places where external antennas are banned by building codes or local zoning regulations???Well amigo, you are right... and I'll tell you about a few ways of getting around intalling HF, VHF and UHF listening or transmitting antennas using other "structures," as you describe them... Here are several of my favorite ones: Garden lamps -- You can install not one, but two, or even three or four garden lamps... The lamp posts can be made of enough length to provide excellent performance on the 15, 12, 10 and 6 meter bands, and slightly degraded efficiency on the ever-popular 20 meter band... In one installation that I designed for a friend, the use of two garden lamp posts led to a bi-directional 20 meter band antenna system... All the grounding system and feedlines are underground, and people just see two very well made lamps separated from each other by exactly a quarter of a wavelength on 20 meters, my friend's favorite DX band!!!
In another stealth antenna design, I advised using a magnetic antenna system that looks exactly like a clothes hanging line... Four poles and the wires make a perfectly disguised antenna that works very well even on 40 meters as a near-vertical incidence skywave or cloud warmer antenna, an ideal system for participating in local and semi-local nets so typical of the 7 megaHertz band during the daytime...
And still another idea for you amigo from Monterrey, Mexico... Not art work, but IT can be made rather beautiful: A bird feeding station, high up at about 15 feet or almost 5 meters, brought no complaints from the zoning laws and regulations watchdogs... and my friend may now operate from 20 to 10 meters... 5 amateur bands, 20, 17, 15, 12 and 10 meters, plus he managed to install a disguised 2 meter band ground plane for local repeater access, too...
Last but not least, is one of my favorites.... a stealth antenna made from copper tape that has an adhesive backing, this stuff is used by glass artists, and can be found at art supply stores. The copper tape I like to use is about an inch wide, or 2.5 centimeters, and with it I have made nice verticals and dipoles for the 10, 6 and 2 meter bands, plus the 70 centimeter band, too. The copper foil tape with the adhesive backing is installed in such a way that it looks like a typical anti-theft system used for the protection of big glass windows, you know the ones that are so popular for the enjoyment of the surrounding scenery!!! The copper foil sticky tape is fed with a short length of thin RG174 cable properly disguised at one end, so that it will look like the connection to the alarm system. Right next to my desk, where I have the computer, there is a nice picture window overlooking my back garden, and there I have installed a 2 meter band copper foil tape vertical that provides access to all the local repeaters... and this is a nice standby antenna to use when thunderstorms are nearby and the emergency net must be kept on the air. It replaces the external high gain 2 meter band phased vertical that MUST be disconnected when the thunderstorms are nearby...
I hope, amigo from Monterrey, that these ideas will help you and others who want to install external antennas that may be able to bypass the everyday more restrictive building codes, covenants, condominium owners association and city zoning laws that make it impossible or nearly impossible to use nice external highly efficient antennas for both HF and VHF work!!!
You are listening to the weekend edition of Dxers Unlimited amigos, and YES, you can subscribe to our low mailing volume but highly efficient mailing list, a surefire way of obtaining the scripts of the show for further reading via an e-mail distribution system. Normally we sent out two mailings per week, with the mid-week and the week-end edition of the show's scripts... and by using the HTML format, we are able now to include graphics, circuit diagrams and small real audio sound cuts too... Subscribe by sending an e-mail to majordomo at rhc dot cu, and leaving the subject line blank, then in the body of the message write the following line subscribe dxers underscore l, that is the word subscribe, a space then dxers, underscore and the letter l like in lima... you will receive an automatic response from the majordomo software... and if you have any problems just send me an e-mail and I will subscribe you manually at the station's server machine... no problem!!!
And now amigos, as always at the end of Dxers Unlimited, here is my exclusive, not copyrighted, in the public domain Arnie Coro's HF plus 6 meters propagation update and forecast.... Solar activity was very low to low for most of this week, and the number of sunspots hit a longtime low of just barely 68 spots Friday, an indication of really very low solar activity, indeed... This solar rotation's minimum is about to end, and I expect solar activity to start to increase beginning Sunday, and reaching an expected peak solar flux of about 170 to 180 units, another indication of the cycle's downward turn.
Propagation on the HF bands continues to be rather poor during the local daylight hours, but we continue to see the nighttime enhancement of the maximum useable frequencies, especially along the North to South paths, and also along the antipodal propagation paths...
Best bands for daytime listening are in the segment from 15 to 22 megaHertz, and best nighttime reception is available from 9 to 16 megaHertz and when the solar 27 day sub cycle peaks we may see nice nighttime openings on frequencies as high as the 15 and 13 meter bands... Keep monitoring 6 meters and low band TV channels for those very interesting sporadic e signals and don't forget to set aside a little time to send me your e-mail report of Dxers Unlimited, send mail to arnie@radiohc.org and don't forget to include your comments about the show, as they do help me a lot making a better program for you all amigos!!!
Prepared 07-July-2001; transmitted 18-July-2001
Arnie Coro CO2KK
Havana, Cuba
July 7, 2001Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
To Arnie Coro's Dxers Unlimited
Back to NY Transfer's RHC main page