Radio Havana Cuba Dxers Unlimited Dxers Unlimited’s midweek edition for December 25-26 2007 By Arnie Coro Radio amateur CO2KK
Hi amigos radioaficionados around the world and circling our planet in Earth orbit… Seasons greetings and a happy new year 2008 with more sunspots is my wish for you listeners of Dxers Unlimited that are now facing yet another chain of day after day of zero sunspots … That’s the end of solar cycle 23, yes it is, and we have yet to see at least one of two more high latitude and reverse magnetic polarity sunspot groups in order to be really sure that cycle 24 has already started. Do remember that solar cycles don’t switch from one to the other by turning off the old one and turning on the new one… Both solar cycles, the old and the new co-exist during several months and scientists believe that that’s exactly what is happening right at this end of the year 2007… More about HF propagation and a Sporadic E events forecast at the end of the show…. Item two: with zero sunspots and the solar flux down to baseline levels, the 21 megaHertz or 15 meters amateur band is absolutely dead for most of the local daylight hours, with maybe a brief opening , but that’s it, we will have to wait until solar flux stabilizes above 90 to 100 units to see 15 meters come back to life… meanwhile, as we wait for more sunspots , the 18 megahertz or 17 meters and the 17 megahertz or 16 meters bands are the best daytime options for Dxers… 18 megahertz for radio amateurs and 17 megaHertz or more precisely from 17.5 megahertz up to 18 megahertz for short wave listeners that want to pick up international broadcast stations… Item three: with the Sun now again absolutely quiet, the night time reception of the lower frequency bands, from 100 kiloHertz up to 5 megaHertz is extremely good, providing excellent Tropical Band DX and also nice two way contacts for radio amateurs operating on the 160 and 80 meters bands… More radio hobby related information coming up in a few seconds, when Dxers Unlimited’s mid week edition continues after a short break for station ID… I am Arnie Coro in Havana … …………. You are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited and yes, sure amigos, we do verify reception reports, we do QSL, and Dxers sending reports during the next few weeks with the postal mailing address included will be receiving our nice 2008 pocket calendar and RHC’s QSL… Now item four: Olivia is the name of a very interesting and rugged digital communications keyboard to keyboard mode that was created by Pavel Walotcha, the same Polish radio amateur that formed part of the team that started the digital revolution on the ham bands by launching the PSK31 digital mode and that together with Peter Martinez, a British radio amateur of Spanish ancestors, made the PSK31 computer code freely available to the world’s amateur radio community in a very nice gesture that is fully appreciated by ham radio operators around the world. Now Pavel has provided us with Olivia, a wider bandwith mode that has an almost hard to believe capability of providing a communications link despite very weak signals and even under heavy interference from other stations near the same frequency the Olivia stations are operating. You can learn more about the Olivia keyboard to keyboard digital communications mode by running a search engine request with the words Olivia , the plus sign and then amateur radio, in order to obtain the fastest and most consistent results from your search. Olivia is very easy to use and my opinion is that it will be winning more and more users as radio amateurs now using PSK31 realize that with Olivia they can achieve better and more reliable communications. Amateur radio is constantly developing and digital voice is slowly growing, but that’s going to be the subject of an analysis at an upcoming edition of Dxers Unlimited. Item five: Also related to digital communications modes as used by amateur radio operators during this rock bottom end of solar cycle 23. Monitoring the 40 meters band during early Tuesday UTC day, that is shortly after 9 pm my local time, or zero two hours UTC, I found the band practically empty, with very few stations operating… After running a propagation analysis software program with the solar data for the past five days, I arrived at the conclusion that the maximum useable frequency was barely reaching seven megaHertz, something that explained why so few stations were heard. During extended periods of extremely low solar activity the ionosphere becomes so weak after local sunset, that it is not surprising to see the maximum useable frequency to drop down below seven megaHertz an even lower amigos… That’s solar minimum at its worst !. Item six, here it is , once again, your favorite section of Dxers Unlimited… LA NUMERO UNO… You have questions and Arnie tries to answer them… you can send your radio hobby related questions to [EMAIL PROTECTED] , or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba. Today’s first question came from a long time listener in India. Rajiv tells me that at this moment he is not able to pick up our station on the shortwave bands, and he rightly assumes that this is because of the very low solar activity… but Rajiv who lives in the garden city of India, Bangalore, the home of the nation’s electronic and other high tech industries, is able to read the scripts of the program that are made available to several short wave listeners clubs e-mail distribution lists. Rajiv tells me that he wants to obtain the electronic files of the Super Islander amateur radio transceiver to compare the circuit diagrams and design philosophy with a similar project that is becoming very popular among Indian radio amateurs. Ok amigo Rajiv… I have already sent you all the files including some nice digital photos of the first prototype of the Super Islander, that as you will see, has two final amplifier options , one built using NPN RF power transistors, and the other one using two vacuum tubes that are very easy to find here in Cuba from recycled TV sets. The Super Islander is a single band transceiver that can be built for the 160, 80 or 40 meter bands. Here in Cuba amigo Rajiv, the most popular amateur band nowadays is two meters, using the FM narrowband mode, and the second most popular band among Cuban radio amateurs is 40 meters, that’s why most of the Super Islanders are built for operating between 7.000 and 7.150 kiloHertz. The double sideband signal generated by the Super Islander simple circuit is very stable, and very few if any radio amateurs that contact stations using the Super Islander are able to detect that it is a double side band and not a single side band signal what they are hearing. One of the most outstanding features of the Super Islander single band amateur radio transceiver is that it is modular, so those who want to build it, are able to build and test each module as a single project, and after all the modules are fully tested, then they are easily wired together . The parts count, that is the number of components required to build a Super Islander was kept intentionally as low as possible, both to simplify its construction and to increase the reliability. I hope that amigo Rajiv in Bangolore , India will be able to make good use of the Super Islander’s files, and maybe even go ahead and build one , as the parts required are almost universally available, because that was one of the design requirements that I set when starting the Super Islander project more than fifteen years ago….You can learn more about this simple amateur band transceiver by sending a request for the Super Islander files to [EMAIL PROTECTED] … I will send it as a dot zip file and you will be able to see circuit diagrams, photos and full descriptions of the different modules of this nice little rig, that has proven itself under the most difficult circumstances, like handling emergency communications links during tropical storms. ……. Si amigos, yes my friends, oui mes amis, you are listening to the mid week edition of Dxers Unlimited, your favorite radio hobby program covering the more than 82 ways that you and I enjoy this wonderful hobby… from homebrewing a nice little ham band transceiver like the just mentioned Super Islander and then using it on the air, to watching a TV DX signal come and go when a Sporadic E cloud is providing enough ionization for a station operating on frequencies as high as 80 megaHertz to be seen more than a thousand miles away… Sure, radio is a fascinating hobby and you will never be bored with it, as there is always something new that can be done, like for example milliwatting, that is trying to make amateur radio two way contacts while running less than one Watt of power… one Watt is a thousand milliwatts, and that’s why this particular form of QRP or low power operation is also known as milliwatting. I have a little transistorized transceiver for the 20 meters band that can operate running even down to 100 milliWatts, or a tenth of a Watt , and amazing as this may sound to some of you , I have already worked 35 countries using the 20 meters CW transceiver while running it at the one tenth of a Watt power output level…There are several international radio clubs devoted to low power or QRP operation, among them the GQRP Club that edits the very fine SPRAT magazine that provides readers with very nice technical articles about low power radios and how to operate using them. The website of the GQRP club is located at www.gqrp.com , again the URL of the GQRP website is www.gqrp.com. Yes amigos, joining an amateur radio club is very important if you really want to be up to date on what’s going on in a particular field of amateur radio, in this case the GQRP club membership provides you with information about QRP contests, and a treasure chest of extremely useful tried and tested technical information that you can put to very good use when homebrewing amateur radio equipment… And now amigos, as always at the end of the program, when I am here in Havana, ready to copy Arnie Coro’s Dxers Unlimited’s HF plus low band VHF propagation update and forecast… Solar activity is and will continue to be for the next several days at very low levels… Zero sunspots seen during the past six days… solar flux around 70 units and the spotless Sun is also free of coronal holes, so we will enjoy also an extremely quiet geomagnetic field, certainly good news for low frequency bands Dxers, both short wave listeners and radio amateurs… Expect more sporadic E openings to happen as we are now riding trough the peak of the winter E skip season… I wish you all Seasons Greetings and hope that next year you all will be listening to my Dxers Unlimited’s show, that as always, I will try to make it as attractive and interesting as humanly possible for your enjoyment… Happy New Year amigos ! ---[Start Commercial]--------------------- Order your WRTH 2008: http://www.hard-core-dx.com/redirect2.php?id=wrth2008 ---[End Commercial]----------------------- ________________________________________ Hard-Core-DX mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/hard-core-dx http://www.hard-core-dx.com/ _______________________________________________ THE INFORMATION IN THIS ARTICLE IS FREE. 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