Radio Havana Cuba Dxers Unlimited Dxers Unlimited’s week end edition for 6-7 October 2007 By Arnie Coro Radio amateur CO2KK
Hi amigos radioaficionados listening to the program or reading the scripts available at several of the world’s most well known SWL and Ham Radio e-mail lists… You are all welcome to the weekend edition of Dxers Unlimited, our twice weekly radio hobby program that covers practically all aspects of our wonderful hobby, from AM broadcast band Dxing at the bottom of the solar cycle, to home brewing simple receivers, from making your own highly efficient and low cost antennas for the 2 meters band FM ham radios, to watching TV DX signals via meteor scatter… Yes amigos, there are more than 81 different ways you and I enjoy this hobby… and here is a nice example: the thrill of picking up a distant AM broadcast band station using your standard bedside radio is absolutely great… As a matter of fact many people have discovered this hobby by picking up long distance stations, especially at the high end of the AM broadcast band, between 1400 and 1700 kilohertz, because that segment of the band propagates better during local evening hours… Now that solar cycle 23 is moving along its minimum, AM broadcast band DX is at its best, and even with a very simple receiver you can pick up far away stations… Recently I gave it a try, and was able to pick stations from eleven countries during a three hour period from about eleven PM to 2 AM local time… Propagation conditions were so good, that several of the DX stations sounded just like another local one. I kept a log of the DX stations and next day in the morning sent AIR MAIL postcards to all of them, a total of 37 stations… And, amazing as it may sound, just two weeks later I received a QSL from a Mexican station, signed by its Chief Engineer, who also sent an e-mail with a full description of his transmitting site. But, let me warn you that this is an exception, as normally QSL’s take much longer to arrive at your doorsteps… This Mexican QSL super service was , according to what the station’s Chief Engineer said in his lengthy e-mail and in a short handwritten note on the postcard QSL , a courtesy of a long time listener of Radio Havana Cuba and Dxers Unlimited. As a matter of fact, he had been listening to Dxers Unlimited for more than 10 years!!! So now I have a beautiful Mexican postcard in my AM band QSL collection that already adds up to 91 countries around the world!!! Si amigos, yes my friends, radio need not be an expensive hobby at all… even with a very modest AM and FM broadcast bands receiver you can start searching for far away stations and sending out reports… Dxers Unlimited’s weekend edition will continue in just a few seconds…. After a short break for station ID I am Arnie Coro in Havana….stay right on this frequency or World Wide Web connection amigos!!! ……… This is Radio Havana Cuba, the name of the show is Dxers Unlimited and you can send me your signal reports and comments about the program to [EMAIL PROTECTED] or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba, now here is item two of today’s show…. A nice senior high school radio related project that can certainly win a science fair award is designing and building an amateur radio telescope for listening to the powerful signals from both Planet Jupiter and the Sun… A wire antenna and a sensitive short wave receiver capable of tuning from 20 to 40 megaHertz will bring in Jupiter’s radio emissions loud and clear… The signals emitted by planet Jupiter sound like ocean waves washing ashore… and you can be sure that you are picking them up because at several World Wide Web Internet sites there are MP3 recordings of Jupiter’s radio signals… At this stage of the solar cycle, your 20 to 40 megaHertz short wave receiver won’t pick up loud signals from the Sun, but in about two years from now, our nearest star will be very active, and signals from solar radio storms will be very easy to pick up. Amateur radio astronomy is not limited to such a simple set up… Many enthusiasts of this way of enjoying the radio hobby use retired TV satellite dishes to pick up very distant radio sources, like Cygnus A and Cassiopeia…By the way, it was a radio amateur, by the name of Grote Reber, who during the very early days of radio, built a parabolic reflector and started to explore in search of signals from outer space, and he succeeded… His original dish antenna is now preserved at one of the world’s most important radio astronomy observatories, and scientists recognize the contributions made by amateur radio operator Grote Reber to the development of radio astronomy, now one of the leading aspects of scientific exploration of the Universe. Reber decided to build his own radio telescope in his back yard in Wheaton, Illinois, when he could not get a job with Karl Jansky the Bell Telephone Laboratories scientist that discovered radio waves from outer space.Reber, who was a university trained electrical engineer was able to design a radio telescope that was considerably more advanced than Jansky's equipment. He made the world’s first parabolic antenna using sheet metal for a mirror 9 meters in diameter, focusing to a radio receiver 8 meters above the mirror. The entire assembly was mounted on a tilting stand allowing it to be pointed in various directions, although not turned. The telescope was completed in 1937. One very interesting fact about the first radio telescope made by a radio amateur operator was that Reber designed it to operate at a microwaves frequency of 3300 MHz and failed to detect signals from outer space, he then built another receiver for operating at 900 MHz, a UHF frequency that also proved to be a failure because the state of the art of receivers for such frequencies did not allowed for very weak signals to be picked up. Finally, Reber, a very dedicated person, moved down in frequency making his third attempt at 160 MHz and successfully picking up signals from space in 1938, confirming Karl Jansky's discovery. Reber then turned his attention to making a radio-frequency sky map, which he completed in 1941 and extended in 1943. He published a considerable body of work during this era, and was the initiator of the "explosion" of radio astronomy in the immediate post-WWII era. And amigos, he always considered himself as an amateur…and his call sign W9GFZ is very well known among the world’s radio astronomers, of which many, I must add, are also active radio amateurs, as well as many of the engineers and technicians that work at the world’s most important radio astronomy observatories…Grote Reber died in Tasmania, where he was doing very low frequency radio experiments at the age of 91, and his ashes were distributed to 24 radio astronomy observatories around the world, as a tribute to this radio amateur that was one of the first to ever pick up radio signals from outer space… …………… Si amigos, you are listening to Dxers Unlimited, your favorite radio hobby program… and here is la numero UNO, the number one favorite section of the show… ASK ARNIE… where I am able to answer your radio hobby questions here, and also via e-mail…. Today’s question is about the MOXON rectangle antenna, and it was sent by listener Eddy from Scotland… He tells me in his e-mail that his 2 meters band MOXON antenna works very well, and asks why he hasn’t been able to find a commercial version of the MOXON antenna so far… Well amigo, that’s a good question, because what we see normally in radio magazines adds are Yagi and Log Periodic beam antennas… covering from 40 meters or 7 megaHertz all the way up to the upper UHF bands, and during the past three or four years, I have just seen one single ad about a commercially built MOXON rectangle antenna for the HF bands from 20 meters to 6 meters. As you already know well amigo Eddie, the MOXON is a single band two elements close coupled antenna, that has a truly remarkable front to back ratio when properly built, combined with a much wider coverage area than a similar two element Yagi array… I am now in the process of building a batch of 2 meters band MOXON antennas, as part of a Radio Club project that will use them for the installation of very simple antenna systems that are going to provide much better coverage to our stations than when using simple omni directional vertical antennas. The system that I designed uses two or four MOXON antennas made with copper tubing… They are assembled on the mast or tower so as to provide optimum coverage into the areas where the amateur radio activity is higher… For example here in Havana, our first system has one of the MOXON antennas beaming to the center of the island, at 110 degrees azimuth, while the other antenna is beaming to the 240 degrees to reach the mountain top repeater located at the Sierra del Rosario national park and biosphere reserve… The switching between the two antennas is done right at the top of the mast, by means of a single pole double through relay that is remotely controlled from the operating position… Because the MOXON antennas have a horizontal pattern that is about 140 degrees between the minus 3 dB points, this system has proven to be very efficient, and is much cheaper than having to buy and install an antenna rotor… With a stack of two MOXONS in each direction, the estimated antenna gain is around 6 dB, the equivalent of a well designed and built three element YAGI, but with the advantage that the MOXON covers a much wider area due to its better horizontal pattern…For those of you listeners of Dxers Unlimited that are also radio amateur operators, I have here all the design information for this simple , easy to build and rugged dual directions antenna system for the two meters band , based on the MOXON rectangle antenna that is becoming more and more popular these days among the world’s ham radio operators due to its excellent characteristics. And now amigos at the end of the show, as always when I am here in Havana, listen now to Arnie Coro’s Dxers Unlimited’s HF plus low band VHF propagation update and forecast… More and more days with ZERO sunspots and extremely low solar flux levels… solar scientists are now almost sure that since July the SUN is going trough the minimum of cycle 23… Equinoctial propagation conditions are slowly fading away, as the northern hemisphere winter and the lower hemisphere summer approach… so be prepared for many more days of very low maximum useable frequencies, and also of very low ionospheric absorption … Transequatorial propagation on the 10 and 6 meters band is now happening every day, from the Caribbean to the extreme end of South America, and here in Havana, a good example is the fact that 10 meter band pirates stations from Argentina and Brazil are coming in every afternoon… See you all at the mid week edition of the program , Tuesday and Wednesday UTC days amigos !!! And don’t forget to send me your signal reports and comments to [EMAIL PROTECTED] or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana Cuba. ---[Start Commercial]--------------------- Preorder your WRTH 2007: http://www.hard-core-dx.com/redirect2.php?id=wrth2007 ---[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. It may be copied, distributed and/or modified under the conditions set down in the Design Science License published by Michael Stutz at http://www.gnu.org/licenses/dsl.html
