Radio Havana Cuba Dxers Unlimited Dxers Unlimited's weekend edition for January 12-13 2008 By Arnie Coro radio amateur CO2KK
Hi amigos radioaficionados around the world and those of you orbiting the Earth and also enjoying amateur radio. I am Arnaldo, Arnie, Coro , radio amateur CO2KK, your host here at the weekend edition of Dxers Unlimited, your favorite listener oriented and technically minded radio hobby program. Si amigos, YES... we have just seen solar cycle 24's start up, but so far it has been a very modest beginning, with the first sunspot region at high solar latitude and reverse magnetic polarity fading away quietly, without producing any solar flares. Now solar scientists are once again scratching their heads as yet another reverse magnetic polarity sunspot has appeared, but this time it has shown up near the solar equator, the area supposed to be reserved for the sunspots of the old cycle... Anyway, for us radio hobby enthusiasts, the start up of a new solar cycle is always very good news, because it signals the end of the extended period of extremely low solar activity that has so badly affected short wave propagation during the past two years... Item two: More about compact antennas for the short wave bands, especially antennas that can be used by amateur radio operators living in downtown areas, where space is at a premium and there are many rules and regulations regarding the installation of any type of antenna systems. But very clever antenna designs are able to bypass some of those CCR's rules, by disguissing the radiating systems as beautiful bird feeders, flagpoles and even as fake power company overhead distribution lines. Flagpoles , when made of high mechanical resistance plastic materials can serve as the housing, or radome speaking in more proper engineering terms, for very nice multi band vertical antenna systems. And don't forget that an elevated bird feeder can provide support for two antennas.... the support pole works as a HF bands vertical, typically able to operate from 40 to 10 meters, and at the top of the antenna, by means of proper decoupling you can install a 2 meters band or 70 centimeters band omnidirectional antenna to access distant repeaters that can't be reached using the handie talkie's small compact rubber covered antenna. Last but not least, experiments with underground antennas have provided a lot of valuable information about how they work, and be aware that an underground antenna about a meter below the garden may work quite well according to results obtained by amateur radio operators in Austria and Germany. Standby for more radio hobby related information, coming to you from Havana, that will follow 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 here is item three of today's weekend program... for all practical purposes the winter sporadic E season of the northern hemisphere is coming to an end, but I still see reports of E skip openings happening over Europe , especially around the Mediterranean region... The spring-summer sporadic E DX season will start at the end of April, and will last until August, with the peak happening between the end of May and mid July. Sporadic E clouds provide amazing DX on frequencies that can reach as high as 200 megaHertz, but more typically are in the range between 25 and 60 megaHertz. At frequencies higher than about 100 megaHertz, sporadic E DX is not as frequently seen as events happening on the lower frequencies. One interesting fact about sporadic E DX is that the ionization of those clouds is so intense that very low power stations can be picked up with amazingly strong signals at distances of up to two thousand kilometers that correspond to the geometry of the sporadic E single hop propagation path. Item four: Homebrewing radio equipment was once practically the only way that amateurs could own and operate a ham radio station... but nowadays, the standard practice seems to be just to go to a store and buy a brand new super sophisticated receiver or transceiver... or if the amateur is on a shoestring budget , they just look around at hamfests for used equipment in good shape, or that can be repaired. But now, the option of homebrewing radio gear is winning back more and more supporters, and the presence of some extremely nice kits with very well written and illustrated instruction books is making possible for the more advanced radio amateurs to assemble extremely nice transceivers that offer equal or better performance than off the shelf equipment. Another option is homebrewing from scratch, and that one is also winning more and more enthusiastic hobbysts that enjoy such wonderful project as designing and assembling ultra low power transmitters, like a recent microwatt power tunnel diode transmitter that has already make possible two way contacts on the 80 meters amateur band during peak propagation periods. Homebrewing radios requires some unique skills like learning how to read and interpret circuit diagrams, how to solder, and also how to design and make printed circuits, but I must add that some of my nicest homebrew projects were made using point to point wiring techniques and they work very well. The two best examples of such homebrew projects are my REGENERODYNE R-7 receiver project, and the SUPER ISLANDER, a double sideband and CW transceiver that has become very popular among Cuban radio amateurs. Both use point to point wiring, and in the case of some of the Mark II and III versions of the Super Islander's the VFO is now built on a high quality fibreglass circuit board with excellent results. Si amigos , yes my friends, oui mes amis, homebrewing radios, or assembling nice radio kits is one of the many aspects of our hobby that provides double enjoyment... first you have a nice time when building the equipment, and then when using it, the unique experience of listening to or communicating with a radio that you have built is something ... well , unique !!! ..... QSL on the air , QSL on the air, to the many Radio Havana Cuba listeners that have sent New Year's good wishes to us... Muchas gracias amigos, and yes, we have sent out lots of pocket calendars for 2008 to a long list of regular RHC listeners that send reports to us ... Now here is item five: - Digital amateur radio communications is on the rise, due to a number of very interesting and coincidental factors. First of all, there are more computers available now than ever before, and the fact is that older machines can handle amateur radio digital modes very well, maybe not all of them , but some of the more popular ones can be operated using semi-retired laptop or desktop machines that may not be fit to handle today's super sophisticated graphics and other new software. Using the LINUX operating system on Pentium I and II machines, it is possible to operate using PSK31, the most popular keyboard to keyboard communications mode . PSK31 is so efficient that it works under rather poor HF propagation conditions and while running low power, and that has made it very attractive to a generation of new amateurs that are also very good typists, because they grew up with computers from elementary and junior high school days... Watching PSK31 contacts on the popular twenty meters band frequency of 14.070 you can see that many of the operators are really good at typing and can make some very nice two way QSO's using that mode while running between 10 and a maximum of 50 Watts, with the typical station operating at around 25 Watts and with a modest antenna, like a quarter wave vertical or a half wave wire dipole. As I said a while ago, the evolution of amateur radio into the digital world is a really interesting phenomena to watch, including the development of ultra sophisticated digital communications modes that are the brainchild of a radio amateur that also happens to be a Nobel Prize laureate !!! More about the advanced digital modes in an upcomind edition of Dxers Unlimited, so if you have an old computer that is still operational and you can't find a job for it, keep it ready to install LINUX and a digital modes software package that works very well with several LINUX operating system distributions... ..... From Havana, this is Dxers Unlimited, our station's radio hobby program... and now here is item six ... playing with my little Grundig FR-200 recycle power radio recently, I decided to add two modifications that have proven to be an excellent addition to this small analog portable receiver that has its own electric generator so that it can be kept running even when you can't charge the batteries from the power line. The crank up generator works very well and I was able to modify the circuit so that it will recharge the three double AA batteries instead of recharging a small battery pack . By spending about 10 minutes cranking power to the batteries, the radio works for more than one hour. The other modification consisted of stuffing in a beat frequency oscillator and a bandspread circuit. So now I can pick up 40 meter band amateur radio stations that operate on CW Morse radio telegraphy and single side band voice, something that was impossible with the original FR200 recycle power radio. And, a reminder, about two years ago, I was able to replace the incandescent light bulb of the radio's flash light with a cluster of three white light emitting diodes, that as expected produce a much better light output while using about half the electricity from the batteries. Fitting the BFO on off switch and BFO frequency control was not too a too difficult job, but finding the right place for the electrical bandspread was more of a challenge. I believe that Grundig now under the name of ETON is selling a similar radio as the old FR200 with the light emitting high intensity flash light already, but that the receiver still lacks a better bandspread than the one available on the original model. By the way, by changing just one transistor on the FR200 I increased its sensitivity a lot, but this is a modification I won't recommend to beginners as it can be described as state of the art electronics microsurgery !!! ... And now amigos, as always, your comments about this program are invited ... and most welcome.. send them to [EMAIL PROTECTED] or VIA AIR MAIL to Arnie Coro , Radio Havana Cuba, Havana, Cuba... Ready to copy, here is our exclusive and not copyrighted HF plus low band VHF propagation update and forecast... Solar flux again at rock bottom levels, sunspot count is ZERO, again for the past three days a totally blank solar disk, and the daytime maximum useable frequencies are barely making it up to 21 megaHertz at the peak times. Nightime propagation , in contrast, is excellent on our hemisphere , from the long wave broadcast band all the way up to around six or seven megaHertz, so enjoy low frequency DX before cycle 24's sunspots begin to spoil it !!! See you all at the mid week edition of the program next Tuesday and Wednesday UTC days 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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