Radio Havana Cuba Dxers Unlimited Dxers Unlimited’s mid week edition for 24-25 April 2007 By Arnie Coro Radio amateur CO2KK
Hi amigos radioaficionados around the world and in space… this is the mid week edition of your favorite listener oriented and technically minded radio hobby program… I am Arnie Coro, radio amateur CO2KK, your host here for the next seventeen minutes , inviting you to stay with us for the most up to date HF plus low band VHF propagation update and forecast, and a lot more radio hobby related information… So, here we go, first things first… the spring – summer Sporadic E season has already started, and I am receiving reports from Mexico, Central America, the South of the USA and the Caribbean that VHF openings reaching well into the FM broadcast band are now happening on an everyday basis, having started to occur, according to the reports received since last Friday. Scientists don’t know yet what causes Sporadic E layer high free electron concentrations that lead to quite spectacular DX on frequencies from 25 up to 250 megaHertz. But on a day to day basis during the spring-summer Sporadic E DX season; band openings between 25 and 100 megaHertz are much more common. As a matter of fact, the frequency range between 25 and about 75 megaHertz shows much more frequent openings. So, here is your amigo Arnie Coro’s advice, monitor the low band TV channels, especially TV stations operating on channels 2 and 3 for signs of Sporadic E openings… And if you are a radio amateur, and have a rig that is capable of operating on 10 meters or on 6 meters, then keep it on scanning the 10 and 6 meter bands for signs of skip signals. As solar cycle 23 is now passing through its minimum, propagation gurus believe that this actually helps Sporadic E openings to occur… as there seems to be a link between minimum solar activity and the frequency and duration of the Sporadic E events… More about HF propagation conditions at the end of the program… Now here is item two: Very low solar activity is also good for AM broadcast band Ding, something that I enjoyed Monday evening after the national baseball championship game was over. Using my ultra small portable receiver, stations from the USA, Mexico, Puerto Rico, Colombia and Venezuela were heard here between midnight and about 1 AM local time… Amazing as this may sound, the ultra small portable using just a pair of triple A size batteries brings in a lot of DX because of the fact that it uses a relatively large ferrite rod antenna. Before going to bed, I ran another AM broadcast band scan from about 1 AM to 1.30 AM using my homebrew super high gain double conversion receiver, and could pick up several heterodynes at the high end of the band, indicating the presence of transatlantic signals from Europe … Si amigos, yes my friends, oui mes amis… AM broadcast band Dxing is still peaking, despite the fact that the spring equinox happened a month ago… As a good friend of mine that loves Dxing on the AM band likes to say… there is nothing better for that band than very low solar activity that comes together with very quiet geomagnetic conditions… Stay tuned for more radio hobby related information, as the mid week edition of Dxers Unlimited continues in a few seconds, after a short break for station ID. I am Arnie Coro in Havana, and my e-mail address is [EMAIL PROTECTED] ……. You are listening to Radio Havana Cuba, soon to be celebrating its 46th birthday… Yes amigos, on the first day of May of 1961, our station went on the air as Radio Havana Cuba, and that’s why we will be celebrating 46 years on the air… From February 24th of 1961 until May first of that year, we were on the air using the name Cuban Experimental Short Wave, or in Spanish, Onda Corta Experimental Cubana… Now here is item three of today’s program… ASK ARNIE, the number one most popular section of the show… according to the e-mail messages, letters, and whenever I have the nice opportunity of talking to Dxers Unlimited’s listeners on the air while operating on the amateur bands. Unfortunately, at this solar minimum, short wave propagation conditions are very poor, especially for low power amateur radio stations… But the good news is that scientists are expecting solar activity to start moving up fast by the end of the year, and that will mean that next spring HF propagation conditions are going to be much better… By the way, you have just heard the answer to a question sent by listener Carlos from Mexico City, who asked in his e-mail to [EMAIL PROTECTED], when solar activity of the new cycle will begin to move up, and how fast this is going to happen… Again, expect the solar “numbers” to start climbing by the end of 2007 and be well on their way to much better figures about a year from now… In the meantime, do as I do, and keep those radios on especially around your local sunset, when propagation conditions are better than at any other time of the day… Item four: A quick visit to Arnie’s workshop, where yet another SUPER ISLANDER homebrew amateur radio transceiver is in the works… This version of the SUPER ISLANDER is a hybrid, using both solid state and vacuum tube components and it is a GREEN RADIO…. You know why amigo Jose, CO2JA described it as a GREEN RADIO… well, because it uses 100 percent recycled components, that otherwise in most cases will end up polluting landfills… The SUPER ISLANDER is an optimized version of the original ISLANDER double side band and CW transceiver designed by amigo Pedro Rodriguez, CO7PR from Ciego de Avila province in central Cuba. Pedro designed the ISLANDER so that young radio amateurs that had taken their ham radio license tests and had no rigs, could build the ISLANDER and go on the air on 40 meters. The project has proven to be not only extremely popular among newcomers to the hobby, but also among many old timers that after hearing them on the air, decided to start collecting the parts to homebrew their own ISLANDERS , to be used as a standby transceiver or for portable work. During the frequent tropical storms and hurricanes that get near to Cuba or go across our archipelago, one can frequently hear the ISLANDERS and SUPER ISLANDERS on the air on 40 and 80 meters passing weather related and emergency traffic. Running between 20 and 50 Watts, these radios are very rugged, can be easily repaired with standard tools and common test instruments, and when connected to a Near Vertical Incidence Sky wave type of antenna , they provide excellent emergency communications within a radius of between 10 and 500 miles, exactly what we need here for our emergency amateur radio networks. The fact is that the original CO7PR has evolved into a still easy to build with locally available parts single band transceiver, that Cuban radio amateurs keep home brewing and using despite the availability of much more modern multi-band transceivers, because as someone was commenting during the weekend over the air, there is nothing that can be compared to working a DX station with a radio that you have built yourself!!! And YES, I fully agree with that remark amigos!!! …… Dxers Unlimited’s mid week edition coming to you from Havana… via short wave on 9550 kilohertz from 23 to 00 hours UTC… Yes you can also listen to this program on the 31 meters band when Radio Havana Cuba’s English language program to the Caribbean and Southern United States of America is on the air on 9550 kilohertz with 100 kilowatts and our 6 dB gain omni directional antenna… And of course, that if you have Internet connectivity, you can also listen to our English program from 05 to 07 UTC by visiting our website rhc.cu, again, rhc.cu and clicking on the loudspeaker icon at the top of the page… Now here is item five of today’s program> More about the SUPER ISLANDER double side band and CW transceiver, that now has a much better receiver thanks to the use of triple tuned band pass input filter… The signal from the antenna is fed to a very simple, but also very effective radio frequency attenuator… and then it goes through an easy to homebrew triple tuned band pass filter…The filter was designed so as to limit the pass band response to just 200 kilohertz, effectively removing other signals from the radio frequency amplifier stage. The SUPER ISLANDER receiver is something quite unusual according to today’s design standards, because it is a vacuum tubes direct conversion radio… The loss introduced by the triple tuned filter is compensated by the RF amplifier stage that feeds a vacuum tube product detector…As you may realize most of the receiver’s gain is obtained at the audio frequency section, so one most follow good audio circuits construction practices… The SUPER ISLANDER uses regulated and very well filtered DC, that is direct current on the filaments of the product detector and the first audio amplifier stage, and that has proven to be quite an improvement over the original ISLANDER, that required the use of small coupling capacitors between the audio stages to remove the low frequency hum that was always present in the background of the received signals. The SUPER ISLANDER receiver is not as sensitive as a thousand dollars amateur bands transceiver, but all I can tell you is that Cuban several Cuban radio amateurs have already achieved DXCC, that is worked more than 100 countries or DX entities as they are now known, using both the ISLANDERS and SUPER ISLANDERS on the 40 meters band… Si amigos, low cost, homebrew radios for the enjoyment of our wonderful hobby can be designed and built… the ISLANDERS and SUPER ISLANDERS are a good example of what can be achieved by clever use of hybrid circuits, recycled components and ham radio ingenuity… And now as always at the end of the program, here is Arnie Coro’s Dxers Unlimited’s HF plus low band propagation update and forecast… Here are the predictions for 25 Apr 2007 10CM FLUX: 070 /, geomagnetic disturbance indicator nice and low AP: 007 Now the predictions for 26 Apr 2007 10CM FLUX: 070 / with slightly higher Planetary an index expected to reach: 010 Solar activity is expected to be low during the next 48 hours. Geomagnetic activity is expected to be mostly quiet with a risk of Isolated unsettled conditions as the Earth is within a high-speed solar Wind stream from a coronal hole. The solar wind speed as measured by the ACE spacecraft is however moderately high with values around 400 km/s. Now, something that is becoming quite common during this solar minimum: ZERO SUNSPOTS… a BLANK SUN, and the WOLF NUMBER CATANIA : 000 Expect some nice Sporadic E openings to happen between 7 AM and 11 AM local time, with a second round from about 3 PM to 8 PM local time… See you all at the weekend edition of Dxers Unlimited amigos, and don’t forget to send me your comments about the program and radio hobby questions… mail to [EMAIL PROTECTED] , or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, and 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. 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