Radio Havana Cuba Dxers Unlimited Dxers Unlimited’s weekend edition for 28-29 April 2007 By Arnie Coro Radio amateur CO2KK
Hi amigos… welcome to the weekend edition of your favorite radio hobby program, coming to you from Havana, I am Arnaldo, Arnie, Coro, radio amateur CO2KK, your host here now ready to start today’s show with a news item… It’s about the upcoming solar cycle 24 that is expected to reach its maximum activity late in 2011 or mid-2012 But scientists trying to forecast the next solar peak activity • are split over whether there will be 90 sunspots or 140 sunspots…And as many of you Dxers Unlimited’s listeners know very well Solar storms can disrupt Earth communications An Associated Press news dispatch on this topic says that the peak of the next sunspot cycle is expected in late 2011 or mid-2012 -- potentially affecting airline flights, communications satellites and electrical transmissions. But forecasters can't agree on how intense it will be. A 12-member panel charged with forecasting the solar cycle said last Wednesday it is evenly split over whether the peak will be 90 sunspots or 140 sunspots. The US Space Environment Center in Boulder, Colorado, tracks space weather and forecasts its changes, which can affect millions of dollars worth of activities such as oil drilling, car navigation systems and astronauts. Half of the specialists predicted a moderately strong cycle of 140 sunspots expected to peak in October of 2011, while the rest called for a moderately weak cycle of 90 sunspots peaking in August of 2012. "We're hoping to achieve a consensus sometime in the next six to 12 months," said Douglas Biesecker, a space environment center scientist who is chairman of the forecast panel. An average solar cycle ranges from 75 to 155 sunspots. During an active solar period, violent eruptions occur more often on the sun, the agency said. Solar flares and vast explosions, known as coronal mass ejections, shoot highly charged matter toward Earth. Making these predictions is important for many businesses, which have been asking for a forecast for nearly a year, Biesecker said. Just like coastal residents want a hurricane forecast as early as possible, so do those affected by solar activity, said Joseph Kunches, chief of forecast and analysis at the center, which is part of the National Oceanic and Atmospheric Administration. Daniel Baker, director of the Laboratory for Atmospheric and Space Physics at the University of Colorado-Boulder, noted that more than $200 billion satellites in space can be affected by changes in solar radiation as the cycle rises and falls. In addition, Baker said, other problems include: • Airlines flying over the pole face loss of communications that could force them to use a different, longer route at an added cost of as much as $100,000 per flight. • The Global Positioning System is immensely important to commerce and can be disrupted by solar activity. • Operating floating oil rigs in the ocean requires keeping them positioned within a few inches to prevent damaging drilling gear. "They have to know when GPS is going to be accurate." • There is an increased radiation risk to humans in space. • Currents can be induced in long electrical transmission lines, causing blackouts. In the past, such problems have been caused by solar super storms, he said. "Storms don't have to be so super any more" to cause problems, Baker said, as more and more systems become susceptible to solar effects. W. Dean Pesnell of NASA's Solar Dynamics Observatory said the solar storms also can heat the Earth's upper atmosphere, causing it to expand. This increases drag on satellites, slowing them down. It also affects the position of the space debris encircling the planet, and it is essential to keep track of that debris for the safety of space flight. The forecasters said the current solar cycle will probably end next March 2008, when Solar Cycle 24 will begin. That will mean Cycle 23 lasted 12 years, slightly longer than the usual 11-year cycle. But now let me add that the forecast calling for Solar Cycle 24 about a year from now may prove to be wrong according to other solar astronomers that have been very carefully studying the past seven solar cycles. For those of you wanting to know why the higher frequencies of the short wave spectrum are so quiet, the explanation is quite obvious; there is very little solar activity at this moment with many, many days without a single sunspot seen on the solar disk. Stay here with me for more radio hobby related information as the weekend edition of Dxers Unlimited continues in a few seconds… I am Arnie Coro in Havana, and my e-mail is [EMAIL PROTECTED] ……. Si amigos, yes my friends, oui mes amis…when propagation conditions on the HF bands, from about 6 to 30 megaHertz are very poor, this is the time to enjoy VHF at its best... According to ionosphere research experts, very low solar activity seems to enhance the number and duration of sporadic E events, something that brings in DX on frequencies as high as even 250 megaHertz at times…And, as expected is ideal for amateur 10 and 6 meters band DX, TV DX on channels 2 to 6 in the Americas and FM broadcast band DX… Reports about sporadic E openings continue to come in from Dxers Unlimited’s listeners at many locations of the Northern Hemisphere…. Especially from North America, Southern and Central Europe and the Caribbean… Now here is item three of today’s program, answering many requests received recently, here is more information about the SUPER ISLANDER single band amateur transceiver and how it is now evolving into a much more advanced, but still easy to build and adjust set. The SUPER ISLANDER MARK II is still in the process of final assembly at my workshop, but already I was able to test the VFO for stability and the receiver for both sensitivity and audio output. A local radio amateur that visited me last Tuesday came up with the idea of designing and building a solid state VFO, in order to replace the now classic vacuum tube design that goes back to more than 25 years ago , when the original Islander was born… On Friday, when I was starting to write the script of this program, he visited again with the prototype circuit board for the solid state VFO, and we connected it to the SUPER ISLANDER Mark II prototype by unsoldering the coaxial cable from the vacuum tube VFO and soldering in its place the new solid state VFO… All I can say is that we were both very pleased with the results, as frequency drift was really minimal, and the power drawn by the solid state VFO was really small, as expected. Because the SUPER ISLANDER’s power supply already provides a source of plus fully regulated plus 12 volts DC , this modification is one that is very easy to implement, and one that I am recommending to all Islander and Super Islander owners, as something really worthwhile to build and install. The other module that we are now aiming to replace is the receiver’s audio section… that will also be converted to solid state… Currently we are testing different circuits, with two options in the works, one with discrete solid state devices that requires the use of several silicon NPN transistors, and the other that uses a low noise NPN silicon transistor pre-amp and an integrated circuit power output module. As we always think in the actual possibilities of home brewers located at remote places, the two options will be published, so that builders can choose the one that is most convenient to them. By using both a solid state VFO and also a solid state audio amplifier module, the SUPER ISLANDER MARK II will use up less electric power, and generate less heat. As the project evolves, it seems that soon we may end up with a totally solid state receiver section of the transceiver, using the locally available active devices. This will make possible running the SUPER ISLANDER MARK ll on receive only mode directly from a storage battery, a very useful feature when the station is used as part of an emergency communications network. In an upcoming edition of Dxers Unlimited, I will continue to provide more information on how this homebrew amateur double sideband and CW transceiver continues to evolve into a much more up to date piece of equipment… …… QSL on the air, QSL on the air… yes amigos QSL on the air to listener Craig near Ottawa , Canada that reports difficulties in picking up our 6 megahertz band frequencies during the past several days of extremely low solar activity…These reports are a clear demonstration that during the period of really minimum solar activity the nighttime maximum useable frequency for the typical 2000 kilometers F layer single hop propagation path can dip below 6.5 megaHertz and even lower, making reception rather difficult to say the least…But as already mentioned at the beginning of the program, solar cycle 24 seems to be just around the corner, and as soon as we see the first reverse magnetic polarity sunspots that signal the start up of the new cycle, propagation is going to take a turn for the better … ….. This is Dxers Unlimited’s weekend edition and here is ASK ARNIE, the most popular section of the program … Listeners Harry and Claude from Iowa and South Carolina in the USA want to know if backscatter propagation can happen during solar minimum, and the answer is that unless extremely high transmitter powers are involved, backscatter ionospheric propagation is not going to happen during extended periods of very low solar activity… So again, HF backscatter propagation is a phenomena strongly associated with periods of high and very high solar activity, which are a few years away from now … And now just before going QRT here is Arnie Coro’s HF plus low band VHF propagation update and forecast… One rather large sunspot came into existence this week, it is solar active region 953 and it has sent up the daily solar flux from baseline levels to well past the 80 flux units mark… Due to its present position on the solar disk, there are good chances for this sunspot active region to grow in size and further boost the solar activity that as I said earlier, has seen many days with a totally blank solar disk, with zero sunspot count. Be on the lookout for Sporadic E openings that will be happening mainly from 7 am to 11 am local time and from 3 pm to 9 pm local time. Send your signal reports and comments about the show 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. 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
