By Arnie Coro CO2KKHi amigos radioaficionados around the world and those of you orbiting planet Earth too… I am Arnie Coro, radio amateur CO2KK in Havana and here is our first news item of today´s Dxers Unlimited…. According to several groups of scientific researchers involved in the analysis of solar activity, the still ongoing solar cycle number 23 may be the one with the longest most extended period of extremely low activity. In other words and in plain language, cycle 23 has extended its minimum beyond any of the forecasts and may be a record breaking solar event as compared with the last seven solar cycles.
So amigos, we must continue to wait until solar cycle 24 really starts changing what is happening 93 million miles away from us and that has such a tremendous impact here were we all live : Planet Earth.
Item two: Still catching up with the e-mail backlog , and the reason is no other than the fact that many of the messages sent by Dxers Unlimited listeners around the world include radio hobby related questions that do require comprehensive and easy to understand answers, something that , believe me, is not an easy job at all…
But don´t worry my friends, because each and every e-mail, postcard , letter or FAX received here is answered as soon as possible.
And of course, some of those questions are answered also on the air for the benefit of other listeners that may then learn more about the hobby.
There are many examples of how our YOU HAVE QUESTIONS and Arnie tries to answer them section of the program has helped radio hobby fans to solve some of the problems that they may have. Here is a recent example: A recent reply about the challenges that repairing present day sophisticated radio and other electronic equipment , led to several listeners deciding to buy or homebrew the so called ESR or equivalent series resistance meters, a test instrument that has really changed the way electronic technicians approach the repair of broken down equipment… More about the ESR meter and how it has helped to rescue a lot of broken down radios that were thought to be beyond repair , later in today´s program.
Stay with us amigos, as Dxers Unlimited will continue after a short break for station ID…
I am Arnie Coro in Havana…
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This is Radio Havana Cuba, the name of the show is Dxers Unlimited, and si amigos, sure, we do QSL, we do verify your reception reports absolutely free of charge and VIA AIR MAIL, as we believe, from the very first day that we went on the air , that international shortwave broadcasters must develop very good ties with their listeners , and one way of doing it is precisely by verifying reception reports…
Now, let me continue with today´s Technical Topics section of the program, that is devoted to what many electronic engineers and technicians consider to be an outstanding breakthrough in the repair of broken down equipment…
I am talking about the ESR or Equivalent Series Resistance Meter, a relatively simple test instrument that provides the repairman with most reliable information about the state of electrolytic capacitors, the electronic components that according to very trustworthy statistics account for the greatest number of electronic equipment failures during the past 20 years…
A repair technician that has access to an ESR meter will be able to fix equipment in a much faster and easier way, while at the same time he will be able to do advanced diagnostics that will allow the preventive replacement of electrolytic capacitors even before the equipment shows any signs of failure, including the challenging intermittent faults that are so typical of bad electrolytics …
One very interesting fact about the ESR meters is that you can learn how to use them very easily , and that the interpretation of the meter´s readings will lead to the decision of replacing capacitors that you will never had thought that required to be changed.
There are several very good designs of ESR meters, from a very simple one that uses an already existing oscilloscope as its output indicator, to an expensive model that provides digital readings of the equivalent series resistance, the parameter that provides the most reliable information about the state of electrolytic capacitors of any type, and by that I mean that tantalum capacitors can also be tested with the ESR meters.
Finally, let me add that you won´t need to desolder the electrolytic capacitors from the printed circuit boards in order to test them with the ESR meter, because in my opinion the most outstanding feature of this unique test instrument is that it is used by placing the two test probes to the terminals of the electrolytic capacitors and reading the result of the test directly on the instrument´s meter.
On my second homebrewed ESR meter, the instrument´s output meter movement was calibrated using a large number of both good, not so good and bad capacitors, and no matter how they were intermixed, the ESR meter always found the actual state of the capacitor beyond any possible doubts.
If you figure out that bad or in poor shape and not yet really bad electrolytic capacitors are the main cause of present day electronic equipment failures, it is easy to figure out how important this relatively new test instrument has become for performing electronic equipment repairs.
Also, it must be underscored that radio receivers, transmitters, and transceivers that are more than ten to fifteen years old usually hide many electrolytic and tantalum capacitors that may be starting to show signs of problems that eventually will lead to breakdowns that can be prevented by checking all the electrolytics with an ESR meter … Sure, it will take some time to do it, but it will be worth every minute spent doing it, as I have found out here at my electronics and radio workshop amigos…
Finally, the ESR meter is of tremendous help also when computer motherboards fail, as one of the main causes of those failures are bad electrolytics !!!
For technically minded Dxers Unlimited´s listeners, I have here ready to be sent, several computer files with information on how to homebrew your own Equivalent Series Resistance Meter . Send your request for the ESR meter files to inforhc at enet dot cu… Again, inforhc at enet dot cu… With just a few electronic components and several hours of your spare time, you will be able to assemble a really useful electronic test instrument that will be really useful to repair broken equipment.
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Si amigos, yes my friends, oui mes amis, you are now listening to your favorite radio hobby program, Dxers Unlimited with Arnie Coro…
And now here is our next feature here:
March the 30th marked the day that international short wave broadcasters started to use the new A08 schedule, that will be used until October. According to the International Telecommunications Union, the administrations must file the use of the short wave broadcast bands twice every year, and a year that , by the way, does not coincide with the actual year that begins on the first day of January and ends on the 31st of December… The A period starts in March and lasts until October and the B period starts in October and lasts until March, something that was done in order to simplify the previous scheduling system that implied four frequency changes per year.
The broadcasting schedules are sent to the ITU in Geneva to be registered in the general data base that is kept there, and the telecommunications administrations can see how their registered stations are providing services to the target areas, if there are any collisions of frequencies and the effects of adjacent channels too.
Since Radio Havana Cuba went on the air in 1961, the Cuban Ministry of Communications has registered the use of our station´s frequencies with the International Telecommunications Union in Geneva, that is the United Nations oldest specialized agency, since its origins can be found way back in 1865, when several nations started to coordinate the use of the Morse wired telegraphy lines …
The existence of voluntary frequency coordination groups around the world is also recognized by the ITU, but it is left to the decision of the national telecommunications administrations to participate or not participate in those not official groups that may have a regional or a worldwide scope.
So, again and to make it very clear to those listeners that have recently asked about the topic of frequency coordination, let me emphasize that what the ITU requests is that the national telecommunications send to Geneva the data about the use of the short wave broadcast transmissions according to a previously arranged time schedule, then the data is processed and results are sent back to the administrations showing how each entry behaves in relation to other entries on the same frequency and others that operate on adjacent channels 5 kiloHertz to each side of the frequency that is analyzed.
So, in other words, an administration may decide to join or not to join, to participate or not participate as part of frequency coordination groups or nation , but independently of forming part or not forming part of one or more coordinating groups, the
Telecommunications Administrations must file with the ITU in Geneva and register the use of each frequency by providing a set of well known transmission parameters that include transmitter power, antenna types, target areas CIRAF zones to be served etc.
The data is processed by the ITU using sophisticated computer software and the results are sent back to each administration so that the broadcast schedules can be optimized to the best possible extent…
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And now amigos, just before going QRT here, ready to copy, this is Arnie Coro´s Dxers Unlimited´s HF plus low band VHF propagation update and forecast … solar activity still at the bottom of the cycle´s very much extended minimum,ZERO SUNSPOTS , with solar flux at rock bottom 69 units and the A index was near 15 yesterday… So don´t expect DX stations to show up above 17 or 18 megaHertz during the local daytime hours , while during the evening hours propagation conditions will be good only to around 10 or maybe 12 megaHertz… No signs of sporadic E openings yet, but I expect those openings to start by the end of the month amigos !!! Send me your signal reports and comments about the program to inforhc at enet dot cu, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba
(Arie Coro, Radio Havana Cuba)