Dxers Unlimited's weekend edition for 26-27 July 2008By Arnie Coro CO2KK
Hi amigos radioaficionados ! Yes !!! You are on the right frequency… Your radio is now tuned to Radio Havana Cuba's twice weekly radio hobby program, the one and only with the most up to date short wave propagation updates and forecasts...
By the Way ... propagation is rather poor right now, so if you notice poor reception , it is certainly a consequence of the effects of the extremely low solar activity ...
Item two: Radio is a lot of fun, and you can become part of more of it by exploring the different ways that you and I can enjoy the hobby.. for example, normally few of the regular international broadcasts short wave listeners are aware of the fact that radio receivers capable of picking up single side band signals and CW Morse code signals,as well as digital modes will open up a completely new world for them.
That's why I insist on the fact that when you are ready to upgrade to a better radio receiver, ALWAYS, and I mean it amigos, ALWAYS go for a radio that has a beat frequency oscillator and a product detector, the two circuits that make the whole difference, so that you can listen not only to CW Morse Code amateur radio communications, but also to Single Side Band voice, and pick up , with the help of your computer some of the very interesting digital communications modes that are now regularly on the air.
Are you ready to UPGRADE to a better radio ? OK, sure, go ahead, but don't dispose of your present receiver amigos... because owning two radios will allow you to enjoy the hobby a lot more....
Here is why….
For example, you can be taping a program on one radio, for listening to it later, and then continue to explore a specific band for DX at the same time. Some hobbyists have more than 2 or 3 radios, usually devoting one of them for portable work when traveling.
Item three: One of the problems that homebrewers of radios have to deal with is how to find the parts , the electronic components to make them, YES, its becoming more and more difficult , but keep listening to Dxers Unlimited's weekend edition and I will be telling you where to find lots of parts to be able to start up many of your electronic projects .
Item four: Our very popular YOU have Questions and Arnie tries to answer them, a fast tract way of solving your radio hobby related problems... send your questions to inforhc at enet dot cy and also via e-mail Arnie Coro, Radio Havana Cuba, Havana, Cuba.
Then as always at the end of the program, you will be able to hear our exclusive and not copyrighted , in the public domain, HF plus VHF low band , up to 50 megaHertz propagation update and forecast.
I am Arnie Coro in Havana, stay tuned, Dxers Unlimited will continue in just a few seconds.
.........
You are listening to the weekend edition of your favorite radio hobby program, coming to you from Radio Havana Cuba, and here is now you have questions and Arnie tries to answer them... Today's question comes from several listeners, from as far apart locations as Argentina and Norway !!!
Six of them happen to be amateur radio operators, two are short wave listeners, and one tells me in his e-mail that he just took his ham radio license test and will soon be on the air with his own amateur radio station, All of them have asked for my opinion about the HALF SQUARE antenna .
All of them are Dx hunters at heart, and are looking forward to the upcoming increase in solar activity, expected to begin sometime during the next year, while at this moment we continue to see very low solar activity.
Well amigos, once again I must declare myself as n advocate of the HALF SQUARE antenna array, even though, I must emphasize that it is a SINGLE BAND ANTENNA ...
Among the many advantages I see for the HALF SQUARE, is the fact that it is a low cost antenna, easy to install and self adjusting system that will provide the all important LOW TAKE OFF ANGLE essential for working DX. My experiments with HALF SQUARE antennas have gone from the 2 meter band all the way up to 20 meters, and I have not tested on the lower frequencies, because the HALF SQUARE antennas for the 40 and 80 meter bands need rather tall masts that I don't have available at my home QTH.
Anyway, the answer to your question amigos !!!
SURE, go ahead, try the HALF SQUARE, but be careful with the way you feed the antenna, as you should avoid feedline radiation, and the only way to achieve this is to install a coaxial choke balun right at the feedpoint.
For those of you not familiar with the coaxial choke balun, it is a very simple way of canceling the radiation from the outside of the shield of the cable by coiling no less than six turns of the coaxial cable with a diameter that will depend on the operating frequency.
For the typical 20 to 10 meter bands HALF SQUARE, the coaxial cable coil diameter should be about 20 centimeters or 10 inches, and it is not really critical. The HALF SQUARE antenna radiates on two main lobes,and this you must take into consideration, because you will want to install the antenna favoring the most wanted directions. Or you can do what I did with my 6 meter band HALF SQUARES, just install two of them with a switch , so that I may cover DX signals from all compass headings !!! The HALF SQUARE is easy to build, and also very easy to adjust, but again, I
must remind you that it is a single band antenna. Dxers at this stage of the solar cycle will like to build HALF SQUARES for 40 and 20 as the higher frequency bands are now much less active, to say the least, due to the lower solar activity !!!
......
Amigos, you are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited, and this is not the only show I do here... May I invite you to join me Sundays and Mondays UTC days or Thursdays and Fridays UTC days at Breakthrough, our Science, Technology and the Environment update... a program where you will learn about how Cuba is working to apply the most recent advances of science and the technology to develop the nation, and also to protect the environment for the future generations... You can visit our website at rhc.cu, just that easy, just type rhc dot cu in your browser window and then go to the English page to pick up our program schedule. There you will also find the Dxers Unlimited's WebPages, with the scripts of the most recent shows for you to read... Now here is another of today's topics, as promised at the start up of the program ... how to find parts for your radio hobby projects…
First of all, I recommend that you join a local radio club, and learn about the many activities that radio clubs organize, including, of course, the fleamarkets and hamfests... There at the hamfests you can have a good time, learn a lot about the radio hobby, and explore the many items for sale that radio amateurs usually bring to the hamfest's fleamarkets.
For example, a Canadian friend told me recently in an e-mail that he had bought a plastic bag full of obsolete transistors, no less than 500 of them for just two Canadian dollars... the transistors were a very popular small signal type that could best be described as a sort of universal device, and that bagfull will soon be landing here in Havana, as my friend has donated it to the Plaza Radio Club's beginners project... Similarly you can find resistors, capacitors, printed circuit boards full of highly valuable parts that can be desoldered and recycled very successfully...
Another excellent source of electronic components is recycling old computers of the first generations, as the newer ones have such a high degree of integration that they are not worth the effort. Computer power supplies have proven to be a treasure chest of parts for the parts required to assemble vacuum tube radio's power supplies, as they are always high capacity high voltage electrolytics and silicon rectifiers. My 150 volts DC standard power supply that provides all the needs of the popular REGENERODYNE home brew receiver, uses a lot of parts recycled from an old AT machine switched mode power supply...
You can also look around for old TV sets, fax machines, old radios, computer monitors... you name it !
But be especially careful when handling TV sets and computer monitors, as the cathode ray tubes are really dangerous to work with when you are trying to remove the parts... In that case, don't attempt
to work with them if you are not fully aware of how to deal with the high vacuum picture tubes !!!
Si amigos, yes my friends, oui mes amis, you do need electronic components, nuts and bolts, fittings , PC boards etc. to make your own radios , but they can be found at very low cost or even for free if you know where to look !!!
............
Radio Havana Cuba recently celebrated its 47nd anniversary... And I am studying the possibility of organizing acontest for Dxers Unlimited's listeners that will end in May of 2009, when the station will be having its 48th birthdayt... The contest will be a lot of fun, and as soon as I have the rules ready, you will be learning about it... The idea is to run the contest during the whole period from September to March, from the autumn equinox to the spring equinox, so that everyone participating may have a good chance to win one of the prizes !!! !!!
OK ! Now let me see if there is something else that is missing from today's menu...OK, I found it, I wanted to mention the fact that SOLAR CORONAL HOLES receive designator codes too, like sunspot active regions.
Now, as always at the end of the program, here is Arnie Coro´s Dxers Unlimited´s , exclusive and not copyrighted HF plus Low Band VHF , from 30 to 50 megaHertz, propagation update and forecast.
The geomagnetic field is expected to be very quiet during the next three to five days, and the solar flux will continue to be at the bare minimum levels of between 65 and 67 units… No geomagnetic disturbances are expected during the next three days….. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is going to continue to be poor, propagation along north-south paths is fair.
I expect more Sporadic E events to happen from now until the end of the month, with some of them sending the maximum useable frequency curve up past the FM broadcast band and even into the 2 meters amateur band for very short periods… Amigos , I hope to see you all back here at the mid week edition of Dxers Unlimited next Tuesday and Wednesday UTC days and don't forget to send me your signal reports and comments about the show, as well as any radio hobby related questions you may want to know about. send mail to inforhc at enet dot cu, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba
By the Way ... propagation is rather poor right now, so if you notice poor reception , it is certainly a consequence of the effects of the extremely low solar activity ...
Item two: Radio is a lot of fun, and you can become part of more of it by exploring the different ways that you and I can enjoy the hobby.. for example, normally few of the regular international broadcasts short wave listeners are aware of the fact that radio receivers capable of picking up single side band signals and CW Morse code signals,as well as digital modes will open up a completely new world for them.
That's why I insist on the fact that when you are ready to upgrade to a better radio receiver, ALWAYS, and I mean it amigos, ALWAYS go for a radio that has a beat frequency oscillator and a product detector, the two circuits that make the whole difference, so that you can listen not only to CW Morse Code amateur radio communications, but also to Single Side Band voice, and pick up , with the help of your computer some of the very interesting digital communications modes that are now regularly on the air.
Are you ready to UPGRADE to a better radio ? OK, sure, go ahead, but don't dispose of your present receiver amigos... because owning two radios will allow you to enjoy the hobby a lot more....
Here is why….
For example, you can be taping a program on one radio, for listening to it later, and then continue to explore a specific band for DX at the same time. Some hobbyists have more than 2 or 3 radios, usually devoting one of them for portable work when traveling.
Item three: One of the problems that homebrewers of radios have to deal with is how to find the parts , the electronic components to make them, YES, its becoming more and more difficult , but keep listening to Dxers Unlimited's weekend edition and I will be telling you where to find lots of parts to be able to start up many of your electronic projects .
Item four: Our very popular YOU have Questions and Arnie tries to answer them, a fast tract way of solving your radio hobby related problems... send your questions to inforhc at enet dot cy and also via e-mail Arnie Coro, Radio Havana Cuba, Havana, Cuba.
Then as always at the end of the program, you will be able to hear our exclusive and not copyrighted , in the public domain, HF plus VHF low band , up to 50 megaHertz propagation update and forecast.
I am Arnie Coro in Havana, stay tuned, Dxers Unlimited will continue in just a few seconds.
.........
You are listening to the weekend edition of your favorite radio hobby program, coming to you from Radio Havana Cuba, and here is now you have questions and Arnie tries to answer them... Today's question comes from several listeners, from as far apart locations as Argentina and Norway !!!
Six of them happen to be amateur radio operators, two are short wave listeners, and one tells me in his e-mail that he just took his ham radio license test and will soon be on the air with his own amateur radio station, All of them have asked for my opinion about the HALF SQUARE antenna .
All of them are Dx hunters at heart, and are looking forward to the upcoming increase in solar activity, expected to begin sometime during the next year, while at this moment we continue to see very low solar activity.
Well amigos, once again I must declare myself as n advocate of the HALF SQUARE antenna array, even though, I must emphasize that it is a SINGLE BAND ANTENNA ...
Among the many advantages I see for the HALF SQUARE, is the fact that it is a low cost antenna, easy to install and self adjusting system that will provide the all important LOW TAKE OFF ANGLE essential for working DX. My experiments with HALF SQUARE antennas have gone from the 2 meter band all the way up to 20 meters, and I have not tested on the lower frequencies, because the HALF SQUARE antennas for the 40 and 80 meter bands need rather tall masts that I don't have available at my home QTH.
Anyway, the answer to your question amigos !!!
SURE, go ahead, try the HALF SQUARE, but be careful with the way you feed the antenna, as you should avoid feedline radiation, and the only way to achieve this is to install a coaxial choke balun right at the feedpoint.
For those of you not familiar with the coaxial choke balun, it is a very simple way of canceling the radiation from the outside of the shield of the cable by coiling no less than six turns of the coaxial cable with a diameter that will depend on the operating frequency.
For the typical 20 to 10 meter bands HALF SQUARE, the coaxial cable coil diameter should be about 20 centimeters or 10 inches, and it is not really critical. The HALF SQUARE antenna radiates on two main lobes,and this you must take into consideration, because you will want to install the antenna favoring the most wanted directions. Or you can do what I did with my 6 meter band HALF SQUARES, just install two of them with a switch , so that I may cover DX signals from all compass headings !!! The HALF SQUARE is easy to build, and also very easy to adjust, but again, I
must remind you that it is a single band antenna. Dxers at this stage of the solar cycle will like to build HALF SQUARES for 40 and 20 as the higher frequency bands are now much less active, to say the least, due to the lower solar activity !!!
......
Amigos, you are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited, and this is not the only show I do here... May I invite you to join me Sundays and Mondays UTC days or Thursdays and Fridays UTC days at Breakthrough, our Science, Technology and the Environment update... a program where you will learn about how Cuba is working to apply the most recent advances of science and the technology to develop the nation, and also to protect the environment for the future generations... You can visit our website at rhc.cu, just that easy, just type rhc dot cu in your browser window and then go to the English page to pick up our program schedule. There you will also find the Dxers Unlimited's WebPages, with the scripts of the most recent shows for you to read... Now here is another of today's topics, as promised at the start up of the program ... how to find parts for your radio hobby projects…
First of all, I recommend that you join a local radio club, and learn about the many activities that radio clubs organize, including, of course, the fleamarkets and hamfests... There at the hamfests you can have a good time, learn a lot about the radio hobby, and explore the many items for sale that radio amateurs usually bring to the hamfest's fleamarkets.
For example, a Canadian friend told me recently in an e-mail that he had bought a plastic bag full of obsolete transistors, no less than 500 of them for just two Canadian dollars... the transistors were a very popular small signal type that could best be described as a sort of universal device, and that bagfull will soon be landing here in Havana, as my friend has donated it to the Plaza Radio Club's beginners project... Similarly you can find resistors, capacitors, printed circuit boards full of highly valuable parts that can be desoldered and recycled very successfully...
Another excellent source of electronic components is recycling old computers of the first generations, as the newer ones have such a high degree of integration that they are not worth the effort. Computer power supplies have proven to be a treasure chest of parts for the parts required to assemble vacuum tube radio's power supplies, as they are always high capacity high voltage electrolytics and silicon rectifiers. My 150 volts DC standard power supply that provides all the needs of the popular REGENERODYNE home brew receiver, uses a lot of parts recycled from an old AT machine switched mode power supply...
You can also look around for old TV sets, fax machines, old radios, computer monitors... you name it !
But be especially careful when handling TV sets and computer monitors, as the cathode ray tubes are really dangerous to work with when you are trying to remove the parts... In that case, don't attempt
to work with them if you are not fully aware of how to deal with the high vacuum picture tubes !!!
Si amigos, yes my friends, oui mes amis, you do need electronic components, nuts and bolts, fittings , PC boards etc. to make your own radios , but they can be found at very low cost or even for free if you know where to look !!!
............
Radio Havana Cuba recently celebrated its 47nd anniversary... And I am studying the possibility of organizing acontest for Dxers Unlimited's listeners that will end in May of 2009, when the station will be having its 48th birthdayt... The contest will be a lot of fun, and as soon as I have the rules ready, you will be learning about it... The idea is to run the contest during the whole period from September to March, from the autumn equinox to the spring equinox, so that everyone participating may have a good chance to win one of the prizes !!! !!!
OK ! Now let me see if there is something else that is missing from today's menu...OK, I found it, I wanted to mention the fact that SOLAR CORONAL HOLES receive designator codes too, like sunspot active regions.
Now, as always at the end of the program, here is Arnie Coro´s Dxers Unlimited´s , exclusive and not copyrighted HF plus Low Band VHF , from 30 to 50 megaHertz, propagation update and forecast.
The geomagnetic field is expected to be very quiet during the next three to five days, and the solar flux will continue to be at the bare minimum levels of between 65 and 67 units… No geomagnetic disturbances are expected during the next three days….. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is going to continue to be poor, propagation along north-south paths is fair.
I expect more Sporadic E events to happen from now until the end of the month, with some of them sending the maximum useable frequency curve up past the FM broadcast band and even into the 2 meters amateur band for very short periods… Amigos , I hope to see you all back here at the mid week edition of Dxers Unlimited next Tuesday and Wednesday UTC days and don't forget to send me your signal reports and comments about the show, as well as any radio hobby related questions you may want to know about. send mail to inforhc at enet dot cu, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba
(Arnie Coro)