By Arnie Coro, CO2KK
Radio Havana Cuba
Hi mis amigos radioaficionados around the world and in space.. Hello short wave listeners, radio amateurs, TV Dxers, Low frequency LOWFERS, homebrewers of radios... hello to all of you my good friends and listeners of Dxers Unlimited. I am Arnie Coro, radio amateur CO2KK, and as always, its my pleasure to share with you about seventeen minutes of airtime...
Here is now today's program menu: Item one: One single solar active region on sight...... it has already produced class B and C flares and scientists predict that more are possible.
More about sunspots and short wave propagation later , at the end of the show when I will be presenting Arnie Coro's Dxers Unlimited HF propagation update ... Item two: The electromagnetic ground plane single band antenna for amateur radio stations reviewed during a recent edition of Dxers Unlimited brought a lot of feedback from ham operators around the world... I have already sent out more than twenty e-mail messages with all the information, including graphics and a table of measurements to help build the EMGP antenna for different amateur bands... The EMGP is a very low height antenna system that although it requires very small masts, its radiation efficiency compares to a full size quarter wave vertical antenna system.But I warn you...it does has two drawbacks.. you have to adjust the antenna system very carefully for a centerfrequency of operation and there is not a lot of bandwidth either side of the optimum frequency to which the antenna is tuned, and matching the antenna to the typical 50 ohm coaxial cable downlead may be a time consuming job. But on the brighter side, once the antenna is adjusted it is a set and forget procedure.... I tested several EMGPs and although the tests were not over a long period of time, the EMGP compared to a standard reference half wave dipole at the typical height that we radio amateurs can install HF antennas, produced very nice results...
If you want to know more about the EMGP low profile single band antenna, just send me an e-mail to arnie@rhc.cu, again, arnie@rhc.cu , or VIA AIR MAIL, send a postcard to Arnie Coro, Radio Havana Cuba, Havana, Cuba , more radio hobby related information coming up in a few seconds after a short break. This is Radio Havana Cuba, you are listening to Dxers Unlimited's mid week edition, stay tuned...
....
Si amigos, yes my friends, sure, there are many ways to enjoy our spare time by playing with our radios, antennas and all the associated equipment... Take for example the wonderful time spent assembling a new two meters or 70 centimeters band repeater that will be placed at a high rise building or maybe at a TV transmitter site way up atop a mountain, to provide coverage of an extensive area when using just small hand held FM transceivers or mobile radios installed on cars and trucks. Two meters and 70 centimeters band repeaters, when properly installed and mantained have proven, once and again, that they are able to provide excellent quality and very reliable communications links during emergencies, when many commercial systems just fail due to heave traffic... Yes cellphones are wonderful, cellphones are practical, cellphones are convenient... but each cellphone system has a preset capacity to create links, and what that capacity is exceeded, the cellphone base stations simply fall into a lockout mode... something that simply can't happen with an amateur band FM repeater... Here in Cuba, we have assembled and installed many two meter band repeaters during the past 5 years, and they have proven to be really useful during the any communications emergencies. If your local radio club has a two meters or a seventy centimeters band repeater, or for that matter an FM repeater operating on any of the amateur bands authorized for that type of automatic station, by all means help the persons running and mantaining the repeaters... One never knows when the next emergency will come out of nowhere and that nice repeater station that you normally use to chat while driving to work, may turn into the most useful communications tool to handle emergency traffic !!!
.......
This is Dxers Unlimited's mid week edition amigos, and here is item five : YOU HAVE QUESTIONS AND ARNIE TRIES TO ANSWER THEM, the most popular section of this program according to the statistics of our correspondence department ... Today's question, came from seven listeners located at such distant places as Alaska, Japan, New Zealand, Sweden , Ireland, India and Malaysia... They all want to learn more about the compact MOXON rectangle antenna system and why I have recommended it so much to Dxers Unlimited listeners... Well amigos, the MOXON rectangle antenna has a unique property as compared to a standard 2 element YAGI antenna... and it is the fact that one can build a MOXON RECTANGLE antenna so as to make it a very rugged system, that can stand extremely high wind gusts without been damaged.
Some 2 meters band repeater operators are now using the MOXON rectangle antennas at sites where wind gusts may peak regularly above the 80 to 100 miles per hour mark... While classical arrays of half wave dipoles may fail under such harsh weather conditions, the Moxon rectangle arrays stay up, increasing the all important reliability of the repeater even under stormy weather conditions.
Now, I am sure you all will want to know why the MOXON RECTANGLE antenna offers that high reliability,and the reason is no other than its mechanical design.
Contrary to the very exposed to wind gusts induced vibration typical of dipole elements, the MOXON's closed rectangle construction makes this antenna a very rugged radiating system. If built using large diameter copper pipe, a MOXON antenna for the 2 meters or 70 centimeters bands, will provide very good operating bandwidth and high reliability even under the most extreme weather conditions.
One further advantage of the MOXON antenna , is that it is very easy to build using common tools and readily available materials. The ones I have built here for the 6 meters band work very well and can be easily rotated by hand, because by building them using lightweight materials, this antenna is easily transportable and makes an ideal one for contest operation from a remote site.
So far I have seen MOXON RECTANGLE antennas made by using copper wire and fiberglass spreaders for the 20, 17, 15, 12 and 10 meter bands...
The MOXONS are single band antennas, that provide an apparent gain similar to a well designed 2 element Yagi , but that are more rugged and easier to build than the YAGIS, especially for the HF bands...
I hope that this answers your questions about the MOXON Rectangle antenna, and for all of you highly motivated with antenna design, a visit to www.cebik.com, will allow you to learn a lot more about this compact and efficient antenna, that also has an additional advantage, because it matches to 50 ohms coaxial line really well...
You can send your radio hobby related questions directly to my e-mail address... its's very easy to remember... arnie@rhc.cu, again, arnie@rhc.cu , and VIA AIR MAIL, send a postcard to Arnie Coro , Radio Havana Cuba, Havana , Cuba, and now here is another very popular section of Dxers Unlimited, our technical topics section ... Today 's tip is related to the revival of gell cell sealed accumulators... the ones used for computer UPS systems, home alarms and of course portable low power amateur radio stations... The typical gell cell accumulator is capable of providing either 6 volts or 12 volts, at current ratings that go from about 4 to 10 ampere hours... Anything higher than 10 ampere hours will be rather large sized and bulky...
If you take a look at the typical gell cell accumulator, you will see that it is totally sealed, and there is no way to add electrolyte or deionized water to each of the battery elements connected in series to provide 6 or 12 volts to our radios...
Here is what I do here to revive GELL CELL accumulators, although after using the process to be described, the GELL CELL battery can no longer be moved around as it will be loosing its "sealed" nature.
Well, what I do is simply to drill trough each of the battery cells so that deionized water or battery electrolyte can be added with the help of a plastic syringe.
Be extremely careful when handling the battery and the electrolyte, and after topping up each cell, then proceed to put back the plugs, recharge the battery at a rate of one tenth of its capacity , and then run a test with your radios... In most cases I have obtained very good results that have prolonged the useful life of the GELL CELL ACCUMULATOR , for up to one more year of continuos use.
.....
And now amigos , ready to copy, here is our exclusive and not copyrighted HF plus low and VHF propagation update and forecast... Solar activity has continued to be at very low levels, with solar flux barely moving above 70 units... The effects of a high speed solar wind are now subsiding, and the geomagnetic field is expected to be back to normal when you are hearing this program. The all over darkness path from the Caribbean to Australia is providing excellent reception of short wave stations during the local time period here extending from about one o clock in the morning, that is zero five hours UTC until a few minutes after local sunrise... It is certainly a very interesting propagation path that radio amateur have enjoyed for 40 meters band contacts at this time of solar minimum activity, I hope to have you listening to our weekend edition next Saturday and Sunday UTC days , and also don't forget to send me your signal reports and comments about the program as well as any radio hobby related questions to arnie@rhc.cu, again arnie@rhc.cu or via:
AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba
Radio Havana Cuba
Hi mis amigos radioaficionados around the world and in space.. Hello short wave listeners, radio amateurs, TV Dxers, Low frequency LOWFERS, homebrewers of radios... hello to all of you my good friends and listeners of Dxers Unlimited. I am Arnie Coro, radio amateur CO2KK, and as always, its my pleasure to share with you about seventeen minutes of airtime...
Here is now today's program menu: Item one: One single solar active region on sight...... it has already produced class B and C flares and scientists predict that more are possible.
More about sunspots and short wave propagation later , at the end of the show when I will be presenting Arnie Coro's Dxers Unlimited HF propagation update ... Item two: The electromagnetic ground plane single band antenna for amateur radio stations reviewed during a recent edition of Dxers Unlimited brought a lot of feedback from ham operators around the world... I have already sent out more than twenty e-mail messages with all the information, including graphics and a table of measurements to help build the EMGP antenna for different amateur bands... The EMGP is a very low height antenna system that although it requires very small masts, its radiation efficiency compares to a full size quarter wave vertical antenna system.But I warn you...it does has two drawbacks.. you have to adjust the antenna system very carefully for a centerfrequency of operation and there is not a lot of bandwidth either side of the optimum frequency to which the antenna is tuned, and matching the antenna to the typical 50 ohm coaxial cable downlead may be a time consuming job. But on the brighter side, once the antenna is adjusted it is a set and forget procedure.... I tested several EMGPs and although the tests were not over a long period of time, the EMGP compared to a standard reference half wave dipole at the typical height that we radio amateurs can install HF antennas, produced very nice results...
If you want to know more about the EMGP low profile single band antenna, just send me an e-mail to arnie@rhc.cu, again, arnie@rhc.cu , or VIA AIR MAIL, send a postcard to Arnie Coro, Radio Havana Cuba, Havana, Cuba , more radio hobby related information coming up in a few seconds after a short break. This is Radio Havana Cuba, you are listening to Dxers Unlimited's mid week edition, stay tuned...
....
Si amigos, yes my friends, sure, there are many ways to enjoy our spare time by playing with our radios, antennas and all the associated equipment... Take for example the wonderful time spent assembling a new two meters or 70 centimeters band repeater that will be placed at a high rise building or maybe at a TV transmitter site way up atop a mountain, to provide coverage of an extensive area when using just small hand held FM transceivers or mobile radios installed on cars and trucks. Two meters and 70 centimeters band repeaters, when properly installed and mantained have proven, once and again, that they are able to provide excellent quality and very reliable communications links during emergencies, when many commercial systems just fail due to heave traffic... Yes cellphones are wonderful, cellphones are practical, cellphones are convenient... but each cellphone system has a preset capacity to create links, and what that capacity is exceeded, the cellphone base stations simply fall into a lockout mode... something that simply can't happen with an amateur band FM repeater... Here in Cuba, we have assembled and installed many two meter band repeaters during the past 5 years, and they have proven to be really useful during the any communications emergencies. If your local radio club has a two meters or a seventy centimeters band repeater, or for that matter an FM repeater operating on any of the amateur bands authorized for that type of automatic station, by all means help the persons running and mantaining the repeaters... One never knows when the next emergency will come out of nowhere and that nice repeater station that you normally use to chat while driving to work, may turn into the most useful communications tool to handle emergency traffic !!!
.......
This is Dxers Unlimited's mid week edition amigos, and here is item five : YOU HAVE QUESTIONS AND ARNIE TRIES TO ANSWER THEM, the most popular section of this program according to the statistics of our correspondence department ... Today's question, came from seven listeners located at such distant places as Alaska, Japan, New Zealand, Sweden , Ireland, India and Malaysia... They all want to learn more about the compact MOXON rectangle antenna system and why I have recommended it so much to Dxers Unlimited listeners... Well amigos, the MOXON rectangle antenna has a unique property as compared to a standard 2 element YAGI antenna... and it is the fact that one can build a MOXON RECTANGLE antenna so as to make it a very rugged system, that can stand extremely high wind gusts without been damaged.
Some 2 meters band repeater operators are now using the MOXON rectangle antennas at sites where wind gusts may peak regularly above the 80 to 100 miles per hour mark... While classical arrays of half wave dipoles may fail under such harsh weather conditions, the Moxon rectangle arrays stay up, increasing the all important reliability of the repeater even under stormy weather conditions.
Now, I am sure you all will want to know why the MOXON RECTANGLE antenna offers that high reliability,and the reason is no other than its mechanical design.
Contrary to the very exposed to wind gusts induced vibration typical of dipole elements, the MOXON's closed rectangle construction makes this antenna a very rugged radiating system. If built using large diameter copper pipe, a MOXON antenna for the 2 meters or 70 centimeters bands, will provide very good operating bandwidth and high reliability even under the most extreme weather conditions.
One further advantage of the MOXON antenna , is that it is very easy to build using common tools and readily available materials. The ones I have built here for the 6 meters band work very well and can be easily rotated by hand, because by building them using lightweight materials, this antenna is easily transportable and makes an ideal one for contest operation from a remote site.
So far I have seen MOXON RECTANGLE antennas made by using copper wire and fiberglass spreaders for the 20, 17, 15, 12 and 10 meter bands...
The MOXONS are single band antennas, that provide an apparent gain similar to a well designed 2 element Yagi , but that are more rugged and easier to build than the YAGIS, especially for the HF bands...
I hope that this answers your questions about the MOXON Rectangle antenna, and for all of you highly motivated with antenna design, a visit to www.cebik.com, will allow you to learn a lot more about this compact and efficient antenna, that also has an additional advantage, because it matches to 50 ohms coaxial line really well...
You can send your radio hobby related questions directly to my e-mail address... its's very easy to remember... arnie@rhc.cu, again, arnie@rhc.cu , and VIA AIR MAIL, send a postcard to Arnie Coro , Radio Havana Cuba, Havana , Cuba, and now here is another very popular section of Dxers Unlimited, our technical topics section ... Today 's tip is related to the revival of gell cell sealed accumulators... the ones used for computer UPS systems, home alarms and of course portable low power amateur radio stations... The typical gell cell accumulator is capable of providing either 6 volts or 12 volts, at current ratings that go from about 4 to 10 ampere hours... Anything higher than 10 ampere hours will be rather large sized and bulky...
If you take a look at the typical gell cell accumulator, you will see that it is totally sealed, and there is no way to add electrolyte or deionized water to each of the battery elements connected in series to provide 6 or 12 volts to our radios...
Here is what I do here to revive GELL CELL accumulators, although after using the process to be described, the GELL CELL battery can no longer be moved around as it will be loosing its "sealed" nature.
Well, what I do is simply to drill trough each of the battery cells so that deionized water or battery electrolyte can be added with the help of a plastic syringe.
Be extremely careful when handling the battery and the electrolyte, and after topping up each cell, then proceed to put back the plugs, recharge the battery at a rate of one tenth of its capacity , and then run a test with your radios... In most cases I have obtained very good results that have prolonged the useful life of the GELL CELL ACCUMULATOR , for up to one more year of continuos use.
.....
And now amigos , ready to copy, here is our exclusive and not copyrighted HF plus low and VHF propagation update and forecast... Solar activity has continued to be at very low levels, with solar flux barely moving above 70 units... The effects of a high speed solar wind are now subsiding, and the geomagnetic field is expected to be back to normal when you are hearing this program. The all over darkness path from the Caribbean to Australia is providing excellent reception of short wave stations during the local time period here extending from about one o clock in the morning, that is zero five hours UTC until a few minutes after local sunrise... It is certainly a very interesting propagation path that radio amateur have enjoyed for 40 meters band contacts at this time of solar minimum activity, I hope to have you listening to our weekend edition next Saturday and Sunday UTC days , and also don't forget to send me your signal reports and comments about the program as well as any radio hobby related questions to arnie@rhc.cu
AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba
