Radio Habana Cuba
Dxers Unlimited
By Arnie Coro, CO2KK
Hi mis amigos radioaficionados... 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: Very few sunspots, as expected during solar
minimum, and that has sent the daily maximum useable frequency curve way
down... as expected. 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 and for the next four days... Item
two: The electromagnetic ground plane single band antenna for amateur
radio stations is a very special type of antenna that I have already
talked about here at Dxers Unlimited but it continuues to bring a lot of
feedback from ham operators around the world... I have already sent many
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, as always you don't get something for
nothing. and this antenna does has two drawbacks... you have to adjust it
very carefully for a center frequency of operation and there is not a lot
of bandwidth either side of the optimum frequency to which the antenna is
tuned, also 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...That's
because it is certainly a lot take off angle radiator... the low angles
you want to work DX amigos !!!
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, but each cellphone system has a
preset capacity to create links, and when 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 recent communications emergencies that happened when several
hurricanes have struck our archipelago ... one of them was hurricane
Dennis, the fourth tropical storm of a very active season, that reached
up to Category 4 in the Saffir-Simpson scale that has a top limit of 5.
More than eight hundred Cuban radio amateur operators volunteered their
services during the hurricane Dennis emergency in 2005, providing vital
links between weather stations, high power weather radar installations,
the command posts of the National Civil Defense organization and many
other sites, like the water reservoirs . 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 very low with the effective sunspot number
at a rather low figure. The solar wind gust that was expected to impact
the Earth's magnetosphere simply didn't happen, and that's good news for
those of you living a latitudes above 40 degrees North, where the impact
of those proton showers really make the ionosphere behave very poorly
....now much higher than one week ago....Solar flux is running around 75
units, with the A index at a nice and low 03 around 15 hours UTC
Tuesday, the effective sunspot number was 15 at that same time, and the
optical sunspot count went up to 22 on Monday… Hope to have you
listening to the weekend edition of Dxers Unlimited next Saturday and
Sunday UTC days, and don’t forget to send me your signal reports and
comments about the program to arnie@rhc.cu, of VIA AIR MAIL to Arnie
Coro, Radio Havana Cuba, Havana, Cuba
(Arnie Coro)
Dxers Unlimited
By Arnie Coro, CO2KK
Hi mis amigos radioaficionados... 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: Very few sunspots, as expected during solar
minimum, and that has sent the daily maximum useable frequency curve way
down... as expected. 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 and for the next four days... Item
two: The electromagnetic ground plane single band antenna for amateur
radio stations is a very special type of antenna that I have already
talked about here at Dxers Unlimited but it continuues to bring a lot of
feedback from ham operators around the world... I have already sent many
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, as always you don't get something for
nothing. and this antenna does has two drawbacks... you have to adjust it
very carefully for a center frequency of operation and there is not a lot
of bandwidth either side of the optimum frequency to which the antenna is
tuned, also 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...That's
because it is certainly a lot take off angle radiator... the low angles
you want to work DX amigos !!!
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, but each cellphone system has a
preset capacity to create links, and when 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 recent communications emergencies that happened when several
hurricanes have struck our archipelago ... one of them was hurricane
Dennis, the fourth tropical storm of a very active season, that reached
up to Category 4 in the Saffir-Simpson scale that has a top limit of 5.
More than eight hundred Cuban radio amateur operators volunteered their
services during the hurricane Dennis emergency in 2005, providing vital
links between weather stations, high power weather radar installations,
the command posts of the National Civil Defense organization and many
other sites, like the water reservoirs . 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 very low with the effective sunspot number
at a rather low figure. The solar wind gust that was expected to impact
the Earth's magnetosphere simply didn't happen, and that's good news for
those of you living a latitudes above 40 degrees North, where the impact
of those proton showers really make the ionosphere behave very poorly
....now much higher than one week ago....Solar flux is running around 75
units, with the A index at a nice and low 03 around 15 hours UTC
Tuesday, the effective sunspot number was 15 at that same time, and the
optical sunspot count went up to 22 on Monday… Hope to have you
listening to the weekend edition of Dxers Unlimited next Saturday and
Sunday UTC days, and don’t forget to send me your signal reports and
comments about the program to arnie@rhc.cu, of VIA AIR MAIL to Arnie
Coro, Radio Havana Cuba, Havana, Cuba
(Arnie Coro)