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Re: [HCDX] Dxers Unlimited's weekend edition for 15 -16 Sept 2007
Radio Habana Cuba
Dxers Unlimited
Dxers Unlimited's weekend edition for Sept 15-16 2007
By Arnie Coro
radio amateur CO2KK
Hi amigos radioaficionados ! This is the weekend edition of Dxers
Unlimited coming to you from Havana. I am Arnie Coro, radio amateur
CO2KK,your host here at this twice weekly program, Radio Havana Cuba's
contribution to the promotion and development of the radio hobby in all
its many fascinating aspects, from enjoying a two way ham radio contact
with an astronaut orbiting the Earth to providing vitally needed
emergency communications during a hurricane, from spending the weekend
participating in an amateur radio contest, to carefully soldering the
last electronic component to a homebrew radio project...
Si amigos, radio is a very special hobby, that you can actually start
enjoying today, simply by chasing for long distance stations on the AM
medium wave broadcast band with a small portable receiver... by the way,
AM broadcast band Dxing is already seeing much better propagation during
the now in progress autoumn equinoctial Dx that officially starts,
according to propagation gurus around the second week of September.... I
Item two: thank you very much, muchas gracias , merci beaocuop amigos...
for the many nice e-mail messages, postcards and letters that I receive
here every day from listeners of Dxers Unlimited all around the world...
Although the range of short wave broadcasts is limited by many different
elements, like transmitter power, the antenna in use and propagation
conditions, the fact is that this show is heard all around Planet Earth
according to what I monitor every day... and those e-mails , postcards,
letters and fax messages are very encouraging, because they tell me that
there is a lot of interest and enthusiasm for the radio hobby from
people of all ages...
I do insist ,radio need not be an expensive hobby at all, and it will
help you learn many useful and practical things too... For example a
Canadian school teacher Neil Carleton, uses short wave radio
broadcasting as a way of making his students learn more about geography
and the way people in other nations live, a Cuban medical doctor uses
his amateur radio station to talk to other physicians around the world
to learn more about tropical diseases, and those radio amateurs involved
in VHF propagation continue to provide extremely valuable information to
researchers trying to decode the mysterious sporadic E layer events that
no one knows why they happen... Enjoy radio, and maybe today, staying
right here on this same frequency or web connection, you can learn a bit
more about this wonderful hobby, yours and mine...
I am Arnie Coro in Havana, back with you in a few seconds amigos....
Si, yes, oui, your receiver is tuned to Radio Havana Cuba's Dxers
Unlimited and here is now our next item of today's program: Got several
e-mail messages talking about the crank power radios, and how convenient
they are at times of emergencies... Now, let me clarify to listeners
that have asked about them..., there are two types of crank up power
radios, the ones that use a clockwork mechanism, that you wind up to
obtain a certain operating time as the clockwork slowly unwinds to power
the generator, and the much more rugged and reliable for emergencies
crank up power radios that charge a battery inside the radio by cranking
a direct current generator. These are the ones I recommend for emergency
duty, because they will run even with totally dead batteries, keeping
the radio alive as long as you keep cranking the generator. A good
example of this type of portable receiver is the Grundig FR200 that has
become more a less a classic by now ,it that has AM, FM and two short
wave bands, although the very simple receiver circuitry doesn't make
this radio a Dxers choice .
The Grundig FR-200 I have tested here receives on all four bands even
with the nickel metal hydride battery removed, as long as one keeps
cranking the generator. AM and FM broadcast band reception is excellent
when powering the radio directly from the crank up generator, but, as
expected it's no good at all on the short wave bands, because the
receiver's local oscillator keeps moving up and down as the voltage
changes during the cranking process... So , follow your friend's Arnie
Coro's advice, and shop around for your emergency radio, remembering
that the ones that use clockwork mechanisms are not as reliable as the
radios that use a direct action crank up generator...
For those of you in the Caribbean, Central America and the Southern
United States of America, the hurricane season started on the first day
of June, and according to weather long range forecasts, this hurricane
season is going to be at least as active as the 2006 one...
So, it's nice to be prepared with your new portable radio that is
totally independent of external power sources... !!!
Item three: A nice e-mail message from a long time Canadian listener
tells me that the Canadian International DX CLub monthly bulletin is
from now on an e-publication, that is,its no longer going to be printed,
but distributed electronically... Congratulations amigos for this new
breakthrough that will make CIDX club members able to receive the
magazine by means of an e-mail attachment !!!
CIDX and ODXA, the Ontario DX Association are among the two long lived
Canadian radio clubs, that have survived the impact of the Internet due
to the hard work and dedication of their devoted executive board members
!!!
Item four: Antenna experiments are always fascinating, and one learns a
lot whenever playing with antennas, both by means of the advanced
antenna simulation software now available, and when actually building
and testing them. A recent example was brought to my attention by my
good friend Osvaldo Victores , CO3OV, who designed a very low cost, easy
to homebrew three element Yagi antenna for the two meters amateur band.
Osvaldo tested his antenna recently. Cuban radio amateurs will be
providing next month, once again, back up communications links to many
remotely located polling stations, so that election results can be known
at the municipal , provincial and national elections commissions as soon
as possible.
Osvaldo's three element Yagi uses a very short boom, and provides about
6 dB gain over a half wave dipole antenna. He told me that matching is
easily achieved with a GAMMA match rod and a series air spaced variable
capacitor. The antenna is lightweight, can be assembled and disassembled
in a few minutes and is built using recycled materials. Antenna elements
from discarded TV antennas were used in this project, and the short boom
came also from a damaged TV antenna... Total cost of CO3OV's three
element YAGI 00.00 Pesos and OO cents....I have asked Osvaldo to pass
along to me the design information of his optimized low cost three
element Yagi for the 2 meters ham band, so that in an upcoming edition
of the program I can make them available to you all amigos !!!
Ah... before I forget, Osvaldo's Yagi uses, as I explained a very short
boom, as the reflector to driven element distance is around 40
centimeters, and the driven element to director distance is about 30
centimeters... So the boom is just about 75 centimeters long, and it can
be made from aluminum tubing, copper tubing or plastic PVC water pipe...
although Osvaldo told me that the antenna elements lengths were
calculated for a metal boom, so that using a plastic boom will require
re-calculating the length of the elements...He also added that placing
the director element farther away from the
driven element will increase the gain of the antenna a little bit, but
it then will require using a longer boom to support the three elements.
Keep listening to Dxers Unlimited amigos, more radio hobby related
information coming up ...
......
This is Radio Havana Cuba... the name of the show is Dxers Unlimited,
and yes we do QSL, we do verify reception reports, and we do it
absolutely free of charge to listeners , as we consider this an
essential part of running an international broadcast station
amigos...Send you reception reports directly to me ... mail to
arnie@xxxxxx, yes, easy to remember... arnie@xxxxxx, or via air mail
send a postcard to Arnie Coro, Radio Havana Cuba, Havana, Cuba...and if
you use the postal system , be patient , especially if you happen to
live in the USA, as direct postal exchange with the United States of
America does not exist, requiring the mail to go via a third country...
Now here is our numero uno section of the program... YOU HAVE QUESTIONS,
and Arnie tries to answer them , as soon as possible... delivering the
answers directly to your computer if you ask your questions via e-mail
to arnie@xxxxxxxxxxxxxxx question came from listeners in Germany, the
UK, Canada and South Africa, they all want to know more about the
possibility of using discarded laptop or notebook computers battery pack
cells for assembling batteries for their radios... Sure amigos, as a
matter of fact, my two meters band handie talkie has used recycled
nickel cadmium and metal hydride cells for years and years... The
individual battery cells are obtained in this case from discarded
cellphone batteries... The typical cellphone battery fails after a
certain number of charge and discharge cycles, and exactly the same
happens to laptop and notebook computers battery packs... What very few
people realize is that those battery pack failures, in many cases are
due to just one maybe or two, or even three or four cells going dead,
while the rest of the pack is still in good working order...
Carefully opening up the discarded battery packs , you can detect, even
by simple visual inspection the cells that are leaking at the seals, and
send them to the proper recycling organization, as you don't want to
pollute Mother Earth with heavy metals at all... The other cells that
look good, are then carefully removed and tested, using a procedure that
I will describe in detail during an upcoming Dxers Unlimited ...
Assembling a recycled battery pack made from those cells that are in
good shape is not difficult at all, and as I have just stated, my two
meters band FM handie talkie has used this form of recycled battery pack
for several years with a very high degree of reliability...
Si amigos, you can save a lot of money by recycling laptop and notebook
computers battery packs , and also by doing the same with cellphone
batteries too... With simple hand tools, a digital multimeter and a
simple test procedure , plus a few hours of your spare time, I can
assure you that you won't need to spend a single cent buying new
rechargeable batteries for your radios...
And now as always at the end of the program , here is our exclusive and
not copy righted HF plus low band VHF propagation update and forecast...
Yes this is Arnie Coro's Dxers Unlimited exclusive and not copyrighted
HF plus low band VHF propagation update and forecast//// Solar activity
is at extremely low levels, and the zero sunspot count has continued for
many days... no signs at all of new active solar regions, and
geomagnetic activity is also at a minimum... The solar optical count of
sunspots is ZERO and the solar flux is between 65 and 68 units,
indicating an absolutely quiet Sun. Nightime Dx conditions will be
limited to frequencies below 14 megaHertz just a few hours after sunset,
and chances are good for transequatorial propagation to take place. I
Hope to have you listening to the midweeke edition of Dxers Unlimited
next Saturday and Sunday UTC days, and don't forget to send me your
signal reports and comments as well as radio hobby related questions to
arnie@xxxxxx, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana,
Cuba.
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