Dxers Unlimited
Dxers Unlimited's mid week edition for 7-8 October 2003
By Arnie Coro
Radio amateur CO2KK
Yes amigos, your radio is tuned or your computer is connected to the best
possible source for radio
hobby information, and not only for one single aspect of this wonderful and
fascinating hobby, Dxers
Unlimited covers each and all of them, SURE, we provide you with up to date info
about the more than
70 ways that both of us can enjoy RADIO, the magic hobby !
Radio if fact is such a flexible hobby that people as young as five or six years
old may actually
start building crystal receivers with the help of an adult, at the same time, an
80 year old senior
citizen may find that the radio hobby provides her or him with a unique way of
keeping communicated,
something that in some cases have even saved lives... More than 70 different
ways of practicing the
radio hobby give you a beautiful rainbow from which to choose, and let me add
that none of them
exclude each other... You can be an amateur radio Dxer, and at the same time be
a satellite operator
and also enjoy daily nice chats on the local repeater while driving to work...
Now that I mention
amateur radio, let me encourage you to learn more about this most fascinating
aspect of our hobby,
perhaps one of the few hobbies that employers will use as an additional positive
evaluation aspect
when people apply for a new job !
Item two: Had a nice chat on the 40 meter band Monday evening local time,
stations from all over the
Cuban archipelago gathered on 7120 kiloHertz lower side band , and we all, about
ten of us, enjoyed
a round table in which we discussed technical topics related to antennas,
crystal filters, the
selection of intermediate frequencies for homebrew transceivers and how we could
put to good use
some circuit boards recovered from equipment that was given away by a local
company that is
upgrading its communications system... The 40 meter band provides a unique Near
Vertical Incidence
Skywave propagation mode, that makes possible such nice chats and round tables,
using power outputs
of from 10 to 100 Watts and antennas that are rather close to ground.
NVIS propagation, Near Vertical Incidence Skywave is certainly a very useful
mode for local and
semi-local contacts,and becomes extremely useful during emergencies, as you can
set up the stations
almost anywhere and they will link up without the need of repeaters or tall
masts, something that is
essential for good VHF and UHF emergency communications systems. That's why more
and more radio
clubs are setting up their NVIS 80 and 40 meter band systems, that have proven
to be extremely
reliable .
Here in Cuba we have used NVIS during the three most recent hurricanes ,
Michelle, Isidore and Lili,
with very good results. So here is your friend's Arnie Coro'advice, study more
about the Near
vertical Incidence Skywave or cloud warmer propagation mode, and prepare your
station for using it
if you ever have to operate during an emergency...
Item three: E-mails, letters, postcards keep coming in everyday not only with
signal reports and
comments about this and other Radio Havana Cuba programs, almost all of the
correspondence,
electronic or hard copy seems to bring in at least one radio hobby related
question amigos ! So, the
YOU HAVE QUESTIONS and Arnie tries to answer them section of Dxers Unlimited
today has reached a
historic turning point... You heard it right, and I am sure that regular Dxers
Unlimited's listeners
will be able to guess what I am going to say now... Today, YOU HAVE QUESTIONS
has become THE most
popular section of this show, leaving our HF plus low band VHF propagation
update and forecast in
the second place... AND YOU KNOW, that makes me a very happy radio program host...
because the
questions tell me that lots of people all over the world are finding in this
hobby a way of learning
more about electronics , antennas, propagation.... etc. Something that will help
them to enjoy this
hobby much more...
Be ready for more radio hobby related information coming to you via short-wave
and streaming audio
on the world wide web from Havana. My sound engineer and producer today is
>...................,
I am Arnie Coro in Havana, back with you in a few seconds
.........
This is Radio Havana Cuba, the name of the show is Dxers Unlimited and here are
now the contents of
page two: Part one of YOU HAVE QUESTIONS and Arnie tries to answer them: This
very interesting
question came from a listener in Belgium , who picks up our streaming audio on
the INTERNET... Jean
Paul wants to know about how to properly install his dual band 2 meters and 70
centimeters FM
transceiver in order to provide maximum coverage. Well amigo Jean Paul near
Brussels, first of all,
keep in mind that the 70 centimeters radio waves are in the 430 to 450 megaHertz
range, so the
transmission line losses are really significant. Your station , located two
floors below the roof,
will require a relatively long length of transmission line to connect the
transceiver to the
antenna, and choosing the right type of transmission line AND connecting it
properly will make a lot
of difference in performance. My advice is for you to spend a little more money
and install two
different antennas, one for the two meter band , and the other for the 70
centimeter band. You will
need two coaxial cable runs, and if your rig has a single output coaxial
connector, then you will
have to use an antenna diplexer to split the signals of the two bands right at
the output and input
of the FM transceiver. The 70 centimeter band antenna's coaxial cable MUST BE A
VERY LOW LOSS CABLE,
otherwise your transmitted signal will suffer severe attenuation on the way up
to the antenna, and
likewise, the received signal will reach the receiver after suffering itself
also a severe reduction
in strength to put this in layman's terms... If you want full around the compass
coverage on both 70
centimeters and 2 meters, install two separate omnidirectional gain antennas,
looking for antennas
that must have a gain above a reference dipole of no less than 3 dB... The more
typical VHF and UHF
omnidirectional gain antennas provide from 5 to 7 dB gain, and when properly
installed high and in
the clear, with good quality low loss coaxial cables will provide excellent
coverage.
Some VHF and UHF operators using the FM mode also want to reach far away
repeaters or talk simplex
to stations at the edge of the possible ground wave coverage area, so you can
follow what they do,
installing high gain vertically polarized YAGI or QUAD antennas... My son Arnie
Jr. CM2KW is an FM 2
meter band Dxer, and he has installed a pair of 9 element Yagis that provide
about 14 dB gain over a
dipole... BUT, like Arnie Jr. If you install high gain directional antennas, you
will need to rotate
them around the compass with an antenna rotor !
Si amigos, yes my friends , oui mes amis... I am sure that Jean Paul will soon
be installing his
brand new dual band FM transceiver following my advice, and maybe in a few weeks
time we will be
receiving here his reports...AH ¡ amigo Jean Paul, before I forget,be very
careful with the coaxial
connectors, solder them very carefull to the cables and provide full , total
protection against the
weather, in other words seal them properly following the local TV cable industry
practices, that you
can learn from the local TV cable repair personnel !
FM 2 meters and 70 centimeters communication provides also access to several
amateur satellites, but
that's another story for a future edition of Dxers Unlimited
......
Si amigos, yes my friends, signal reports and QSL requests are most appreciated
here, and we do QSL
one hundred percent, its absolutely free of charge, and we consider QSLing as a
very important part
of station activities... So send your QSL requests together with your comments
about our programming
to arnie@rhc.cu, again
arnie@rhc.cu or via AIR MAIL to Arnie Coro,
Radio Havana Cuba, Havana, Cuba
