Dxers Unlimited weekend editions
by Prof. Arnaldo Coro Antich
radio amateur CO2KK
Radio Habana Cuba
Radio Havana Cuba
Hi amigos radioaficionados around the world, and especially those of
you getting ready to
I am your host , Arnie Coro, radio amateur CO2KK, and here is our
But, a very interesting observation regarding the five active sunspot
regions on the solar
Item two...Cuban radio amateurs getting ready for the upcoming ham
radio contest, where
The low power , single operator, single band
Competing against high power stations
There is also a very nice contest slot that , when propagation
conditions are good enough
If short wave propagation conditions are good enough so that the
Item three: Brazilian radio amateurs are among South America's most enthusiastic homebrewers of radios...
Among their very elegant designs , an ultra simple single transistor
The CURUMIN, named after a small colorful bird from the Amazonian
forests, easily delivers 1 Watt output on CW, using a quartz crystal
My own version of the CURUMIN, uses a transistor recycled from the electron gun assembly of a computer monitor that delivers about 900 milliWatts of nice clean CW on 14.032 kiloHertz... the frequency of a quartz crystal that was also recycled from another circuit board that a friend gave to me some time ago.
The CURUMIN is a minimum parts count transmitter...and is powered
from a gel cell
Stay tuned for more radio hobby related information, coming to you from Havana...
I am Arnie Coro, radio amateur CO2KK, back here in a few seconds after a short break for station ID...
Si amigos, this is Radio Havana Cuba, soon to be celebrating our 50th
Next year, on the first day of the month of May, we will be marking 50 years of short wave broadcasting !!!! Now here is item four of the mid week edition of the program...
It is still a rumor... but it is now so widespread that it looks like something is really happening regarding DRM , Digital Radio Mondiale , short wave broadcasts by the BBC and Deutsche Welle....
Both the British and the German broadcasting organizations are going
through a complete
DRM short wave broadcasts provide good audio quality, certainly better than the regular , traditional analog transmissions, but there are two things that make DRM short wave broadcasting at this moment a very poor investment of resources.
First of all, the lack or receivers continues to be the number one problem... DRM Digital Radio Mondiales receivers are very hard to find, to say the least, and when found, they cost a lot of money, as compared to a good quality analog radio.
In second place comes the fact that DRM via shortwave has a big shortcoming... once there is a fadeout, the program's audio comes to a total silence...
This is a very annoying problem, because in contrast to the slow
fadeout and fade in of
According to several telecommunications experts with whom I have
discussed DRM recently...the system seems to work quite well on the AM
broadcast band during daylight hours but does not provide good reception
at night via skywave, because the multi path propagation present during
the evening hours behaves
Among the items discussed was one focusing on the need to rewrite the computer code that makes DRM work, so that the audio can be recovered , even after a very deep fade has happened...
In the meantime, it seems quite logical that international
broadcasters pressed with budget cuts , will drastically reduce, or even
completely stop the DRM transmissions due to extremely low number of
listeners capable of picking
Item five: ASK Arnie, certainly the most popular section of Dxers Unlimited, brings in a lot of correspondence from listeners all around the world... I do reply directly via e-mail as soon as possible, and many of those replies do make it to the script of the program, because the questions asked are in my opinion of great interest to other listeners of the program...
Here is a good example, last Friday, listener
Arnie, I know that there is no possibility of protection against a direct hit by a lightning bolt, except at extremely professional installations... and even then, many times those TV , radio and cellphones towers suffer damages when they take a direct hit....
But, Gary added, can you give me some guidelines about how to protect my radios , computers and TV sets from a nearby hit ….. Well amigo Gary... my first bit of advice , I am sure that you have heard it here many times before.... every time you finish playing with your radios, simply disconnect everything..
I mean everything, including the AC line power and your ground or earth connection. I
If you happen to be listening to your radios or using your ham radio station on the air, and you start to pick up loud static crashes... watch the local weather carefully, and if there are any signs of a thunderstorm... disconnect everything fast... at once... don't even wait to say goodbye if you are talking on the radio ….
Place the antenna cables far away from the operating table , because a nearby lightning strike may induce very high voltages that will make a spark jump to the nearest piece of electrical or electronic equipment that is at ground potential or near ground potential...
Make it a standard practice to keep all your radios disconnected from
And now here is our also very popular antenna topics section... that
today will be reviewing an antenna that according to CO6CAC, Carlos, who
is a very active Cuban radio amateur who you will be able to work during
ham radio contests...
It is known as the DELTA LOOP, that when fed to generate a vertical
radiation pattern, shows a very low wave take off angle that is ideal
for Dxing.... Carlos told me recently that he was able to work many DX
stations on the 30 meters band using the vertically polarized delta loop
He used a four to one balun at the end of the 110 ohms twin line , and connected the 75 ohms coaxial feedline to his antenna tuner.
As a matter of fact the 30 meters band DELTA LOOP, proved to work very well also on the 20 and 17 meters band... because it was very easy to match using the PI network antenna tuner.
One interesting fact about the DELTA LOOP or triangular antenna is that it requires just a single mast, and can be rotated manually very easily around the mast.
Also this antenna is a very good option for city dwellers, because it
produces a vertically
You can feed the DELTA LOOP directly with a quarter wave length of 75 ohms coaxial cable, and then connect the 50 ohms cable to it... But, then it will operate as a single band antenna system...
And now, as always at the end of the show, when I am in Havana, here is Arnie Coro's exclusive and not copyrighted , in the public domain HF plus low band VHF propagation update and forecast...
As we approach November, and the Sun continues to show signs of waking up, HF propagation conditions are taking a turn for the better...
The Catania Solar Observatory WOLF number broke the record for solar cycle 24 on Tuesday October 26 when it reached 92 ... November is the month of the year when the ionosphere shows its highest concentration of free electrons at the different layers , that are also closer to the ground than at anytime of the year...
So expect with the current solar numbers, that the HF bands will be
opening up much more frequently...something that will be most welcome by
the participants during this next weekend worldwide amateur radio
contest, and dont forget to send your signal reports and comments via e
mail to inforhc at enet dot cu , or VIA AIR MAIL to Arnie Coro, Radio
Posted by Arnaldo Coro at 9:27 AM 0 comments Links to this post
FRECUENCIAS EN INGLES
Zona Geográfica Frecuencias Horarios
Norte, Centro y Suramérica 11760 Khz/ 25 m 20 - 21 UTC 100 kW ND
Banda Tropical 5040 Khz /60m 24 – 01 UTC 50 kW ND
San. Francisco 6010 Khz / 49 m 05 – 07 UTC 100 kW HR 4,4 0,8
Chicago 6050 Khz /49 m 01 - 07 UTC 100 kW HR 4,4 0,8
Washington 6000 Khz / 49 m 01 – 07 UTC 250 kW HR 4,4, 1,0
New York 6060 Khz /49 m 05 – 07 UTC 100 kW HR 4,4, 0,8
Norte, Centro y Sudamérica 6150 Khz/49m 05 – 07 UTC 250 kW ND
Posted by Arnaldo Coro at 7:45 PM 0 comments Links to this post
FREQUENCIES in FRENCH
North, Central and South America
Europe 11770Khz/25 m
Posted by Arnaldo Coro at 6:40 PM 0 comments Links to this post
Description by Arnie Coro CO2KK
There is another form of long wire antenna which provides uni-directional coverage and is easy to build.
Here is the description.
From the transmitter or transceiver, you go to an antenna tuner via coaxial cable. The tuner is placed at the base of the antenna, not at your operating position.
From the tuner's single ended output comes a wire that first goes
STRAIGHT UP for about ONE WAVELENGTH at 50 mHz...
REMEMBER to aim your antenna to SLOPE in the DIRECTION that you want
to communicate with....
The antenna seems to work also on 10 meters , with the appropriate
tuner, and I have tested it on 2 meters too, but have yet to do some
really good comparative tests against my "standard" 5 element portable
Hope this helps those in need of a very simple, low cost, unidirectional field antenna for VHF use
Arnie Coro CO2KK
RADIO HABANA CUBA.
ITU Broadcast period B10 October 2010 to March 2011