Dxers Unlimited
Dxers Unlimited's weekend edition for May 24-25 UTC days

By Arnie Coro

radio amateur CO2KK




Hi amigos radioaficionados around the world ! You are most welcome to join me here at the weekend of
your favorite listener oriented radio hobby program. Short wave propagation conditions are not that
good, and when I started to write the script of the show, during the very early morning hours
Saturday , the K index was hitting FIVE, an indication that the Earth is once again receiving the
impact of a high speed solar wind event. Solar flux is between 115 and 120 units , but don't expect
much DX on the higher bands until the disturbance subsides. Item two: May 20th 2003 will be recorded
as the day when Cuba was , once again, the object of an intensive radio war event, that violated
international radio rules and regulations . A US armed forces EC-130 type Hercules aircraft,
especially equipped for psychological warfare operations went up to broadcast TV signals on VHF
channel 13, while the plane was flying at about 18,000 feet or 5,500 meters. The TV broadcast was
specifically beamed to Cuba from a location above the Florida Keys, and because VHF TV Channel 13 is
used by several Cuban television stations, the propaganda broadcast from the EC-130 produced
malicious interference to the regular programming of Cuban television networks.

A legal analysis of the action shows that it violated several articles of the International
Telecommunications Convention's Rules and Regulations, an international agreement of which the
United States of America is one of its signatories. The unprecedented action, that was once proposed
way back in 1962 to President John F Kennedy, was at that time not approved, considering the fact
that it was a very aggressive move... But 41 years later, the broadcast of propaganda type TV
programs from a plane flying at high altitude took place.

Cuba has denounced the actions, fully documenting to the International Telecommunications Union, all
the violations incurred by the Government of the United States of America. At the same time that the
unprecedented TV transmissions took place , an also unprecedented increase in short wave frequencies
beamed to Cuba for the anti-Cuban Miami based broadcasts, that went up to 24 channels , in what
could best be described as a barrage !.

The anti-Cuban TV broadcasts funded from the United States of America budget started in 1990, and
have never been seen in Cuba, because of the protective actions designed and built by Cuban
engineers and technicians, that have proven to be an insurmountable barrier to those aggressive
transmissions...

Item three: Natural radio, yes, natural radio waves that can be picked up using different
wavelengths are one of the more than 70 ways, yes, 70, that you and I can enjoy our hobby. Among the
most popular natural radio signals are the Very Low Frequency emissions known as whistlers.
Experimental receivers designed for picking up signals in the frequency range from about 2 kiloHertz
to 30 kiloHertz do require very special antennas, but they usually won't work at all in areas where
man made radio noise reaches high levels... So picking up natural radio signals usually involves
going out to remote locations , far away from computers, TV sets, high voltage transmission lines,
neon signs, alarms, fish tank thermostats or for that matter all types of thermostats etc. etc. And
that's why natural radio enthusiasts usually combine two hobbies... radio and camping out in the
wild !!! Natural radio signals come from many different sources like thunderstorms that generate
lightning . Tornado watchers are able to follow the path of those dreadful storms using direction
finding techniques with the receivers tuned to very low frequencies, the radio waves emitted by
lightning generated near the core of the storm... Si amigos, natural radio waves have many different
forms, and form part of the so many fascinating aspects of this fascinating hobby

Item four: YOU HAVE QUESTIONS or as some of you like to call it, ASK ARNIE , the section of Dxers
Unlimited devoted to answering your radio hobby related questions amigos !!! Item five today will
deal with an antenna topic, and as always at the end of the program, you should have your notepad or
tape recorder ready to pick up Arnie Coro's Dxers Unlimited's HF plus 6 meters propagation update
and forecast...Margarita Delgado is my sound engineer and producer. Standby for more radio hobby
related information coming up in a few seconds amigos !!!

.......

This is the weekend edition of Dxers Unlimited coming to you from Havana.

More about item three... Tornadoes do generate a lot of radio signals, but tropical hurricanes do
not... well, not exactly, tropical hurricanes do travel in association with areas of thunderstorms,
but what I want to say is that tornadoes do generate very intense signals that can be picked up even
on VHF receivers... A small portable AM broadcast band receiver, tuned to an empty channel at the
low frequency end of the dial will help you understand natural radio... Just try this experiment...
tune your portable AM broadcast band radio to an empty low frequency channel, the lower the better,
say between 540 and 640 kiloHertz , when a thunderstorm is near to your QTH... Do not use an
external antenna, just the radio's internal ferrite rod to pick up the powerful radio waves emitted
by lightning... Phase two of the experiment is also simple.. turn your radio slowly around in order
to minimize the level of the noise bursts... The minimum signal pick up will give you two possible
azimuths for the bearing of the area where the thunderstorm is located... Si amigos, yes my friends,
oui mes amis... simple direction finding can give you an idea of the general location of a
thunderstorm because lightening strikes behave as extremely powerful radio transmitters....

NOW , item four: The very popular ASK ARNIE section of Dxers Unlimited...

Question sent in by exactly seventeen listeners, from nine different countries, a good indication of
how popular Dxers Unlimited is among radio hobby enthusiasts... They all want to know if the coaxial
cable used for networking computers some years ago, and obviously not used anymore, can be used for
installing radio antennas... Well amigos, SURE, GO AHEAD AND USE IT !!!

Especially if you can obtain a good supply of the typical RG58-U used during the early days of
computer networking... remember the ETHERNET cards with the BNC coaxial connectors ??? Well, as a
matter of fact, those now obsolete network cards are also a source of nice female BNC connectors
that you can recycle too !!!

Going back to the coaxial cable, there is a type with a label that says PLENUM, indicating a
somewhat better quality cable... RG58-U cable and all similar types used for computer networking are
50 ohms impedance cables, and due to their small diameter, they are a bit lossy above 30 megaHertz,
especially if you have to use more than about 20 meters or about 66 feet of cable at frequencies
higher than the ten meter band limit... According to what I have seen and heard, there are many good
lengths of RG-58-U computer grade coaxial cable hanging around , just waiting for someone to ask the
computer technicians for them... In my own case, I was able to retrieve several nice lengths of
cable from ducts that go above the false ceilings, and despite having spent almost 10 years there,
the cables proved to be in like new condition... one of those lengths is now feeding by 2 meter band
portable J pole antenna that I keep always ready with all the emergency communications gear !!!

.......

arnie@rhc.cu, yes, you heard it right, arnie@rhc.cu is the fastest, easiest way of getting in touch
with yours truly, and also for requesting your Radio Havana Cuba QSL..

If you are not yet cybersurfing and don't have e-mail, send a postcard to Arnie Coro, Radio Havana
Cuba, Havana, Cuba, ... no need for PO BOX number or postal code, just write on your postcard
address box : Arnie Coro, Radio Havana Cuba, Havana , Cuba, and my good friends at Havana's
international post office exchange will route your postcard to RHC's correspondence department !!!
Dxers Unlimited continues with the antenna topics section of the program, another of the most
popular ones... my very good friend Jose Amador, CO2JA is a Professor at Havana's CUJAE, our
engineering and technology university... Jose is an avid radio experimenter with well above average
computer expertise,and that's why I ask him to run some of his software when I have doubts about an
antenna's performance.. That was the case with a very popular 2 meter band antenna that is simple to
build and can, for that reason be duplicated by radio amateurs with typical hand tools. The so
called SUPER J array of two phased half wave dipoles fed at the bottom of one of them , popularized
under the commercial name of RINGO RANGER, was subjected to Jose's computer analysis, and the
results showed something that I had suspected for a long time... The antenna's vertical radiation
pattern is far from ideal for ground wave communications... In other words, a lot of the radiated
energy is sent at angles much higher than the horizon.

So we decided to do some experiments, and after some time playing around with the computer modeling
software, we figured out that installing a third radiator of just one quarter of a wavelength atop
the second half wave section, would definitely improve the antenna's vertical pattern... Now my
elder son Arnie Jr. CM2KW is building the prototype antenna so I expect to be testing it very soon .
VHF and UHF antennas designed for ground wave communications must have a vertical radiation pattern
that sends out most of the radio wave's energy as close to the horizon as possible,something that
after running several computer simulations we have seen that is not so frequent among the commercial
antenna designs studied . In an upcoming edition of Dxers Unlimited, I will provide 2 meter and 70
centimeter band enthusiasts with the results of the experimental antenna with two half wave plus one
quarter wave element fed in phase !!!

....

And now amigos, as always at the end of the program , here is our exclusive and not copyrighted HF
propagation update and forecast... Solar flux is hovering around 115 units, and it looks like solar
activity will decline during the next several days... A solar coronal hole has caused yet another
geomagnetic disturbance that has sent the A index to figures as high as 5 during the past 24 hours..
Sporadic E events are likely to happen mostly between 7 am and 11 am local time, and again from
about 3 PM to 8 PM local time... Be on the alert for possible double hop sporadic E, as the
probability of E skip events increases as we approach the month of June, so chances of two or more
sporadic E clouds forming at different geographical locations are most likely at this moment, and
that will lead to some interesting double hop DX , typically seen on the 6 meter amateur band. See
you all next Tuesday and Wednesday UTC days amigos at the mid week edition of the program, and don't
forget to take a little time and send me an e-mail with your comments about the program that help me
to keep it going the way you Dxers Unlimited listeners like it !!!