Dxers Unlimited
Dxers Unlimited's weekend edition

For 21-22 June 2003

By Arnie Coro

radio amateur CO2KK




Hi amigos radioaficionados around the world and also in space ! This is the weekend edition of Dxers
Unlimited reaching you just as the SUMMER SOLSTICE is happening here in the Northern Hemisphere...
For those of you not familiar with astronomical terms, SOLSTICE means that SUMMER is officially
starting and that we are into the year's longest day... or in other words, that the number of hours
of solar illumination to our hemisphere reaches its peak for the whole year... AND OF COURSE, that
this has a lot of influence on short wave radio propagation ! More about the SUMMER SOLSTICE and the
peak of the sporadic E skip season later in today's program. I am Arnie Coro, radio amateur CO2KK
your host here in Havana now inviting you to join me for about eighteen minutes of on the air and on
the web time devoted to our wonderful hobby: RADIO. Now item two: More about short wave
propagation... according to scientists closely following the evolution of solar cycle number 23, the
almost continuos combination of solar flares and coronal holes that has so severely disrupted HF
propagation conditions for the past several weeks is quote " quite normal for this phase of the
solar cycle " unquote , and that the planetary A index or geomagnetic disturbance indicator is
showing now a very clear tendency to increase . More about HF and low band VHF propagation later at
the end of the show, when I will bring you our popular Arnie Coro's Dxers Unlimited's HF and low
band VHF propagation update and forecast. Item three: The piece about three way powered radios
generated a lot of interest among Dxers Unlimited's worldwide audience , and many of you sent e-mail
messages giving thanks for the alert regarding the widespread differences of quality seen on those
receivers that obtain their operating power from the Bayliss crank up , wind up generator, a solar
panel and an a set of batteries that may or may not be rechargeable. Again, if you plan to buy a
three way powered radio that uses the Bayliss crank up ,wind up generator , be extremely careful
before buying ... and check for signs of poor quality control... Remember that those radios main
application are to provide you with access to emergency broadcasts , so they must be reliable. Item
four: ASK ARNIE, our number two most popular section of Dxers Unlimited will answer today a question
sent in by a group of listeners from several different countries

including Canada, the USA, the UK, Germany, Jamaica, and even as far away as New Zealand... New
Zealanders listen regularly to our 9820 kiloHertz broadcasts from around 0400 to 0700 UTC.. Well,
now back to the question, they all want to know more about the use of indoor receiving antennas...
As more and more people around the world live in urban areas, installing short wave receiving and
amateur receiving and transmitting antennas becomes more and more difficult. Urban and suburban
areas continue to enforce restrictions regarding the installation of towers , masts and antennas,
making the life of the urbanites and suburbanites more and more difficult. Indoor antennas are the
only choice for many of you listening to this program, and that's why today I will provide a few
tips regarding them in the ASK ARNIE section of the show. AND AS ALWAYS at the end of the program,
have your tape recorder or notepad ready to copy the most up to date HF plus low band VHF
propagation update and forecast. Margarita Delgado is my sound engineer and producer. I am Arnie
Coro in Havana back with you in a few seconds amigos !!!

......

You are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited, and if you are a
first time listener, send me a signal report and your comments about the program via e-mail to
arnie@rhc.cu, and I will be very happy to send you one of our beautiful Radio Havana Cuba's QSL
cards...If you are not

yet surfing the web, just send me a postcard to Arnie Coro, Radio Havana Cuba, Havana, Cuba ... Now
here is our popular ASK ARNIE section of the show...Indoor antennas are the only choice for many of
you amigos , and I am fully aware of that problem... Of course that installing an indoor antenna is
always much better than having no antenna at all, or just using your radio receiver's telescopic
whip. Even very simple and easy to build antennas will improve your reception quite a bit ... when
compared with what you hear using the radio's telescopic built in whip. Among one of the most
popular indoor antennas for short wave reception is the so called magnetic loop ... an antenna that
can be homebrewed using a length of coaxial cable, a variable capacitor and some kind of frame to
support the coaxial loop. A loop having diameter of as small as 80 centimeters will improve short
wave reception dramatically on frequencies from about 10 megaHertz all the way up to the top end of
the amateur ten meter band , that is 29.7 megaHertz. For all practical purposes the 80 centimeter's
diameter magnetic loop can be considered as an antenna capable of a 3 to 1 frequency ratio coverage,
from 10 to 30 megaHertz, and as I just said, connecting this antenna to your receiver to replace the
telescopic whip will improve reception quite a bit.

Frequencies lower than 10 megaHertz do require a larger loop, one that may be a bit difficult to
install indoors, but many people have found out that a 2 meters diameter magnetic loop will fit
quite nicely in an apartment's balcony , so that they can tune down even to 5 megaHertz . But, the
magnetic loop has one important drawback, an unquestionable limitation... it is an antenna that
tunes very sharply to an operating frequency... actually it tunes so sharply that it acts as an
excellent additional radio frequency input filter for your receiver. The very high Q or figure of
merit of the magnetic loop antenna requires constant retuning of the variable capacitor, and that's
why commercially built magnetic loops usually have a remotely tuned capacitor that is coupled to
control box located right next to your receiver... Homebrew magnetic loops like mine , are manually
tuned... so every time you change frequency, even just a few kilohertz, there is no other choice but
to retune the antenna for maximum signal . That means that you must have the loop right next to the
radio, something that is not necessary when the loop is provided with the remotely tuned system. A
magnetic loop designed to be used as a receive only antenna can use almost any air spaced variable
capacitor, but that is not the case when you want to use your magnetic loop for transmitting... even
a QRP five 5 watt transmitter will generate extremely high voltages at the antenna , so that you
must use very well insulated air spaced variable capacitors, some of them of very special design,
like the so called trombone capacitors...There is a lot of technical information about magnetic loop
antennas that can be found by just typing MAGNETIC LOOP ANTENNAS to the search box of any of the
popular INTERNET search engines amigos ! So next time that you are doing some web surfing, type
MAGNETIC LOOP ANTENNAS and start learning more about this unusual antenna that for many short wave
listeners and radio amateurs limited by zoning laws and covenant restrictions has meant the
difference between having the opportunity to enjoy the radio hobby or having to start learning about
model airplanes, hang gliding or fishing !!!

.......




Si amigos, yes my friends and for those of you that speak English as a second language in Canada,
oui mes amis !!! Radio is a fascinating hobby that has unique properties... For example, what other
hobby can you enjoy that will link so nicely together with other hobbies... Radio enthusiasts can
have a nice time flying their radio controlled model airplanes... absolutely fascinating with the
latest digital remote controls that provide almost perfect feeling of flight parameters, or what
about hang gliding pilots that combine amateur radio on the VHF and UHF ham bands while flying their
delta wing gliders ? Fishing and radio go together very well, as having a ham radio set on board is
always a nice extra, additional safety precaution. Several Cuban radio amateurs that are also
fishing hobby enthusiasts carry their two meter band FM handy talkies with them every time they go
out on a fishing trip... Radio is a great hobby, and if you take some time to study and obtain your
amateur radio license, then you can enjoy radio a lot more, and make new friends across town or half
way around the world... Then don't be surprised when someone knocks at your door late in the evening
, just after arriving to the local airport to say, as it often happens to me ... " Hello Arnie, I am
so and so, your ham radio friend of many years from , and then what follows is one of those moments
that only amateur radio can give you !!! Many countries around the world have now reduced the speed
requirement for the Morse Code tests down to a very easy to achieve 5 words per minute, and anyone
with a high school diploma and some time to study can certainly pass the written test to obtain an
amateur radio license... Equipment is also becoming easier to obtain, and 2 meter FM handy talkies
are now cheaper than many portable radios amigos , due to the popularity of the Personal
Communications Systems, that have allowed manufacturers to mass produce those two way radios and
reduce prices to even the less than 100 dollars mark for a brand new two way radio !!! Enjoy the
summer , get in touch with your local radio club, participate in the activities organized by the
club and learn how you can pass the amateur radio license test... As many Dxers Unlimited's
listeners around the world have written to me, life is always a bit better when you have an amateur
radio license and can talk to the world !!!

......

Dxers Unlimited's weekend edition is coming to you from Havana, and amigos don't forget to tune 9820
kiloHertz after 0500 UTC and until 0700 UTC .. We are continuing to test our new high gain curtain
array beaming to the Pacific Coast of North America and signal reports are much appreciated... If
you can compare the signal on 9820 kiloHertz from 0000 to 0500 UTC , with the signal after 0500 UTC,
then that will be much better, as that will let our engineering staff more about the difference
between the two antennas... Send your reports to arnie@rhc.cu, or VIA AIR MAIL to Arnie Coro, Radio
Havana Cuba, Havana, Cuba...

And now amigos, as always at the end of the show , here is Arnie Coro's Dxers Unlimited's HF
propagation update and forecast... SUMMER SOLSTICE typical propagation in progress... HIGH DAYTIME
absorption of HF signals due to the very much ionized D layer typical of this season, while night
time MUF or Maximum Useable Frequencies are higher than during the winter. Sporadic E season now in
full swing, and openings may be happening at any time, even late in the evening !!! Solar flux near
120 units, but geomagnetic disturbances continue to make short wave reception not too good, as the A
indexes are still very high... Expect some interesting AM medium wave broadcast band DX conditions
to your SOUTH if you live at locations higher than 40 degrees North latitude.. Don't forget to take
a little time after listening to the program and sending me an e-mail report to arnie@rhc.cu with
your valuable comments and new ideas about how to improve Dxers Unlimited amigos !!! See you all at
the mid week edition of the show , next Tuesday and Wednesday UTC days , until then enjoy our
wonderful hobby as much as I do !!!