Re: [HCDX] Dxers Unlimited´s mid week edition for 11-12 March 2008

["Prof. Arnaldo Coro Antich" <coro@xxxxxxx>]

Radio Havana Cuba

Dxers Unlimited

Dxers Unlimited´s mid week edition for 11-12 March 2008

By Arnie Coro

Radio amateur CO2KK



Hi amigos radioaficionados ... with our now traditional salute, we are 
saying hello to radio hobby enthusiasts around the world from sunny 
Havana, Cuba. I am Arnie Coro, radio amateur CO2KK, inviting youth to 
join me for about seventeen minutes of on the air and also on the web 
time, plus the now regular option of reading the scripts of this program 
by subscribing one of several Internet radio hobby mailing lists.

Here is today's show first item...Another week of very little solar 
activity reported by scientists, who continue to wait for the expected 
increase in the number of sunspots from the new cycle. So far, the new 
sunspots are just missing, and the daily solar microwave flux continues 
to be at extremely low levels. Item two: Just a few days away from the 
spring equinox here in the Northern Hemisphere, and already we are 
seeing somewhat better propagation conditions especially just before 
sunrise  and just after sunset local time. Item three: Cuban radio 
amateurs began the new training program during the weekend, at my local 
club, the Plaza Radio Club we had a very nice meeting and the group of 
newcomers to the hobby started to receive their lessons in electronics, 
rules and regulations, radio wave propagation and communications 
procedures. The training course is programmed to last until May and the 
radio amateur operator's tests will take place in June.

The Radio Amateurs Academy as this program is known counts with 
experienced certified instructors selected among the nation's first 
class operators, the ones that are on the air with the CO, the Charlie 
Oscar prefix. Cuba has four prefixes for its stations registered at the 
ITU, that include CL, used or the beginner's license, the CM 
intermediate class amateurs , CO used for the first class licensees and 
the T4 prefix that is only assigned to special event stations.

More about our wonderful radio hobby here in Cuba and in the world after 
a short break for station ID... I am Arnie Coro, radio amateur CO2KK in 
Havana...stay with us amigos... I will be back in a few seconds...

......

Yes, you are listening to Radio Havana Cuba, and if the bad weather is 
keeping you at home, it's good time to start tuning around for new 
stations. Amateur radio operators that are stranded at home due to bad 
weather enjoy working DX when there is no other choice but to wait until 
the weather clears. And now there is yet another incentive to go on the 
air... the new Clipperton Island DX expedition is on the air, with high 
hopes of making a good showing as the just finished Ducie Island 
expedition achieved.

Ham radio expeditions to put on the air remote places are a great 
incentive for Dxers and the dream of any devoted Dxers is always fixed 
at having the unique opportunity of taking part on one of the real 
prominent DX expedition. I remember way back in 1965, when a group of 
Cuban radio amateurs activated for the first time in many years the CO4, 
the Charlie Oscar 4 prefix , by putting on the air a station at a remote 
little island to the south east of the Isle of Youth, how a fascinating 
experience it was for the team , despite the many mosquitoes and one 
dangerous encounter with a big salt water alligator, a cayman, that 
enjoyed swimming swiftly between the small little islands , something we 
discovered many days after going out to swim at the beautiful deserted 
beach...

We made a large number of two way radio contacts using CW and phone, but 
at that time we had no digital modes equipment and taking to the Avalos 
key location radioteletype equipment was not possible. Another nice way 
of enjoying group activities is to take part of a station participating 
on a ham radio contest, a very demanding activity that will require for 
you to take a Monday and possibly Tuesday break after the contest weekend!!!

More than two and half million radio amateurs around the world enjoy 
communicating using their own equipment and antennas, sometimes from the 
most unique locations, like an Antarctic scientific expedition or the 
cockpit of an airliner cruising at thirty seven thousand feet, something 
that airline pilots that are also ham operators do more often than what 
you may think, because as a very good friend of mine that seats on the 
left hand seat of wide body jets likes to say... cruising at high 
altitudes over the world's oceans can be really boring, due to the high 
degree of automation of modern aircraft !!! Aeronautical mobile, from a 
glider or a wide body jet is equally enjoyable and is one of the more 
than 80 ways that people enjoy amateur radio!!!

......



Yes amigos, we do QSL, we do verify well written and documented 
reception reports, something that is very easy to do, you will only need 
to send us an e-mail to arnie at rhc dot cu that includes the date, 
time, frequency, signal intensity and short description of the program 
content at the time you were listening. Of course that you can add 
whatever comments you may think will be useful to us, and that's the way 
that Dxers Unlimited´s worldwide audience has helped to shape this show 
so that it will be attractive to the most diverse audiences, from dyed 
in the wool radio experimenters to the casual short wave listener that 
has just bought a small portable radio...

You can also send your signal reports , comments and ideas on how to 
improve our programs , as well as any radio hobby related questions VIA 
AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, CUBA... and now here 
is our next item of the mid week edition of Dxers Unlimited...

Our very popular technical topics section of the program now ranking 
third among the most favorite ones... ASK ARNIE is still la numero UNO, 
the most popular part of the show, closely followed by the HF and low 
band VHF propagation update and forecast, and then in third place is 
this one just starting now...

Technical topics that today will be discussing how radio amateur 
operators are collecting broken down microwave ovens, to salvage their 
high voltage power transformers. After several not too difficult to 
implement modifications that include the removal of the magnetic shunt 
devices, the typical microwave oven power transformer can be rather 
easily modified to become the heart of a high power linear amplifier 
power supply... The high voltage rectifier diodes salvaged also from 
microwave ovens are ideal for the job, but you must look to other 
sources in order to obtain the required high capacity high voltage 
filter capacitors. By the way, handling microwave oven power 
transformers is something that should only be done by persons that are 
really experienced about the safety measures required, because the high 
voltages involved can be lethal...

You will never want your hobby to be the way to death, so whenever 
working with high voltages, please follow all the safety measures and 
recommendations, because at voltages that can go as high as four 
thousand volts, you will usually make just one single and certainly 
fatal mistake. That is why high voltage power supplies that are 
homebrewed must be built with all the recommended protection measures, 
including safety interlocks and a crowbar assembly that short the output 
to ground when the door of the power supply is opened...

......



This is Dxers Unlimited´s mid week edition coming to you from sunny 
Havana, where there are now fifteen radio clubs, one at every 
municipality of the City of Havana province... The Habana del Este Club 
is one of the more enthusiastic of them all, closely followed by La Lisa 
at the other end of the city and Cotorro at the extreme south east . 
Each of the radio clubs has encouraged among its member that they 
monitor what is known as an internal 2 meter frequency, that meaning a 
simplex channel that all members of each municipal club know well and 
keep a watch on them when they are at home or moving around with a handy 
talkie...

The internal frequencies have proven to be an asset because they help to 
develop local communications between radio amateurs that live in the 
same area.  The City of Havana province has a flagship long range 
repeater, located at 500 feet above the street in downtown Havana, at 
the rooftop of the 35 stories high Habana Libre hotel, The 145.190 
repeater can be accessed using handy talkies from locations that 
continue to amaze me. Of course that keeping the receiver of the 
repeater in good shape and the diplexer of the antenna system tuned 
properly helps to keep the sensitivity of the repeater station well 
below half a microvolt, an outstanding figure even for professional 
installations.

Many City of Havana radio amateurs have homebrewed a very simple 
portable antenna for the two meters band FM transceivers of handy 
talkies...something that help to access the long range repeater from 
much farther away distances than the ones possible with the radio's 
factory built antennas.





QSL on the air, si amigos, QSL on the air to the many RHC listeners that 
have written to me asking for more information about Cuba's AM and FM 
radio broadcasting stations...

So following the request, I will tell you today about one of the most 
widely heard AM stations from Central Cuba. It is the Santa Clara Radio 
Reloj station relay operating on 570 kilohertz running now a nice new 25 
kilowatts solid state transmitter, after the old Tesla vacuum tube 
technology that served there for many years was finally taken off the 
air. Radio Reloj´s Santa Clara City relay station has a very nice 400 
feet high antenna, with a very good ground system, and the reason that 
this low frequency channel was selected for Radio Reloj´s relay serving 
Villa Clara, Cienfuegos and Sancti Spiritus provinces was no other than 
the mountainous characteristics of most of the service area, where lower 
AM broadcast frequencies provide much better ground wave service than 
stations operating on the part of the band
above 800 kilohertz or so...

And now amigos, as always at the end of the program, here is as always 
and absolutely free, Arnie Coro´s HF plus low band VHF propagation 
update and forecast... Solar activity is expected to continue at very 
low levels, but the equal illumination of Planet Earth during the 
equinox will improve short wave propagation during the next three to 
five weeks amigos... So, enjoy it !!!

See you all at the weekend edition of the program Saturday and Sunday 
UTC days... and don´t forget to send your signal reports , comments 
about the program and radio hobby related questions to arnie at rhc dot 
cu. Or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba



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