Dxers Unlimited

15-16 Mayo 2004

By Arnie Coro

Radio Amateur CO2KK




Hi amigos radioaficionados, I am Arnie Coro radio amateur CO2KK, your friend in Havana and host of
this twice weekly radio hobby show, a program entirely dedicated to the promotion and development of
our wonderful hobby , yours and mine, RADIO !!! Here is now item one for today.A fast growing
sunspot active region is developing in front of our eyes. Sunspot region 609 is showing a rather
fast growth curve, but so far scientists have not found a complex magnetic structure that could
produce really big solar flares. Solar flux is now near 100 units and moving up, so we may see
somewhat higher maximum useable frequencies during the next few days.

Item two: Extremely low power transmitters operating at a maximum output of 4.7 milliwatts are
providing researchers with extremely useful information about the ionosphere, more on this topic
later in the show, item three: Cuban radio amateurs getting ready for the upcoming Convention to be
held in the city of Santa Clara, where ham operators from all over Cuba will be meeting for three
days to discuss the most important issues of amateur radio in Cuba and the world, and also to elect
the executive board of the Federacion de Radioaficionados de Cuba for the next 5 year term. I will
be there and provide complete coverage of the event. Item four: BPL , broadband over the power lines
continues to attract the attention of radio engineers all over the world, and in my opinion it will
continue to be a hot topic for the next two or three years.. so I'll keep you all up to date on what
's happening with BPL technology and how radio reception is affected at locations where BPL is
implemented. Item five: Our ASK ARNIE section of Dxers Unlimited will be answering listeners
questions, then I'll take you all to a quick visit to my workshop, and at the end of the program,
have your notepad or tape recorder ready for the HF plus low band VHF propagation update and
forecast. Stay tuned for more radio hobby related information that will follow in a few seconds
after a short musical intercut:




...

Si amigos, you are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited and here
is our most popular feature. ASK ARNIE, that today will be answering in the first place a question
sent by listener Thomas from Kitchener, Ontario, Canada. Tom wants to know if he can make his VHF
antennas using copper pipe instead of what seems to be the standard material for building them:
aluminum. Well amigo Tom , of course that you may use copper pipes for making VHF and UHF antennas,
and as a matter of fact, when properly made and welded of soldered using silver based solder, those
antennas will last a lifetime, and they will also provide you with a much more reliable service
life, provided that they receive proper maintenance.The problem with antennas built using copper
tubing is that they will certainly weight a lot more than the ones made using aluminum. One of my
favorite VHF antennas, the stacked J pole for the two meter amateur band, when built using copper
tubing weights a lot more, and requires a much heavier mast. but , it will , as I said a while ago,
last a lot longer than the same antenna made with aluminum tubing. Small and medium sized Yagis that
may have from two to about six or seven elements for the two meters and seventy centimeters bands ,
when made of copper pipe will outlive the ones made with aluminum by many years, but again, the
extra weight does require heavier rotors !!! Whenever you want a rugged VHF or UHF antenna, that
will perform reliable even under very bad weather conditions amigo Tom , by all means switch to
copper tubing, and don't forget to use proper soldering techniques and the highest quality silver
based solder in order to obtain the best possible results.

Now the second question for today. It came from England, where our good friend Geoff is picking up
the 6000 kiloHertz Eastern North America beam at very late in the evening his local time. Amigo
Geoff sent this question: Dear Arnie, now that there is no CW Morse Code test required in at least
16 countries around the world, and probably more to follow, how to you think this will help amateur
radio to grow and develop. Well amigo Geoff, although this is not a purely technical question for
the ASK ARNIE section of the program, I do think that it's certainly a very good question indeed. My
perception is that the removal of the CW Morse Code test BARRIER, will allow many persons to become
amateur radio operators with full operating privileges for the HF frequency bands, and althoug I don
't foresee a phenomenal growth of the hobby, the fact is that the learning of the Morse Code was a
stumbling block for many people wanting to become radio amateurs !!! One can learn technical matters
by studying and putting time into a training program but CW Morse Code skills are in a certain way
connected to the person's natural abilities, somewhat similar to music, and as a matter of fact, I
have known many musicians that were able to learn the Morse Code in a very short time frame, and
that also enjoy CW operating a lot, as their musical brains do seem to help !!! My perception of
amateur radio growth is that the hobby needs a lot more of promotion,and that we should use the New
Information and Communications Technologies to make more people aware about our wonderful hobby.
Along this line the INTERNET is an excellent platform for the promotion and development of our radio
hobby amigo Geoff, and we all who care about the future of this hobby should use the INTERNET more
and more to promote our wonderful passtime !!!

.

This is Radio Havana Cuba, and let me invite you to listen to our 9655 kiloHertz frequency from 05
to 07 UTC, in English, and if you do want to practice your Spanish, tune in earlier, as 9655
kiloHertz is on the air from 00 to 05 UTC in Spanish with our evening local time magazine show.

Now here is, as promised, a visit to my workshop. that by the way, is still in urgent need of an
organizing sprint !!! At one corner of the amateur radio operating desk, I am giving the finishing
touches to an ultra low power five milliwatt , yes just five one thousands of a watt radio
transmitter, to be used for propagation tests.The idea came from the QRP-L a low power radio
enthusiasts INTERNET e-mail forum were the following information was just recently posted by Stan,
radio amateur AK0B. Here is what Stan explains in his posting to the QRP-L list: And I quote:

The past week I have been copying numerous micro powered HiFer stations operating on or near 13.555
MHz.   These stations run a maximum of 4.7 mW into a simple dipole and many run only 1 or 2
millwatts.   Some use PC generated digital signals, but others run slow CW ID or 12 wpm ID.  I have
confirmed Canada, Connecticut,Maryland,Florida,Louissiana, Tennessee and Arizona.The rules limit
these stations to antenna without gain (simple half wave dipole) at 4.7 mW output.



It has been obvious that the reception of these stations follows the sun with east coast starting in
late afternoon and ending with west coast about 10:30 PM CDST.  It appears that one or both sending
and receiving station must be In the GrayLine zone.

And amigo Stan is quite right. so called Terminator Line or Gray Line propagation provides a really
significant enhancement to the radio transmissions along that path, and that's exactly what is
happening with those extremely low power 13.555 kiloHertz experimental transmission, againg the
frequency is just below the 20 meters amateur band, at 13.555, plus of minus 2 kiloHertz or so..by
the way, there are several different types of modulation modes used by the ultra low power
transmitters in the 13.555 kiloHertz band, so you may try to pick up from standard carriers keyed
using CW , to sophisticated digital modes that provide complete station id's.

Once again, that magic carpet sorrounding the Earth that we all know as the ionosphere shows its
tremendous and surprising capacity to send back to to our Planet's surface extremely weak radio
signals.

Not too long ago, someone ran a one milliwatt beacon on the 30 meters amateur band and many radio
amateurs were surprised to hear the CW signals come out of the noise so that the complete callsign
of the station could be copied.

Be aware that these extremely low power beacons may also be used to communicate with other stations
too , if the owner simply disconnects the automatic keyer and uses a manual key or a software
program that turns a computer into a CW transmitting setup.

..

Si amigos, we do QSL, and we do appreciate very much your signal reports and comments about our
programs. You can get in touch via e-mail directly to my computer. send mail to arnie@hc.cu, again,
arnie@rhc.cu, and don't forget to include your postal mailing address so that Irma Veitia ,from our
correspondence department my send you one of our beautiful QSL cards that will confirm reception of
Radio Havana Cuba. Now part two of today's visit to my workshop.as I told you a while ago, the
extremely low power beacon transmitter is now almost finished, as I need only to solder two
connectors and put the QRP rig into a box. the operating frequency of my extremely low power rig
will be very near 10.116 kiloHertz, as that is the crystal that I have at hand . In the past I have
operated very low power rigs on the 10 meter band, and received lots of reports from the Americas
and Europe, and even some from Japan, while running about 100 milliWatts. now as solar cycle 23
moves into its tail end, 30 meters, the 10 megaHerts amateur band will be a much more adequate
frequency range to run propagation experiments with very low power.

..

You are listening to Dxers Unlimited's weekend edition and here is now tips and techniques, that is
becoming also very popular among you all. Today's tip, if your short wave reception is difficult
because of man made noise and interference, you can use a small AM broadcast band portable receiver
as a noise finder. Tune the radio to and empty spot at the high end of the dial, and try to find the
noise source. Remember that those AM radios use a highly directional ferrite rod antenna, that
produces very sharp nulls. that will help to pin point the location of the device or devices
generating the noise. Last week I visited a friend that had a pulsating noise making his short wave
reception difficult. Using the AM broadcast band receiver tuned to the top end of the band, around
1700 kiloHertz , I was able to locate the source of the pulses. his beautiful fish tank aquarium air
pump.Disconnecting the pump made the noise dissapear,so we then proceeded to add two bypass
capacitors in pararell with the pump's AC power line connection and the noise almost vannished.
making reception much better , especially between 2 and 10 megaHertz !!!

And now amigos , as always at the end of the program, here is Arnie Coro's Dxers Unlimited's HF
propagation update and forecast, that will include today a special sporadic E layer report. Solar
flux is now near 100 units and moving up, solar sunspot active region 609 continues to grow and is
now as large as planet Jupiter, and it may possibly continue to grow and increase its magnetic
complexity during the next three to five days. Daytime maximum useable frequencies on the best North
to South and South to North paths may go up as high as 30 and even 35 megaHertz during the peak
hours, and we will start to see higher nighttime maximum useable frequencies that are typical of the
summer season in the northern hemisphere.Be on the look out for excellent Sporadic E openings during
the whole week, starting by early Sunday morning. TV DX on channels 2 , 3 and 4 will be an excellent
indicator of such openings.. See you all 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 radio hobby related questions, signal reports and
comments about Dxers Unlimited, send mail to arnie@rhc.cu, again arnie@rhc.cu, and VIA AIR MAIL to
Arnie Coro, Radio Havana Cuba, Havana, Cuba.