RADIO HAVANA CUBA

RADIO HAVANA CUBA DXERS UNLIMITED

DXERS UNLIMITED'S MID WEEK EDITION 31 OCT- 1 NOV 2006

BY ARNIE CORO

RADIO AMATEUR CO2KK

Hi amigos radioaficionados around the world, and in outer space too...
welcome to the mid week edition of Dxers Unlimited. I am your friend in
Havana, Arnie Coro,radio amateur CO2KK, and here is item one ot today's
show: Worldwide radio amateur single side band contest that took place
during the weekend drew thousands of radio amateurs into operating on
the HF bands for at least a few hours... Some dyed in the wool contest
operators stayed awake for the full duration of the contest, while
others, like yours truly, just devoted a few short periods to operating
, spending part of the week end with the family... in other words, this
is what you may describe as casual contesting... Anyway, in the case of
CO2KK, my ham radio station, the few hours on the air during the CQ
Radio Amateur Magazine Worldwide Single Sideband Contest, gave some
seventy stations the new Zone 8 multiplier, and what was more important,
it allowed me to say hello on the air to many old time friends. My very
modest less than 100 Watt peak envelope power station , connected to my
old time favorite fan broadband dipole, went on the air on the 10 meters
band early morning Saturday local time, then , I shifted to 15 meters
where propagation was a lot better. I also made several 20 meters band
contest QSO's ,but it was evident that ionospheric absorption on the 20
meters band was much higher, so I went back to 15 meters where CO2KK was
heard quite well all across North America, the Caribbean and South
America, with even a few European stations added to the log too,although
propagation to Europe was not good at all, even at the time that HF
propagation forecasting software was showing the maximum useable
frequency curve going above 21 megaHertz... The very low solar activity
was the worst enemy of contest operators that thought that 10 meters
could provide more multipliers...

I don't expect very high scores for this years CQ contest winners, but
this annual competition proved once again that the amateur bands are
open to one part of the world or another much more than what one may
think !!!

Si amigos, operating amateur radio contest stations is one of the more
than 80 ways that you and I enjoy this wonderful hobby, even when
propagation conditions are not that good at all ,as it happened during
this past weekend. Stay tuned for more radio hobby related information
coming to you from Havana. I am Arnie Coro, radio amateur CO2KK, back
with you in a few seconds amigos...

..............

You are listening to Radio Havana Cuba, the name of the show is Dxers
Unlimited and here is item two of today's program... La NUMERO UNO....
your favorite section of Dxers Unlimited... ASK ARNIE...With a very
interesting question sent in by listener Gustav from Sweden... Here is
the question: Dear Arnie, my touch sensitive lamp, located at the
bedside table, goes on and off following the keying of my little QRP
transceiver... Any ideas that could help to stop this from happening ?

Well amigo Gustav, you are facing a typical case of radio frequency
interference that is disturbing the normal operation of an electronic
device. The energy that your transmitter puts on the air, somehow is
leaking into the electronics of the touch sensitive lamp and triggering
the circuit to go on an off... My advice is to put the bedside lamp
power cord through a ferrite core choke that must be located as near as
possible to the lamp's circuit... Try this one and tell me later what
happened amigo Gustav... I am almost sure that the ferrite RF choke will
solve your problem, but I will also recommend that you carefully check
all of your QRP transceiver antenna connections, and be sure that your
standing wave ratio on the antenna systems is as low as possible...

Question number two: sent by listener Darcy from Canada... Darcy asks
what he can do to improve the range of his two meters band amateur
station , even when he cannot install an external antenna... Well amigo
Darcy, you can certainly homebrew a small 2 or three element YAGI or
CUBICAL QUAD ANTENNA, and place it behind a window or better yet, at
your apartment's balcony, where it can be hidden from the landlord
during the daylight hours, and put up to work at night... A typical easy
to homebrew 3 elements YAGI will provide no less than 6 dB gain over a
dipole and that means that your transmitter power will be multiplied
four times in the direction that the antenna is aiming at... AND in that
same direction your reception is also going to improve dramatically....
From your 10th floor apartment balcony you can cover about 140 degrees
azimuth, probably reaching several far away repeaters and making
possible simplex QSO's with stations much farther away than when you are
using your rig's small vertical helix antenna ...

Question number three of today's ASK ARNIE section of Dxers Unlimited...
came from South Africa, listener Erik in Pretoria wants to know what can
be done to improve short wave reception using his small portable radio
that according to him seems to "go crazy" when he connects to it a new
external fan dipole that was recently built...

Well amigo Erik, I can assure you that your antenna is working very well
indeed, and that the problem is that your little very low cost short
wave receiver can not handle the signal input levels that reach its
front end when your new external fan dipole is connected to it... Try
burrowing a table top receiver from another radio hobby enthusiast , and
test your antenna with it... Yes, you will notice that reception on the
"big radio" is much better when the new antenna is connected, indicating
that the problem is that your low cost receiver simply overloads badly
when connected to the external antenna... The only thing you can try is
to very loosely couple the new antenna to the radio's telescopic whip by
means of winding one or two turns of plastic insulated hookup wire to
the base of the telescopic whip and leaving the end of the wire
floating... You can also try connecting the end of the wire after the
two turns coil to the negative battery terminal of the small portable
radio...But be aware that those very inexpensive radios were designed
with many cost cutting ideas in mind, so as to lower the production
costs to a bare minimum, and the designers never contemplated the use of
an external antenna with them !!..

.....

A weekend scan of the B-06 period frequency changes showed that many
international broadcasters had dropped the higher frequencies in favor
of the 25, 31 and 49 meters bands... The B-06 period will last until
March of 2007 during one of the worst periods of extremely low solar
activity... making it necessary for stations to go to the lower bands if
they want their signals to be heard when the maximum useable frequency
curve takes a nose dive after local sunset at most locations around the
world...

Item five: More about the low cost two meters band wire SUPER J
antenna... in between contest operating during the weekend , my neighbor
Reynaldo CM2IRG and yours truly spent about two hours Saturday afternoon
building a new SUPER J for Reynaldo's two meter band station.. We used a
two and half meters long length of PVC pipe and number 12 copper wire to
assemble the antenna, that during our first on the air test , made
possible a nice two way contact with a station located about 50 miles
away , while the antenna was still at less than 3 feet above the
rooftop... A comparison with a half wave dipole demonstrated that the
Super J could be heard at 50 miles, while the dipole provided no useful
signal at CM1NO's station. Rolando, CM1NO was amazed by the results that
we obtained , and as expected asked for the step by step building
instructions for the SUPER J wire antenna...

He asked us to change from one antenna to the other as fast as possible,
to run a true comparative test that proved once again that the new
antenna was indeed working very well... We were able to obtain a perfect
one to one standing wave ratio on one hundred and fourty five megaHertz,
the center of our two meters band here in Cuba, where the ham radio
allocation goes from 144 to 146 megaHertz... At both the lower and
higher end of the band, the SWR barely went to about 1point two to one,
an almost perfect match...

Reynaldo, CM2IRG is now looking for copper fittings to make a copper
pipe version of the SUPER J antenna that he want to install at his home
QTH using a new tall mast. Meanwhile , the antenna we finished
homebrewing Saturday afternoon is already in service at his station, and
when the new one is completed, he will keep the low cost antenna for
standby emergency use, because it is very easy to transport and provides
almost 5 dB gain over a dipole....

If you want to learn how to make your own wire plus PVC pipe Super J
antenna, send me an e-mail to arnie@rhc.cu, and I will send you the
complete , detailed, step by step building instructions and several
illustrations and photos ...

....

For those of you just learninga about the short wave listening hobby,
don't be surprised if you hear absolutely no signals on your radios both
day and night on frequencies above 20 megaHertz... there is nothing
wrong with your radios amigos... the problem is happening 93 million
miles or 150 million kilometers away from us... as the Sun is going
trough solar minimum, the part of the 11 years average duration solar
cycle when the number of sunspots is very low... For example during the
past 15 days , we have seen several days when no sunspots were seen...
so the sunspot count was ZERO... And unfortunately we expect many more
ZERO sunspot count days during the next several months !!!

And now amigos, just before going QRT here, listen to Arnie Coro's Dxers
Unlimited HF plus low band VHF propagation forecast and update.... Solar
cycle not dependent transequatorial propagation is working once again,
as reported by several Brazilian FM band Dxers that are picking up
Barbados FM stations in southern Brazil with excellent signals... HF
propagation on the frequency range between 15 and 30 megaHertz is now
extremely poor. with the number of openings going to a a bare minimum
and when the bands above 20 megaHertz do open up for DX the openings are
of very short duration. Solar flux is at very low levels... around 75
units and the A index, planetary geomagnetic disturbance indicator is
also at a low figure of 4 at 15 30 UTC when I was recording this show
here in Havana.

Send me your radio hobby related questions, signal

reports and comments about Dxers Unlimited to Arnie Coro, Radio Havana
Cuba, Havana, Cuba, or VIA e-mail to arnie@rhc.cu... Hope to have you
listening to the weekend edition of the program next Saturday and Sunday
UTC amigos !