Dxers Unlimited weekend editions
by Prof. Arnaldo Coro Antich
radio amateur CO2KK
Radio Habana Cuba
Radio Havana Cuba
Dxers Unlimited's mid week edition for 16-17 February 2010
Hi amigos radioaficionados around the world now enjoying the ongoing upsurge in
solar activity that has brought to us DX signals as strong as we had not heard
them since 2005 !!!
Yes my friends, finally, after waiting, and waiting, and waiting, we are seeing
a nice comeback of the sunspots... As a matter of fact, only two days of 2010
had gone by with a totally blank Sun.
The all important R number from the very much respected Catania, Sicily
reference solar observatory was 39 yesterday... and two other sunspot groups are
just about to turn into view...
As a result of the sustained increase in sunspot count, we are seeing the 15
meters or 21 megaHertz amateur band opening up every day.
I will tell you more about amateur radio Dxing later , here at the mid week
edition of Dxers Unlimited... The daily solar flux is very near 90, and
forecasters were looking at a lower flux during the next three days, but this
may change dramatically and in just a few hours, if the new solar sunspots
regions that are rotating into Earth's view show high activity.
Item two: The amateur radio hobby is alive and in good health... ham radio
operators are enjoying the hobby and finding new ways of improving their
Here is a recent example, by carefully studying the behavior of activity on the
40 meters band, I was able to find out that the band segment from 7105 to 7125
kiloHertz was seeing very little use here in ITU Region II, that is the Americas.
So I launched the idea to start using that segment by low power stations, on
several of the popular ham radio Internet mailing lists. In just a couple days ,
CW activity , mostly by low power or qRP stations on that segment roughly 20
kiloHertz segment has increased dramatically... For many operators, finding such
a nice and clear , interference free segment, has meant having the opportunity
of making many more two way contacts.... and not only exchanging reports, but
also thanks to less interference, we have carried out some really nice ragchews,
and just notice that I have just said WE, because I am , of course, one of the
happy radio amateurs operating on CW between 7105 and 7125 kiloHertz.
There are no digital stations using that segment... as they are now present
between 7030 and 7040 kiloHertz, the two frequencies were QRP , or low power
operators, are used to gather, and where for the past year or so, it has become
extremely difficult at times to make even a single two way CW contact.
I am not saying that QRP operators should abandon the two favorite watering
holes, 7030 and 7040, what I have told the QRP , GLOWBUGS and Regenerative
receivers Internet list members, is that the segment between 7105 and 7125 is in
a much better shape regarding QRM... yes there is a let less interference from
other communications modes...so chances to make nice contacts increase in a very
Si amigos , Yes my friends , Oui mes amis...amateur radio operators around the
world are now enjoying the upsurge in solar activity, and with it, we all must
look around the bands and find ways to make better use of them... After all,
many other users of the radio spectrum are always monitoring the ham bands, just
to have data available to substantiate their requests for more spectrum space....
In other words, if we, amateur radio operators are able to be more time on the
air, and the bands sound like a beehive of activity, chances that those spectrum
hungry users will just go elsewhere !!!
Stay tuned for more radio hobby related information, coming up in a few seconds...
I am Arnie Coro in Havana...
This is Radio Havana Cuba, the name of the show is Dxers Unlimited, and here is
the latest activity report about amateur radio entities on the air around the
world... According to the AR-Cluster Network for the week of Sunday,
7th-February, through Sunday, 14th-February there were
231 countries, or shall we say more precisely 231 active entities.
For those of you new, and also for some not so new to ham radio, working amateur
radio stations located in Africa has proven to be a challenge.... So, here are
now a few examples of stations that are or will soon be on the air from several
African nations... Uganda, 5X is the prefix of that country that is now active
thanks to Jack ,home callsign NP2OR, that is using the 5X7JD call sign from
Uganda. Jack can be found on 40 and 20 meters single sideband, during the time
frame from 0500 to 1550Z. He is running 100 Watts into a simple vertical antenna
that radiates equally in all directions.
If you are able to make a two way contact with 5X7JD or in case you are a short
wave listener picking up his transmissions, then you can send your QSL card to
Jack Dunigan, BOX 100 , Masaka, Uganda.
And another African nation also on the air now and until May , is operated by a
Norwegian radio amateur presently in Kenya. Cato, home callsign LA9PF , is now
active using the call 5Z4 stroke LA9PF.
Cato is sharing his operating time between single side band voice and digital
modes, especially on the most popular of them all PSK31 keyboard to keyboard
mode... Cato's QSL receiving address is Cato B. De savigny PO BOX 5642, Malindi,
80200 , Malindi , Kenya.
Si amigos , the upsurge in solar activity , is making possible to pick up more
and more DX stations, that you can add to your logs much more easily than during
those years of extremely low solar activity !!!
This is Dxers Unlimited's mid week edition, and here is now our technical topics
section, where you can learn about the technical aspects of our wonderful hobby.
There is no doubt that the 2 meters amateur band is among the most popular
segments of the radio spectrum used at a worldwide level. The availability of
portable hand held stations, the well known handie-talkies , plus the
installation by radio clubs of 2 meter band repeaters have done a lot to
popularize the use of 2 meters around the world.
The typical 2 meter hand held FM transceiver runs between 1 and 5 Watts, and
uses a rather inefficient antenna system consisting of a helically wound compact
vertical, that employs the small metal case of the handie talkie as its ground
plane or counterpoise.
So, the range that you can achieve using the FM hand held transceivers is pretty
limited to say the least..
That's why it is always a good idea when travelling to include among the extra
batteries and earphones, an easy to install antenna that can be plugged to the
FM 2 meters band handie talkie. My number choice for that role is the J pole
half wave vertical made of a length of high quality 300 ohms TV twinlead... the
antenna can be rolled into a very compact , easy to transport form... and it can
be made in less than an hour.
My number two choice is a more sophisticated and higher gain antenna , but also
easy to make portable antenna, known as the HALF SQUARE , that can be made in
such a way that it can easily be assembled and dis-assembled for easy
My portable 2 meters band HALF SQUARE is made using 22 millimeters outer
diameter thick wall PVC pipe, split into three parts , so that it can be easily
transported in your backpack. The antenna provides about 4 dB gain over a half
wave vertical dipole, and it is capable of providing an amazing 10 to 12 dB gain
over the typically helically wound short vertical antenna that is the factory
option coming with the 2 meter hand held FM transceiver.
As a local Havana radio amateur recently told me after building and using the
portable HALF SQUARE 2 meters band antenna .Arnie, he said ...“ it is like if
you were using a 50 Watts power amplifier connected to your handie talkie ” ,
when you switch from the rubber ducky short helically wound vertical to the
portable HALF SQUARE, and he added that his HALF SQUARE is assembled in less
than three minutes, and knocked down in two.
Technically speaking a HALF SQUARE antenna is a two elements vertical beam fed
with at a corner using 50 ohms coaxial cable... that doesn't require any
matching systems , because the HALF SQUARE has a feedpoint impedance that is
remarkably near to 50 ohms, so the standing wave ratio is pretty low.
You can learn how to homebrew a two meters band HALF SQUARE amigos ! Just send
me an e-mail to inforhc at enet dot cu, and you will be receiving a small
computer file containing the step by step instructions on how to make your HALF
SQUARE antenna using readily available materials, and hand tools that can be
found at almost any household.
Again, send your request for the HALF SQUARE antenna building instructions to
inforhc at enet dot cu...
Si amigos, we do QSL, we do confirm your reception reports, and we are now in
the process of preparing a new very special QSL card to celebrate Radio Havana
Cuba's 50th anniversary, that will take place next year , so now we are on our
49th year on the air … For some of us who were among the small group of very
enthusiastic workers that had the unique experience of putting our experimental
station's signal on the air, the day to celebrate is on the 24 th of February,
when running a 1 kiloWatt Gates short wave transmitter, and a Brown Boveri 10
kiloWatts transmitter that were installed inside a provisional building and
connected to two half wave dipoles supported between utility wooden poles the “
Onda Corta Experimental Cubana “ “ Cuban experimental short wave station went on
the air … A few weeks later on the first day of May 1961 we used, for the first
time on the air the name Radio Havana Cuba.
And now before going QRT , here is the most recent solar report picked up early
morning Tuesday , local time here in Havana... Solar flux 88 units and moving
down, but it may move up again soon, solar activity is LOW, the effective
sunspot number is at the nice value of 32... and the Catania observatory latest
visual sunspot count available at their website has an R value of 39.
Expect good propagation conditions during the local daylight hours at mid and
lower latitudes, with the segment between 14 and 22 megaHertz providing the best
chances for Dx.
I invite you to join me next Saturday and Sunday UTC days at the weekend edition
of Dxers Unlimited amigos... and don't forget to send your signal reports and
comments about the program to inforhc at enet dot cu , or VIA AIR MAIL to Arnie
Coro, Radio Havana Cuba, Havana, Cuba...
Posted by Arnaldo Coro at 9:32 AM 0 comments Links to this post
Labels: amateur radio, Arnie Coro, Dxers Unlimited, QRP, Radio Havana Cuba 40
meters amateur band, radio hobby
Saturday, February 13, 2010
A very nice photo of the Sun's active sunspots regions
This is a photo of the Sun taken with a filter at 195 nanometers wavelength .
Several sunspot regions can be seen , with the very powerful 1046 looking at the
Earth in a geoeffective position. Sunspot active region 1046 generated the
strongest flare so far seen during solar cycle 24... an M8.3 type that produced
radio blackouts in the parts of Earth where the Sun was above the horizon.
You can also see a new active sunspot region right at the limb of the solar
disk, that will soon turn into view, thus keeping the daily sunspot count above
30 , even when active regions 1045 and 1046 turn around and are no longer seen