Dxers Unlimited
Dxers Unlimited weekend edition for Oct 3 - 4 2010
By Arnie Coro
Radio amateur CO2KK

Hi amigos radioaficionados around the world and in space! Welcome to the
weekend edition of Dxers Unlimited reaching you when solar activity is
continuing a rising trend month by month, as solar cycle 24 is finally moving
forward !!!…

I am Arnie Coro, radio amateur CO2KK and
here is item one of today’s program, solar scientists continue to
scratch their heads about cycle 23’s final months… some researchers
are studying what was happening in the Sun during the rather extended tail end of cycle 23.

Some heliophysicists continue to underscore the very high probability that the present solar cycle 24 is going to be another record breaker, even capable of matching the super cycle 19 that sent the average monthly sunspot count up to two hundred and seven. But from what cycle 24 has shown to us so far, my point of view is to support those scientists that are forecasting a rather weak solar cycle peak...

For us radio hobby people, a super solar cycle, with a very high average sunspot count will also mean many solar flares and geomagnetic storms too !!! But chances of that happening are now very, very low indeed. So, we must just wait and see what’s going to happen during the next year and a half or so, when it would be possible to have a fairly good knowledge of the behavior of cycle 24…

Item two: The most popular amateur radio band around the world continues
to be two meters, spanning in some parts of the world from 144 to 146
megaHertz, while in other areas amateurs are assigned two more
megahertz, so the band in those parts of the world goes from 144 to 148
megaHertz. Two meters is very popular because with very simple equipment
and low cost antenna systems, radio amateurs are able to communicate
locally and even at longer distances when propagation conditions are
good.

But the two meters band is not only a good place for FM voice mode
communications. Amateur operators can make good use of existing
satellites, and also enjoy very sophisticated communications modes, like
sending signals of high power transmitters to the Moon, using it as a
passive reflector as part of an Earth – Moon – Earth or EME link, something that now is much easier thanks to the marvelous digital communications modes developed by Nobel Prize Laureate Joseph Taylor, radio amateur W1JT.

I have made several two way amateur radio contacts using the Earth –Moon
- Earth or EME mode while running at CO2KK, my ham radio station not too
much power output and a pair of small size Yagi antennas.
But, fully equipped EME capable stations use huge antenna arrays, high
power transmitters of up to the maximum legal power authorized to
amateur operators and extremely low noise signal preamplifiers… EME is
one of the more than 86 ways that you can enjoy our wonderful hobby…
yours and mine: RADIO !!!
Amigos, Dxers Unlimited’s weekend edition will continue in just a few
seconds… I am Arnie Coro in Havana, stay tuned or connected to our server: www. radiohc dot cu

……..

Si amigos, you are listening to Radio Havana Cuba, the name of the show
is Dxers Unlimited, and as always its my pleasure to share with you this
on the air and on the web time devoted to this wonderful hobby “RADIO”
here is our next item, the most popular section of the show “ASK ARNIE
“answering listeners questions as fast as they come in via e-mail sent
to arnie@rhc.cu...

Today’s number one question: came from the USA, from Nevada, USA,
Dxers Unlimited's long time Reginaldasks if he can adapt an FM band Yagi antenna
that is sold at a popular electronics retailer outlet near his home, so
that the antenna will work on the 2 meters amateur band… Amigo

Reg, the answer is YES… Sure, it can certainly be done, and as a matter of fact, you will end up with a very nice looking 2 meters band antenna, and at a much
lower cost than if you try to homebrew one from scratch,. The typical FM band 5 or 6 elements YAGI antenna has a boom length that provides more than enough
space for a 6 to 7 element 2 meter band Yagi, and the length of the
elements allow you to cut them to the segment of two meters where you
want to operate.

After buying the commercial FM broadcast band YAGI, you must
proceed to carefully measure each element and write down the result of
the measurement.

You will find that as in any typical Yagi parasitic array, the elements
lengths go from the longest one, the reflector, that will be very near a
half wavelength at the operating frequency, to the shortest one , the
last director, that will be much shorter than a half wavelength.
The FM band Yagi will probably be cut for a frequency around 100
megaHertz, because that is roughly the center of the FM broadcast band
that spans from 88 to 108 megaHertz, and that means that the longest
element of your commercially built Yagi will be very near 1. 5 meters
long, that is almost 5 feet long.

The second step required for converting a commercial FM band Yagi for
the amateur 2 meters band is to decide to which segment of two meters
you want new antenna to be optimized. For example you may enjoy talking
to friends on repeaters located in the upper two megahertz of the 2
meters band, from 146 to 148 megaHertz, so you may want then to optimize
your YAGI for a center frequency of 147 megaHertz, which is not exactly
the optimum way of doing it, but that in actual practice works quite well.
The third step is to use any of the available freeware programs that
calculate YAGI VHF antennas, and run it with the 147 megaHertz center
frequency design target.

Those programs generate several outputs: they will give you the length
of each element; how the elements are spaced along the antenna’s support
boom and also you will be able to see the actual theoretical horizontal
and vertical radiation patterns.

Your fourth step requires the use of a measuring tape and a hacksaw, to
cut the elements to the required lengths, following the data provided by
the YAGI antenna calculating software.

Fifth step, requires using an electric drill to carefully locate and
drill the holes where the elements will be fixed to the boom, that will
not be the same ones used for fitting the elements to the original FM
Yagi antenna

The sixth and almost last step requires a decision on your part, it you
want to operate using horizontal or vertical polarization. Using
horizontal polarization as needed for operating on CW and single side
band modes at the lower edge of two meters needs no change to be done to
the boom, but if you want to use vertical polarization, as required for
FM voice and packet radio modes, then you must drill new holes so that
the antenna may be installed for vertical polarization, in other words
the support clamp will be at 90 degrees from the original position used
for receiving FM broadcast band horizontally polarized signals..

The last step is to adjust the antenna for minimum standing wave ratio,
and for doing this you will need a VHF standing wave ratio meter, and
the help of an experienced radio amateur that has adjusted Yagi antennas
before…

And don’t forget that a YAGI with 5, 6 or 7 elements is a highly
directional antenna that requires the use of an antenna rotor if you
want to have around the compass coverage!!!

…….

QSL , QSL , QSL on the air from Havana to the many Dxers Unlimited
listeners around the world that have written during the past several
weeks reporting good reception of our 6060 kiloHertz English language
program heard between 05 and 07 UTC. The antenna we are using on 6060
kiloHertz is our East Coast of North America curtain array, it is
technically speaking according to ITU definitions an HR 4, 4 , 0.8
system, that meaning that it has 4 sets of dipoles set in four rows and
four columns a configuration that provides close to 20 decibels of
effective antenna gain over a half wave dipole placed at the center of
the array.

The antenna is also getting reports from Europe, where
listeners that wake up very early in the morning are picking up the last
hour of the English program between 06 and 07 UTC. If you are picking up
Radio Havana Cuba on 6060 kiloHertz in Spanish from 00 to 05 UTC,you are
listening to the same antenna and transmitter combination too.

And now, as always at the end of the show, here is Arnie Coro’s Dxers
Unlimited, HF plus low band VHF propagation update and forecast…Let’s
begin by saying that radio amateurs and short wave listeners are right
now enjoying the best HF propagation in the past four years, according to
my personal observations and reports received from all around the world !
We are still under the equinoctal DX season period, that will be lasting
for about two more weeks, and then HF propagation will shift to the
typical winter patterns, but this winter season of the northern hemisphere
you can be sure that will be the best one since 2003 !!! I

And don’t forget to send me your comments about this program, signal
reports QSL requests and radio hobby related questions to inforhc at enet dot cu,
or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, and Havana, Cuba.

Posted by Arnaldo Coro at 9:13 AM 0 comments Links to this post
Labels: Arnie Coro, CO2KK, Dxers Unlimited, Radio Havana Cuba, radio hobby program, short wave propagation
Trying to update DXers Unlimited's blog at blogspot
Hi amigos !

After a long delay due to many different difficulties, including computer problems... today I will try to access the Dxers Unlimited's blog at blogspot dot com and see how it works !

Will appreciate reports to this posting sent to
inforhc at enet dot cu

73 and DX
Arnie Coro
CO2KK
Host of Dxers Unlimited
Radio Havana Cuba
Posted by Arnaldo Coro at 9:05 AM 0 comments Links to this post
Labels: Arnie Coro, CO2KK, Dxers Unlimited, Radio Havana