Hola amigos of Dxers Unlimited....
Lost in cyberspace... was this blog... Now I will try to keep it up to date, by the simple expedient of, among other things uploading the actual scripts of the two weekly editions of Dxers Unlimited, the radio hobby show soon to be celebrating its 25th year on the air...
So here we go:
Radio Havana Cuba
Dxers Unlimited middle of the
week edition for
Tuesday 15 March 2016
By Arnie Coro
radio amateur CO2KK
Hola amigos radioaficionados
all around the world now starting to enjoy the equinoctial
propagation conditions despite several solar related disruptions
during the past two days....
The daily solar
flux continues to be holding below 100 units, and that is an
indication that the solar cycle continues its slow but continuos
downward trend.
By the middle of the A'16
broadcast period of the ITU in July we are expecting an effective
sunspot number of around 40.... In the meantime we are now also
approaching the spring and summer sporadic E season, that according
to my own forecast should provide us this year with more openings and
longer lasting events... something that is connected with the lower
solar activity without doubts...
I am your host here in hot,
sunny and dry La Habana Cuba, my name is Arnaldo, but everyone
involved in radio knows me as Arnie.... well actually as Arnie Coro,
the long time host of Dxers Unlimited...
Now
here is item two.... in the field of electronics technologies
something new happens every day, and that is why developments are so
fast... take for example the Software Defined Radios technologies
that are making possible to create radio receivers, transmitters and
transceivers that provide amazing performance, and as a matter of
fact, performance parameters that can be tailored to exactly what is
required...
Also I just saw a new model of the Raspberry Pi ultra
small computer, that when associated with Software Defined Radios
programs are making possible to provide radio amateurs and short wave
listeners with radios that match and exceed in many aspects the
performance of analog classic radios that cost several thousand
dollars...
So here is my advice, if you really want to improve your
monitoring post and your amateur radio station if you happen to have
one, NOW is the moment to start learning about Software Defined Radio
or SDR technologies , you will not regret all the time devoted to
learning about what is going on in the SDR world...
Item three: several amateur
radio contests during the upcoming weekends will provide you with
opportunities to work many DX entities, and thanks to the electronic
certified QSL cards, you can claim having worked them much sooner
than when one has to wait for a hard copy air mail QSL card to reach
the post office box.
Ham radio contests in my
opinion are seeing some changes, like practically eliminating
competitors that do not have access to the Internet and can send
their logs electronically..
And that amigos , again in my
personal opinion is not fair at all.... I wish that contests
organizers should think about the fact that although connectivity to
the Internet is increasing , there are still billions of people that
do not have access to the Internet services, while
in many countries the quality of service is very low, having to deal
poor bandwidth connections....
Now more about contests.... as
a good friend of mine that has participated in many contests both as
an individual station and forming part of a group effort has
underscored, ham radio contests seem to produce a unique effect on
the ionosphere....
One day before the contest, just to give you an
example, the 10 meters band was practically dead... with maybe one or
two CW beacons heard at the peak of the propagation curve.... then
the next day, same time, same solar flux, same A index , same K
index... you find the SSB segment of 10 meters full of stations
working the contest...
This is something that is
really hard to explain, and some experts say that especially 15, 12
and 10 meters are open for DX during the local daily hours much more
than one may believe... This is why I insist on calling CQ DX many
times around the spot frequencies used by DX expeditions...
Just to give you an example...
calling CQ DX on SSB on
28495 on 10 meters or 21295 on
15 meters has made possible for my QRP or low power station to
establish many very good two way contacts at times when scanning the
first 500 kiloHertz of 10 meters or the first 300 kiloHertz of 15
meters brought no signals at all....
Then after several CQ DX calls
of those two frequencies , I find that there are people monitoring
them and ready to come back to my call... Although a CO station is no
longer considered DX, there are many radio amateurs that do need Cuba
confirmed for their DXCC Award request...
By the way, there is an
ongoing debate as regards of the SSB calling frequency for DX on the
12 meters band... so if you know about this topic please write to
inforhc at enet dot cu , again inforhc at enet dot cu and tell me
what frequency of the 12 meters band you
consider to be the SSB calling spot.
For those of you not familiar
with the 12 meters band it is an allocation won by the amateur radio
service back in 1979 and it spans from 24890 to 24990 kiloHertz, but
do not ask me why the International Telecommunications Union
Conference did not allocated the band from the much more logical
24900 to 25000 megaHertz....
Someone told me that this not so logical
frequency assignment had to do with spot frequencies assigned for
radio astronomy use....
Stay here , in a few seconds I
will be back with more
radio hobby related
information...
................................
musical intercut
This is Radio Havana Cuba, the
name of the show is Dxers Unlimited, and here is item four of this
middle of the week edition of this program... Outstanding results on
the two meters amateur band using a very simple three elements
vertical antenna made with very low cost and easy to find
materials...
This version of the BOBTAIL VERTICAL adapted for the 2
meters band FM segment is really easy to build and matching it to the
50 ohms coaxial cable is done by cutting bits from the three vertical
elements until the one to one or near one to one standing wave ratio
is achieved...
It uses a simple choke made
from coaxial cable as an effective decoupling between the antenna and
the long 50 ohms feedline. I have also built the two elements version
of this antenna, knows as the HALF SQUARE, but the three elements
version is certainly better at the expense of just a longer center
boom support and one additional vertical element.
This same type of
antenna can be built for 6 meters and you may want to install it to
provide a North to South and South to North coverage.... Its low
vertical departure angle will make possible many DX contacts too.
If you want to learn more
about the BOBTAIL Three Elements vertical array , just send an e'mail
to inforhc at enet dot cu, again inforhc at enet dot cu, and I will
send you the schematic diagrams and photos of this BOBTAIL three
elements beam without reflectors, and I will also add a nice photo of
the BOBTAIL with reflectors that provides a very clean unidirectional
antenna pattern, very useful to reach distant FM repeaters....
Item six: Also connected with
antennas... Recently I was invited to visit the amateur radio station
of a friend that lives in a 12 floors high apartment building... when
he showed to me the noise level
that he has to deal with on the 20 meters band I was really
impacted...
I told amigo Peter, that we should try a folded dipole to
replace his 20 meters ground plane quarter wave vertical... So we
made the design , went for the materials and the next week end we
proceeded to build and install the folded dipole antenna , feeding it
with a four to one balun.... The antenna was tuned nicely for minimum
standing waves , and we found out that the noise level had dropped
significantly... A similar result was experienced at the apartment
building in Ciego de Avila province of central Cuba where my good
friend Pedro Rodriguez CO7PR has his ham
radio station installed.
Pedro commented that the 40 meters band
folded dipole was easy to build and install. Also he said that no
traces of TVI on his TV were seen and so far no complaints from any
ot the more than 90 apartments in the building were
registered,something that has made possible for him to enjoy his
retirement a lot more by going on the air on 40 meters much more
often...
Now pretty fast , at the end
of the show... solar activity continues to be very low with the solar
flux around 90 units, but we will be still receiving the impact from
a solar particles event that will soon fade out....Send your signal reports and comments to inforhc at enet dot cu or Via Air Mail... a postcard will be OK sent to Arnie Coro, Radio Havana Cuba, Havana, Cuba
