Re: [HCDX] Dxers Unliimited's weekend edition for 10-11 March 2007

["Prof. Arnaldo Coro Antich" <inforhc@xxxxxxx>]

Radio Havana Cuba
Radio Havana Cuba's Dxers Unlimited
Dxers Unlimited's weekend edition for 10-11 March 2007
By Arnie Coro
radio amateur CO2KK

Hi amigos radioaficionados ! If you are a short wave listener, a radio 
amateur, TV Dxer, AM Broadcast band Dxer, amateur radio astronomer, or 
homebrew radios, this is your show amigos !
And of course that all of you that also enjoy the other many ways of 
having a good time with radio, are also welcome to.
For example, I have a friend that is an antenna fan, don't talk to him 
about any other aspect of the radio hobby than antennas, all he wants to 
know is about the latest antenna designs, and of course  he runs some 
very interesting antennas modeling software, and ends up by deciding or 
not deciding  to actually build the new antenna design...
One of his latest tests has proven to be quite succesful... he has just 
finished assembling a four element MOXON rectangle array for the two 
meters band, that were easy to build, required no adjustments and 
provide about 9 dB gain over a half wave dipole. Si amigos, there are 
more than 80 ways of enjoying this wonderful hobby ,and listening to 
Dxers Unlimited you are most likely to learn more about each and every 
of them...
Item two: ... : Also antenna related... Listener Bert from Southhampton 
, England sent me an e-mail describing how well his very simple 
magnetic loop antenna is working. Bert says that he had heard that 
magnetic loops had to be built using large diameter tubing, but he 
decided to experiment using the coaxial cable  shield placed  around a 
cross made of PVC water pipe, because his antenna was going to be used 
only for receiving... He used an old radio receiver's air spaced 
variable capacitor, and with it the antenna tunes from 5 to 12 
megaHertz, making evening reception very nice at his location.
Bert told me in his e-mail that he can only listen to the higher bands , 
above 12 megaHertz during weekends, when he is at home all day. During 
weekdays, when he comes back from work, he is finding that signals on 
the 19 meters international broadcast band, and the 20 meters amateur 
band vanish very fast after local sunset, so he can only pick up 
stations tuning from 5 to 12 megaHertz. When I asked him why he didn't 
try to pick up stations below 5 megaHertz, he said that the noise level 
from the top end of the broadcast band up to 5 megaHertz or so was 
extremely high at his location...
Bert's coaxial cable loop is very easy to reproduce by anyone capable
of cutting lengths of PVC pipe with a hacksaw, and soldering the air 
spaced capacitor to outer shield of the coax cable, that is the actual 
antenna... He hangs the loop from a wood beam of his attic, right next 
to his short wave monitoring station, equipped with three different 
radios, a very nice Marconi professional receiver, a more modern Kenwood 
and a small digital readout battery portable. Bert also has an amateur 
radio station that he operates on the 10, 6 and 2 meter bands.
More radio hobby related information coming up in a few seconds
when Dxers Unlimited's weekend edition continues amigos !!!
.......

Yes my friends, you are listening to the weekend edition of your 
favorite radio hobby program... if you happen to have any questions 
about technical aspects of our hobby, send them directly to arnie@xxxxxx 
, again arnie@xxxxxx, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, 
Havana, Cuba... and for those of you that tuned in late,
Item five: The City of Havana's latest new TV station is now one year 
old , CANAL HABANA is broadcasting regularly on UHF Channel 27 since 
last 28th of January of 2006 , and has received a very warm welcome by 
city TV viewers, because it has a very appealing program schedule.
The new UHF channel 27 station is the third UHF on the air here in the 
Cuban capital, the other two are channel 15 broadcasting the Second 
Educational Channel, Canal Educativo Dos and channel 44 re-broadcasting 
the same program to the high rise buildings area of the city, where 
reception from Channel 15 is difficult. As the sporadic E TV DX season , 
let me tell you that the most popular DX catch for TV Dxers from Cuba 
are the Channel 2 stations , one operating in Havana, and another one in 
Santiago de Cuba, They are both high power , and it is easy to tell that 
they are from Cuba as they all carry the Tele Rebelde national program 
most of the time, with just a one or two hour segment devoted to local 
programming of the City of Havana and the City of Santiago de Cuba.
The city of Havana now has FIVE TV stations on the air, TeleRebelde, 
broadcasting on channels 2 and 10, Cubavision on Channels 6 and 8, 
Educational Channel One on channels 4 and 12 and Educational Channel Two 
on channels 15 and 44...
Canal Habana, the fifth station , with local programming is operating on 
channel 27 from the city's highest building, the Jose Marti Memorial 
located at Revolution Square.
The capital city of Cuba has around two million two hundred thousand 
population, and  practically every family owns a TV set, at this moment 
about a  quarter of a million of those TV receivers will soon be 
replaced by high tech  low energy use “green - environmentally friendly 
" color sets, that are also capable of tuning to the UHF frequencies, 
something that was missing from the older TV sets.
.....
Si amigos, the spring-summer Sporadic E short skip season is about to 
start,and there are many expectations with this particular season, 
because it is going to happen during solar minimum. Several well known 
propagation researchers keep voicing the opinion that during solar 
minimum years, the number of sporadic E events and their duration in 
terms of total minutes of activity increases... So, here is what we all 
need to do... after we pass the spring equinox keep a close watch on 
frequencies above 25 megaHertz for any signs of openings, and one of the 
best and cheapest indicators of such sporadic E openings are Citizens 
Bands transceivers connected to an external antenna... A simple quarter 
wave ground plane vertical or a half wave dipole cut for the center of 
the 27 megaHertz Citizens Band fed with coaxial cable is all you will 
need to use the CB radio as a short skip detector as a good friend of 
mine likes to call his installation. He uses an HTX-100 originally 
designed to be used on the 10 meters amateur band, but that can be 
easily modified to cover from 26 megaHertz all the way up to 29.99 
megaHertz. The HTX-100 was originally a UNIDEN CB radio transceiver, 
that was modified to work on the 10 meters band...so my friend found out 
how to do  a very easy modification so that he may receive CB stations. 
As activity on the Citizens Band although not as high as it used to be, 
there are still many stations operating there, including some high power 
illegal ones, while on the  adjacent 10 meters amateur band there is 
very little activity, especially now that we are going through solar 
minimum so, keeping the HTX100 tuned to any of the popular CB channels 
usually detects the presence of CB stations coming from within 
ionospheric E skip distance...
AND... the shorter the skip distance, the higher the maximum useable 
frequency at a given moment on that particular path...
Installing the wire half wave dipole for 27 megaHertz in parallel with 
another half wave dipole cut for 28.5 megaHertz and both fed at the 
center insulator with 50 ohms coaxial cable will give you the 
possibility of monitoring the CB band openings and a few seconds later 
start calling CQ DX on 10 meters and try to work some stations on that 
band, that when open via E skip provides excellent signals from within 
the skip area...
For those of you not familiar with antenna calculations, the half wave 
dipole for exactly 27 megaHertz must be 5.3 meters long and the one cut 
for 28,5 megaHertz must be exactly 5 meters long...Of course that I am 
talking about the antenna's overall length , so each side of the 11 
meters CB band antenna has to be cut to 2.65 meters, and each side of 
the 10 meters band antenna has to be cut to 2.5 meters. Both antennas 
are connected in parallel and you will can install the dual band antenna 
as a horizontal dipole, or if short of space, you can use it as a 
sloper, with the downward end aiming at your favorite direction... Here 
at CO2KK my amateur radio station, I used to had,  two of these dual 
band "E skip detector antennas" one aiming to
340 degrees and the other one in the opposite direction aiming at 160 
degrees... Plans are now in the works to restore this nice E skip 
detector antennas that give me plenty of advance warning of upcoming 6 
meters band openings too...
....
ASK ARNIE, the most popular section of Dxers Unlimited is now on the 
air... Today's question, sent by several listeners that are just 
starting to enjoy TV Dxing... They all ASK ARNIE what's the best 
possible TV antenna for TV Dxing...
Well amigos from Texas, Iowa, Alberta, Berlin and Madrid, plus several 
others from other locations... this is a very difficult question to 
answer , because I need to know many more things about your location in 
order to make a good recommendation for a TV Dxing antenna...
First things first... YOU will want to have at least two TV Dxing 
antennas... if you live in the Americas, where low band TV channels are 
still on the air, then an almost omnidirectional wideband dipole is 
essential, but in Europe where I believe there are no more low TV VHF 
band stations there is no need for such an antenna...The best bet for a 
start up TV Dxing installation is a log periodic covering from 50 to 220 
megaHertz , and another similar antenna covering from 470 to 800 
megaHertz...
Both can be installed on the same mast, and turned by a single rotor. I 
recommend feeding both antennas with ultra low loss foam type coaxial 
cable and keeping the cable run as short as possible.. And now before 
going QRT here is our exclusive and not copyrighted HF plus low band VHF 
propagation update and forecast... High speed solar wind with high 
concentration of protons will be impacting the Earth's magnetosphere 
sending the Planetary A index geomagnetic indicator way up by Sunday, 
and people living at high latitudes will notice the propagation 
disturbances. This high speed solar wind is coming from a coronal hole 
and it is expected to continue disturbing HF propagation until it moves 
away from a geoeffective position. Solar flux around 75 units with the A 
index moving up to more than 25 units.
See you all at the mid week edition of the program amigos, and don't 
forget to send  me your signal reports, comments and radio hobby related 
questions to arnie@xxxxxx and VIA AIR MAIL to Arnie Coro
Radio Havana Cuba, Havana, Cuba.





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