Re: [HCDX] Dxers Unlimited´s weekend edition for 19-20 April 2008

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

Dxers Unlimited
Dxers Unlimited's weekend edition for 19-20 April 2008

By Arnie Coro
radio amateur CO2KK



Hi amigos radioaficionados ... welcome to the weekend edition of your 
favorite listener oriented radio hobby program... I am Arnie Coro, radio 
amateur CO2KK your host here in Havana, and as always its my pleasure to 
share with you about seventeen minutes of on the air and on the web 
showtime ...
YES, you can listen to our live audio stream from www.rhc.cu 
<http://www.rhc.cu/> ! again, our URL is www.rhc.cu 
<http://www.rhc.cu/>, in English from 05 to 07 UTC. and now here is item 
one for today: May is just around the corner, and according to solar 
scientists we are going to see a significant increase in Sporadic E 
layer events during next month, also during June..Item two: 11760 khz 
making it nicely to the Toronto , Canada area during the local afternoon 
hours according to several very nice reports sent by listeners in that 
part of Canada that are members of the Ontario DX Association . The e- 
mail messages tell me that the 11760 kiloHertz transmitter has nice 
audio and that the signal level is quite good there during the whole 
afternoon Havana local time transmission. By the way , we are testing 
11760 kiloHertz with another antenna from 0500 to 0700 UTC with our 
regular English language broadcast, in parallel with 6060 and 9550 
kiloHertz... Item three: Especially shielded, and of course much more 
expensive computers , designed so that they will produce minimum radio 
frequency interference , cost a lot of money, but they are required by 
many professional users. For example, sophisticated command, control and 
communications centers, like the Air Traffic Control systems, that are 
so dependent nowadays on the use of computers, have found out that 
standard run of the mill personal computers, the popular PCs are not 
suited for the job, as they may interfere, sometimes at the most 
critical moments, with the radios used to handle emergency traffic... More
about shielded computers, and how you can learn from what it's done to 
reduce the radio frequency energy leaking from the machines , later in 
today's edition of Dxers Unlmited : Item four, our popular ASK ARNIE 
section of Dxers Unlimited will be answering today a question sent in by a
listener in Georgia, USA... Al, who is a high school science teacher, 
wants to know what's the best frequency or frequencies to pick up planet 
JUPITER radio signals, as he wants to show to his students how JUPITER 
sounds can be heard on the radio... I will also answer another question 
from a listener in northern Mexico, Gabriel , wants to know about the 
real possibilities of producing an artificial ionosphere...And at always 
at the end of the program, have your notepad and or tape recorder at 
hand for picking up Arnie Coro's Dxers Unlimited's HF plus low band VHF 
propagation update and forecast... , stay tuned as the program continues 
in just a few seconds...

.......

inforhc@xxxxxxx <mailto:inforhc@xxxxxxx> again, let me repeat it slowly, 
that's my new direct e-mail address, inforch, the one I check many times 
each day in order to keep in touch with Dxers Unlimited's worldwide 
audience...
YES, its certainly nice to receive so many e-mail messages from all 
around the world telling me both what you like and what you don't like 
about the show amigos !.... And now here is item three: totally shielded 
computers and monitors... yes, they do exist and they do cost a lot of 
money... they actually cost ten to twenty times as much as standard 
consumer´s equipment.
Yes,totally shielded machines , with special interfacing interconnecting 
cables, power supplies that have a lot of radio frequency suppresion 
devices inside and monitors that are built into steel cases instead of 
plastic, are mandatory at many specialized applications. Command, 
control and communications centers are the number one clients for those 
especially built machines... as I said they do cost a lot of money, 
because among other things they are not mass produced... BUT, we can
learn from those especially shielded computers... for example, I found 
out that now practically all of those special machines come with solid 
state displays, flat panel screens that operate using low voltages and 
don't require the dreadful sawtooth high voltage waveforms that generate 
such terrible radio noise. But even those flat screen monitors are not 
like the ones that are used regularly , because they are packed into 
steel cases, and the power supplies are also of a very special noise 
suppressing design… I also learned more about several of those specially 
built machines and found out that the keyboards, yes the keyboards are 
especially built, and instead of a plastic case, again ,they are
embedded into a steel casing... And last but not least, the cables 
connecting the machine to the power line go first trough special radio 
frequency filters, that are also used to prevent radio frequency leaking 
from the keyboard connecting cable... Infra-red light is used for the 
mouse, and the motherboards are selected so that they don't have 
oscillators that operate on certain specific frequencies.

Si amigos, you want a computer right next to your radios... among other 
things to keep a nice log with a logbook software program of your 
choice, and also to enjoy the myriad of digital communications modes, 
without forgetting about the wonderful propagation predictions that can be
made in just a couple of minutes with a computer... BUT at the same time 
, you don't want that machine to generate S9 PLUS noise all over the 
spectrum, or as it often happens right on the frequency of your favorite 
net or short wave broadcast station…and that's why we can all benefit 
from the noise reduction technology for computers developed for those 
specialized applications... At CO2KK my amateur radio station, I 
achieved a rather significant reduction in noise level, by just 
installing four ferrite split core chokes... two for the keyboard to 
desktop computer cable, one for the mouse and another one for the 
monitor's video cable... By the way , the monitor video cable already 
had on ferrite toroid choke built in,but adding the second one reduced 
the noise level , so I just kept it right at the connector that sends 
the video from the desktop machine to the monitor...
Older machines, the ones that are now going into retirement , are ideal 
for radio hobby applications... even rather slow by today standards 
computers will provide valuable service at your amateur radio station or 
short wave listening post !!! By adding just a few easy to install radio 
frequency noise suppresion devices, you can certainly improve the 
compatibility between your computer and your radios amigos !!!

.......

This is Dxers Unlimited's weekend edition coming to you on the air and 
on the web... you can also read our scripts by subscribing to one of the 
several e-mail distribution lists that regularly carry our show´s 
scripts twice weekly... Now amigos here is our popular ASK ARNIE,the 
section of Dxers Unlimited that answers your radio hobby related 
question NO MATTER WHAT DIFFICULT THEY MAY BE... Yes , this is Arnie's 
no matter what difficult question you make gets answered here as part of 
the program, and remember that there are more than 83 ways you and I can 
enjoy this wonderful hobby: RADIO... Question one for today, came from
nearby Florida, listener Al wants to know the best band or specific 
frequencies to pick up Planet Jupiter's radio signals.... Well amigo 
JOVIAN RADIO ASTRONOMY, as it is known among scientists, is made 
possible by the super high energy radio transmissions originating from 
Planet Jupiter... they are natural radio signals, and they can best
be picked up with simple equipment from about 18 to 40 megaHertz, with a 
very nice area listening area in the 20 to 22 megaHertz region of the 
short wave spectrum. JOVIAN RADIO ASTRONOMY is practiced on a regular 
basis by a small group of enthusiasts, that even build their own 
receivers and antennas for picking up those signals, that when heard 
trough earphones of loudspeakers sound to me like waves washing ashore 
at the beach..
An simple antenna array of two phased dipoles, or a two to four element 
Yagi antenna is enough to pick up Jupiter´s signals loud and clear , and 
if you use sophisticated digital signal processing software and a 
computer sound card, your observations can make significant 
contributions to radio astronomy Do remember that the world's first full 
time radio astronomer was a radio amateur, an American by the name of 
Grote Reber, who designed and built the first parabolic radio telescope 
!!! So amigo Al, do a nice INTERNET Search Engines sweep and learn more 
about JOVIAN RADIO ASTRONOMY , one of the more than 83 ways to enjoy 
playing with your radios !!! Now today's number two question.. Miguel 
from Baja California, where he listens every day to RHC on 11760 
Kilohertz, send this question to ASK ARNIE...
Miguel wants to know if an artificial ionosphere can be produced.... 
Well amigo Miguel, there are two ways to do it,and both seem to me quite 
aggressive to mother Nature... One is the horrendous ionospheric heaters 
using high power radio transmitters coupled to high gain vertical 
incidence antennas in order to heat up the ionosphere and generate more 
free electrons... Experiments have shown that it is technically possible 
to heat the ionosphere to such an extent so as to produce a localized 
area where free electron concentration will reach very high levels... 
Concerned scientists have warned against such experiments, as no one 
really knows the possible consequences of the artificial heating of the 
ionosphere to enhance its radio refractive properties... The other , 
also very aggressive to the environment technology, is launching into 
the ionosphere certain chemicals or even millions of very small copper 
needles in order to increase the maximum useable frequency reached at a 
certain location... Chemicals interact with the rarified gases above the 
Earth, and again, no one really knows what possible consequences this 
may have... So amigo Miguel, the answer is YES, it has been
done, the ionospheric heating experiments and the launching of chemical 
into the ionosphere using rockets are the two ways that I know by means 
an artificial ionosphere of sorts can be produced, and as I said, both 
ways are terrible to the environment to say the least !!!

.....

And now amigos, as always at the end of the show, here is Arnie Coro's 
HF plus low band VHF propagation forecast..... Solar flux hovering 
around 70 units, and as a matter of fact rather stable ... Propagation 
conditions are now becoming more and more like the typical summer, and 
the trend should continue as we approach summer solstice next June. Late 
night local time reception in the region of the spectrum between 7 and 
10 megaHertz should bring in some interesting DX...See you all next 
Tuesday and Wednesday UTC days at the mid week edition of your favorite 
radio hobby program, Dxers Unlimited with Arnie Coro


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