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Re: [HCDX] Dxers Unlimited's weekend edition for 29-30 December 2007 LAST EDITION OF 2007 HAPPY HOLIDAYS TO YOU ALL AMIGOS
Dear amigos of Dxers Unlimited:
I want to thank you all for the many nice e-mail congratulation messages
received here at arnie@xxxxxxx
Wish you all a very properous and peaceful YEAR 2008 !
Dxers Unlimited is a labor of love, as you all know, and I will try
to make it more interesting and appealing during 2008 for your enjoyment.
HAPPY NEW YEAR 2008 TO ALL DXERS UNLIMITED LISTENERS !!!
AND NOW HERE IS THE SCRIPT OF THE LAST SHOW OF 2007...
Radio Havana Cuba
Dxers Unlimited last weekend edition for 2007
December 29-30 2007
By Arnie Coro
Radio amateur CO2KK
Hi amigos radioaficionados around the world and in space… this is the
year’s 2007 last Dxers Unlimited program, and I wish you HAPPY NEW
YEAR 2008 TO ALL !!!!
Welcome to the weekend edition of your favorite radio hobby program,
coming to you from sunny Havana, where our very specially mild winter
weather is providing us with beautiful days for going to the beach ,
swimming , sailing or just relaxing in the shade watching the blue sea
!!! I am Arnie Coro, radio amateur CO2KK, your friend here in Cuba, now
ready to read today’s menu: ITEM ONE
No sunspots in sight at this moment, putting an end of what may now be
surely described as the year of the solar minimum or as scientists like
to call it, the Year of the Quiet Sun… Amigos as 2007 comes to an end,
the very quiet Sun tells us that the chances of solar flares happening
during the next several days are practically zero,so the solar flux
levels are going to stay at extremely low levels down during the first
few days of 2008. … ITEM TWO:TV DX winter season well in progress at
this moment, with sporadic E skip events happening all around North
America, the Caribbean Europe and Northern Africa. At least TWO recent
sporadic E opening sent the maximum useable frequency up past the two
meters amateur band , making reception of FM stations from more than one
thousand miles away possible even with portable radios and their
telescopic whip antennas… ITEM Three: Listeners questions continue to
come in via e-mail, postcards, letters and fax messages, a recent one
from India, really surprised me, as normally the show is not heard so
far during the solar minimum years… But the use of high gain curtain
antennas and 100 and 250 kiloWatt transmitters explains why English
speaking listeners from India, Pakistan and Bangladesh are picking up
Dxers Unlimited.. NEXT: More about low cost , easy to build ham radio
equipment, in this particular case as part of the ASK ARNIE section of
the program ,and at the end of the show, our exclusive and not
copyrighted HF YEAR 2008 HF PROPAGATION FORECAST , a special feature of
this year end edition of Dxers Unlimited.Stay tuned for more radio hobby
related information, coming to you from Havana. , I am Arnie Coro radio
amateur CO2KK ,ready to be back with you in just a few seconds…
….
Si amigos , this is Radio Havana Cuba, and you can send your signal
reports and comments about our program sto arnie@xxxxxx, or VIA AIR MAIL
to Arnie Coro, Radio Havana Cuba, and we will send you our nice QSL card
for your collection of station’s verified .
And NOW , here is ASK ARNIE, THE most popular section of Dxers
Unlimited., QUESTION number sent by listener Marlon in Ireland: Marlon
collects old radio magazine, that he says, and I fully agree with him ,
have a wealth of radio hobby related know-how. Marlon wants to know more
about a regenerative receiver circuit he saw published by Radio
Communications magazine Technical Topics Section. Marlon tells me that
the actual detector circuit is a cascode formed with two triodes, and he
wants to know If I have tested this regenerative detector configuration.
Well amigo Marlon those old radio magazines often provide unique
opportunities for assembling circuits that show amazing performance,
exactly what will happen to you if you carefully duplicate the circuit
of the regenerative cascode detector receiver published by the British
Radio Communications magazine many years ago. I found out that the
control of regeneration with this circuit is amazingly smooth, and that
using a ECC88 dual triode, I was able to make if work nicely even on
the 6 meters or 50 megaHertz amateur band. Instead of using the so
called converters ahead of short wave receivers to pick up the higher
frequency bands, you may want to try this cascode regenerative with the
ECC88 VHF type dual triode . Well amigo Marlon, as you may realize a
converter is nothing but a complete front end of a radio receiver, it
usually includes a radio frequency amplifier stage, a mixer and a local
oscillator, while the cascode regenerative receiver operates right on
the frequency you are going to try to receive.You you can get away
without the radio frequency amplifier stage by using a well designed
front end filter, but adding a radio frequency amplifier to the cascode
detector will certainly improve its performance. Converters designed for
the VHF and UHF bands do need the RF stage, but VHF regenerative
detectors were usually built without the benefit of the RF amplifier
stage,and one could tell people in the neighborhood were listening,
because regenerative detectors radiate a signal on the same frequency
they are picking up, so you could always hear a swish swich sounding
signal when a nearby regenerative detector was tuning across the
frequency you were listening two. Also in the old days used the then
best available vacuum tubes that provided good gain and low noise were
used for the radio frequency amplifier stages, but common triodes
prevailed for the regenerative detector stages.. The really good
converters used a crystal controlled local injection oscillator. Even
today, adding a homebrew converter ahead of a regenerative detector
receiver cost receiver can provide outstanding results, s an antenna.
VHF Converters are no longer required for all practical purposes, as
like I explained here recently, modern HF receivers are including an
extended tuning range up around 54 megaHertz and in some cases up to the
two meters amateur band. Amigo Marlon, the cascode regenerative detector
circuit receiver is not too difficult to homebrew, and the ECC88
followed by a dual triode audio section feeding a beam tetrode audio
output will provide room filling audio . The cascode regenerative with
the ECC88 dual VHF triode tube will make a nice low band VHF receiver ,
useful for monitoring 6 meters during the summer sporadic E season.
Remember to tune set the receiver to the calling frequency of your part
of the world… In the Americas it is 50.125, while in other regions world
it is 50.110. megaHertz where most of the activity on 6 meters is
concentrated around the world. You are listening to Radio Havana Cuba,
and this is our most popular section of the program ASK ARNIE, now with
QUESTION NUMBER TWO,it Came from Trinidad and Tobago, another
beautiful Caribbean nation that I have had the nice opportunity of
visiting and sharing time with many of the local enthusiastic radio
amateur operators. Llistener Mark , who tells me that he picks up our
9550 kiloHertz Caribbean edition, tells me in his e-mail that he wants
to know more about the Near Vertical Incidence Skywave antennas, that
are now so often mentioned in amateur radio publications. Well amigo
Mark, NVIS or Near Vertical Incidence Skywave antennas are becoming very
popular among radio amateur emergency networks, because they will
provide reliable communications at short distances on the 80, 60 and 40
meters bands, while using average power outputs of between 20 and 100
Watts. As you well know, when a tropical hurricane impacts upon one of
our island nations, electricity distribution networks are disconnected
by the power company for safety reasons, and you must operate using
batteries or a diesel or gasoline engine coupled to a generator. When
using battery power, you want to keep the power output as low as
possible, and this is why the NVIS mode is so effective. Here in Cuba we
have found that by installing a highly effective NVIS antenna, we can
keep communications going while the stations are running between 20 and
50 Watts, and when conditions are good, we can switch down to 10 Watts
and keep the emergency net operating. An effective NVIS antenna for the
80, 60 or 40 meters bands is not too difficult to design and install,
and one nice feature is that you won’t need tall masts to make it work
nicely. NVIS are also very useful at noisy locations, because they don’t
pick up signals at the lower take off angles. . Well amigo Mark, NVIS
systems are first of all low profile antennas, they are easy to install,
and above all, NVIS systems can be built very easily and at low cost by
anyone . My NVIS 40 meters band antenna is a nice example of what I am
talking about. Many Cuban amateur radio stations have built it and keep
it ready all the year round, but especially from June to the end of
November during the Atlantic and Caribbean Tropical Hurricane Season…
And for those of you who listen regularly to Dxers Unlimited let me add
that the number one most popular project,the one that received more
requests from listeners for its complete building instructions and
circuit diagrams was the AUSTRALIAN FUN MOORABIN
regenerative solid state receiver.
My prototype HULA HOOP magnetic antenna that is built using a toy HULA
HOOP , a length of TV type coaxial cable, and a receiving type variable
capacitor and takes less than a couple of hours to complete, was the
second most popular project requested to arnie@xxxxxx via e-mail or to
Arnie Coro, Radio Havana Cuba, Havana Cuba, via AIR MAIL postcard or
letter. About the second most popular project , the HULA HOOP antenna,
you will be spending most of your construction assembling the base
where the HULA HOOP is fixed, so that it may be rotated. My HULA HOOP
MAGNETIC LOOP provides excellent reception from 10 to 30 megaHertz, but
it also works quite well with powerful station from 5 to 10 megaHertz. .
The HULA HOOP MAGNETIC LOOP is possibly one of the lowest cost high
performnce indoor antennas that exists,maybe second only to my very
popular BROOMSTICK antenna. Let me add that the HULA HOOP MAGNETIC LOOP
tunes quite sharply and it does require constant retuning of the air
spaced variable capacitor with even a very slight change in frequency.
BUT, peaking the antenna tuning for maximum signal is quite easy to do,
and at the same time it provides ultra-sharp selectivity right at the
antenna, that helps a lot to reduce unwanted noise and cross modulation
problems caused by high powered stations that affect low priced
receivers so badly. As a matter of fact, using my HULA HOOP MAGNETIC
LOOP with a low cost digital receiver has proved to be a very
interesting experience, as the radio’s performance is enhanced
signficantly due to the extra selectivity at the front end provided by
the magnetic loop antenna system.
And now amigos, at the end of the program, here is Arnie Coro’s Dxers
Unlimited’s 2008 HF propagation forecas, yes you heard it right, this
is an advance of what should be happening next year on the HF
bands.…Expect low solar activity to continue during the first half of
2008, solar cycle 23 keeps fading away, but at the same time we should
start to see more high latitude and reverse magnetic polarity sunspots
that belong to the new cycle 24, overlaping with an eventual low
latitude sunspot belonging to cycle 23. During the second half of 2008,
HF propagation conditions will take a turn for the better and we will
all be able to once again enjoy nice DX that will be heard better and
better during 2009, 2010 and of course during the peak year of cycle 24,
expected to happen sometime between 2010 and 2012, something that is
difficult to predict right at this moment. Amigos HAPPY NEW YEAR 2008 TO
YOU ALL, and don’t forget to send your much appreciated comments, signal
reports and of course radio hobby related questions that help to keep
Dxers Unlimited alive for your enjoyment… Send mail to arnie@xxxxxx or
VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba. See you all
at the NEW YEARS EDITION OF DXERS UNLIMITED AMIGOS !
I AM YOUR FRIEND ARNIE CORO IN HAVANA WISHING
YOU ALL NOTHING BUT THE BEST,AMIGOS.
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