Re: [HCDX] Dxers Unlimited´s mid week edition for 1-2 July 2008 Arnie´s Birthday Program
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Re: [HCDX] Dxers Unlimited´s mid week edition for 1-2 July 2008 Arnie´s Birthday Program
Radio Havana Cuba
Dxers Unlimited
Dxers Unlimited´s mid week edition for 1 -2 July 2008
By Arnie Coro
Radio amateur CO2KK
Hi amigos radioaficionados... welcome to the mid week edition of Radio
Havana Cuba´s Dxers Unlimited, our twice weekly radio hobby program... I
am Arnie Coro, my ham radio callsign is CO2KK, and I invite you to stay
with me for the next sixteen to seventeen minutes to listen to , among
other topics, an update of solar activity, with details of why
scientists are becoming more and more concerned about the lack of
activity of the new solar cycle.
You will also be able to learn more about homebrewing of receivers,
transmitters , transceivers and amateur radio station accessories, learn
more about our hobby when our ASK ARNIE section of the show is on the
air, and also learn a little bit more by listening to our technical
topics section that today will be devoted to the half square antenna , a
very simple antenna that when built following the design formulas
requires no adjustement at all, a very nice feature if you don´t have at
hand a standing wave ratio meter or the more sophisticated antenna
analyzer or impedance or admittance radio frequency bridge instruments.
Stay right on this frequency , Dxers Unlimited´s mid week edition will
continue in just a few seconds, after a station ID.
I am Arnie Coro , CO2KK in Havana...
...........
This is Radio Havana Cuba, the name of the show is Dxers Unlimited and
our e-mail address is inforhc at enet dot cu, again inforhc at enet dot
cu... our postal mailing address is Arnie Coro, Radio Havana Cuba ,
Havana, Cuba, there is no need to include the post office box number as
my good friends at the Cuban Postal Service, Correos de Cuba, will sort
out and deliver immediately any letter or postcard that has as its first
line the three words... Radio Havana Cuba...
Now amigos, at the request of many listeners , more information about
homebrewing radio equipment and station accessories...
People ask me quite often about the tools required for assembling and
repairing radios , and I always start my list with the soldering iron...
You will quickly find out how important the soldering irons are, and why
experienced radio hobbysts usually have no less than three and sometimes
up to five different types of soldering irons.
For beginners , I recommend at least two of them, one with between 20
and 30 Watts of power, and another one with no less than 100 Watts of
power. If your budget makes it possible, the lower power soldering iron
of your choice should be a thermostatically controlled soldering
station, a workshop instrument that although expensive, is worth what
you pay for it many ,many times.
A sophisticated soldering station with a digital temperature indicating
panel and variable control of the temperature of the tip of the
soldering iron is really essential if you are really interested in not
only doing repair jobs, but also assembling kits or homebrewing your own
equipment.
A temperature controlled soldering station with digital readout is a
costly item , and you should find out with other radio hobby veterans
which ones are the best options, and also which ones have easy access to
the soldering iron replacement tips .
A second soldering iron of around 100 Watts power is essential to deal
with heavy jobs, like soldering connectors to coaxial cables.
You must also buy several types of solder, of different diameters and
made of alloys that will make soldering easier. My favorite alloy is one
that contains at least two percent of silver metal, and has a core made
of a flux that will aid soldering.
Do remember that learning how to solder properly is an essential skill
if you really want to homebrew radios or assembly some of the very nice
kits that are now available once again, after several years of an almost
absolute lack of that option in developed nations.
For assembling the more sophisticated kits you will also needs besides
the thermostatically controlled soldering station, a large illuminated
magnifying glass, and a set of high quality hand tools.
Si amigos, yes my friends, oui mes amis, one of the more than 84 ways
you and I may enjoy our wonderful hobby is homebrewing radios and
accessories and also assembling some very nice radio kits !!!
.........
QSL on the air ; QSL on the air, to the many participants of the
GLOWBUGS e-mail list, that so kindly share their know how about vacuum
tubes technology with newcomers to the hobby.
That´s the same spirit of cooperation that you also feel at the
Regenerative receivers Yahoo e-mail list, where participants help each
other a lot to build radios that provide really astonishing results ,
considering how simple some of those circuits are.
Regenerative receiver technology is not dead at all, as some people
might think, there are an infinite number of everyday life gadgets ,
like garage door openers, automobile computerized remote key locks and
other devices that use regenerative receivers to operate. But, it is
also true that regenerative receivers for the low frequency , medium
frequency and high frequency bands, spanning from 10 kiloHertz all the
way up to 30 megaHertz are only used by radio hobbysts .
Among the most outstanding solid state regenerative receiver circuits
that I have ever built and used here, Paul Harden´s Desert Rat and
Charles Kitchin simple radio are the best of them all when you consider
the low parts count and how easy to get going they are. Paul and Charles
are both radio amateurs, and they have promoted the homebrewing of their
excellent designs by means of several magazine articles and Internet
websites...
Vacuum tube regenerative receivers do require using electronic
components that nowadays may be not so easy to find as the ones used by
the Harden and Kitchin radios, so, if you want to start to homebrew a
nice receiver with parts that can be found easily , even by recycling
that old VCR now replaced by the DVD player, or the obsolete FAX machine
that is gathering dust, my advice is to by all means try to gather the
components for one of those two receiver circuits.
The third option that you may want to try , if you are only interested
in listening to radio amateurs communications on the 40 meters band, is
Michael Rainey´s AA1TJ Polyakov detector receiver, an amazing radio by
all standards... By the way I have already sent out many copies of the
AA1TJ dot PDF file with the circuit diagram of the Polyakov
anti-parallel diodes detector, and
I have also available for sending to Dxers Unlimited´s listeners via
e-mail the circuit diagrams of Paul Harden NA5N Desert Rat receiver and
of Charles Kitchin N1TEV solid state regenerative receivers projects
that use common electronic components.
......
And now here is ASK ARNIE, the most popular section of Dxers
Unlimited... la numero uno,the number one in the number of e-mail
messages, letters, postcards and phone calls... My perception is that
among the world´s radio hobby enthusiasts there is a great interest to
learn more about the many different aspects of our wonderful way of
spending our spare time...
Here is today´s question... sent in by thirteen different listeners from
eleven countries, not a record, but certainly very near it, when some
time ago fifteen listeners from twelve countries asked almost exactly
the same question.
Today´s question has to do with mobile amateur radio stations and some
rumors that certain models of new cars may actually stop operating if a
radio frequency signal of a certain power density is detected by the
car´s electronics...
Well amigos, the answer is sadly a big YES... it seems like many car
manufacturers have not taken the necessary measures to properly shield
the electronic equipment that form an essential element of today´s
automobiles, trucks, vans, SUV´s... etc. And a radio signal of a certain
intensity may , and not only may, but has actually caused a total
interruption of the vehicle´s electronics, something that may prove to
be extremely dangerous.
So here is your amigo Arnie Coro´s advice: Before installing a ham radio
transceiver to a car built after the year 2000 or so, ask the vehicle
manufacturer if that specific model has experienced problems in the
presence of transmitting equipment.
Again, be very careful, as just pressing the push to talk button at the
wrong moment may disconnect all of your vehicle´s electronics, leaving
you in a very difficult situation, especially in heavy traffic or under
complex driving conditions.
One also not so nice incident that is now becoming more and more a news
item, is the appearance of some misterious dead spots where some
vehicles simply refuse to operate, not even responding to the owners
remote controlled keys to open the doors.
What was at first thought as just heresay, rumors or fairy tales, has
proven to be true, after engineers equipped with electromagnetic waves
field intensity measuring equipment verified the existence of extremely
high intensities at certain frequencies that completely block the
operation of the vehicles electronics in general and of computers in
particular.
Once again, don´t install an amateur radio transceiver in your vehicle,
especially if it runs more than 10 Watts of power output, if you are not
sure that the operation of that radio may compromise the safety of your
driving....
........
You are listening to Dxers Unlimited´s mid week edition amigos, and here
is now our technical topics section , that today will be dealing about
the half square antenna , an easy to build, low cost, highly effective
for DX and anti-TVI antenna...
The half square is a vertically polarized two element antenna system
that when properly built shows an impedance very close to 50 ohms,
making it unnecessary to do any matching adjustments.
I have used half squares on frequencies from 20 meters and up, and have
never installed lower frequency ones because at my home QTH there is not
enough space for them.
Results achieved on the 20 meters band are much better than with a half
wave sloping dipole, or a quarter wave vertical, and installing two half
squares at 90 degrees to each other provides a very low cost way of
reaching stations around the compass.
My two meters band half square portable antenna is a much better choice
for emergency work than a quarter wave or even a 6 dB gain three element
Yagi, because the half square provides a much wider coverage , with gain
above the quarter wave vertical ground plane , and with a much broader
horizontal pattern than the Yagi.
This antenna is very rugged from a mechanical point of view and lends
itself for portable use, because it is very easy to design it or easy
assembly and disassembly. I use half inch or 12. 7 millimeters or half
inch elements for the fixed station version, while the portable antenna
is made using 6.25 millimeters or quarter inch diameter elements that
are lighter.
The support structure is made of PVC heavy wall high pressure water pipe
of 25 millimeters or one inch diameter, and both the fixed station and
the portable antenna required no adjustment when field tested for the
first time, as they both showed a standing wave ratio of less than 1.2
to one...
The half square is a bi-directional antenna, with a horizontal radiation
pattern that is slightly elliptical... When installed at an adequate
height above ground, it provides a very nice low take off angle vertical
radiation pattern ideal for DX work on the HF bands and for ground wave
communications on the VHF bands.
And now amigos, as always at the end of the show here is Arnie Coro´s
Dxers Unlimited´s HF plus low band VHF propagation update and forecast...
Solar activity still at rock bottom levels, with the solar optical
observers detecting not a single sunspot for the past several days.
Solar flux is at baseline activity , registering just 65 units... and
correspondingly the daytime maximum useable frequency curve raises very
slowly after sunrise and reaches rather low frequencies at the peak
propagation times for even the best North to South paths...
Sporadic E events are still possible,although this year´s season in my
opinion has not been a really outstading one, although some nice
multiple hop oppenings have happened, including transatlantic and
transpacific six meter amateur contacts that somehow made me remember of
the peak years of solar cycle 23 when F2 transcontinental contacts on 6
meters happened quite often .
See you all at the weekend edition of Dxers Unlimited, when I will be
one year older amigos, because tomorrow, July 2^nd is my birthday amigos
!!! So when you hear me during the weekend edition of the program I´ll
one year older !!!
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