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Re: [HCDX] Dxers Unlimited's weekend edition for 6 -7 October 2007 by Arnie Coro CO2KK



Radio Havana Cuba
Dxers Unlimited
Dxers Unlimited’s week end edition for 6-7 October 2007
By Arnie Coro
Radio amateur CO2KK

Hi amigos radioaficionados listening to the program or reading the 
scripts available at several of the world’s most well known SWL and Ham 
Radio e-mail lists… You are all welcome to the weekend edition of Dxers 
Unlimited, our twice weekly radio hobby program that covers practically 
all aspects of our wonderful hobby, from AM broadcast band Dxing at the 
bottom of the solar cycle, to home brewing simple receivers, from making 
your own highly efficient and low cost antennas for the 2 meters band FM 
ham radios, to watching TV DX signals via meteor scatter… Yes amigos, 
there are more than 81 different ways you and I enjoy this hobby… and 
here is a nice example:  the thrill of picking up a distant AM broadcast 
band station using your standard bedside radio is absolutely great… As a 
matter of fact many people have discovered this hobby by picking up long 
distance stations, especially at the high end of the AM broadcast band, 
between 1400 and 1700 kilohertz, because that segment of the band 
propagates better during local evening hours… Now that solar cycle 23 is 
moving along its minimum, AM broadcast band DX is at its best, and even 
with a very simple receiver you can pick up far away stations… Recently 
I gave it a try, and was able to pick stations from eleven countries 
during a three hour period from about eleven PM to 2 AM local time… 
Propagation conditions were so good, that several of the DX stations 
sounded just like another local one.
I kept a log of the DX stations and next day in the morning sent
AIR MAIL postcards to all of them, a total of 37 stations… And, amazing 
as it may sound, just two weeks later I received a QSL from a Mexican 
station, signed by its Chief Engineer, who also sent an e-mail with a 
full description of his transmitting site. But, let me warn you that 
this is an exception, as normally QSL’s take much longer to arrive at 
your doorsteps… This Mexican QSL super service was , according to what 
the station’s Chief Engineer said in his lengthy e-mail and in a short 
handwritten note on the postcard QSL , a courtesy of  a long time 
listener of Radio Havana Cuba and Dxers Unlimited. As a matter of fact, 
he had been listening to Dxers Unlimited for more than 10 years!!! So 
now I have a beautiful Mexican postcard in my AM band QSL collection 
that already adds up to 91 countries around the world!!!
Si amigos, yes my friends, radio need not be an expensive hobby at all… 
even with a very modest AM and FM broadcast bands receiver you can start 
searching for far away stations and sending out reports…
Dxers Unlimited’s weekend edition will continue in just a few seconds…. 
After a short break for station ID
I am Arnie Coro in Havana….stay right on this frequency or World Wide 
Web connection amigos!!!
………

This is Radio Havana Cuba, the name of the show is Dxers Unlimited and 
you can send me your signal reports and comments about the program to 
arnie@xxxxxx or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, 
Cuba, now here is item two of today’s show…. A nice senior high school 
radio related project that can certainly win a science fair award is 
designing and building an amateur radio telescope for listening to the 
powerful signals from both Planet Jupiter and the Sun… A wire antenna 
and a sensitive short wave receiver capable of tuning from 20 to 40 
megaHertz will bring in Jupiter’s radio emissions loud and clear… The 
signals emitted by planet Jupiter sound like ocean waves washing ashore… 
and you can be sure that you are picking them up because at several 
World Wide Web Internet sites there are MP3 recordings of Jupiter’s 
radio signals… At this stage of the solar cycle, your 20 to 40 megaHertz 
short wave receiver won’t pick up loud signals from the Sun, but in 
about two years from now, our nearest star will be very active, and 
signals from solar radio storms will be very easy to pick up. Amateur 
radio astronomy is not limited to such a simple set up… Many enthusiasts 
of this way of enjoying the radio hobby use retired TV satellite dishes 
to pick up very distant radio sources, like Cygnus A and Cassiopeia…By 
the way, it was a radio amateur, by the name of Grote Reber, who during 
the very early days of radio, built a parabolic reflector and started to 
explore in search of signals from outer space, and he succeeded… His 
original dish antenna is now preserved at one of the world’s most 
important radio astronomy observatories, and scientists recognize the 
contributions made by amateur radio operator Grote Reber to the 
development of radio astronomy, now one of the leading aspects of 
scientific exploration of the Universe.
Reber decided to build his own radio telescope in his back yard in 
Wheaton, Illinois, when he could not get a job with Karl Jansky the Bell 
Telephone Laboratories scientist that discovered radio waves from outer 
space.Reber, who was a university trained electrical engineer was able 
to design a radio telescope that  was considerably more advanced than 
Jansky's equipment. He made the world’s first  parabolic antenna using 
sheet metal  for a  mirror 9 meters in diameter, focusing to a radio 
receiver 8 meters above the mirror. The entire assembly was mounted on a 
tilting stand allowing it to be pointed in various directions, although 
not turned. The telescope was completed in 1937.
One very interesting fact about the first radio telescope made by a 
radio amateur operator was that Reber designed it to operate at a 
microwaves frequency of 3300 MHz and failed to detect signals from outer 
space, he then built another receiver for operating at 900 MHz, a UHF 
frequency that also proved to be a failure because the state of the art 
of receivers for such frequencies did not allowed for very weak signals 
to be picked up. Finally, Reber, a very dedicated person, moved down in 
frequency making his third attempt at 160 MHz and successfully picking 
up signals from space in 1938, confirming  Karl Jansky's discovery. 
Reber then turned his attention to making a radio-frequency sky map, 
which he completed in 1941 and extended in 1943. He published a 
considerable body of work during this era, and was the initiator of the 
"explosion" of radio astronomy in the immediate post-WWII era. And 
amigos, he always considered himself as an amateur…and his call sign 
W9GFZ is very well known among the world’s radio astronomers, of which 
many, I must add, are also active radio amateurs, as well as many of the 
engineers and technicians that work at the world’s most important radio 
astronomy observatories…Grote Reber died in Tasmania, where he was doing 
very low frequency radio experiments at the age of 91, and his ashes 
were distributed to 24 radio astronomy observatories around the world, 
as a tribute to this radio amateur that was one of the first to ever 
pick up radio signals from outer space…

……………

Si amigos, you are listening to Dxers Unlimited, your favorite radio 
hobby program… and here is la numero UNO, the number one favorite 
section of the show… ASK ARNIE… where I am able to answer your radio 
hobby questions here, and also via e-mail…. Today’s question is about 
the MOXON rectangle antenna, and it was sent by listener Eddy from 
Scotland… He tells me in his e-mail that his 2 meters band MOXON antenna 
works very well, and asks why he hasn’t been able to find a commercial 
version of the MOXON antenna so far… Well amigo, that’s a good question, 
because what we see normally in radio magazines adds are Yagi and Log 
Periodic beam antennas… covering from 40 meters or 7 megaHertz all the 
way up to the upper UHF bands, and during the past three or four years, 
I have just seen one single ad about a commercially built MOXON 
rectangle antenna for the HF bands from 20 meters to 6 meters. As you 
already know well amigo Eddie, the MOXON is a single band two elements 
close coupled antenna, that has a truly remarkable front to back ratio 
when properly built, combined with a much wider coverage area than a 
similar two element Yagi array… I am now in the process of building a 
batch of 2 meters band MOXON antennas, as part of a Radio Club project 
that will use them for the installation of very simple antenna systems 
that are going to provide much better coverage to our stations than when 
using simple omni directional vertical antennas. The system that I 
designed uses two or four MOXON antennas made with copper tubing… They 
are assembled on the mast or tower so as to provide optimum coverage 
into the areas where the amateur radio activity is higher… For example 
here in Havana, our first system has one of the MOXON antennas beaming 
to the center of the island, at 110 degrees azimuth, while the other 
antenna is beaming to the 240 degrees to reach the mountain top repeater 
located at the Sierra del Rosario national park and biosphere reserve… 
The switching between the two antennas is done right at the top of the 
mast, by means of a single pole double through relay that is remotely 
controlled from the operating position… Because the MOXON antennas have 
a horizontal pattern that is about 140 degrees between the minus 3 dB 
points, this system has proven to be very efficient, and is much cheaper 
than having to buy and install an antenna rotor… With a stack of two 
MOXONS in each direction, the estimated antenna gain is around 6 dB, 
the equivalent of a well designed and built three element YAGI, but with 
the advantage that the MOXON covers a much wider area due to its better 
horizontal pattern…For those of you listeners of Dxers Unlimited that 
are also radio amateur operators, I have here all the design information 
for this simple , easy to build and rugged dual directions antenna 
system for the two meters band , based on the MOXON rectangle antenna 
that is becoming more and more popular these days among the world’s ham 
radio operators due to its excellent characteristics.
And now amigos at the end of the show, as always when I am here in 
Havana, listen now to Arnie Coro’s Dxers Unlimited’s HF plus low band 
VHF propagation update and forecast… More and more days with ZERO 
sunspots and extremely low solar flux levels… solar scientists are now 
almost sure that since July the SUN is going trough the minimum of cycle 
23… Equinoctial propagation conditions are slowly fading away, as the 
northern hemisphere winter and the lower hemisphere summer approach… so 
be prepared for many more days of very low maximum useable frequencies, 
and also of very low ionospheric absorption …
Transequatorial propagation on the 10 and 6 meters band is now happening 
every day, from the Caribbean to the extreme end of South America, and 
here in Havana, a good example is the fact that 10 meter band pirates 
stations from Argentina and Brazil are coming in every afternoon… See 
you all at the mid week edition of the program , Tuesday and Wednesday 
UTC days amigos !!! And don’t forget to send me your signal reports and 
comments to arnie@xxxxxx or VIA AIR MAIL to Arnie Coro, Radio Havana 
Cuba, Havana Cuba.

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