Re: [HCDX] Dxers Unlimited's script for mid week edition 2-3 October 2007

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

Radio Havana Cuba
Dxers Unlimited
Dxers Unlimited’s mid week edition October 2 -3 -2007
By Arnie Coro
Radio amateur CO2KK

Hi amigos, welcome to our mid week edition , coming to you Tuesdays and 
Wednesdays UTC days. I am Arnie Coro , radio amateur CO2KK your host 
here in Havana, and as always it is my pleasure to share with you about 
seventeen minutes of on the air and on the web time. Here is now item 
one of today’s program: The Headline : Back to Zero , yes back to zero 
sunspot count after a very short break , when a single small sunspot was 
seen… according to a recent analysis by a group of well known solar 
scientists, cycle 23 actual minimum has required no less than three 
revisions, and it has certainly extended beyond all forecasts. Another 
relevant piece of information about this solar cycle is that the number 
of consecutive days without sunspots has so far extended into two series 
of great significance, when compared with other previous solar cycles. 
For short wave listeners and amateur radio operators, as well as for 
professional users of the HF spectrum, cycle’s 23 extended minimum has 
already had a very significant negative impact, including, in the case 
of amateur radio, rather low scores during the latest contests !!!
Item two: Less time on the air, or more time using the highly efficient 
digital modes, like the PSK31 keyboard to keyboard brainchild of G3PLX 
Peter Martinez that with just 10 Watts transmitter output and even a 
very simple antenna is capable of providing nice two way amateur radio 
contacts. Yes less time on the air is one option for ham radio operators 
at this present stage of the solar cycle, that can then be devoted to 
more home construction of radios, one of the 81 wonderful ways of 
enjoying our wonderful hobby. At a recent edition of Dxers Unlimited, I 
talked about new approaches to the design and construction of simple 
short wave receivers, that have already proven to be quite feasible for 
the average home builder… The Wheatstone Bridge Regenerative Receiver 
Circuit is now available in both a vacuum tubes and a solid state 
devices versions .. The solid state version provides amazing performance 
according to my breadboard prototype tests, and it is also quite amazing 
that this receiver works from a single 1.5 volts battery and requires a 
current of less than one milliampere to provide full output into the 
headphones. The circuit is very simple, and easy to reproduce without 
requiring the use of a printed circuit board… as a matter of fact you 
can assemble it using the now classic small islands technique, that is 
gaining favor among homebrewers of ham radio gear…
Si amigos, yes my friends, oui mes amis… HF propagation conditions may 
be very poor, band openings above 20 megaHertz rare or non existent, but 
the radio hobby has so many different aspects that can be enjoyed , 
among them homebrewing receivers that have a very special sound when you 
use them… because I can assure you that a radio that you assemble has a 
unique sound to your ears… build your first homebrew radio and when it 
starts bringing in stations, even if the first one is the local AM 
broadcast band super power 50 kiloWatts transmitter , you will agree 
with me that your homebrew radio has that very special sound too…
Stay right here on this same frequency or world wide web connection … 
Dxers Unlimited’s mid week edition will continue in just a few seconds 
amigos …
……

This is Radio Havana Cuba, the name of the show is Dxers Unlimited and 
here is item three of the show… ASK ARNIE, la numero uno, the number one 
most popular section of the program… The question that I will be 
answering today here came from Australia, more precisely from Perth, 
where amigo Ian picks up RHC’s 9550 kiloHertz frequency during the two 
yearly equinoctial periods with what he describes as “amazing 
reception”… Amigo Ian wants to know more about the best antennas for 
picking up very distant stations, that may be reaching his receiver at 
very low angles above the horizon. Well Ian, low take off or receiving 
angle antennas are difficult to install at urban locations, and the only 
type of antenna that provides really low take off and receiving angles 
above the horizon suited for an urban area is unfortunately prone to 
picking up a lot of man made noise, something that will make reception a 
lot more difficult.
During solar cycle 21 , I had installed a vertical antenna for the 20 
meters amateur band that was about 120 electrical degrees high, and had 
six elevated radials . The antenna itself was installed on my rooftop, 
but the bottom of it was elevated about three meters from the reinforced 
concrete roof. The six radials worked as the elevated ground plane, and 
this antenna provided wonderful DX contacts around the world while using 
less than 100 Watts. The zero decimal thirty three wavelength vertical 
with elevated ground plane sent out and received signals at very low 
angles above the horizon , and it worked so well that several of the 
local ham radio Dxers visited me just to see the antenna, as during pile 
ups, I often made contact with the rare DX station before the owner of 
the best 20 meters 4 element Yagi antenna in town.
He was scratching his head how could CO2KK could beat him breaking a 
pile up, when he had installed a huge 4 element full size 20 meters 
Yagi… and I had to spend quite some time to explain to him that he would 
need at least a 120 feet or about 36 meters high tower, in order to 
achieve the low take off angle that my elevated ground plane was 
providing. Fortunately at my city location, the noise level is rather 
low, because as I have explained here several times, the man made noise 
, man made interference is mostly vertically polarized, so a vertical 
antenna picks up a lot more local noise than a horizontally polarized 
antenna…
Amigo Ian, I have already sent to you the sketch of the elevated ground 
plane antenna for 20 meters, which is the most popular DX band among 
radio amateurs. You will also see in the drawings a table of dimensions 
for the 17, 15, 12 and 10 meters band. An elevated ground plane antenna 
for the lower frequency amateur bands like 30, 40 and 80 meters will be 
difficult to build and install, and that’s why I didn’t include 
information about them.
Now another question , this one came from Canada , where the short wave 
listening hobby is , according to my analysis, a mostly winter time 
activity for many Canadians… although as my good friend Bob Chandler , 
radio amateur VE3SRE from Toronto has told me, the summer time ham radio 
contests, like the one held during Canada Day national celebration are 
also very popular… The question came from
Quebec City, where amigo Robert lives. He wants to know about amateur 
radio satellites, and how easy or how difficult it is to operate using 
them. Well amigo Robert, ham radio satellite activities , in my opinion, 
have gone down significantly after the failure of several of the most 
popular birds, as the satellite enthusiasts call them. As a matter of 
fact, the failure of RS10 and RS12 , followed by Oscar 40 has left out 
of the picture both the simple station operators and those who spent a 
lot of time and resources to install a complex Earth station to work the 
Oscar 40 satellite. At this moment the amateur satellites that are 
available provide very short time windows to communicate, due to the 
fact that they are all in the so called Sun synchronous orbits, at 
rather low altitudes, and they don’t have , as far as I know, HF bands 
inputs or outputs… So amigo Robert, we must wait and see if a new ham 
satellite project in the works can finnally be completed , and a Molnya 
elliptical orbit satellite can be launched … As regards to your question 
about why there are not stationary ham radio satellites, like the ones 
used for telecommunications and relaying TV signals, the answer is a 
very simple one amigo: they cost a lot of money, and so far it has 
proven impossible for any of the amateur satellite organizations to 
collect enough resources to even think of starting such a project. 
Another possible approach would had been to find a geostationary orbit 
satellite to which an amateur radio transponder could be attached, but , 
again, so far, this has proven to be impossible…
You can still have fun with a dual band 70 centimeters and two meters FM 
transceiver and a simple hand held antenna by communicating with the low 
earth orbit ham satellites that are now in operation , but your fun will 
have a very limited time , because even on the best passes, the time 
available to communicate is limited to fifteen minutes or less.
And now amigos, just before going QRT, here is Arnie Coro’s Dxers 
Unlimited HF plus low band VHF propagation update and forecast… Solar 
flux continues at very low levels, with the actual flux measurements not 
going over 67 or 68 units… and do remember that the lowest registered 
microwave solar flux was 64 units… Sunspots are non existent… sunspot 
count again zero after a brief spell when a very small sunspot emerged 
and then vannished… Expect daytime maximum useable frequencies not to 
exceed 20 megaHertz for 90 percent of the time, and barely moving above 
21 megaHertz for very short periods on the best possible propagation 
paths, that again will be North to South, and vice versa, with the East 
to West path showing the worst propagation , as expected during extended 
periods of very low solar activity. Trans equatorial DX season still in 
progress, with options opening for 6 meters band ham radio operators for 
nice contacts from the South of the US, Mexico and the Caribbean, to 
Brazil, Argentina, Uruguay, Paraguay and Bolivia, and slightly less 
chances of contacts on six meters via TE scatter to Chile and Peru. Join 
me next Saturday and Sunday UTC for the weekend edition of Dxers 
Unlimited, and don’t forget to send your signal reports, QSL requests 
and comments about the program to arnie@xxxxxx or VIA AIR MAIL to Arnie 
Coro, Radio Havana Cuba, Havana, Cuba

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