Re: [HCDX] Dxers Unlimited's weekend 19-20 May script

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

Dxers Unlimited
Dxers Unlimited's weekend edition for May 19-20 2007
By Arnie Coro
radio amateur CO2KK

Hi amigos radioaficionados... I am Arnie Coro in Havana, and its my 
pleasure to share with you about seventeen minutes of on the air and on 
the web time talking about our favorite hobby, yours and mine... 
RADIO... Item one: Several days in a row with an absolutely spotless 
solar disk... not a single sunspot seen during several days,is something 
that tells us a lot about the way solar cycle 23 is decaying... Now we 
are going to see an increase in the daily sunspot count as an active 
region is developing under the close watch of solar scientists... Item 
two: Everybody knows that whenever there is a massive emergency, 
cellphones simply stop working, or in the best possible scenario, it is 
very difficult to communicate using them. BUT, simple , relatively low 
cost amateur radio two meters and seventy centimeter bands radios 
continue to work nicely ,providing reliable communications links that 
are not dependent of the number of users of the system, like cellphones 
are... That's why amateur radio repeaters continue to be regarded as a 
most reliable way of communicating during emergencies, something that 
here in Cuba we have found out when the last several hurricanes like 
Michelle, Isidore  Lili and Dennis struck our archipelago !!! By the 
way, a low cost handheld FM two meter band transceiver and a very simple 
antenna system is all you will need to stay in touch via a repeater, 
even under the worst weather conditions !!!
Item three: More about the Micro Vert antenna, and how it compared to a 
one meter diameter magnetic loop... Item four: our technical topics 
section today, dealing with battery power as a no-noise alternative to 
powering your radios... We will also feature YOU HAVE QUESTIONS, and 
Arnie tries to answer them section of the show, and at the end of the 
program, our exclusive and not copyrighted HF propagation update and 
forecast... Stay tuned... in just a few seconds radio know-how for your 
enjoyment follows... I am Arnie Coro in Havana...
.....
This is Radio Havana Cuba, the name of the show is Dxers Unlimited, and 
for first time listener's information this is a twice weekly program 
devoted to the promotion and development of the wonderful hobby of 
radio, one you can start enjoying without investing a single cent... 
just by using your already existing radios to catch far away stations, 
in other words to enjoy DXING AMIGOS !!! More about the Micro Vert ultra 
compact single band antenna...Still under a lot of criticism from 
antenna gurus that keep saying that the actual radiation is coming from 
the coaxial feedline. For the past several days I have experimented 
quite a bit with the 30 meters band version of the Micro Vert, and among 
the findings that I wish to share with you is that it makes a nice 
extremely compact and easy to disguise receiving antenna for both the 31 
and 25 meters international shortwave broadcast bands... and that , of 
course is a bonus... as the Micro Vert antenna is usually thought as a 
single band system for amateur radio work, in other words a rather 
narrow band antenna... But, I found this quite by chance, when 
connecting the Micro Vert's 50 ohm coaxial cable downlead to an amateur 
band's transceiver that also has extended coverage of the HF spectrum. 
The transceiver was tuned to Radio Havana Cuba's 9550 kiloHertz 
frequency, and to my surprise, the station came in loud and clear with 
the Micro Vert... I then ran a scan of the 31 meters band and compared 
with my standard TTFD Tilted Terminated Folded Dipole used here for 
monitoring the short wave bands from 6 to 29 megaHertz... The Micro Vert 
cut for the 30 meters ham band , used as a receiving antenna delivered 
excellent reception on 31 meters , as one could expect, but it did also 
provide quite good reception of the 25 meters band broadcasters...Then I 
ran another detailed comparative test on the 30 meters band, using the 
Micro Vert and a One Meter Diameter Magnetic Loop , so that both antenna 
could be switched very fast at the receiver's input.
Results showed that , depending on the distance from the transmitting 
station, one could receive always equal or better signals on the Micro 
Vert... without having to retune every few kiloHertz, as you have to do 
with the Magnetic Loop... Another advantage of the Micro Vert over the 
Magnetic Loop is that it is less noticeable... the capacitive radiator's 
very small size and its resemblance with a piece of plumbing, can make 
possible installing a Micro Vert at locations where other more visible 
antennas simply can not be used due to zoning restrictions.
The Micro Vert is a rather practical single band solution for radio 
amateurs that otherwise can't operate on the HF bands due to lack of 
space for a standard size antenna system.
So far I have built three of these antennas, one for 40 meters, another 
one for 30 meters and still another one for the most popular DX ham band 
of them all: 20 meters. In all three cases it was not really difficult 
to tune up the antennas, and results show, that even under recent poor 
propagation conditions, the Micro Verts have allowed me to carry on nice 
two way contacts, with signal levels just slightly below what could be 
obtained with a resonant half wave dipole or a quarter wave ground plane 
antenna ... The comparison were made dynamically by switching between 
antennas while listening , and also while transmitting, so that both 
receive and transmit comparisons could be made.
The worst signal report given for the Micro Vert on 20 meters by a 
station about 1500 miles away from Havana, was about 2 S units below my 
very efficient quarter wave ground plane ... While the signal from the 
ground plane was reported as S9...the signal from the Micro Vert after a 
fast switch over was S7, an indication that DL7PE, Juergen, the inventor 
of the Micro Vert was absolutely right when he affirmed that his antenna 
design could make possible HF operation for many amateur operators that 
live in the cities...
.....
We have been following solar activity as usual, finding that during the 
past three months we frequently experience several days in a row without 
a single sunspot !!! Some newcomers to solar observations might have 
wondered if this was normal or not... but long time observers, like my 
good friend Angel Gonzalez Coroas a solar scientist, were not shocked by 
the spotless Sun... Angel told me in an e-mail that as we continue to 
approach solar minimum, spotless days will become more and more 
frequent...Now we are seeing very few small spots near the limb of the 
solar disk, and the daily sunspot count is expected to rise for the next 
few days....
If you want to run your own propagation forecasting software , feed the 
program with a solar flux figure of 70 units and you will be hitting 
ballpark figures during the the last 10 day of May !!!
As those of you already familiar with the A index,planetary magnetic 
disturbance indicator may have noticed, the lowest A index produce the 
best propagation conditions .
......
Radio is a nice hobby, it's a never ending hobby like no other one, as 
there are many , really many , different ways that one can enjoy it... 
For example, right at this moment those radio amateurs that made a great 
effort to install stations that could operate using the amateur 
satellites are really worried, because the few operating ham satellites 
have very limited capabilities... The ill-fated Oscar 40 super amateur 
satellite died well ahead of its scheduled expected lifetime... BUT,here 
is my question are those satellite operators, are those hams going to 
stop enjoying radio... Of course NOT... they will soon find one of the 
more than 81 ways of having a good time with their radios that will fill 
the gap of the lost satellite... And speaking of Oscar 40 a bit more, it 
was certainly a very unlucky satellite from its very early life... never 
achieving the designer's goals and ending whatever relay services it 
could provide much earlier than expected ...
Now here is our popular YOU HAVE QUESTIONS and ARNIE has the answers, or 
searches around for them ... QUESTION: Dear Arnie, I have an 
intermittent radio, when you plug it in and turn it on, it starts 
working, but about five minutes later or so, the volume comes down 
abruply... Any ideas of what's going on ? Signed, Dorothy from 
Wilmington, Delaware, where I listen to you on 6000 kiloHertz usually at 
the 0130 UTC run of the show... Well amiga Dorothy, you certainly have a 
problem !!! And this one may actually be more difficult to locate and 
fix than a total breakdown... My advise is to put the radio in the hands 
of an experienced technician that has access to the receiver's workshop 
technical manual... As a matter of fact, I won't even attempt to open a 
modern receiver without the factory repair manual, as you can do a lot 
of damage to the set if you don't follow the exact sequence of 
operations to open it up... Usually the kind of problem that your nice 
radio has, is due to a defective component overheating after a certain 
time of operation has elapsed... My second piece of advise is to stop 
using the radio until it is fixed, as you may produce more damage if you 
continue using it during the few minutes that it works OK !!!.
........
Before time is over, here is another bit of advise regarding the 
operation of solid state radio receivers... it's always a very good idea 
to connect the set using an anti-surge power block, yes, the ones that 
computers are connected to. The anti-surge devices built into those 
multiple power female connectors will provide an extra bit of protection 
against power line transients to modern solid state radios that use 
microprocessors and other very sensitive electronic devices...Here in 
Cuba the local electronics industry manufactures and sells a power line 
protection device that plugs into the wall socket and cuts off the power 
if the voltage increases above a certain preset level, or below a 
specified minimum voltage, and in case the power goes off it doesn’t 
reset the power to the equipment after no less than three minutes have 
elapsed, a measure designed to protect home refrigerators and other 
appliances that may be damaged by high voltage spikes.
And now, just before going QRT , here is Arnie Coro's Dxers Unlimited's 
HF propagation update and forecast...  VHF forecast today,looks good for 
still more Sporadic E events to happen during the weekend and all along 
the next week as the sunspot number is extremely low, and there are very 
few chances if any of maximum useable frequencies going above 30 
megaHertz, except perhaps via Trans Equatorial Propagation.. Solar flux 
is moving now slowly up, and the same holds for the sunspot count...I 
hope to have you listening to our mid week edition of Dxers Unlimited, 
next Tuesday and Wednesday UTC days. And don’t forget to send your 
signal reports and comments about this program to arnie@xxxxxx, or VIA 
AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana , Cuba



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