Re: [HCDX] Dxers Unlimited´s weekend edition 16-17 February 2008

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

RADIO HAVANA CUBA

DXERS UNLIMITED

DXERS UNLIMITED´S WEEKEND EDITION 16 – 17 FEBRUARY 2008

BY ARNIE CORO

RADIO AMATEUR CO2KK

Hi amigos radioaficionados all around the world, and also greetings to 
those radio amateur operators now in orbit around Planet Earth.

Recently a listener asked for the complete detailed list of the the more 
than 83 ways that you can I can enjoy amateur radio, and practically all 
of them are available to almost anyone, except one that is exclusive to 
space travelers...because as you are surely aware not many
of us have the opportunity of flying into Earth orbit !!!.

Enjoying our radio hobby may prove to be as inexpensive as searching for 
DX on the AM broadcast medium wave band with a low cost receiver, or as 
expensive and sophisticated as organizing and participating in an 
amateur radio DX expedition to a very remote location... Between those 
two extremes, there are more than 80 ways of having a good time with our 
radios amigos !!! Here is an excellent example.. become an ultra low 
power amateur radio operator... just recently an American ham was able 
to design and homebrew an ultra low power rig, that was built using a 
Zener diode as its active device... No, this is not a science fiction 
show... amigo Mike, AA1TJ experimented with a Zener diode that he 
operates as a broadband noise generator, and then proceeded to filter 
the radio frequency noise with a quartz crystal , converting it into the 
narrow bandwidth of an 80 meters band signal... Amazing.. , sure !!! But 
amigo Mike has done several other ultra low power or QRP sub P 
experiments that have allowed him to reach the ultimate goal of 
communicating under the criteria of one million miles per Watt of input 
power...

Congratulations to Mike AA1TJ, an excellent example of the many 
experiments that a dedicated radio amateur can do when both know-how and 
the interest in operating homebrew equipment go together... And talking 
about home brew equipment... be it a simple radio receiver or a 
sophisticated digital synthetized ham radio transceiver... there is 
nothing like operating a piece of radio equipment that you have built 
with your own hands... My 2 Watt transmitter , a crystal controlled rig 
that I like to operate on the 30 meters or 10 point one megaHertz 
amateur band, is a good example of what I am talking about... each time 
I finish a two way contact on the very interesting thirty meters band 
with the 2 Watt solid state homebrew rig, I feel a very special 
pleasure, as I know that the two way contact was possible thanks to 
spending many hours experimenting with recycled electronic components 
from TV sets, computers and even an old FAX machine to turn them into an 
effective 30 meters band transmitter...

Now please standby for a few seconds, as the weekend edition of Dxers 
Unlimited continues after a short break for station ID...

.......

You are listening to Radio Havana Cuba, the name of the show is Dxers 
Unlimited and yes, we do QSL, we do thank you all for your reception 
reports and send back a nice QSL card to confirm that you have heard our 
station... Send your signal reports, comments about our programs and 
your radio hobby related questions to arnie at rhc dot cu... again arnie 
at rhc dot cu, or VIA AIR MAIL to Arnie Coro , Radio Havana Cuba, 
Havana, Cuba...

This is our weekend edition and now here is item three :

Solar activity continues to be at extremely low levels, with no sunspots 
seen for a very long period... scientists are now beginning to worry 
about what is really happening som 93 million miles of 150 million 
kilometers away from Planet Earth inside our nearest star... the SUN... 
According to some recently advanced criteria the present solar cycle 23 
may extend well into 2008, with the upcoming cycle 24 not really showing 
up its first continuos sunspots active regions until next year... At the 
present time solar scientists are just scrutinizing the solar disc to 
try to find active sunspot regions that simply are not there..

Item four: Low sunspots or no sunspots are suppsedly the ideal condition 
for low frequency Dxing, and already 160 meters band operators are 
trying to improve their DX entities count to make the best possible use 
of propagation conditions on 160 meters that won´t return until at least 
nine or ten more years... Although operation on the 1.8 to 2.0 megaHertz 
amateur band requires large antennas, during the present period of very 
low ionospheric absorption due to the extremely low solar activities 
some ham radio operators are achieving amazing results on 160 using 
short vertical antennas and the proverbial inverted L, the most popular 
antenna among the 160 meters band operators around the world... Let me 
add that the very good propagation conditions on 160 will continue well 
into the end of March, and that similarly good DX conditions will be 
also enjoyed by 80 meter band operators..

.............................


Si amigos, this is Radio Havana Cuba, the name of the program is Dxers 
Unlimited, this is our weekend edition, reaching you on Saturdays and 
Sundays UTC days and yes
we do QSL, we do verify reception reports with a beautiful QSL card that 
I am sure you will keep in your collection and show to your friends for 
years to come.

Item five: At the request via e-mail of several Dxers Unlimited 
listeners here is once again... what really
happens everytime when I arrive at RHC Studio 6,and my sound engineer of 
many years now, Jose
Costa Pupo, sets the audio frequency equalizer according to my own 
optimized frequency response curve... The shape of the curve is 
optimized specifically for my voice, so you won´t hear audio below 250 
cycles per second, or above 3000 cycles per second...

And sure, it does sound much better under difficult propagation 
conditions... Pepe as we all here call Costa Pupo, also boosts the 
frequency range from 500 to 1500 kiloHertz by 6 dB over our reference, 
to further boost the talk power of RHC transmitters when Dxers Unlimited 
is on the air So what you actually hear is just your´s truly 
optimization of the audio frequency response to achieve the best 
possible reception of voice signals via short wave...

Item six: Our popular antenna topics section today will attempt to 
clarify things for listener Ben from Montana... Amigo Benjamin listens 
to our 6180 kiloHertz transmitter and wanted to improve his antenna for 
the 49 meters band. As he tells me that living out in the countryside 
gives him lots of room to install antennas, here is my advice. You can 
certainly improve your reception of the segment of the short wave 
spectrum from five to ten megaHertz by homebrewing the large size 
version of my FAN DIPOLE antenna. The length of each leg of this antenna 
is 20 meters and each side requires of three wires that fan out from the 
center insulator so that when they reach the end insulator they will be 
spread 5 meters in other words amigo Ben, your wide band fan dipole will 
have a center wire, and then the upper wire ends up two and half meters 
above the center wire, while the lower wire ends up two and half meters 
below the center wire of the dipole.

The antenna is fed using a one to one broadband balun and 50 ohms 
coaxial cable. If you will only be using the antenna for receiving only 
, this arrangement will work very well , but in case you want to use if 
for transmitting, then the antenna must be fed with a 300 to 450 ohms 
impedance balanced transmission line of at least fifteen meters in 
length, and then at the end of that balanced line, you must install a 
pair of balanced to unbalanced transformers or BALUNS, that can be 
switched remotely from the shack. One of the BALUNS is a one to one 
device and the other one is a four to one unit. From the BALUN´s low 
impedance coaxial line output you can run the coax feedline to an 
antenna tuner... In my practical experience such broadband antenna 
arrangement will provide you with an excellent receiving and transmtting 
system...

BUT , let me add that in order for this antenna system to be really 
effective it must be installed at least at a minimum height above ground 
of six meters, or better yet, you will want to install it at 10 meters 
minimum height above the sorrounding terrain. At my home QTH,here in 
Havana, I have a half size version of this antenna, that works well from 
about seven to twenty nine megaHertz, but having using the full size 
version at ham radio contests sites, I can assure you that the full size 
FAN DIPOLE with its 40 meters overall length is an excellent antenna for 
receiving between 3 and 10 megaHertz. If you do homebrew the antenna and 
install it amigo Ben, keep me up to date about the results that you 
achieve during this period of very low solar activity when low band 
Dxing is plentiful ,and of course I also want to know how much does the 
reception of our 6180 kiloHertz transmitter improves at your location...

...................

Now the weekend edition of Dxers Unlimited continues via short wave and 
from 05 to 07 UTC we are also on the world wide web via streaming audio 
from http://rhc.cu.... Just before going QRT, here is Arnie Coro´s HF 
plus low band VHF propagation update and forecast.

It seems like the tail end of solar cycle 23 is going to last for at 
least several more weeks... the most recent forecasts call for extremely 
low solar activity , rock bottom solar flux near 70 units and lower, 
with very few sunspots to be seen for at least six more weeks... so 
,again for your information short wave propagation conditions will be 
limited to the lower frequency bands, with daytime propagation reaching 
only up to 18 or 20 megaHertz, while the night time maximum useable 
frequency on some paths will dip even below seven or six megaHertz , 
amazing as it may sound , but something typical of extremely long 
periods of very low solar activity.

Amateur radio operators that enjoy the use of the 160 meters band will 
be able to work some nice DX during the rest of February and early 
March... something that they will share with AM medium wave broadcast 
band Dxers, they both will be enjoying what could possibly be described 
as the best propagation conditions for the AM broadcast band and 160 
meters for many years to come... I do Hope to have you all listening to 
the mid week edition of Dxers Unlimited , Tuesday and Wednesday UTC 
days, and don´t forget to send me your signal reports , comments about 
the program and radio hobby related questions to arnie at rhc dot cu, or 
VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba...


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