Radio Havana Cuba
DXers Unlimited - Weekend Ediiton
by, Arnie Coro 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...
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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..
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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...
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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...