Tuesday, January 16, 2007

Radio Havana DXers Unlimited Jan 16-17


Our special thanks to Arnie Coro CO2KK for sharing his latest edition of DXers Unlimited radio show with our blog readers.

Arnie, we appreciate your support!

Gayle VH


Radio Havana Cuba
Dxers Unlimited's midweek edition for 16-17 January 2007
by Arnie Coro- Radio amateur CO2KK

Hi amigos radioaficionados... here is the weekend edition of your favorite radio hobby program, coming to you from Havana. I am Arnie Coro, radio amateur CO2KK, and here is item one for today. It's a news item... Cuba has a new satellite TV channel, it was named Canal ACN, and the ACN stands for Cuban News Agency in Spanish. The new satellite channel is on Hispasat Id Transponder 79 vertical polarization, and the footprint of the bird provides practically total coverage of the Americas with just a small area in the Amazonian region of Brazil that is not covered by the satellite signals.

Senal of Canal ACN at this moment is a television text only type of signal, that is created here in Havana using digital technology and then uplinked to the satellite for broadcasting.
In the near future the now text mode signal with accompanying audio background will include graphics too. The main objetive of Canal ACN is to provide Cuba medical doctors and other Cubans providing aid to Latin American and Caribbean nations with up to date , actually up to the minute information and news about Cuba. The same Hispasat ID transponder also is at this moment broadcasting other Cuban live television channels as well as several radio stations, including Radio Havana Cuba spanish language programs , and soon we will also include English and other languages too.

Item two: A now a news update about our Radio Havana Cuba Spanish language morning broadcast... starting next Monday 22 January, we will start using 15190 kiloHertz to South America replacing 15230 kiloHertz. Again, from 1100 to 1500 UTC we will be operating on 15190 kiloHertz instead of 15230 kiloHertz .

Now, here is a short break for station ID. I am Arnie Coro, radio amateur CO2KK and my e-mail is arnie@rhc.cu...
......
Si amigos, you are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited, and here is item three of today's program... It's our antenna topics section, answering a question sent in by a listener that seems to be very enthusiastic with the expected good propagation conditions on the 160 and 80 meters amateur bands during the bottom of the solar cycle. Amigo Glenn from the state of Washington wants to know what could be gained by installing a half wave or even a 5/8 wavelength vertical for 160 meters, even though he did his numbers and knows that these are both very tall antennas, that will require a lot of space and also of top notch mechanical engineering. And Glenn adds that he wants to know if the very high antennas can be also used on 80 meters.

Well amigo Glenn, first of all here is your amigo Arnie Coro's advice regarding the installation of tall towers... If you do have the resources, both financial and of real state to install such an antenna system, by all means put the project in the hands of professional antenna designers and installers... There are no room for mistakes when you are installing a 300 feet or almost 100 meters high tower, and the tuning up of such a system requires using professional instruments and a lot of know how.

Also such a tall steel structure will require placing aircraft beacons and obstruction lights to comply with worldwide aviation safety regulations... By no means I want to discourage you, but it is my duty to provide this initial and very important advise for anyone wanting to design and install really high radio antennas... As a bonus, if you finally are able to complete the project, the same tower, if fed as a vertical grounded folded monopole, will provide an excellent support structure for HF, VHF, UHF and microwave antennas...

Years ago, I exchanged correspondence with an amateur radio operator in Brazil that is a 160 meter band enthusiast, and he was able to install a very tall vertical antenna placed in the center of a small lake, with outstanding results .

Yes, again, any attempts to install very high metal structures should be handled with great care and with the aid of professionals, without forgetting the proper handling of the legal framework with the local authorities and even the requirement to provide insurance against damages that may result from the collapse of the tower...

Last but not least, if you are not properly trained, never work atop a tower , and even if you have training, never do it alone, because you don't need to be added to the very sorry statistics of amateur radio operators that have been killed while working on their antenna systems...
.....
Si amigos, from time to time , we say no to a QSL request, and for good reasons of course, Friday I received a QSL request from Germany stating that he had received Dxers Unlimited on a frequency that our station doesn't use... Together with the request came some quotes from the show's content for the mid week edition of the program, and then you know, after reading the e-mail QSL request twice, I decided to reply to the German short wave listener with a , SORRY , no QSL from Radio Havana Cuba, as the frequency in your e-mail is wrong, and also there was no time included in the report. I expect him to try to listen again to the station and be careful to include the frequency and time in his next report...And why didn't I sent him a QSL if the program content was mentioned.... well for a very good reason, the scripts of Dxers Unlimited are made available by several short wave listeners mailing lists, and the contents could had been taken from any of them....

Item six: DRM noise continues to create lots of problems to adjacent channels operating with standard AM double side band plus carrier signals... In my opinion there is no doubt that the wide DRM transmissions have to do with poorly adjusted final amplifier stages of the transmitters, because DRM requires extremely linear amplification in and a very difficult to meet peak to average power ratio handling capacity of the transmitter driver and final amplifier stages... Let's hope that soon the DRM consortium will take corrective action regarding these problems as they are shedding a very dark image to DRM broadcasts, that again in my opinion , when properly done with adequate equipment should be more compatible with other users of the radio spectrum.

Item seven: More about homebrewing radios, and the joy of operating them... especially after you are able to clean up all the initial bugs that any homebrew project usually has... A unique regenerative radio design that I tested here is capable of operating while using extremely low voltages applied to the vacuum tubes... The regenerative detector stage is able to provide excellent reception while running just two, yes, two volts on the plate or anode electrode, and the audio amplifier stages run from a 9 volts battery. As a friend that has seen this radio said, it's a vacuum tube radio with a transistor set power supply... A further experiment with more common and easier to find vacuum tubes has proven that an excellent radio performance can be achieved while just running 12 volts DC, a voltage that is easily available from a standard accumulator or power supply.

Si amigos, electronics continues to surprise me every day, like in this other example, when I was testing Saturday morning an amateur radio two meters band handie talkie with a dummy load resistor .... and suddenly I heard someone coming back to my hello test... via the local repeater on 145.190 ... So, it was evident that the dummy load was radiating enough signal to trigger the very sensitive receiver of the repeater that is located about three miles from my home QTH, atop the Habana Libre Hotel, a 35 stories high building in the Vedado district.

When discussing this unsual two way QSO using my 50 ohms terminating resistor dummy load as an antenna, with a friend, he recalled a similar contact on 10 meters with the dummy load as an antenna, but not with a local station... He said he has the QSL card to prove that he worked a station in North Carolina on 10 meters single side band, while his 100 Watts PEP transceiver was connected to a dummy load, that it was evidently not very well shielded at all...

The use of rather unusual antenna systems by radio amateurs comes out of circumstances like having to operate from apartment buildings and neighborhoods where antennas are banned by the building regulations or zoning laws... But , once again, ham radio ingenuity comes out with flying colors by building beautiful elevated bird feeders that are excellent 2 meters or 70 centimeters band antennas, the classic flagpoles, made of reinforced polyester glass fiber plastics that serve to provide the ideal support for a short wave bands vertical antennas, and last but not least, the unusual fence antenna that I saw not too long ago... This "fence antenna" provided excellent near vertical incidence skywave performance on the 40 meters band for its owner, who also has another stealth antenna system for the 2 meters band disguised as a sewer system vent....

Si amigos, yes my friends, a ham radio operator or short wave listener will always find a way to install a better antenna, especially when having to face the challenge of those very stringent zoning and the use of rooftops regulations...

If you are not allowed to install an external radio antenna , don't think it twice,and send me a description, a detailed description of your particular situation, and maybe I can give you some ideas on how to design, make and install a better antenna than the indoor one you are using right now to listen to Dxers Unlimited...

And now amigos, as always at the end of the program, here is Arnie Coro's Dxers Unlimited's exclusive and not copyrighted HF propagation update and forecast ....Monday was a day when
G2 class geomagnetic storms were happening, producing poor propagation at high latitudes. Solar flux is now stable around 80 units, and the A sub P index, the planetary geomagnetic disturbance indicator will continue to be above 15 units until tomorrow, when it will start to move down, as the effects of a recurrent coronal hole subside... Expect below average HF propagation for the next three days, with the best bands for daytime operation between 15 and 18 megaHertz, while during your local evening hours the segment between 5 and 10 megaHertz will be the best option ... Hope to have you again listening to my program's weekend edition next Saturday and Sunday UTC days amigos...