RADIO HABANA CUBA
DXERS UNLIMITED
MID-WEEK EDITION
TUESDAY, MAY 29, 2001
By Arnie Coro CO2KKSend your comments, questions and ideas to: arnie@radiohc.org
Hi amigos! Welcome to the mid-week edition of Dxers Unlimited, your favorite radio hobby program via short wave and on our Dxers Unlimited website, with our exclusive free of charge, for the benefit of the radio enthusiasts worldwide... Dxers Unlimited's fast distribution mailing list, offering you, right at your computer the possibility of reading the scripts and NOW also seeing the graphics that I cannot put on the air here on the AM 5 kiloHertz bandwidth!!!
Solar sunspot number is very near 190, but the daily solar flux is not even 150 units.... As many of you are going to ask how is this possible, here is a very fast answer: the actual sunspot count is rather high, but the sunspots themselves are not very active, and that explains how we can see such a wide gap between the relatively high number of sunspots and the rather low 10.7 centimeters microwave energy solar flux coming from the SUN... A talking about what's coming from the SUN, get ready for more geomagnetic disturbances, a rather large solar coronal hole is already sending lots of charged particles towards the Earth's magnetosphere, and as soon as they impact our Planet's magnetic field, we will certainly see a rise of the daily A index, the planetary geomagnetic field disturbance indicator...
Item three: QSL, in the Q code used by CW Morse Code operators since the early days of radio communications, had a very significant meaning... QSL sent with a question mark meant: "do you acknowledge reception?" And in case this was true, the other operator will just send QSL... Today QSL has the same meaning when you are operating an amateur radio station, but QSL is also used to describe the cards or letters that stations send out when someone sends them a signal report... Amateur radio operators collect QSL cards for awards, while Short Wave Listeners collect them, too. You can request a QSL from this station, Radio Havana Cuba, just by sending a signal report and comments about the programs you have just heard... Send your QSL request via AIR MAIL to: Arnie Coro, Radio Havana Cuba, Havana, Cuba. and I'll be very glad to check if the report is accurate, and if so, then send you our QSL card and letter... You can also request our QSL card via e-mail to arnie@radiohc.org.
Now here is item four of the mid-week edition of Dxers Unlimited: Monitoring the 13 meter band nowadays is still an interesting experience for short wave listeners; the 21 megaHertz band is open to one part of the world or another for many hours every day, but it is still very much underused by broadcasters.... Talking with senior international short wave broadcast station's engineers and managers in the past, I have found out that there is a generalized opinion that 13 meters is not a popular band among the world's short wave listeners... another rather generalized opinion is that 13 meters is not very reliable. In other words, managers and engineers prefer to operate whatever transmitters are available on lower frequencies that are not so much dependent on daily maximum useable frequency variations... and last but not least, stations using older equipment prefer to operate them on lower bands, as it is a fact of life that high-power short wave equipment operating on the 21 and 25 megaHertz bands -- 13 and 11 meters -- is more prone to technical problems than when it is operating on lower frequencies...
Nevertheless, I think that 21 megaHertz is an excellent choice for many long range propagation paths, and that today's receivers, even the lower-cost portables, perform rather well on both 13 and 11 meters. Due to the much lower ionospheric absorption on these two higher HF bands, excellent results can be achieved with less transmitter power, and the antennas for the two bands can be built at rather low cost, too... So maybe it's about time that all those involved in frequency planning make it a point to use both 13 and 11 meters more for the enjoyment of the world's short wave listeners... Scan 13 meters from as early as sunrise to as late as several hours past sunset and keep a log of what you are picking up, start listening on 21.455 and move slowly up, try to identify each station as you scan the band... As we approach the spring equinoctial DX season 13 meters will provide many hours of nice, high quality short wave listening, even with a small receiving antenna!!!
Remember, start scanning very slowly just above the 15 meter amateur band, on 21.455 kiloHertz and move slowly up... it may also be a good idea to monitor the 15 meter ham band, from 21.2 to 21.4 megaHertz, for signs of DX activity on SSB... as a matter of fact, radio amateur use the 13 meter band broadcast stations as indicator beacons of DX propagation on 15 meters, as the bands are just right next to each other!!!
Another new section here at Dxers Unlimited? Well, YES!!! absolutely! Anything we can do to improve the show is done as soon as possible, and at the request of many listeners, here is the first installment of the HOMEBREWERS CORNER, a section that will surely become extremely popular very soon, as more and more radio enthusiasts are enjoying home brewing of radio equipment and antennas these days... HOMEBRWERS CORNER today will tell you more about homebrew frequency converters that can extend your receiver's coverage, and in the case of older radios, make them work as dual conversion receivers...
A converter is a very simple and logical gadget. Typically it has a bandpass filter at the input, a radio frequency amplifier stage, a mixer and a local oscillator. Using a quartz crystal for controlling the frequency of the local oscillator, the converter allows its user to tune a segment of the radio frequency spectrum with a receiver tuned typically to a lower frequency band. Here is an example: a converter built to tune from 50 to 52 megahertz, the first two megahertz of the 6 meter amateur band, uses a quartz crystal oscillator resonant to 45 megahertz, so its output is a signal in the frequency range from 5 to 7 megahertz that can be picked up by any receiver able to tune to that lower frequency range. Building frequency converters is a lot of fun -- you are actually building the front end of a receiver, so you learn a lot about receiver construction techniques. The now-popular REGENERODYNE receiver uses a crystal controlled converter that feeds a variable frequency regenerative detector, a combination that is hard to beat for simplicity and performance!!!!
And now, as always at the end of the show, here is Arnie Coro's exclusive but not copyrighted HF plus 6 meters propagation update and forecast: Solar flux is hovering around 140 units, and seems to be at a standstill, while the actual number of sunpsots was 190 on Tuesday, and that's an unusual event, expect a possible geomagnetic disturbance during the next 24 to 72 hours, and enjoy the many sporadic E events that are providing TV Dxers, FM band DXers and radio amateurs that operate on 10, 6 and 2 meters with a lot of fun.... Don't forget to send me your signal reports and comments about the show, as well as your radio hobby related questions to arnie@radiohc.org!
Arnie Coro CO2KK
Havana, Cuba
May 29, 2001Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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