Radio Habana Cuba: Dxers Unlimited weekend edition for December 16, 2000
By Arnie Coro, radio amateur CO2KK
HI! You are listening to the weekend edition of Dxers Unlimited, your favorite listener oriented, all radio hobby air time show. I am Arnie Coro, radio amateur CO2KK, your friend here in Havana, now ready to bring you some sixteen minutes of news, information, tips, and answers to your questions...
Here are the headlines: Expect Aurora Borealis during late Saturday or Sunday if your QTH is at a latitude of 50 degrees North or higher. This highly probable event will be caused by a high speed solar wind which originated from a Coronal Mass Ejection or CME that happened December 14th... Remember? Solar wind takes a certain number of hours to reach the Earth, and that in turns depends on the initial speed at which the solar particles were ejected from the Sun. I am forecasting some interesting HF propagation events during the next 48 hours... all of them associated with the high speed particles impacting on the Earth's magnetosphere.
Headline number two: BAD NEWS... really BAD NEWS for amateur radio operators worldwide, OSCAR 40, the most sophisticated and expensive amateur radio satellite ever in orbit seems to be in deep trouble. The ground control stations have lost contact with the big bird... and experts are now waiting for an expected automatic sequence to happen sometime during the weekend... IF, and that's the critical word, IF the auto reset sequence does happen as expected, the satellite may re-start its telemetry beacon and ground controllers may learn what has happened after they fired a motor to change the orbit of OSCAR 40. In my humble opinion -- and of course this is my own personal point of view -- one of the problems that the Phase III D satellite, now known as OSCAR 40, had to face was the extremely long time it was kept in storage before launching. Again, this is something that may have caused problems with some electro-mechanical devices that are essential for the operation of such a complex satellite, like valves that should open and close very precisely following ground commands. As I am writing the script of this show, Saturday morning my local time here in Havana, at 14 hours UTC, that's 9 oclock in the morning here, I have not heard about OSCAR 40's telemetry coming back yet...
Headline number three: The winter solstice Sporadic E season is now in full swing here in the Northern Hemisphere, and down under, radio enthusiasts are enjoying the summer solstice much longer and more intense sporadic E season... For those of you not familiar with sporadic E, they are one of those yet to be fully understood mother nature's events...
Stay tuned now for more radio hobby related information coming to you from Havana. Margarita Delgado is my sound engineer and producer. I am Arnie Coro, back with you in a few seconds...
You are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited and YES, we do QSL here 100 percent. Send your reception reports and QSL requests via AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba, and don't forget to include your return address in your postcard or letter. You can also get in touch via e-mail by writing to arnie@radiohc.org.
Now here is item two of today's weekend edition -- YOU have questions, and Arnie tries to answer them! Here is a very interesting radio hobby related question sent by a listener in the United Kingdom. He wants to know why, during periods of high solar activity, propagation on the tropical broadcast band is so poor at his latitude. Well amigo, the answer is a rather simple one: As soon as the daily solar flux starts to move above 120 units and just stays there, ionospheric absorption of lower radio frequency waves increases to such a level that propagation of the lower frequencies is severely attenuated. That's why radio is such a wonderful hobby if you know about propagation... during peak years of the solar cycle, radio hobbyists enjoy the wonders of excellent DX conditions on the higher frequencies, from 15 all the way up to 50 megaHertz... then, when the solar cycle hits bottom, the best propagation conditions are found on the lower frequencies, among which the Tropical Bands are located. By the way, the three Tropical Broadcast Bands are popularly known as 120, 90 and 60 meters, of which nowadays 60 meters is the most populated one. BUT, even the 60 meter Tropical Band is losing many of its old time favorite stations, which in most cases are switching to FM for local coverage. Tropical Band DXing is yet another one of the more than 50 ways that you can enjoy this wonderful hobby, yours and mine... RADIO!!!
Now item three: Another question, this time from a listener in Australia... yes, sometimes our broadcasts are heard in Australia when HF propagation conditions are good. Our 13750 kiloHertz broadcast to Europe is often heard there during the Australian Summer DX season, especially when solar activity is above 150 solar flux units or higher. Well, our Australian listener wants to know how he can make a low-cost antenna for his 2 meter band FM handie talkie, in order to increase its range. He tells me in an e-mail message, and I quote: Arnie, need your advice, I am on a shoestring budget here, still attending the University, and need to increase the range of my 5 watt 2 meter band FM handie talkie... please give me some information about simple 2 meter band antennas....
Well, amigo from Australia, there are three very easy-to-build and low-cost antennas that will increase the range of your two meter handheld FM transceiver or handie talkie. To begin with, your handie talkie comes with a factory antenna which is popularly known among radio amateurs as a rubber duck or rubber duckie antenna, due to it resembling the tail of duck. The rubber duckie is technically speaking a very short vertical antenna, which is really a very inefficient antenna system by all standards. If you compare the rubber duck helically loaded handie talkie antenna against a half wave dipole, you will find that the efficiency of the antenna that comes with the FM transceiver, the rubber duckie, is very, very low... As a matter of fact, those antennas have losses that are anywhere between minus 5 and minus 8 decibels in reference to a standard half wave vertical dipole. SO... imagine a -6 dB loss... what does that mean when we are transmitting?
Well, it means that of the 5 watts that your radio is feeding to that antenna, only 1.25 watts are going out. See, that's why when you connect a 2 meter or a 70 centimeter band handie talkie to a better antenna system, the radio's range increases dramatically.... BUT, you may also have to face another problem -- receiver front end overload, as many of those FM hand held transceivers are not designed to use an external high gain antenna system...
NOW, to answer your question in detail... You have three options to improve your radio's coverage: Build a 0.28 wavelength whip that can be attached to the handie talkie's antenna connector directly; second, build a 300 ohm twin lead J antenna that you can hang from a support and connect it to the transceiver via a short length of coaxial cable; and your third option is to build a low cost HALF SQUARE wire antenna, that you will also need to connect via a length of 50 ohm coaxial cable. Of the three options, I will recommend you to go ahead and build all three!!! SURE... why not? They are very easy to homebrew, they will cost almost nothing, and you will learn a lot about antennas by spending some of your spare time building them....
I have sent you already the text file and some nice drawings that show how to build the 0.28 telescopic whip, using one half of a TV rabbit's ears antenna, the text file and a .jpg file on how to build yourself an excellent J type antenna, and I also sent you, my Australian friend, the text file and graphics describing in detail how to make yourself a two meter band HALF SQUARE antenna....
Now, let me tell you all amigos, that those files are here ready to be sent to any of you who would like to do some 2 meter band antenna experiments. Send your requests via AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba, and via e-mail to arnie@radiohc.org. ASK FOR Arnie's 2 meter BAND ANTENNAS INFO PACKAGE... If you do have e-mail, use that much faster communications system! By the way, I recently ran some very interesting tests comparing my factory supplied FT411 rubber duck antenna against the 0.28 wavelength telescopic whip, the 300 ohm Twinlead J antenna and the HALF SQUARE, as part of a demonstration to young radio amateurs at our radio club. Needless to say I had to print no less than 20 copies of the 2 meter BAND ANTENNAS INFO PACKAGE to bring to the next club meeting!!!!
Amigos, now as always at the end of this weekend edition of Dxers Unlimited, here is Arnie Coro's exclusive, but not copyrighted, in the public domain, quotable and printable HF PLUS 6 meters propagation update and forecast: SOLAR ACTIVITY IS MOVING UP!!! And a bit faster than expected, too... Solar flux will soon reach the magic 200 units mark, and the next 10 days are going to be very rewarding for radio amateurs who want to work DX on the higher bands, from 15 meters all the way up to 6 meters.
There are two active solar regions that may produce class M and even class X flares during the next two to four days, and if one of those big flares does occur, we may witness yet another radiation storm with a possible coronal mass ejection, and if this happens to occur at a properly located active sunspot region, we may see yet another geomagnetic storm of the present solar cycle. And talking about geomagnetic storms, we may see one during this weekend... The December 14th coronal mass ejection may trigger a high latitude magnetic disturbance by the time you are listening to this show.
NOW a brief forecast: Expect nice and high daytime maxium useable frequencies, with the 12 and 10 meter bands opening up very early in the morning local time and staying open even after your local sunset. High probabilities of 50 megahertz, 6 meter band openings during the next 5 days, and nighttime propagation in the range from 7 to 15 megaHertz is going to be good, too... See you on 10 meters... I'll be operating on 28.5 megahertz plus or minus 5 kiloHertz, but always trying to be exactly on 28.5 so that you can find CO2KK and have a nice talk while these nice propagation conditions last!
Do remember that YOUR LETTERS and E-MAIL messages are very important to keep this show on the air with the topics that you really want to hear about!!! Send your e-mail reports, questions and comments to arnie@radiohc.org, and via AIR MAIL postcard or letter to Arnie Coro, Radio Havana Cuba, Havana, Cuba...
See you at the mid week edition of Dxers Unlimited, next Tuesday and Wednesday UTC days...
Arnie Coro CO2KK
Havana, Cuba
December 16, 2000Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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