Radio Habana Cuba: Dxers Unlimited mid-week edition for June 6, 2000
By Arnie Coro, radio amateur CO2KK
Hi amigos! Welcome to the mid week edition of Dxers Unlimited, your favorite technical radio hobby program on short wave. I am Arnie Coro, your friend here in Havana, and it's my pleasure to share with you about fifteen minutes of all radio hobby related information.
First things first, so let's start with a brief HF plus 6 meters propagation update: Solar flux moving up, and is now around 170 units, the 90-day average is higher, at almost 190 units today, solar activity is expected to range between moderate and high. So be ready for some interesting fireworks, as scientists are expecting more solar flares to erupt during the next five days. You may even have the chance of witnessing a Moss Dillinger event; in other words, a total short wave blackout like the one I was able to observe a few days ago.
Item two: homebrewing radio gear is fun, a lot of fun, and there is nothing like listening to a radio you have build yourself, or even better yet, talking to someone half a mile away -- or halfway around the world -- with a homebrew rig... BUT, finding parts for building your own radios is sometimes difficult, that's why designers of radio hobby gear are now carefully considering parts availability before publishing their designs... More on this subject later in today's show.
Item three: 6 meters opened June the 5th "A LA GRANDE." So far this one was, according to many experienced operators, the best opening of year 2000. Sporadic E was the predominant mode, but many of us are asking a few questions, as some of those DX signals sounded more like F2 propagation... Well, it's June and the Sporadic E season, as Dxers Unlimited's regular listeners know very well, is now well under way, so be ready for more action on the 10, 6 and possibly 2 meter bands, and if you are a TV DXer or an FM broadcast band DXer, be on the lookout for those elusive skip signals.
NOW, stay tuned for more radio hobby related information coming up in a few seconds amigos. Margarita Delgado is my sound engineer and producer; I am Arnie Coro in Havana back. with you after this brief musical interval. You are listening to Radio Havana Cuba, 39 years on the air via our short wave transmitters in Havana.
Yes, parts availability is becoming a problem, but amateur radio ingenuity can bypass many difficulties, as Cuban amateurs have demonstrated many times during these past four decades. For example, Cuba's most popular VFO, or variable frequency oscillator, for HF radio gear was adapted about fifteen years ago from several different designs. Our "Jaguey " three bipolar transistor VFO is very stable in the frequency range from 500 kiloHertz all the way up to 10 megaHertz or so, which makes it an ideal circuit to use in beginners' direct conversion receivers. Parts availability was carefully analyzed by the "Jaguey VFO" design team, CO5GV, CO2JA and yours truly. After more than 15 years, this VFO design is still in use by cuban hams, and the only two real upgrades -- which are quite logical by the way -- were changing the zener diode voltage regulator to an integrated circuit high performance regulator, and when available, using an FET, or field effect transistor, in the oscillator circuit. So nowadays you can homebrew two different versions of this universal VFO, one using only discrete components, and the newer one, using the IC voltage regulator and the FET.
Of course the newer version shows better performance, but to tell you the truth, both VFO's work quite well, and in actual operation it is really hard to tell which unit is on the air, as both of them are pretty stable WHEN PROPERLY BUILT, and let me emphasize that last phrase -- WHEN PROPERLY BUILT -- because, amigos, VFO construction does require a lot of care, good mechanical design and complete Radio Frequency shielding of the circuits in order to obtain adequate performance. Yes, when properly built, a homebrew VFO is one of the basic building blocks of other radio equipment. For example, we combine the "Jaguey" three-transistor VFO with a very simple 2-diode mixer, an antenna input filter and a high gain audio amplifier to build a very simple, but nevertheless good-performance single-band direct-conversion receiver for 160, 80 or 40 meters, one of the most popular projects among the ever-growing population of Cuban amateur radio enthusiasts.
Yes, we do QSL 100 percent here. Send your QSL request via Air Mail to Arnie Coro, Dxers Unlimited, Radio Havana Cuba, and via INTERNET e-mail send it to arnie@radiohc.org.
And now that we are talking about QSL's, here is QSL on the air, one of the very popular sections of this program. So QSL on the air to John, amateur radio operator N4HV in Northern Florida, grid locator EM70. John listens regularly to Dxers Unlimited, and is one of the many users of our HF Plus 6 meters propagation updates and forecasts, because John N4HV is a very enthusiastic 6 meter band operator whom I had the pleasure to talk with Monday evening during a nice band opening that provided us with very short skip DX.
QSL on the air also to another MAGIC BAND Dxer, N4JK Art, who operates from North West Florida, grid locator EM 60. Art uses a rather unusual antenna system for his VHF-UHF ham radio equipment; it is a log periodic wide band array, that operates from 50 megaHertz all the way up to the 23 centimeter band and has a total of 31 elements. During our nice QSO Monday evening, Art and I discussed the possibilities of a simpler log periodic antenna that could operate from 40 megaHertz all the way up to about 200 megaHertz, an antenna that could prove to be very useful during the upcoming solar cycle 23 PEAK...
As you realize, Dxers Unlimited's listeners who are also amateur radio operators enjoy a lot having a two-way QSO with CO2KK, something I also find a really rewarding experience everytime it happens.
QSL on the air to yet another 50 megaHertz band enthusiast, Otis in Georgia. Otis lives in grid square EM83 and operates his ham radio station KE4VWJ a lot. He listens to Dxers Unlimited using his ICOM 706 rig which, as many of today's amateur transceivers do, also has the additional feature of a wide coverage HF receiver.
This is Dxers Unlimited's mid week edition and here is item four, the very popular "YOU HAVE QUESTIONS" section of the show. OK, here is today's question sent in by a canadian listener:
Arnie, I know -- I am almost sure -- that someone has asked this question before, but I do want to hear your opinion... here is my question: What antenna would you recommend to use at my apartment? I am on the tenth floor, and there is a small balcony, about 4 meters by 2 meters, available but nothing can be installed there that hangs down the building walls. of course....
OK, amigo from Canada, here is my advice: Install a magnetic loop antenna, and use the largest possible loop that can fit at your location. I won't recommend monopole whips, or even short dipoles made with loading coils and whips. The magnetic loops are the way to go, and although you do have to retune them every few kiloHertz, they have three really outstanding features that make them the winners for apartment dwellers' installations: Number one, the magnetic loop is a compact antenna; number two, it is a really efficient antenna system, especially in the frequency range from about 10 megaHertz all the way up to 50 megaHertz, although a one and a half meter diameter magnetic loop will provide a lot of fun when operating 40 meters; and finally the number three feature: magnetic loops have very sharp radiation patterns that can help null interference from local sources, like computers, TV sets, building elevators. etc.
So, again, no doubt, I am for the magnetic loops, which are expensive when bought from commercial suppliers, but which amateurs have learned to build from easily available parts and at low cost. NOW, a final warning: Install your magnetic loop in such a way that no one can get near it when you are transmitting, even with low power or QRP equipment, as this antenna system develops an extreme Radio Frequency voltage when fed even with a few watts.
And now amigos, as always at the end of Dxers Unlimited, here is Arnie Coro's exclusive and not copyrighted HF propagation update and forecast:
Solar activity is expected to hover between moderate and high during the next several days. This present solar rotation is moving up towards an expected peak that should happen from June 12 to June 16, and may reach as high as 250 solar flux units or more. As I was typing the script for this show, around 1600 hours UTC Tuesday, June 6, there was one rather large active region which was had what scientists describe as an E type Beta Gamma Delta magnetic configuration, which usually is an indication of a region capable of generating many high intensity solar flares.
Solar flux is now very near 170 units and moving up. Another significant event that radio amateurs, TV Dxers and FM band Dxers should take notice of is the already in progress June's invisible meteor showers. They are described as invisible because they happen in broad daylight, so the meteors cannot be seen as they enter the Earth's upper atmosphere, but they can certainly be detected when they provide short bursts of radio propagation all the way up to more than 100 megaHertz... AND some scientists believe that these June meteor showers are related in one way or another to the Sporadic E events that are so frequent during this time of the year.
Remember to send me your signal reports and comments, and any radio hobby related questions, to arnie@radiohc.org, and Via Air Mail to Arnie Coro, Radio Havana Cuba, Havana, Cuba.
Arnie Coro CO2KK
Havana, Cuba
6 June, 2000Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba
PO Box 6240, Havana, CUBA 10600
phone: 53-7-814243
phone res: 53-7-301794
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