Radio Habana Cuba: Dxers Unlimited Weekend edition for June 10, 2000
By Arnie Coro, radio amateur CO2KK
Hi amigos! You are now listening to the weekend edition of your favorite radio hobby show... This is Dxers Unlimited and here is the menu for today:
Item one: YES! Another geomagnetic storm, but not as severe as scientists thought it was going to be... and another one is in the works as particles from coronal mass ejections continue to travel towards the Earth...so, you may or may not notice some abnormal propagation during the next 48 hours... depending on how those particles reach the magnetosphere...
Item two: VHF contest during this weekend -- expect a lot of amateurs in the Americas on the air on 6 meters, so there are good chances of working new countries and new grid squares.
Item three: PSK31, the keyboard-to-keyboard digital communications system continues to make headway... now a new frequency is in use by PSK31 operators, 28.120, again 28.120 on the 10 meter band is showing a lot of activity when the band opens... but so far, the most active PSK31 spot is around 14070 kiloHertz on the 20 meter band. PSK31 is very easy to implement for receiving, requiring only a computer with a sound card, a PSK31 computer program, of which there are several versions available, and a shielded cable connecting the receiver's audio output to the sound card line input. By the way, this cable may require including a resistor network to reduce the input level to the sound card.
Item four: futuristic yes, and also realistic... talk about a future amateur radio repeater to be installed on the Moon... OK, it is not just around the corner, but who thought about radio amateurs building and operating Earth orbiting satellites in 1950???
Stay tuned for more radio hobby related information coming to you from Havana. My sound engineer and producer is Margarita Delgado, I am Arnie Coro.
So far there is no match to the extraordinary PSK31 keyboard to keyboard communications protocol... Signals so faint that they can't be even heard with headphones are succesfully picked up by the PSK31 software and decoded into readable text on the computer screen. PSK31 is also a very city dweller friendly mode, as it works using very low power ouput... That's why PSK31 is becoming more and more popular. There are now several PSK31 websites full of information about this new communications mode, and the software needed to use it is freely available for downloading. Download one version here!
As more and more radio amateurs around the world learn about PSK31 the mode is becoming more and more popular, and new countries are going on the air every day. The most popular PSK31 frequency to monitor is around 14070, again one four zero seven zero on the 20 meter band, and now 28120, that is two eight one two zero on 10 meters, is becoming very active whenever the band opens. On the six meter band, PSK31 operators are now monitoring 50.290, five zero two nine zero, 50.290 and there is one cuban station now on the air on that frequency, my good friend Oscar Morales Jr., CO2OJ, the Secretary General of the Cuban Amateur Radio Federation and longtime VHF enthusiast. For those of you interested in this new mode, the good news is that software is becoming more and more user friendly, and connecting the computer to the radio is really a very easy job, requiring just soldering some plugs and maybe a few resistors... Once the computer's sound card is connected to your receiver's audio output, that's the start of the HOW TO TUNE TO PSK31 learning process, which will take a little time and patience, but that life is showing almost everyone is able to master in a few hours all by her or himself.
Among the most important applications I am foreseeing for the PSK31 keyboard-to-keyboard teletype style communications protocol is its use during emergencies, as a small laptop or notebook computer, and a very low power radio connected to a makeshift antenna can provide very reliable communications, with the added bonus of a very small drain on the batteries. Yes amigos, jump into the bandwagon, PSK31 is here to stay, and more and more radio amateurs and short wave listeners around the world will become regular users of this mode from now on.
You are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited and yes amigos, our QSL's are here, freely available to all of you that send a standard form signal report of our broadcasts. Send your QSL requests directly to Arnie Coro, Radio Havana Cuba, Havana, Cuba; there is no need for a PO BOX number etc, as everyone at the Post Office's international section knows us very well.
Now, let's visit Arnie's workshop, one of the popular sections of this show... Today, Arnie's workshop is devoted to giving the finishing touches to one of my pet projects: a very low parts count, easy to build, reliable and rugged single band ham transceiver for beginners. The project is now coming to an end after almost a year of hard work, and I hope to have it available at Dxers Unlimited's website soon. This small but not miniature transceiver has a 10 watt output stage, which was the power level that proved able to get through even when propagation conditions are not so good. I stayed away from a one or two watt rig, as those can discourage newcomers to amateur radio, when they try and try to make a QSO and the radio just doesn't seem to reach anyone.
The architecture of the single 40 meter band transceiver is such that its modules can be built and tested independently, and one can start using the receiver for monitoring the band as soon as it is completed. in other words, you can use it as a very nice SSB and CW receiver, and then, when you obtain your amateur radio license, proceed to build the rig's transmitter module. YES, it is all solid state, but I am thinking now about adding a simple, also easy to build, 50 watt linear amplifier module using vacuum tubes that are available as surplus from old TV sets. The KK-40 Dash One, a single band 40 meter transceiver for both beginners and experts, is now about to be completed... and soon to be made available, to visitors of RHC's website... just go to Dxers Unlimited's page and download all the files when they are there... as easy as that. By the way, this is not a one weekend project, BUT, once finished, you are going to be really proud of your KK40 Dash One, a low cost transceiver designed so that newcomers to the radio hobby can learn a lot while building it!
Do you have any radio hobby related question? If so, just e-mail or Air Mail it to me, and it will be answered on the air, and a written reply will be sent directly to you too.
YOU HAVE QUESTIONS??? Well, amigos, Arnie has the answers... And here is today's question: It came from a radio amateur in the state of Colorado... He asks: Arnie, you have talked about a very special vertical antenna system that does not require a ground system, and yet according to what I heard you saying works very well indeed... I think you said the name of it was the HALF SQUARE, OK? Here is my question: what's the theory behind that no ground wires required vertical???
Well, amigo, the HALF SQUARE and the BOBTAIL CURTAIN, which is its big brother, are what antenna gurus describe as self contained vertical arrays, which I insist, do not require a ground system. Two vertical elements of 0.28 of a wavelength height, and a single wire transmission line of approximately 0.45 wavelengths is all you will need for building a HALF SQUARE, and let's add that this antenna array has a very friendly feedpoint impedance at two points, which very closely match 50 ohms coaxial cables... Radio amateurs should learn more about the HALF SQUARE and use it more, as it is a unique, easy to build, low cost and high performance antenna system that works very well from 160 meters all the way up to two meters, something that is really outstanding. My 2 meter band HALF SQUARE array works beautifully, providing a nice bidirectional pattern with which I cover FM 2 meter band repeaters located both to the East and to the West of Havana with a single low cost antenna made with Number 10 copper wire and PVC pipe!!!
If you want to learn more about the HALF SQUARE no ground wires verticals, just e-mail me to arnie@radiohc.org and I'll be very happy to send you more information about this really interesting antenna system.
And now just before going QRT, here is Arnie Coro's exclusive and not copyrighted HF plus 6 meters propagation update and forecast: Solar activity went down to LOW, but there are two large active regions with many sunspots clearly visible on the Sun's surface. Solar flux is still moving up, and IF -- again IF -- we are not impacted by the stream of particles from one of the recent coronal mass ejections, propagation should be really interesting especially after local sunset. For example, I had a very nice QSO with two Spanish stations, one in the Canary Islands and the other in Barcelona, using 15 meters or 21 megaHertz phone, while here in Havana the Sun had already set, and in Tenerife and Barcelona it was, of course, very, very, late in the evening.
So, here is my advice: Keep an eye on frequencies between 14 and 22 megaHertz after your local sunset. For Six Meter Band and TV and FM band Dxers, Sporadic E skip may appear at anytime during the next several days, so enjoy it!!
I'll be monitoring 50.125 kiloHertz when at home, so maybe we can have a nice QSO there soon, amigos!
Arnie Coro CO2KK
Havana, Cuba
10 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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