Radio Habana Cuba: Dxers Unlimited Mid-week edition for August 15, 2000
By Arnie Coro, radio amateur CO2KK
Hi amigos! Welcome to the mid-week edition of your favorite radio hobby show via short wave. I am Arnie Coro, radio amateur CO2KK, your friend here in Havana now ready to share with you about sixteen minutes of all radio hobby related information. Here is item one: Very interesting events during the recent geomagnetic storm caused by an increase in the solar wind hitting the Earth's magnetosphere... At the same time the storm was in progress, the Perseids meteor shower reached its peak, making many radio hobbyists see, for the first time, a combination of both meteor scatter and auroral propagation. Solar activity is now between low and moderate, and an active region is developing into what may become a source of more solar flares...
Item two: You have questions, and Arnie has the answers, but don't worry-- If I can not find the answer to your radio hobby related question, there are lots of very nice friends to whom I may refer the question and come back with the answer!!! The latest question was sent, not by a radio hobbyist himself, but by his wife!!! She wants to know how computer-generated interference can be attenuated, as her computer causes a lot of interference to her husband's short wave radio... I'll answer this question, and give some advice, later in today's edition of Dxers Unlimited.
Item three: How thin can antenna wire be? That's a question sent in by a listener from Jamaica. He listens to our local late afternoon broadcast on 9550 kHz, when we use our Caribbean Phased Dipoles Antenna Array... Straightforward answer to Jamaica: For receiving and low-power transmitting, up to about maybe 100 watts, you can use copper wire as thin as it will be strong enough to keep itself up. In other words, you have to install the thin small diameter copper wire, and see how it behaves under stress. Of course, the question has to do with the installation of a stealth or invisible antenna... My own practical experience shows that copper wire as thin as no.26 will work, but it will need replacing from time to time. No.28 copper wire is practically invisible, but again it breaks down easily. When travelling I carry a spool of no.24 enamelled copper wire, which I use to make end fed dipoles, long wires and even dipoles, but when making a dipole from such thin antenna wire, the center insulator must be supported properly and the two legs of the antenna must not carry the weight of the feedline. Stay tuned for more radio hobby related items; I'll be back in a few seconds... I am Arnie Coro in Havana.
You are tuned to Radio Havana Cuba's English language service, the name of the show is Dxers Unlimited, and here is item four: Simple amateur radio equipment, something you can build and repair yourself, is today as hard to find as a living dinosaur!!! That's the impression I am forwarding to you after reading some of the advertisements in 5 of the world's leading ham radio magazines... There is not a single piece of equipment that can be described as simple, low cost, easy to assemble, and of course easy to repair... Even the simplest QRP, or low power amateur radio transceiver, kits available are rather difficult to assemble, requiring above-average skills in electronics, soldering and radio technology... Want to know the reason behind this comment? Well, it is no other than to make radio kit suppliers aware that there is something missing-- which I could describe as a simple 5 to 20 watt output CW transceiver and power supply that can be built by anyone with the ability to solder components and follow instructions. The transceiver should be solid state, use no hard-to-find components, the parts must be placed far apart from each other, so that repairs can be made easily, and above all, the circuit must be easy to understand and thus easy to follow if something breaks down... With a receiver having adequate sensitivity and proper selectivity, such a beginner's radio today could play the same role as the simple radios that made three previous generations of amateur radio operators homebrewers!!!
Again, a simple, but well designed receiver, with a nice bandpass input filter, air core coils, so that anyone in Third World nations may reproduce the circuit, no rare components, and a very well written with full schematics multi-language manual... Hard to imagine? I don't think so! Maybe some of you Dxers Unlimited's listeners who are also amateur radio operators may like to make your contributions to this project... You can send your ideas on what the low-cost, easy-to-build and operate beginners' amateur radio transceiver should be like. Then we can start adding them up altogether at our website, and who knows-- maybe the DXERS UNLIMITED DX1 will be designed and built from the wealth of information and design ideas provided by many of you... Send your ideas for the beginners' simple transceiver directly to arnie@radiohc.org... very easy e-mail to remember, or via Air Mail to Arnie Coro, Radio Havana Cuba, Havana, Cuba, and I'll start collecting and analyzing all the design criteria...
Just as a starter, I would like to say that the power supply for the rig is already a reality, so don't worry about that part of the project, it is an easy to build 13.5 volts at 3 amperes fully regulated, filtered and wrong polarity protected supply, of which two models are available, one with a very common integrated circuit voltage regulator and the other just using discrete components...
Don't forget! Describe your concept of an ideal low-cost beginners' ham radio transceiver via e-mail to arnie@radiohc.org, or via Air Mail letter to Arnie Coro, Radio Havana Cuba, Havana, Cuba.
This is Radio Havana Cuba... Dxers Unlimited now continues with the answer to the question in Item Two, remember? The wife of a short wave listener who wanted to find how to make her computer compatible with her husband's radio receivers... First of all, amiga, try to locate your computer as far away as possible from your husband's radios. Physical separation helps a lot, as well as electrical isolation, meaning that if at all possible, try to run the computer from a wall plug that is not the same as the one he is using for the radios. You can even find, in some houses, different circuit breakers protecting separate areas of the house or apartment, and if that is the case, run the computer and the radios from different AC power line circuits. That is easy to find out, by disconnecting the breakers one by one, and watching if the computer and the radios are or are not on the same circuit.
Step two is using external antennas, which are connected to the radios with well-shielded coaxial cables that are fitted with well-soldered plugs. I have found that interference from computers goes way down just by connecting the radio to an external antenna with a high-quality and thus well-shielded coaxial cable. You may also want to install a well designed and built antenna tuner. One interesting fact about computer-generated interference is that the newer high speed CPU's running at more than 233 megaHertz tend to generate less radio frequency noise than older machines.
One very important source of computer-associated noise must not be forgotten, and that is none other than the monitor. If you use a laptop computer with a liquid crystal display, you will find that the noise level goes down a lot, compared with using a standard cathode ray tube monitor, and let me add that the larger the picture tube, the more noisy the monitor will be, something that is due to the very high voltages required for operating the large size cathode ray tubes.
There are many more things that can be done; I can't list them all here today, but there is one more that should not be forgotten, and that is the use of ferrite isolators on all computer cables -- each and every cable coming in and out of the computer must be fitted with a ferrite isolation system, of which there are many types, and they are all well known by computer technicians. You can save by fitting the ferrite isolators all by yourself, as they are very easy to install, following the instructions that come with them. Try all the above sequence, including installing the ferrite Radio Frequency chokes or isolators, and then come back with your results, as I am sure that they will be of great interest to other Dxers Unlimited's listeners around the world who are facing the same computer-generated radio interference problems.
arnie@radiohc.org quick and easy, is my e-mail address, to which you can send your signal reports, comments about the show, and of course, any radio hobby-related questions... and now amigos, just before going QRT here for today, ready to copy? Here is Arnie Coro's exclusive and not copyrighted HF plus 6 meters propagation update and forecast:
Solar activity is hovering between low and moderate, but there is an area of sunspots that is expanding and may switch on some extra activity during the next two to three days. The daily sunspot number, that is the physical optical countdown is around 260, and the daily solar flux was 190 units and slowly moving up, as we are approaching the expected peak activity for this solar rotation. The A index, the planetary geomagnetic disturbance indicator, is certainly moving down, and we are enjoying the post-storm effects, which include something that is still not known by scientists... and that is the fact that the E and F regions become very stable after a geomagnetic storm, bringing with that a period of very good HF propagation.
So, enjoy the good HF DX conditions, which are especially noteworthy on 15 and 20 meters... 15 meters during the early morning and late afternoon, and 20 meters during the local sunset and beyond. I see little chance for sporadic E events, but the number of radio detected meteors is still high, as the Perseids meteor shower continues after its peak.
Let's have a nice time listening and communicating on the HF bands amigos, I'll be hanging around 21210 and 21310 kiloHertz on 15 meters and around 14210 and 14310 on the 20 meter band whenever I have a little chance to be on the air at CO2KK. See you on the air soon!!!
prepared 15-aug-2000; transmitted 16-aug-2000 19:02
Arnie Coro CO2KK
Havana, Cuba
15 August, 2000Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
To Arnie Coro's Dxers Unlimited
Back to NY Transfer's RHC main page