Radio Habana Cuba: Dxers Unlimited Weekend edition for October 28, 2000
By Arnie Coro, radio amateur CO2KK
Hi! Welcome to the weekend edition of Dxers Unlimited, coming to you from Havana, and with really excellent propagation conditions on the HF bands prevailing around noon Saturday when I was writing the script for the show.
Yes amigos, old SOL, our nearest and most important star, is becoming active again, and we are expecting the daily solar flux to move up past the 180 mark during the next two to three days.
Item two: CQ World Wide SSB contest in full swing at the time you are hearing this program, lots of active stations... Jorge CO2II was working DX contest stations one after the other on 10 meters when I monitored the band to get an idea of what was going on... CO2II from CQ Zone 8 in Havana, Cuba should be a natural multiplier for contest operators... he was operating around 28.485 kiloHertz, and will very possibly be around that frequency tomorrow too... And, of course, on Sunday yours truly will enjoy QRP or low power contest operation on 10 meters also. I will be running 5 watts to my ASD, or asymmetric dipole antenna.
Item three: Margarita Delgado, my sound engineer and producer, has the day off today, so my good friend Jose Costa Pupo is doing the difficult job, running both the mixer board and the stopwatch at the same time.
Stay tuned for sixteen more minutes of all radio hobby-related information mis amigos. I am Arnie Coro CO2KK here in Havana, back with you all in a few seconds....
Yes, the scripts of Dxers Unlimited are posted on our Dxers Unlimited website ... you can visit and download the scripts for future reference, or just read them at your pleasure... On the website, you'll also find specs for many of the easy-to-build projects described on the air.
Item four: Simple projects, the ones that you can complete in one or two hobby working sessions, are always very enjoyable. Here is one that I always try to "sell" to everyone that visits my shack... I have not one, not two, but three of them. Guess what it's all about... Nothing other than a simple antenna switch. I started by building a three-position antenna switch with BNC-type connectors for my TV DX antennas; it worked so well, and I was so tired of plugging and unplugging coaxial connectors, that I built another antenna switch for my VHF ham station; this one has 6 positions, and it is wonderful for antenna tests, and one can switch real fast between any of six VHF antennas... Finally one day my elder son Arnie Jr. CM2KW came in with some female SO239 connectors and a really nice ceramic insulated wafer switch. They all ended up inside yet another antenna switch; this time we built a 5-position switch that works very well, something we know as we tested it with professional RF measuring equipment and found out that the antenna switch introduced just a very slight bump in the 75 ohm cable system I use for my HF antennas.
A small box, a few female connectors, a high-quality ceramic insulated multi-position rotary switch, a few hours of your spare time, and the homebrew antenna switch will be your pride and joy. Then you can run those always-amazing antenna comparison tests, something I do here quite often to show visitors why I prefer the ASD antennas, yes the asymmetric dipole antennas, above all wire antennas ever tested here.
Dxers Unlimited is coming to you from Havana... you can send your signal reports, comments about the show and questions to arnie@radiohc.org, and I will be happy to QSL back to you. Via Air Mail, just send a postcard with the signal report and your QSL request to Arnie Coro, Radio Havana Cuba, Havana, Cuba -- and don't forget to include your postal mailing address!
Now item five: DX expedition to a very interesting DX location... My good friend G3WOS, Chris Gare, is traveling to Ascension Island, grid locator India India two two. Chris will use the callsign ZD8SIX, and he has already received a lot of support from the only two amateurs who live on this isolated island of volcanic origin right next to the west coast of Africa. ZD8SIX will be active for seven days, and Chris selected the period from October 31st, that is next Tuesday, to November 8th because during those days we will go through propagation conditions that will favor rather high maximum useable frequencies. I hope to work ZD8SIX on six meters from Ascension Island, and add it to my list of worked countries on the magic band.
Item six, answering a question about the asymmetric dipole antenna... It came from a listener in the USA, and here is the question: Arnie, can I use the ASD antenna on the two meter ham band? Answer: I am afraid I never thought of testing the ASD above 50 megaHertz! As a matter of fact, you have brought up a very good question... The ASD will provide gain in the direction it is sloping, but the polarization of the transmitted wave will be horizontal, so... you can't use the ASD for vertical polarization, which is the type of polarization used for 2 meter FM work. Anyway, try it -- and send an e-mail to arnie@radiohc.org telling us about your results! The ASD antenna for 2 meters can be as small as just 2 meters long, but real high gain will occur when you make the long leg from 5 quarters of a wavelength on... So, a three-meter-long ASD will probably provide as much gain as a three-element Yagi, with the advantage that it can be transported, erected and dismounted much easier and faster than either a Yagi or a Cubical Quad. The basic configuration of the Asymmetric sloping dipole, just to refresh your memory, is a standard quarter-wave on one leg of the dipole, and an odd number of quarter-waves on the long leg. So, for the two meter band, you can make a very nice portable, low-cost antenna which is about just 3 meters or nearly 10 feet long. Feed it with 50 ohm cable via a coaxial choke balun, and install it so that it will slope at a 45-degree angle in the direction of the stations you want to contact.
And now that we are talking about the ASD, this is an ideal antenna for FM broadcast band Dxing while mountain climbing, as you can carry it in your pocket. Imagine -- just wire and a lightweight coaxial cable -- you don't even need standard insulators, as you can use nylon fishing line directly tied to the wire ends as both long insulators and antenna supports. The dimensions for the FM band ASD are easy to calculate: for the center of the band, 100 megaHertz, the short leg will be 75 centimeters long, and the long leg -- for a five three quarters wavelength option -- the long leg will be 75 times 5 or 3.75 meters, which is an antenna of very reasonable dimensions. Try making one and aim it to a DX FM station for a test. As most FM broadcasters are using circular or elliptic polarization, there is always a presence of horizontally polarized radiation that the ASD dipole will pick up nicely for you. Don't forget to make the antenna slope at a 45-degree angle in the direction of the station or stations you want to pick up!!!
And now amigos, as always at the end of the show, here is Arnie Coro's HF plus 6 meters propagation update and forecast: Solar flux moving up; expect a peak of just below 200 units for this solar rotation. There are at least two solar active regions that have a potential to generate flare activity. The daytime MUF is really good for ham radio operation on the 10 meter band, and there are high probabilities of 6 meter openings, too.
Just after your local sunset DX conditions will be at their best to your South, your West and Northwest, even for really very long paths. QRP or low power operators will have a nice time on 10 meters very early in the morning, when solar noise is low and ionospheric absorption is also low.
For short wave listeners, the best bands for easy listening during your local evening hours are 31, 25 and 22 meters, but don't forget to scan both 19 and 16 meters for really long distance DX, too.
See you at the mid-week edition of the show. Look for CO2KK on 28.5 and 21.4 megaHertz for a nice chat, too!!!
Arnie Coro CO2KK
Havana, Cuba
October 28, 2000Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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