Radio Havana Cuba Dxers Unlimited Dxers Unlimited's mid week edition for 17-18 April 2007 By Arnie Coro radio amateur CO2KK
Hi amigos radioaficionados around the world... welcome to the mid week edition of Dxers Unlimited, coming to you when the Sun is showing practically no signs of activity... no sun spots , a blank solar disk for many days, and the daily measurement of the microwave solar flux is at minimum levels , between 60 and 70 units, the lowest figures registered by microwave radiometers at any time since those measurements began in 1947. So, in other words amigos, we seem to be right in the middle of solar minimum for cycle 23.... and that of course means that HF propagation conditions are very poor to say the least, so poor in fact that frequencies above 20 mega-Hertz remain totally dead for long distance ionospheric propagation just as if they were VHF frequencies. But what is bad for some radio hobbyists is good for others, and due to the very low solar activity we are enjoying exceptionally good medium wave broadcast band DX conditions during the extended spring equinoctial season. Item two: Noise, noise sources of all types are making reception of short wave signals very difficult for listeners that can not install external antennas well away from noise sources. That's why every time someone tells me that their local noise level is very high, I provide the following two bits of advice. Number one: Try, by all means to pinpoint the main source of the noise that is affecting your reception, and Number two: Don't think it twice,and go ahead and home brew a magnetic loop antenna... Following my advice , listener Gary from Vermont, found out, using a very simple VHF directional antenna , that his main source of HF noise was very clearly coming from a specific electricity pole, where a 50 kilovolt ampere transformer was installed. It wasn't even the distribution transformer that fed his house, it was almost a city block away, just around the corner, but , sure, it was the noise generator... I'll tell you more about how Gary dealt with the noisy transformer and how you can home brew a direction finding antenna following Gary's experience... Stay tuned, as Dxers Unlimited's mid week edition continues with more radio hobby related information , coming to you from Havana, I am Arnie Coro, radio amateur CO2KK ... ..... This is Radio Havana Cuba, the name of the show is Dxers Unlimited, and yes, you can listen also via our Internet streaming audio, from rhc.cu yes, just type, rhc.cu on your browser and it will do the rest... Our streaming audio is on the Internet from 05 to 07 hours UTC... Now as promised , how amigo Gary dealt with the noisy power utilitity transformer that he pinpointed with his two meters band three element Yagi antenna. Yes, you heard it right, Gary connected a portable three element Yagi antenna he built using a short length of PVC pipe and aluminum tubing to his two meters band handie talkie, and went around the neighborhood searching for the noise sources. He told me that when he turned around the corner , the noise increased dramatically when the Yagi was aiming at the other street's utility distribution transformer...Arnie, he said, it was so clear, that there was no chance for a mistake... I then called the power company customer service and they sent an engineer that had a noise finder of a different nature. His equipment was tuned below the AM broadcast band, and could not locate the noisy transformer until it was placed exactly below it, while my handie talkie and Yagi combination could pick up the noise source almost a block away from it. In fact, Gary explains, the very cooperative person from the power utility went to my home and asked for a diagram of my noise finder Yagi, because he said that he was going to build one . The next morning the utility crew came with a new transformer and replaced the faulty one. Two days later, Gary said that the engineer that had worked with him to find the noise source called on the phone to tell him that the transformer was opened at the repair shop and they found damages done by an arc over that was due to a faulty insulator, and he also said that anytime that he had a noise problem he could call directly to his cell phone. Now, that's service at its best, and it shows that many times power company people learn from radio amateurs and short wave listeners when trying to find noise sources. ...... ASK ARNIE, the most popular section of Dxers Unlimited amigos, no doubt, according to your e-mail , letters and also you tell me when we have the opportunity of talking to Dxers Unlimited's listeners that are also amateur radio operators. By the way, I am just giving the finishing touches to my new digital HF station, so soon CO2KK will be back again on the air using PSK31, MFSK16 and other digital keyboard to keyboard modes. According to propagation forecasts for the next three months or so, you will probably be able to work CO2KK digital on either 20 or 40 meters, as my main HF transceiver is a very old radio that doesn't have the WARC bands. ASK ARNIE today has to do precisely with a question sent by listeners from Canada, the USA, South Africa, New Zealand, Nigeria, and India. They all want to know if there are any possibilities of new amateur HF bands to be discussed during the upcoming World Administrative Radio Conference 2007, that is to be held in Geneva, Switzerland at the end of the year. Well amigos, this is my personal point of view... all I see happening there in relation to the HF amateur bands is the possibility of a better realignment of 40 meters worldwide, but due to the extreme pressures by other users of the radio spectrum, and the certain decline seen on the use of the HF amateur bands, I don't think that any new bands will be discussed by the world's regulating agencies. On the contrary what I am seeing is the possibility that at a future WARC or World Administrative Radio Conference amateur radio may be loosing spectrum space now assigned to this service, because many government telecommunications agencies are carefully monitoring the present use of the amateur bands from 160 meters all the way up to six meters... And according to what I have heard, it is clear that the figures are not encouraging at all... as a matter of fact, the famous phrase use it or loose it may soon become a reality if radio amateurs around the world don't increase as soon as possible their on the air activities... ...... From Havana, this is the mid week edition of Dxers Unlimited, and here is item four... a connector related item... Yes radio frequency connectors for coaxial cables are something difficult to deal with, so my advice is that you select the ones to use at your ham radio station or short wave listening post, so that they are of the best possible quality. Yes, good quality RF connectors for coaxial cables are expensive, but they will last forever it properly installed. Poor quality connectors are a source of headaches and they seem to fail always at the worst possible moment. At CO2KK my amateur radio station I use three types of RF connectors, the standard BNC for thin coaxial cables, the PL259 male and SO239 female coaxial connectors for quarter inch and half inch diameter cables for HF and low band VHF applications and the expensive N type connectors for UHF signals. All my tests with high quality PL259 connectors show that there is no difference at all on 2 meters between the PL259 and the more expensive N type constant impedance connectors, so the obvious thing to do is to use the N connectors only above 150 mega-Hertz... And by all means amigos, learn how to properly install all the RG connectors at your shack, it will take some time and practice to do it properly,but time spent learning how to install RF coaxial cable connectors is well worth every minute of it.. Also, any connectors that are exposed to the weather must be properly sealed and protected, because there is nothing worse than humidity leaking inside a coaxial cable ... So, when installing new antennas or providing maintenance to existing ones, don't forget to have at hand all the necessary sealing items, including special elastic tapes, silicon sprays and weather protection boxes. I had recently the very bad experience of a faulty junction box that provides the phasing to a two Yagi 2 meters band array, that happened because the connectors were not properly sealed against the weather... It took several hours, and three new connectors to do the repair job... that would had been totally unnecessary if I had installed the phasing box properly to begin with !!! But this was done a day before a contest, and you know, then the new antenna was left to its own luck , only to find about six months later that the standing wave ratio of the antenna system had gone up dramatically... then it was too late... My elder son Arnie Junior reminded me of what I had done the day before the VHF contest, and how the connectors were not protected against the weather. - Dad, he said, its your own fault, so now I must take the whole array down and do a complete repair job for you. But this time , the antenna system will last for at least three years, that is the maximum time that we have found out that an antenna in Cuban weather will last without a major overhaul of the weather protection for the RF coaxial cable connectors !!! ..... And for those of you that have asked about our Internet audio in English, here is again the information on when and how to listen to it. The English language program is on the Internet streaming audio from 05 to 07 Hours UTC, and the URL of the site is very simple, just rhc.cu, so you need only to type rhc.cu on your browser and that will take you to the web site, then click on the loudspeaker icon, and that's it... Now as always at the end of the program here is Arnie Coro's Dxers Unlimited's HF plus VHF low band propagation update and forecast... Solar activity at rock bottom levels, with extremely quiet geomagnetic field conditions. |Sporadic E spring-summer season due to begin in around two weeks from now or maybe earlier, so watch for signs of low band TV channels skip signals.Expect excellent nighttime AM broadcast band conditions , but now they may be slightly spoiled as spring thunderstorms start to generate static crashes that make reception difficult especially during the summer season. Don't forget to send me your signal reports and comments about the program to [EMAIL PROTECTED], again [EMAIL PROTECTED] or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba ---[Start Commercial]--------------------- Preorder your WRTH 2007: http://www.hard-core-dx.com/redirect2.php?id=wrth2007 ---[End Commercial]----------------------- ________________________________________ Hard-Core-DX mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/hard-core-dx http://www.hard-core-dx.com/ _______________________________________________ THE INFORMATION IN THIS ARTICLE IS FREE. It may be copied, distributed and/or modified under the conditions set down in the Design Science License published by Michael Stutz at http://www.gnu.org/licenses/dsl.html
