Radio Havana Cuba Dxers Unlimited
Dxers Unlimited’s mid week edition for 14-15 August 2007 By Arnie Coro Radio amateur CO2KK Hi amigos radioaficionados, it’s nice to have you all listening to the mid week edition of this radio program that is entirely, absolutely devoted not to one specific aspect of the hobby, but to all the more than 81 ways that you and I enjoy it! I am Arnie Coro, radio amateur CO2KK , your host here in sunny Havana and here is today’s menu: If you followed yours truly advice during our last several programs, I am sure that you have enjoyed listening under excellent propagation conditions late in the evening local time… Monday, after 0500 hours UTC I did a band scan here, and was able to pick up very nice DX on the 40 meters amateur band, clear signals on the CW segment, between 7000 and 7050 kilohertz, and even on the QRP spot frequencies where low power enthusiasts gather to challenge operator’s skills while running extremely low power transmitters, 7030 and 7040 kilohertz I was able to pick up several stations … Then I moved up a bit to the 25 meters international broadcast band, and sure enough ! several nice DX stations from the Pacific Basin provided armchair copy too. So, again, whenever your having a hard time falling asleep during the next several weeks, remember that summer propagation conditions on the HF bands are much better after local sunset, because during the daytime, ionospheric thermal expansion sends the maximum useable frequency way down !!! And by the way, very late in the evening listening or operating HF ham radio equipment is also much better due to a general reduction in man made noise !! Item two: Sporadic E season is now coming to an end, and I am writing this script at just after nine thirty in the morning local time, while keeping my TV set tuned to channel 2, and my 6 meter band transceiver tuned to 50.125 kilohertz , the calling frequency for the North America and Caribbean regions… Monitoring the low band TV channels provides very early warning of a Sporadic E event in progress… Item three: one of the main topics among radio amateurs that live in areas that may be affected by tropical storms is “Amateur radio operations during emergency situations”, and Cuban amateurs that have had first hand experience keeping communications operating even during the middle of a category four hurricane that have proven to be very valuable for ham operators of other nearby nations. Item four: Yes, I won’t forget of including ASK ARNIE in every Dxers Unlimited that goes on the air, because, according to your e-mail messages and letters, it is certainly the most popular section of the program closely followed by Arnie Coro’s Dxers Unlimited’s HF plus low band VHF propagation updates and forecast... If time permits, I will also include today our tips and techniques section, as it is becoming quite popular too... Standby for more radio hobby related information, coming to you from Havana… I’ll be back in just a few seconds after a brief musical intercut.. …. You are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited, and yes, we do encourage listener’s feedback, as a very effective way of improving this program, send your comments, opinions, and ideas on how to make Dxers Unlimited better directly to my computer … send mail to [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>, again, slowly and phonetically, [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>, and if you are not yet in cyberspace, just drop me a postcard to Arnie Coro, Radio Havana Cuba, Havana, Cuba. Now here is ASK ARNIE… THE most popular section of this show. Today‘s first question came from New York, USA.. listener Jonathan from Syracuse wants to know if he can adapt a discarded cell phone for amateur radio use. Well amigo Jonathan, thanks for a very nice question, as first, second and third generation cell phones are now becoming an environmental problem in many countries, as technology evolves into much more sophisticated systems that require different cell phones to operate with them. The only amateur radio band that is near to the older and still in use cell phone band around 900 megaHertz is not authorized by telecommunications administrations at a worldwide scale, as a matter of fact, only a few countries authorize their amateur radio operators to use the 900 megaHertz band, the one that is close enough to the first cell phone band to make a conversion practical. According to what I have seen inside discarded cell phone sets, the only possible approach for converting them into ham radio transceivers for the 900 megaHertz band is by means of software access to the programming of the cell phone set, using the proper interphase that is often kept as a trade secret by the cell phone manufacturers, but apparently some radio amateurs have already achieved positive results with some specific types of older technology cell phones…an indication that they had access to both the interface and the software to reprogram the cell phones. By the way amigo Randolph, a much easier conversion from new information and communications technologies professional equipment to amateur radio applications can be achieved with the so called WI-FI wireless networking equipment, which can be easily adapted for ham radio use !!! Question number two: Came from Sweden, where listener Bjorn is picking up our 11760 kilohertz transmissions just after midnight his local time. Olaf wants to know why it is possible to pick up Tropical Band stations from Latin America at his QTH near Malmo, Sweden, with such good signals, and he mentions picking up Radio Rebelde on 5025 kilohertz very clearly after the station installed its new transmitter and antenna. Well amigo Bjorn, Tropical Band signals will continue to propagate better and better as solar activity continues to move down towards the end of solar cycle 23. When solar flux figures between 70 and 80 units prevail for many days, ionospheric absorption is at a minimum and that will certainly help signals below 5 or 6 megaHertz propagate much better. Another important factor regarding low frequency propagation is the connection between geomagnetic latitude and signal attenuation, something that has puzzled scientists for many years. So, now the bad news for you up North, is that the expected increase in solar activity will certainly spoil your reception of Tropical Band stations as soon as the solar flux figure moves to a monthly average of more than 100 units amigo !!! When old man Sol comes back into high activity, ionospheric absorption will increase and Tropical Band signals will not propagate so well during solar maximum years. Question number three: This one came from Kansas, USA, listener Barry ASK’s ARNIE about static electricity charging his antenna all the time, and the problems associated with sudden sparks coming from the antenna even when it’s disconnected… Well amigo Barry, here is my advice… install a good ground system at your location, even a single ground rod , well driven into the soil of the garden will work, and then buy a pair of 10 kilo Ohms two watt carbon resistors and connect them between thee antenna and ground… The 5 kilo Ohm effective resistance will continuously drain the static electricity picked up by your antenna to ground, saving your radio receiver’s front end solid state devices from a quick death, caused by the static discharging trough the radio, as it has unfortunately happened to you already… My advice is that you connect the antenna to the radio only when you are using it, and at any signs of even a far away thunderstorm or the presence of CUMULUS NIMBUS type of storm clouds, disconnect the radio and start reading or assembling your new homebrew radio project !!! Static electricity discharging to ground trough your radio’s very delicate solid state devices will burn them up, as many solid state receiver users have learned the hard way. My latest HURRICANE TWO ham radio transceiver, intended to operate during emergencies has a unique front end protection, provided by the use of a vacuum tube radio frequency amplifier stage, that is much more immune to static damages than solid state transistors of any type. Although the vacuum tube stage requires an additional 150 volts DC power supply, the protection provided is well worth the additional components required !!! By the way amigos, don’t forget that we are now well into the summer thunderstorm season, so it is always a very good practice to keep all your radio and electronic equipment disconnected from the antennas, ground systems and power line when they are not in use, and as I said a while earlier, it is also extremely good practice to disconnect all radio equipment whenever a thunderstorm is approaching !!! …. TIPS and TECHNNIQUES is fast becoming popular among Dxers Unlimited’s worldwide audience and cyber surfers that read my scripts via the INTERNET… so, I am trying to include this section in almost every program. Today’s tip : When you are going to use any radio equipment connecting it to an automobile or truck electrical system as a power source, STOP, STOP, STOP, before doing it, and build yourself or ask an electronic hobbyist friend to assemble for you a well protected interface… I have seen too many radios, handie talkies, cell phones and CD portable players killed by connecting them directly to automotive electric systems that may generate , under the worst case scenario conditions, voltages as high as 17 or even 20 volts from alternators that are not properly regulated… The typical automotive electric system goes normally up to 15 or 16 volts to be able to charge the battery, so any electronic device that is not properly protected against such high voltage will simply be killed sooner or later by the over voltage damage. Before connecting any radio or electronic equipment to a car, truck, airplane or boat electric system run a very exhaustive check of the system while it is operating and be sure that your equipment is capable of handling the highest voltages that are generated by the particular system. My practical solution to this problem for the typical 12 to 14 volts required by amateur radio equipment, is to assemble an interface that provides both reverse polarity and over voltage protection, and install such interface in the car, truck, mobile home, boat or aircraft, so that the radios are always safe from both reverse polarity connection and over voltage accidents !!! And now amigos, as always at the end of the program, here is Arnie Coro’s HF plus low band VHF propagation update and forecast… Solar flux is moving at extremely low levels, the sunspot count on Tuesday was ZERO, and the solar flux barely reaching 68 units, the Sun is spotless at this moment. I expect that this very low solar activity will continue right trough the present solar rotation. Sporadic E events are still probable during the next 10 days, so be on the lookout for this unique propagation mode that sends the maximum useable frequency curve shooting up even as high as 150 megahertz at times !!! See you all at the weekend edition of Dxers Unlimited amigos !!!And don’t forget to send your signal reports and comments about the program to [EMAIL PROTECTED] <mailto:[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. 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