Radio Habana Cuba: Dxers Unlimited weekend edition for December 2, 2000
By Arnie Coro, radio amateur CO2KK
Hi amigos, welcome to the weekend edition of Dxers Unlimited reaching you under excellent short wave propagation conditions indeed... Solar flux is a nice and healthy 185 units, the Saturday morning UTC sunspot count was 157 and not any one of the SIX active sunspot regions is showing signs of complex magnetic configuration that may lead to BIG FLARES... And by the way, solar active region 9236 has now rotated to the side of the Sun that we can't see from Earth!!! Dx conditions on the higher bands during the daytime hours are excellent, so enjoy your weekend more by listening to your radio a lot, and if you are already an amateur radio operator, these next three days are ideal for adding some nice DX stations to your log.
Item two: Questions, questions and more questions keep coming in via e-mail and Air Mail... it is nice to see how many of you have just "discovered" or "rediscovered" the radio hobby during the peak period of solar cycle 23.... Among the most frequently asked questions are:, how to add a simple antenna to your radio, what type of earphones are better for picking up DX, is it true or not that running radios from batteries will bring in less noise than when they are operated from an A/C adapter, and many others.
Today in the YOU HAVE QUESTIONS... and Arnie answers section of Dxers Unlimited I'll answer several of the more popular radio hobby questions recently asked by beginners ...
Item three; homebrewing of simple radio equipment is yet another of the more than 50 ways you and I can enjoy this hobby; today I will tell you about another regenerative radio receiver circuit that uses a cascode detector, an unusual circuit to say the least, but first tests show it works very well. Only two dual vacuum tubes give you an excellent receiver with a enough audio output to fill a conference room!!!
All this and maybe a little more if I can negotiate an extra minute or two of air time with our anchor Isabel Garcia... Now stay tuned right on this frequency; after a brief musical interval that Margarita now has ready, Dxers Unlimited's weekend edition will continue...
Amigos, you are listening to Radio Havana Cuba. The name of the show is Dxers Unlimited; this is our radio hobby program coming to you twice weekly with the most up to date short wave plus 50 megaHertz band propagation forecasts... I am Arnie Coro, radio amateur CO2K. Now listen carefully to the answer to one of the more frequently asked questions reaching me here via e-mail and Air Mail... The question: Arnie, is it true or not that short wave reception improves when one uses battery power for the receiver?
Well my friends, I must say that in many cases this is absolutely true, especially when you are using small portable receivers that are connected to the power lines via a so-called wallplug or wall wart power supply. I have tested no less than fifty, yes, fifty, and maybe more of those wall plug power supplies that turn the AC power line into Direct Current a low voltage to power your radio receiver... and let me tell you that I have yet to find ONE, yes, I have yet to find ONE that was properly designed and built. SO, one very practical and not too expensive approach is to buy yourself two sets of nickel cadmium rechargeable batteries and a battery charger, and forget about the wall wart power supply... Having two sets of nickel cadmium batteries you can have one running the radio while the other is charging.... OR, you can homebrew a properly designed and built AC power supply ... a well-filtered, well-regulated supply that will be capable of supplying your radio receiver with clean power. You can even attempt to modify one of the existing wall plug or wall wart power supplies by adding an integrated circuit voltage regulator, a few capacitors and other parts, but this will require not only opening the unit-- a somewhat difficult task in some cases-- but also finding one that has enough space inside for you to be able to add the extra components.
SO, HERE IS ARNIE CORO's advice: Find a good regulated power supply design in one of the popular amateur radio handbooks, collect the parts and build your well-filtered, well-regulated low voltage DC supply.... A few years ago I designed the KK-12 12-volts DC well-filtered and regulated power supply, that could be adjusted to operate from 4.5 volts all the way up to 12 volts, and with a current rating that made of it a very handy addition to my workbench too. In other words I use the KK-12 to power any equipment that requires from 4.5 volts all the way up to 12 volts at a current of up to 1 ampere. So the little KK-12 also makes a nice battery eliminator for my 2 meter band handie-talkie!!!
If you want to know more about the KK-12 simple, easy to build power supply, just drop me an e-mail to arnie@radiohc.org, or send an AIR MAIL post card to Arnie Coro, Radio Havana Cuba, Havana Cuba... I will send you a complete description of this little and very practical power supply that you can build at home with a few hand tools and a soldering iron. In fact, it works so well that I have built three of them: one to replace the original external power source of my bedside tabletop digital receiver, a Grundig Satellite 700; another one powers my Yaesu FT411 handie talkie, and the original version never moves from my workbench, where it has helped to repair I can't recall how many radios in the past five years!!!! Si amigos, my friends, mes amis, the KK-12 variable voltage DC power supply is a worthwhile addition to your shack.... send for the information on how to build it yourself to arnie@radiohc.org, or send an AIR MAIL postcard to Arnie Coro, Radio Havana Cuba, Havana, Cuba.
Attention Six Meter band enthusiasts....more 50 megaHertz band openings expected during the next two to three days... If you are a ham radio operator and have a six meter band capable radio and no antenna, this is the moment to install a simple ASD or Assymetric Dipole Antenna for the Six Meter Band. It won't take a lot of space, is easy to adjust and you can set it up in a couple of hours using an existing mast or tower. The ASD for six meters is fed using 50 ohm coaxial cable... and YES, I do have a very nice illustration of the ASD that I can send as an attachment to e-mail, or as a print out via AIR MAIL. The ASD or Assymetric Sloping Dipole is your fast track way to begin enjoying the 6 meter band openings that are now in progress due to the enhanced solar activity. Send your request for the ASD file to arnie@radiohc.org, and for a printed version of the illustrations send a post card VIA AIR MAIL to Arnie Coro, Radio Havana Cuba,Havana, Cuba.
Just to give you an idea... I have worked no less than one hundred six meter band stations in the past two weeks using my ASD wire antennas. YES, I have three of them installed now... one pointing to Europe, another one to cover South America, and a third one beaming to the center of North America; a three-position homebrew switching system allows me to select any of the three antennas really fast. Among the stations worked with the Six Meter Band Asymmetric Sloping Dipoles are operators in Spain, Africa, South America, Central America, the United States and Canada, and I have received some excellent reports.
The reason why the ASD works so well for F2 layer propagation is that it has a very low take off angle... something that is difficult to achieve with other antennas if you don't install them using high towers or masts. My ASD's are all supported by the same 10 meter or about 33 feet high mast!!! So, again, if you happen to own one of those nice new amateur radio transceivers that include the 6 meter band and don't have an antenna to work the MAGIC BAND, jump onto the bandwagon and join us in the best six meter DX season of the last 9 years!!!
This is the weekend edition of Dxers Unlimited amigos... and here is item three, a rather unusual regenerative detector circuit that works very well, is also easy to build, and provides room-filling volume. The two vacuum tubes, a 12AT7 or better yet, a 6BK7 cascode regenerative detector, and an 6AW8 or ECL84 audio pre-amplifier and power output stage, are powered using two readily available 115 volts AC to 6.3 volts transformers connected back-to-back to provide both line isolation and the 6.3 volts for the tube's filaments. The cascode regenerative detector is a rather unusual approach, but let me tell you that experiments I have made so far show that it has an excellent sensitivity and a very smooth regeneration control. This is one of the simplest vacuum tube receivers that you can build, and you will be amazed by its performance. I am going to draw the schematic of the final version this weekend and make it available on our Dxers Unlimited website for you to download....
And now amigos, as always at the end of the show, here is Arnie Coro's Dxers Unlimited's HF plus 6 meters propagation update and forecast, free of charge -- you may reproduce it in your club's bulletin, post it at your website, etc., but please do mention the source.
Solar activity is now going down slowly, there are no less than SIX sunspot groups, but not one of them has the complex magnetic activity required to produce big solar flares. The actual number of sunspots has followed this pattern: six days ago it took a dip at 95, then the sunspot count showed 121, 154, 160, 191 on Friday and 157 on Saturday. And sure enough, this has kept the higher HF bands from 21 megaHertz up pretty active, and DX on 6 meters is been worked by stations in Europe, North, Central and South America on an everyday basis for the past 10 days!!! Here in the Caribbean we have had some nice openings on 6, too. Expect a rather quiet geomagnetic field for the next three days, something that will combine with the above 170 solar flux units to provide EXCELLENT nighttime short wave reception all the way from 5 megaHertz up to 18 megaHertz...
See you on the amateur bands, amigos... When at home I monitor 28.885 on 10 meters for indications of 6 meter DX, and when some spare time is available you will hear me on 28.5 megaHertz enjoying the excellent propagation conditions. Don't forget to send me an e-mail report to arnie@radiohc.org. Your comments about the show, questions and ideas on how to improve Dxers Unlimited are most appreciated, so keep them coming!!!
Arnie Coro CO2KK
Havana, Cuba
December 2, 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