RADIO HABANA CUBA
DXERS UNLIMITED
WEEKEND EDITION
SATURDAY, MAY 5, 2001
By Arnie Coro CO2KKSend your comments, questions and ideas to: arnie@radiohc.org
Hi, amigos! Welcome to the weekend edition of this, your favorite radio hobby show via shortwave and online at Dxers Unlimited's website.
I am Arnie Coro, your friend here in Havana and host of this twice-weekly unique program spanning all of the more than 50 ways you and I may have a nice time with our radios!!!
Here is item one: Just one big sunspot group... region 9445... but many other smaller sunspots to see on the solar disk... total number of sunspots Saturday actually went up to 186, something that scientists were certainly not expecting. Actual microwave solar flux on the 10.7 centimeter band, the parameter now accepted as the best possible indicator of solar activity, was at barely below 180 units Satuday morning, BUT, BEWARE -- due to a combination of many odd elements, propagation conditions on the higher HF bands, from 20 to 30 megaHertz was not good at all, according to my observations that started at around 1000 hours UTC and continued until 1600 hours UTC...
Item two: Oscar 40, the AO40 satellite, should be undergoing a full transponders test during this weekend... unfortunately the testing will be well out of reach for I would say 99 percent of the world's amateur radio population, as the bands that will be made available are ones that do require very special equipment and antenna systems. Few amateurs around the world have single side band receiving equipment that is capable of operating on the 2 gigaHertz or two thousand megaHertz ham radio assignments! Anyway, it's good news to see that the satellite is making at least a partial recovery from the terrible mishap that it went through!!!
Item three: ETA AQUARIDS meteor shower in progress as you are hearing this show... and there are very good chances that sporadic E propagation will show up during the whole weekend....
Stay tuned for more radio hobby related information, coming to you from Havana...Margarita Delgado is my sound engineer and producer, and as always Chief Transmitter engineer Dictinio Diaz is overlooking our 100 kilowatts rigs... I am Arnie Coro in Havana, back with you in a few seconds...
You are listening to Radio Havana Cuba, 40 years on the air at your service, amigos!!! The name of the show is Dxers Unlimited, and our e-mail address is arnie@radiohc.org.
And here is item four: More and more Dxers Unlimited's listeners are telling me in their letters and e-mail messages that they cannot install external antennas due to restrictions imposed by building codes, condominium governing boards, city ordinances etc... That's why attic antennas are becoming more and more popular, and let me tell you something... attic antennas, when properly designed, built and installed do provide radio fans with real-life possibilities of enjoying the hobby...
For example, in a wooden frame house with a large attic, several ham radio and short wave listening antennas can live happily together... you can install VHF and UHF bands antennas, a magnetic loop which can be tuned via a remote control system, and if there is enough space, even a compact 2 element Yagi can be installed. You can even go a step further and design a bi-directional beam, that by simple switching can reverse the direction of maximum gain.
Saturday morning I had a nice QSO with an American amateur radio operator in Illinois, and he was using a two-element attic-installed beam... we had a nice contact on a not-too-good 15 meter band, and he even provided me with a very interesting test by switching from a vertical antenna to the two-element attic-mounted beam. As expected, the beam's gain could be seen on the S meter, and he told me that my signal was a full two S units better on the beam... Later I had another very nice contact, which I will be telling you about later in today's weekend edition of Dxers Unlimited.... Now, let's move fast to page three....
And here we are at Arnie Coro's workshop... Join me now for a few comments about my pet project nowadays: the Solid State Regenerodyne Receiver, a modular short wave receiver that is easy to build, has a lot of gain, is very sensitive, and although it is no match for a one thousand dollar oriental black box transceiver, it does provide excellent reception. This week I added yet another band, and a tuneable input bandpass filter that has two sections -- that, is two tuned circuits which are coupled via a small capacitor. The new band allows me to listen to stations operating between 20 and 22 megaHertz, something that has brought in both the 15 meters amateur band, and the 13 meters international short wave broadcast band.
As those of you who listen regularly to Dxers Unlimited already know, the REGENERODYNE receiver's detector is a tuneable regenerative detector stage that tunes from 2 to 4 megaHertz, so in order to be able to install the new 20 to 22 megaHertz band, I had to look around for a quartz crystal that would oscillate on 18 megaHertz, something that was achieved by making a 6000 kiloHertz crystal oscillate on its third overtone, as I could not find an 18 megaHertz overtone crystal locally. But let me tell you that the 6 megaHertz crystal works very well indeed, providing more than enough injection to the four-diode double-balanced broadband mixer that I am using on this prototype's front end.
And for those of you not yet familiar with this unconventional approach to receiver design, let me say that the REGENERODYNE is a simple receiver that uses a tuneable regenerative detector spanning a one, two, three or four megaHertz segment of the lower HF spectrum, to which you connect a simple crystal controlled converter. By changing the quartz crystals on the local injection oscillator you are able to tune to different bands. The final version of the solid state regenerodyne will cover from 6 to 51 megaHertz in a very ambitious project. But you can build a much simpler version and enjoy listening to a homebrew radio that is both easy to build, sensitive, selective and at the same time has that unique flavor of the regenerative detectors -- which, by the way, are able to tune in AM, CW, Single Side Band and even Narrow Band FM signals!
As soon as the project is completed, you will be able to download the complete step by step building instructions, diagrams and text files, so that you can build your own REGENERODYNE short wave receiver, in both a NOSTALGIA vacuum tube version, and in a very up-to-date SOLID STATE electronics version, too!!! If you want to know more about this very interesting circuit, I can provide you with several circuit diagrams of REGENERODYNE receivers for both HF and VHF coverage, just e-mail your request to arnie@radiohc.org send an air mail postcard to Arnie Coro, Radio Havana Cuba, Havana, Cuba.
This is DXers Unlimited, your favorite radio hobby show with the most up-to-date HF plus 6 meter band propagation updates and forecasts, no long lists of stations that you can never pick up at your QTH, and delivered at a speed that makes it easy to understand....
Now Item six: An anecdote about yet another nice amateur radio QSO, this time with an old timer... His name is Milton, he lives near Chicago, and due to illness has to spend a lot time resting in bed, as he told me... But Milton has his ham radio equipment right next to his bed, and I could hear how important ham radio was for him. Yes amigos, amateur radio is a wonderful hobby indeed, and it has helped thousands of persons go through periods of hardships with their health. That's why I always promote amateur radio among people who have some kind of limitation on getting around, for example. My latest student, Remberto Echemendia needs to use two crutches to move around, but you know -- he is walking four, almost five, blocks to come to the Youth Computer and Electronics Club of my Nuevo Vedado neighborhood to learn enough radio and electronics so that he can obtain his amateur radio license -- something I am sure he will do before the end of the year... And yes, you guessed right, the 02 prototype of the REGENERODYNE receiver, for which I already have almost all the parts at hand, will be built by this young enthusiastic Cuban radio hobbyist who, like my friend Milton in Chicago, will find in amateur radio a very nice place to spend his spare time.
Now item seven: Be on the lookout for TV DX signals on the low frequency channels, it's going to be a lot of fun during the next 16 weeks or so, as the summer northern hemisphere sporadic E season develops.... For ham radio operators the sporadic E clouds provide amazing short skip contacts on the 20, 17,15 and 10 meter bands, and much longer range QSO's on the 6 meters or 50 megaHertz band... Sporadic E also provides FM broadcast band DXers with lots of new stations to add to their logs, too.
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: Solar activity is slowly moving down, but there are a few signs that tell us that perhaps we will have a rather slow glide down until we reach the bottom of this solar rotation sometime around the middle of the month of May. Solar flux was near 180 units Saturday morning here in Havana, at around 15 hours UTC, and let me tell you that there is a very visible coronal hole that may disrupt radio communications on the HF bands during the next two or three days... Expect possible high latitude geomagnetic disturbances to start soon. The ETA AQUARIDS meteor shower will provide a higher-than-usual hourly meteor count, making possible TV DX signals on channels 2 to 4 to appear briefly, especially during the very early morning hours...
I will be monitoring 6 meters, on 50.125 kiloHertz for possible sporadic E openings, and during the time frame from 0100 to 0500 UTC I'll be looking for DX on the 20 meter band, tuning and calling CQ from 14.175 to 14.200 kiloHertz... see you there, amigos!!!
Arnie Coro CO2KK
Havana, Cuba
May 5, 2001Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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