Radio Havana Cuba
Dxers Unlimited
Dxers Unlimited's weekend edition for 27-28 February 2010
By Arnie Coro
radio amateur CO2KK

Hi amigos radioaficionados around the world now enjoying the sustained upsurge in solar activity that has enhanced propagation conditions since the very early days of 2010...

Yes my friends, it seems like if someone flipped a switch 93 million miles away to start the sunspot generating machine.

Early Friday my local time here in Havana, the maximum useable frequency curve was giving me the chance to hear parts of Europe and Western Africa on the 15 meters amateur band.

Signals were so good that I could pick up several stations using my portable radio's telescopic whip.

Scientists have now the full time availability of the Stereo Pair of solar satellites, that can keep a constant watch of almost all of the solar sphere, with only a small wedge behind the Sun that they can't see yet.

The Stereo satellite observations are confirming that cycle 23 is really picking up, as confirmed by just two days of this year that have gone by without sunspots.

Item two: I have received some very interesting feedback from Dxers Unlimited listeners that are always at the forefront of technology. Some of them have alerted me about new developments in amateur radio technology, while others are more interested in learning about already established transmission technologies and how they are evolving.

Listener Paul , who lives near the shores of Lake Erie tells me that the digital modulation technologies can certainly make possible extremely low power two way amateur contacts , but he adds that those QSO's are never as interesting as when you do it all by yourself, without the help of a sophisticated computer and very well written software.

My personal opinion is that making two way contacts between computers is interesting, but I do agree with amigo Paul, about the unique feelings generated by knowing that a human being like you is at the other end of the QSO.

nd talking about two way human to human radio amateur communications... I must show my admiration for the way that hams are operating on the segment of the 40 meters band between about 7100 and 7125 kiloHertz.

Having monitored many CW contacts there for the past several days, it is really nice to listen how people that are able to receive and transmit Morse Code at much higher speeds, are slowing down their sending, adapting themselves to newcomers that are just going through the first steps of using the CW radiotelegraphy mode.

Just to mention one example... I heard a station calling CQ at around five maybe six words per minute... and he was answered by a radio amateur operator that is a well known CW enthusiast, who is capable of sending at more than 30 words per minute ! .

Well, let me tell you that the veteran CW operator came back to the newcomer with perfectly sent Morse Code at about six words per minute... something that make possible a very nice two way contact. By providing to the new amateur the opportunity to polish up his reception , the oldtimer was making an important contribution to the art of amateur radio.

In general that's the spirit that you also perceive when monitoring the QRP or low power transmissions selected frequencies.

For example, you can pick up nice ongoing QSO's at maybe eight to ten words per minute on 14.060 , the 20 meters band spot where QRP operators gather.

Si amigos, yes my friends, oui mes amis, the art of CW Morse Code transmission and reception is very much alive thanks to amateur radio, and let me add now, that some professional users of the radio frequency spectrum are now reconsidering the decision to totally eliminate CW .

Stay tuned for more radio hobby related information, coming to you from Havana... I am your host Arnie Coro extending this invitation to keep listening to Dxers Unlimited's weekend edition...

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This is Radio Havana Cuba, the name of the show is Dxers Unlimited, and here is our technical topics section, the third most popular one of the program according to the correspondence received here.

Today's topic is , once again , recycling electronic equipment to make possible designing and assembling low cost but with reasonable performance amateur radio equipment.

Among the recent e-mail messages received here , was one who came from listener George, who lives near London, and has now no less than fifteen Computer UPS or Unimterruptible Power Supplies, that were collected from several sources, including his own workplace.

George explains that he has already a nice stock of several power transformers , of which two have already gone to new 13.8 volts DC power supplies , one for his HF rig, and the other one that he gave away to a disabled friend , so that he could get back on the air after his power supply went up in smoke and put him off the air.

George says that he soon found out, after carefully dis-assembling the third UPS, that the GEL-CELL accumulators should be tested throughly before deciding to send them to the recycler. Two of the GELL -CELL , gelified electrolyte 12 volts at 7 amperes accumulators were in an almost like new condition, something he found after recharging them with something he described as an intelligent charger and desulphator.

Each of the first three UPS units that he started to work with, were given to him as totally broken down... and in one case the “breakdown” consisted of corroded battery terminal.
Believe it or not amigos... today's throw away without even attempting to repair electronic equipment sends to the dumpsters around the world a significant number of equipment that could had been fixed in just a few minutes by a trained person.

George has already in mind using the nice case of one of the UPS supplies to house a 300 Watts MOSFET linear amplifier for his QRP transceiver.

He found out that by rewinding the secondary of one of the UPS units, he will be able to home brew the 50 volts power supply required by the linear amplifier, and amigo George adds, that the UPS cabinet is very well built, and even has several holes that he will not need to drill, like the round hole for the on – off switch, and a collection of small holes for light emitting diodes that he will use to indicate when the supply is on, and also in case an overload happens.

George also told me that he was able to test half a dozen NPN power transistors used by one of the three UPS units, finding out that only one had an open base to emitter diode, and he reminded me of the very early days of solid state technology, when we all saved those half bad power transistors to use them as rectifier diodes in future projects...

Finally amigo George said that he has already contacted the chief engineer at a company near to his workplace, who offered to donate to his radio club a large number of broken down printers... From where George is hopeful to be able to recycle not only electronic components but also a large number of hardware items that are always needed when you are homebrewing radios and accessories...

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Si amigos , you are listening to the weekend edition of Dxers Unlimited, and yes, we do QSL, we do verify reception reports... send your QSL requests to inforhc at enet dot cu, and do remember that your comments about the program and radio hobby related questions you may have in mind are much appreciated here.

Our postal mailing address is Arnie Coro, Radio Havana Cuba, Havana, Cuba...

And now here is our next radio hobby related item... A visit to Arnie's workshop, now in the process of a much needed upgrade.

Yes, there is lot of space in the large garage, and I have already installed the first big cabinet that was completely full to capacity in just an hour or so.

You can't imagine how much electronic parts and equipment one accumulates all along the years... Sometimes one may thing about sending some of it to the local electronic equipment recycling plant, but then , you think it over, because there are many valuable components that can be used by newcomers to our hobby.

Take for example a Hallicrafters S40-B receiver that was given to me by the relatives of a local ham that passed away sometime ago.

The radio does need a major overhaul, but it is in pretty good shape, changing all the bypass and electrolytic capacitors, checking the values of resistors that are installed along the high voltage bus, and the AGC line, will probably take several hours of valuable time...

The radio also needs a major cabinet restoration and paint job. It is a vintage single conversion AM broadcast band and short wave radio... nothing out of this world by today's standards... but it will make a young radio amateur very happy because she or he can start picking up the HF amateur bands, especially 160, 80 and 40 meters where the more than half a century old Hallicrafters S40-B will perform nicely, opening up the world of HF communications to someone that for two years has held a beginners ham license that only allows to operate on 160 and 2 meters …

Among the tasks to be assumed for the S40-B restoration project is locating a new set of vacuum tubes for it... something that doesn't look to be all that difficult, as I am pretty well in possession of a nice
collection of new old stock vacuum tubes !!!

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QSL on the air... QSL on the air, to the many Dxers Unlimited listeners that have sent e-mail messages to inforhc at enet dot cu giving thanks for the HF propagation tips offered at the end of the program that have led to them working a lot of DX , especially on the 15 meters band.

At this particular point of solar cycle 24, the 21 megahertz or 15 meters amateur band has proven to be the best spot where to go and work DX, because there ionospheric absorption is very low, and sustained solar flux figures above 80 units allow the band to open up for DX on a daily basis.

No amigos, we are not at the peak of the solar cycle, but things have certainly taken a turn for the better...

Now here is Arnie Coro's Dxers Unlimited's HF plus low band VHF propagation update and forecast... Solar flux holding above 80 units, with two active sunspot regions clearly visible, and at least two more ready to come around and show up looking at the Earth.

Expect the best local nighttime conditions at your QTH to offer excellent DX on the 30 and 40 meters amateur bands... while evening short wave listening will have the best results on the 25, 31 and 41 international short wave broadcast bands.

During the local daytime hours, you will be able to work DX on 15 meters and listen to excellent international shortwave broadcast station's signals on the 19, 16 and 13 meters bands.

And please ,don't forget to send me your signal reports and comments about the program, send mail to inforhc at enet dot cu and VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana , Cuba

My apologies to those who listened to the program on the air or picked up the streaming audio via the world wide web from www.radiohc.cu, I have a bad cold, and my voice is in pretty poor shape... Did my best to record the program on the digital equipment, but as expected it doesn't sound good at all... As usual with the treatment for the cold includes lots of fluid, fever reducers and nice chicken broth that Roxana , my wife ( callsign CL2ROX ) makes for me. I hope to be with "better audio" for the mid week edition of the show !!