Radio Havana Cuba
Dxers Unlimited's weekend edition for Sunday 16 August
and Monday 17 August 2015 UTC days
By Arnie Coro
radio amateur CO2KK

Hi amigos radioaficionados now listening to the weekend edition of Dxers Unlimited . I am your host Arnie Coro, radio amateur CO2KK and here is item one of today's show: Short wave listeners and radio amateurs worldwide are now becoming more and more aware of what the extended period of extremely low solar activity ahead will change our hobby.

Solar scientists equipped with never before available research instruments, and pooling their know how by means of extensive and
intensive interpersonal communications, are now telling us that the Sun is going into a prolonged period of extremely low activity.

Solar cycle 24 continues to prove how accurate some of the forecasts about its peak activity have been. The monthly average sunspot number for the month of July 2013 was just 57.... and the peak months of 2014 proved that scientists forecasts were right…. This was the weakest cycle on record since mankind discovered how to use the radio waves .

As I have told you here recently as we approach the autumn equinox, HF propagations conditions will improve worldwide for a few weeks, giving us radio hobby enthusiasts what will for sure be the last opportunity of enjoying frequent n band openings on frequencies between 20 and 30 megaHertz...and this year they wont last long

So, here is my advice to all of you involved in contacting as many amateur radio stations as possible to achieve the DX Century Club or DXCC award...mprove your present antennas or install new ones and get ready to make the best possible of the upcoming small surge in short wave propagation conditions due to begin in about two weeks from now.

Now here is item two of Dxers Unlimited's weekend edition... several very nice reports received from California, northern Mexico, Oregon and Washington state as well as from British Columbia in Canada, all the reports receive coincide in that reception on 6000 and 6100 kiloHertz frequencies from 05 to 07 hours is excellent.

By the way, let me insist on this fact ALL , each and every frequency used by Radio Havana Cuba is registered at the International
Telecommunications Union using the required registration form that contains all the data about the time schedule and station's technical parameters.

The ITU issues several compact discs to member nations with the provisional and final schedules of the stations registered , that are sent to each member nation telecommunications authority.

All reports related to the 6000 and 6100 kiloHertz Radio Havana Cuba service on from 05 to 07 UTC will be most appreciated by our chief engineer.

Send the reports to inforhc@enet.cu, and it would be nice if you include in your reports how do you pick up other RHC frequencies too.

A short break for a station ID is coming up in a few seconds. I am Arnie Coro, CO2KK, your host here at Dxers Unlimited's weekend edition...

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Here is now our technical topics section of the show, coming up at the request of several listeners that are experimenting with home built short wave receivers, one of the more than 90 ways that you and I enjoy this wonderful hobby....

My personal preference for regenerative radios comes from the fascinating fact of their outstanding performance when well
built and the extreme simplicity of the circuit. A single vacuum tube or a field effect transistor, a battery power supply and a few parts when properly assembled into a regenerative receiver circuit will provide amazing results

Nowadays one has the option to home brew a classic vacuum tubes regenerative, one built using bipolar transistors , or a radio built
using field effect transistors.

Of the mentioned three options I am an all time regenerative vacuum tubes receiver enthusiast... As a matter fact, after testing many different solid state regenerative sets, my thumbs up signal goes to the more sophisticated and complexvacuum tubes designs, especially the non plus ultra of them all , the ZL2JJ design , that I have modified to use more modern vacuum tubes types than the 1930's and 40's types used by the original set.

Regenerative receivers do require a very solid mechanical construction if you really want to achieve top notch performance.

Time spent assembling a very rugged chassis, proper placement of the components and careful assembly of the electronic circuits are the difference between a mediocre set and one that shows really high performance. This is how the Zl2JJ receiver was designed and built ….

More modern designs using the cascode circuit that were experimented by Dutch radio amateurs and later published by the British Radio
Communications magazine, when properly built achieve amazing sensitivity and razor sharp selectivity. Cuban radio amateur CO3BN , Bernardo from Artemisa province of western Cuba recently reported to me that his home brew cascode receiver performance was simply amazing… providing both excellent selectivity and frequency stability as well as a very easy going bandspread tuning .

It is important to keep the power supply of the regenerative radios built on a separate chassis, and connect it to the radio using a well shielded multi conductors cable. Some builders prefer to run the radios using a 6 or 12 volts accumulator for the filaments and a set of series connected batteries for the B plus line. But this may prove to be really expensive, especially when time comes to replace the high voltage battery.

My classic simplified regenerative vacuum tubes radio is fed by a solid state power supply that provides 6.3 volts regulated direct voltage for the filaments and between 50 to 75 volts also regulated for the high voltage.

In a recent e-mail that I received from listener Norbert from Genoa, Italy, he asked why he could not find a single factory made vacuum
tubes regenerative receiver , after searching several radio hobby magazines.

Well amigo Norbert, regenerative receiver circuits, built using vacuum tubes or solid state devices , do not lend themselves to mass
production. Each radio is a one of its kind, according to what practical experience building them shows quite clearly.

But that is precisely what makes regenerative detectors so fascinating... Even the simplest on single active device radio, be it a vacuum tube or a solid state component, does require some experimenting before the best possible results can be achieved, and that amigo Luigi is where the fun of it comes out!!!
 

I do have three or four very well designed and proven in practice regenerative receivers that cover from the very low frequency bands up to around thirty megaHertz, and they are all available by just sending an e-mail to inforhc@enet.cu.

And now just before going QRT here, our exclusive and not copyrighted, in the public domain , free to distribute by any available means, Arnie Coro's Dxers Unlimited HF propagation update and forecast...

Now the summer sporadic E season is simply over, my experience of many years show that after August 15 the number of sporadic E DX event goes down a lot...

Solar flux is hovering around 100 units and that should provide DX conditions during your local night hours on frequencies up to 12
megaHertz or so.

Maybe you can also, enjoy the DX on both the 20 meters amateur band and the 19 meters international short wave broadcast band during the best days ... See you all at the middle of the week program next Tuesday and Wednesday UTC days...