Radio Habana Cuba: Dxers Unlimited weekend edition for February 24, 2001
By Arnie Coro, radio amateur CO2KK
Hi amigos! Welcome to the weekend edition of Dxers Unlimited.... and this is yet another ham radio contest weekend, too... one of the most popular 160 meter contests is now in progress; yes, right now amateur radio operators are competing for the awards using the only MEDIUM FREQUENCY ham band 160 meters which spans from 1.800 to 2000 kHz in many countries, while others have just very limited slots available for amateur radio use...
More about Cuban radio amateurs and the ongoing 160 meter band contest later in today's edition of your favorite radio hobby program on shortwave...
Headline number two: Solar rotation passed through its peak, and it was a really dissapointing one indeed, yet another possible indication that solar cycle 23 is now starting its downward trend...
Headline three: Yet another fascinating REGENERODYNE, this time using a super-regenerative detector at an IF frequency of 12 megaHertz, this is a VHF receiver, an unusual one indeed. Stay tuned for more information about this interesting receiver, now standby for a few seconds.
Margarita Delgado is my sound engineer and producer, I am Arnie Coro in Havana, back with after a brief musical interval...
You are listening to the weekend edition of Dxers Unlimited... and here is QSL on the AIR, to long-time listener Norman Hill from Virginia, thank you very much, Norman, for the nice clippings of recent magazine articles devoted to the revival of old equipment, one of the many fascinating aspects of our radio hobby. QSL on the air to VE6XTC, Bruce in Canada, who is always bringing forward ideas on how to improve this show. By the way, Bruce, your article about the Light Emitting Diode replacement lamps brought a lot of feedback from listeners, and several of them have already wired up several LEDs to experiment with this unique light source that is both an energy saver and absolutely quiet from a radio noise point of view. QSL on the air to the many Dxers Unlimited's listeners around the world who have sent e-mail reports to arnie@radiohc.org or AIR MAIL letters or postcards to Arnie Coro, Radio Havana Cuba, Havana, Cuba... to all of you, a big THANK YOU AMIGOS!!! It is certainly very encouraging to get such fantastic feedback from the show's audience....
Now here is item three in detail: YES, you can start building your own radios... there are several nice kits, with rather low parts counts and easy to follow instructions... NO, NO, NO, they won't compete with an expensive receiver, of course, but those kits do have the tremendous advantage of familiarizing YOU with electronic components, circuit diagrams, soldering and many other important aspects of home brewing, with the added advantage that a KIT will almost always look nicer than a completely homebrewed radio if you are not a mechanical genius! Anyway, kit building is a lot of FUN, and nowadays there are several kits that are, for the first time ever, competitive with even the most sophisticated ham radio transceivers, although they are definetely not beginners' projects!
Now, let me tell you more about the most recent addition to the REGENERODYNE family of homebrew receivers... This one is a real beauty, and so far all the tests show that it is really sensitive, although it is not as selective as one would like for the lower frequencies. This receiver uses a radio frequency amplifier stage, a simple triode mixer and also a simple triode local oscillator... this front end changes the input frequencies to 12 megaHertz, the frequency to which the super-regenerative detector is fixed/tuned to. So, you actually tune the receiver by changing the capacitance of the local oscillator tuned circuit, and your high gain detector stage is working all the time at an optimized frequency. Of course it has a regeneration control, so that you can optimize the detector's operating parameters.
Well, just for your information, I am now using this new REGENERODYNE to monitor the frequency range from 30 to 70 megaHertz, and it is doing a fine job, as I am able to pick up a lot of signals that show me when sporadic E skip is present. No, unfortunately, calibration is not all that good with the very simple dial arrangement I am using here... BUT, this receiver is definitely a nice little rush box, as super-regenerative detectors used to be called by the old timers, due to the characteristic rushing sound of their audio output.
Want to know more about this receiver? I have a complete schematic diagram available... just drop mean e-mail to arnie@radiohc.org and I will send you the schematic diagram plus some notes about this interesting receiver, the VHF Regenerodyne!
And now it's time for Dxers Unlimited's ever-popular ANTENNAS section. Today I will answer a question sent by a listener from Ireland who wants to know more about the DELTA LOOP antennas. Well, amigo, DELTA LOOPS are easy to homebrew, they don't cost a lot of money and when properly installed, they make an excellent antenna for DXing. One variation of the DELTA LOOP is the TWIN DELTAS, which can produce as much gain as a two-element Yagi and even a bit more, with the added advantage of greater bandwidth and a lower take-off angle. TWIN DELTAS also have a very special advantage: they match 50 ohm coaxial lines without the need of any special matching circuits. You only need to include a coaxial choke balun between the TWIN DELTA'S feedpoint and the downlead, something that will decouple the so-called antenna currents from the outer side of the braid or shield of the coaxial cable. I recently tested a TWIN DELTA for the 10 meter band, and was pleasently surprised with the results... the antenna did not require absolutely any adjustments, and DX signals were much louder than on a reference half wave dipole at the same height. Although I did not measure the actual antenna gain, it was clear that the TWIN DELTAS were doing a great job. Now, I must rearrange the masts and towers at CO2KK so that the 10 meter band TWIN DELTAS can be permanently installed... They certainly won the space for themselves!
You are listening to the weekend edition of Dxers Unlimited, and yes we do QSL here one hundred percent. Send your signal reports, comments about the show and ideas on how to improve this program via AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba, or via e-mail to arnie@radiohc.org.
Now more about the 160 meter band contest now in progress... You can pick up the contest stations by tuning very slowly from about 1810 kiloHertz, all the way up to 1950 kiloHertz, where most of the contest activity concentrates. Use your receiver's BFO, or beat frequency oscillator, and tune very slowly to pick up the SSB, single side band, voice signals. You may perhaps be able to pick up several of the Cuban stations that are participating in the contest -- among them T48RAC, a joint operation by Cuban and Canadian radio amateurs that is operating from Santiago de Cuba province in eastern Cuba. Picking up 160 meter band signals is something very similar to Dxing on the AM broadcast band, as 160 meters is just starting 100 kiloHertz higher in frequency from the top end of the new AM X band expansion that ends at 1710 kiloHertz!
And now, as always at the end of the show, here is Arnie Coro's Dxers Unlimited's exclusive and not copyrighted HF plus six meters propagation update and forecast! Let's start with this news item for 6 meter band operators: Reports from Paraguay tell us that signals from the Caribbean, Mexico and the Southern United States are heard and worked on a daily basis now in Paraguay... and the same is happening with stations in Argentina and Uruguay. This is just a good start for the equinoctial TEP, or Trans Equatorial Propagation, six and two meters DX season.
Solar flux is hovering around 145 -- quite stable, but moving slowly down during the next few days if no new active sunspot region starts generating new activity. Actual sunspot count for Saturday UTC day was 135, and the Smoothed Sunspot Number Saturday was 100 -- yet another good indicator of the solar cycle's apparent downward swing.
For short wave listeners, best nighttime reception is still in the range from 6 to 12 megaHertz, while daytime reception is now best between 13 and 22 megaHertz. Amateur radio operators will still enjoy daytime 10 meter band openings, and when 10 is closing, switch to 15 meters to ride the frequency of optimum traffic curve... I am now testing the Radio Teletype mode at CO2KK, and will spend some time during the weekend working RITTY on the 20 meter band... so if your ham station is capable of operating on RTTY, look for CO2KK between 14080 and 14095 kiloHertz. As always, it is really nice to have a QSO with Dxers Unlimited's listeners worldwide! And don't forget to send your signal reports and comments to arnie@radiohc.org ... they sure help make this show a better one for YOU, amigo!
prepared Feb-24-2001; transmitted Feb-26-2001 15:41 EST
Arnie Coro CO2KK
Havana, Cuba
February 24, 2001Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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