Wednesday, March 04, 2009

DXers Unlimited midweek ediition March 3-4

Radio Habana Cuba
Dxers Unlimited Dxers Unlimited's midweek edition for 3-4 March 2009
By Arnie Coro CO2HK

Si amigos ! This is the midweek edition of Dxers Unlimited, coming to you as solar activity goes down again after a brief transit of a small sunspot across the solar disc. The Sun is as quiet as you can imagine, with five days in a row of an absolutely spotless solar disk... Nevertheless, listening to the international short wave broadcast bands Tuesday morning here in Havana, showed once again to me what high power and good antennas can do................It is simply amazing and surprising how many short wave stations can be heard even when solar activity is at minimum levels.

The solar flux is hovering very near the baseline figure of 68 units, and as I said a moment ago, the sunspots are simply absent...Last week's solar report says that only one sunspot group (Catania number 96, NOAA AR 1013) was observed during the week. It was reported as a sunspot group by Catania on February 25, and by NOAA on February 25-27. The only noticeable flare it produced was the A3.2 flare peaking at 07:14 UT on February 27. It was accompanied by an EIT wave and dimming event starting at 07:09 UT. The associated CME was weak and narrow, but was possibly associated with an interplanetary shock registered by ACE and SOHO/CELIAS around 05:00 UT on March 3. The NOAA AR 1013 was visible until the end of the week as an Halpha plage.

Item two: The upcoming Atlantiv, Caribbean and Gulf of Mexico hurricane season is due to start on the first day of June and it will last until the last day of November. Radio amateurs are getting ready to deal with what is expected to be yet another lengthy and active tropical hurricane season, enhanced once again by global warming.
e have seen previous hurricane seasons like the 2005 one when all the letters of the Latin alphabet were used , so it was necessary to name storms Alpha and Beta....because the meteorologists simply had no more names available, after more than 26 storms ... Once again amateur radio emergency nets will be available for linking the affected areas to the rest of the world
when professional communications systems fail due to the hurricane force winds and heavy rainfall.

Item three: A listener wrote from Mallorca, in the Balearic Islands of Spain asking for more information about the NVIS , Near Vertical Incidence Skywave antenna systems. He describes his location as far from ideal for short distance HF communications, and wants to install one of these antennas
that will help him to be able to talk via skywave to the other nearby islands of Menorca Ibiza and Fomentera, that form part of the Balearic Islands archipelago...
Item four: Taking care of rechargeable batteries is a very important aspect of emergency preparedness... overcharging lead acid accumulators will ruin them, and will also generate dangerous fumes... So, later in this program, I will tell you more about safe ways to assure that your rechargeable batteries will be ready when the emergency comes !

Now stay tuned right on this frequency , or if you are listening to our Internet streaming audio in English that is on the air from 05 to 07 UTC, keep the connection , as Dxers Unlimited's weekend edition will continue in just a few seconds... I am Arnie Coro, radio amateur CO2KK in Havana...
This is Radio Havana Cuba, the name of the show is Dxers Unlimited, and for those of you that are picking up this program for the first time, let me say that it's on the air twice weekly with the most up to date radio hobby related information, including my special HF plus low band VHF propagation update and forecast, that today will provide ham radio contest operators with a special report ... Several years ago I wrote an article about my first six meter band contact, that happened way back in 1959, the article was published by the UK 6 meters Group website and their excellent specialized 50 megaHertz band magazine... Now today and at the request of several
listeners of Dxers Unlimited, I am pleased to present here thatarticle, that I hope you will enjoy as many of the UK Six Meter Group members did way back in 1998...So here I amnow starting to read the article:
My First Six Metre QSO
By Arnie Coro, CO2KK (at that time CM2DL)
Issue 57, May 1998

It was way back in 1959... November 16th 1959 to be exact. My good friend Pepe, CO2GX, now a silent key, was keeping his 4-400 with 3000 volts on the plate on 50.400 for me to find his carrier on my 6C4-12AX7-6AQ5 regenerative receiver... For those not familiar with those 'valves' or 'tubes' they are the equivalents, more or less, of an EC92, an ECC83, and the audio output I think is an EL??? Well, that's not really important, what matters is that 2GX kept talking and talking, while I frantically tuned the super-regenerative detector looking for him... Finally, after about half an hour, I hear Pepe's voice loud and clear...

My just finished two element beam fed with RG58U was picking up my friend's signal so loud, that I had to turn down the volume control... (Yes I had to tune a band set capacitor with a screwdriver to find him, that was the reason for the delay).
Pepe was on 40 metres also, as we were using that band for liaison, he asked me many times if I had found his 50.400 AM, and sure enough, I finally came back to him with a " te copio Pepe.", "I read you Pepe ..." and his audio, picked up by my receiver, was going back to his QTH via my own 40 metre rig...

Then Pepe said... go ahead and transmit... I am now tuning the band for you. I fired up my little three watt rig on 50.100 ??? and CO2GX answers my call, not on six, but on 40 metres... and once again there was the feedback... as we soon "discovered" that we had an excellent full duplex link... 7 MHz to 50 MHz !

I marked the super-regen dial very carefully at the 50.400 CO2GX frequency, and asked Pepe to change his crystal, something he did by just removing the quartz from the holder... only to find out that his 'crystal control' was partial, as I could still hear him without a crystal in his rig!

Arnie C02KK plugged in a 50.100 rock, and I found him very easily, as my main variable capacitor had but one single movable plate, so my bandspread was quite nice... (finding the right setting for the bandset was, of course, the real problem!). Two minutes later, I told Pepe to turn down the volume on his 40 metre receiver, proceeded to call him on Six and he came back to me on 50.400! Those were the days of crystal control, when stations had to look for others exploring from about 50.000 to 51.500 Megahertz, as that was the range of the crystal frequencies available here in Cuba. It was not surprising to hear a QSO going on between a station on 50.400 and another guy on 51.500.

Yes, that was my first six metre QSO, followed a few hours later by an F2 QSO with a California ham whose call I can't remember... all I recall that he was in Pomona, and that I could copy him very well for a few minutes around eleven o'clock in the morning my local time...

This was ... many years ago... and Six meters continues to fascinate me, like that very first day I remember so well . Well, that was the article that was published in 1998 by the UK Six Meter Group magazine and website...that I hope you have enjoyed... and of course, even during solar minimum years, Six Meters continues to be THE MAGIC BAND, with many different propagation modes available, like Sporadic E, Auroral E ,FAI an acronymn for a mode of propagation that is known as Field Aligned Irregularities, and from time to time, stationary cold fronts provide tropospheric ducting that sometimes open up six meters for long distance groundwave propagation too...

You can learn more about SIX METERS, the magic band, by visiting http://www, again the URL to go to is

Si amigos, your radio hobby related questions are answered fast when you send them to, I send the answer direct to your e-mail, and many of them also go on the air to help others that may have similar questions and can benefit from the answers... today's question came from Mallorca, Spain... ham radio operator and short wave listener Guillermo, EA6XD, wanted to know why I prefered to use a folded dipole driven element for my special NVIS Yagi antenna instead of a regular single wire half wave dipole... The answer to Guillermo's question is that because reflector element is located very close to the driven element, if you use a standardhalf wave dipole, the impedance at the center will go down to between 12 and 15 ohms... ... then if you use a folded dipole, the impedance will move down from 300 ohms to about 50 to 60 ohms, so you will only need a one to one balun to connect your feedline... By moving the folded dipole driven element up and down, you
can find the height above the reflector that gives the minimum standing wave ratio. In many of the antennas that I have built, the SWR can be brought down to less than 1.2 to 1, an almost perfect match for all practical purposes, and if you are a perfectionist, then , simply connect the antenna to your transceiver or transmitter by means of an antenna tuner !!!

And now amigos, just before going QRT, here is our exclusive and not copyrighted , in the public domain, for free distribution to all radio hobby enthusiasts, Arnie Coro's Dxers Unlimited's HF plus low band VHF propagation update and forecast. Solar activity is at extremely low levels... no less than five days in a row without a single sunspot ... zero sunspot count, and the microwave solar flux at 2800 megaHertz is hovering near the minimum baseline activity figureat just 68 units...

Very quiet geomagnetic conditions will prevail, and the maximum usable frequencies will be rather low, with short , but useable time windows when you can certainly work DX with your average power 100 Watts amateur transceivers... For contest operators, the best bands will be 160, 80 and 40 meter bands and they will let you add lots of multipliers, but during your local daylight hours on Sunday, do try 20 meters I expect some openings on that bands until late afternoon local time. And don't forget to set a little time aside to tell me about how many DX entitities you have worked or monitored , and it this propagation forecast helped you !!! Send mail to, or VIA AIR MAIL, send a postcard or letter to Arnie Coro, Radio Havana Cuba, Havana , Cuba
(Arnie Coro)