Monday, August 20, 2018

Dxers Unlimited – weekend edition, August 19, 2018

Special thanks to Arnie Coro, for sharing his program script with our blog followers


 Hola amigos radioaficionados, I am Arnie Coro, radio amateur CO2KK bringing to you the week-end edition of Dxers Unlimited, and here is our first news item:

The International Lighthouse and Lightships Weekend took place on August 18-19, and several Cuban amateur radio clubs stations participated using the special prefix T4.

For your information the International Lighthouse and Lightships Weekend, is one of the largest yearly operating events in the amateur radio calendar, with more than 400 lighthouse/lightship activations in 40 countries, and tens of thousands of amateur stations wanting to work them.

By the way...this year is the 25th anniversary of the event from which it all began. The very first Northern Lighthouse Weekend was organized in 1993 by the Ayr Amateur Radio Group with activity from just 10 lighthouses in Scotland and the Isle of Man. But something about 'the romance of lighthouses' found a resonance with radio amateurs; the idea quickly spread world-wide and grew into the remarkable event we know it today.

The solar activity is at very low levels... although a single solitary small sunspot broke the sequence of days without sunspots. Experts explained to me that the small active region is not expected to produce powerful solar flares and is expected to fade out soon.

The present summer season of the northern hemisphere has brought a rather normal sporadic E layer activity, with several good days when transatlantic contacts were possible on the 6 meters band.

More information about HF propagation conditions at the end of the show when you will receive the latest Arnie Coro's HF plus low band VHF propagation update.

Answering another question from Dxers Unlimited listeners, they all want to learn more about Trans Equatorial Propagation, also known by its acronym TEP. Amigos TEP is a propagation mode that sometimes even makes possible, two meters band contacts between Caribbean stations and Brazil, Argentina, Chile, Bolivia, Uruguay and Paraguay, while using low power stations.

Well, I must say that the TEP, the Trans Equatorial Propagation opening here in Cuba are not as good as those enjoyed by my amateur radio friends located in Trinidad and Tobago, Saint Lucia and Barbados and Puerto Rico.

Here three band openings start usually are around 20 hours UTC and the peak months are March and September, coinciding with the spring and autumn equinoctal periods and are at a minimum during the summer solstice. I usually monitor six meters on the international DX window frequency of 50.110 kHz, where experienced operators call CQ DX using single side band voice.

Sometimes you can even tell from where the signals are coming, before even picking up a callsign, by paying attention to that very peculiar way of speaking Spanish that is typical of the Argentineans and Uruguayans or the Portuguese language spoken by the Brazilian radio amateurs.

Once again for your information the TEP can link up with Sporadic E propagation and place signals from the far end of South America into the United States and Mexico, and sometimes even as far as Canada.

If you are an amateur radio operator you can make very nice two-way contacts while running low power and a very simple two to three elements Yagi or cubical quad antennas, that can be easily built at home and without expending a lot of money as readily available materials are used.

Again, for those of you radio amateurs that live in the Southern United States and in southern Mexico, and Central America, September will very probably bring in many Trans Equatorial Propagation events that will open up the 10 and six-meter bands during your local afternoon and early evening hours, although I have made contacts with Chile and Argentina on
six meters past midnight my local time here in Havana.

This is the weekend edition of your favorite listener oriented and technically minded radio hobby program, with yours truly Arnie Coro radio amateur CO2KK as your host.

Here is now our next topic... more information about simple end-fed antennas now in use here by several Cuban radio amateurs that operate on the shortwave ham bands from 40 to 10 meters. Operators are achieving good results with a very simple wire antenna that has the advantage over a dipole that it is fed at one end using a balanced to unbalanced broadband transformer.

There are ongoing discussions about the impedance transformation ratio required for this end-fed antenna, and all I can say that my tests using  a second such antenna 25 meters long installed horizontally show that using a standard factory built four to one balun and 50 or 75 coaxial cable makes possible to operate on the 40, 30, 20, 17, 15, 12 and 10 meter bands using my wide range PI network antenna tuner.

The length of the coaxial cable downlead is at my station is less than 15 meters losses due to high standing wave ratio are minimal. The antenna behaves as an omnidirectional system on 40, 30 and 20 meters, but starts to show up some directivity above the 20 meters band...

Si amigos, my friends, oui mes amis, this is the weekend edition of Dxers Unlimited, now ASK ARNIE the second most popular section of this show.

Today answering a question sent by listener Herman from Bogota, Colombia who monitors Radio Havana Cuba via our Internet streaming audio, and via shortwave on 11840 kHz. Herman lives outside the city in a residential neighborhood, so he can install a wire antenna from a 10 meters mast on his roof going to another similar mast at the end of the backyard. I recently told him to try a center fed group of dipoles, cut for the 40, 20 and 15-meter bands, that can also be tuned to 17, 12 and 10 meters with the aid of his antenna tuner. The dipoles are separated from each other by insulators that are 15 centimeters long, made from the dielectric that is used by RG213 coaxial cable, by removing the center conductor using heat from the soldering iron.

Ys, radio amateurs from many different countries that are QRP or low power fans can be heard on the air on the 15 meters band frequency of 21.060, using CW Morse Code with their very low power rigs. Plans are now in the work to make a special operating event next October the fourth to celebrate the 57th anniversary of the launching of the first ever artificial satellite, Sputnik One, that had on board the first radio transmitter that went into space and sent radio signals from an orbiting space satellite. 

Several of the radio amateurs involved in the Sputnik One anniversary in recent years will be again celebrating, having already built a small vacuum tubes transmitter that is an exact replica of the rig that went up and sent its signals on two frequencies, 20.005 and 40.005.

The original Sputnik frequency of 20.005 MHz is not assigned to the amateur radio service, it was decided that the replica transmitters will operate on the nearby 15 meters band, on the frequency internationally agreed to be used by low power, or QRP CW amateur radio stations, that is 21.060 MHz. The transmitter designed by the Soviet radio engineers for the first man made satellite, Sputnik One, used very ruggedly built subminiature vacuum tubes.

Poor propagation conditions on the HF bands continue and solar activity is expected to be extremely low during the next several days.

See you all at the middle of the week Dxers Unlimited edition next Tuesday and Wednesday UTC days.

Send your signal reports, comments about this and other programs, and radio hobby related questions to, and via air mail to: Arnie Coro, Radio Havana Cuba, Havana, Cuba.
(Arnie Coro/R Havana)