By Arnie Coro
radio amateur CO2KK
Hola amigos… sure, you are now listening to Dxers Unlimited’s weekend edition… I am your host Arnie Coro, Radio Amateur CO2KK, and here is item one…
one of the amateur radio most important contests took place this weekend, and took place under somewhat better HF bands propagation conditions… Here are some of the stations that participated in the contest as previously announced… of course I am talking about the famous CQ World Wide SSB contest… From the Caribbean SAINT BARTHELEMY, prefix FJ. Thierry, F6CUK was QRV as F6CUK/FJ from October 21 to November 1. Activity will be holiday style on the HF bands using CW and SSB. And included being an entry in the weekend CQ World Wide DX SSB contest. QSL to home call.
From an Atlantic ocean island that belongs to Brazil that goes by the name of FERNANDO DE NORONHA, using callsign PY0F. Members of the Noronha Contest Group operated QRV as PY0F from October 23 to 29. Activity on 160 to 10 meters using SSB and FT8. Certainly a very nice entry in the CQ World Wide DX SSB contest. QSL direct to PY7RP.
Another South American station that was going to be active during the CQ World Wide SSB Contest SURINAME, call prefix PZ. A group of operators were QRV as PZ5K from October 23 to 30. Activity is on the HF bands using CW and RTTY. QSL via G3NKC.
Si amigos, thousands of amateur radio stations from all around the world were very active during the CQ Worldwide SSB Contest… including several well experienced teams of operators from Cuba, that used the T4 , tango four prefix, preserved here for special events stations…
Due to the expected bands conditions my forecast, that was confirmed by monitoring the first 24 hours of the contest showed clearly that activity was concentrated on the 20, 40 and 80 meters bands, with less number of stations heard on 15 and 10 meters. For those stations capable of operating on 160 meters from nice low radio ambient noise locations, where the large size antennas required for that band can be installed the propagation conditions were better than during last year’s contest.
Stations located inside the areas covered by TEP, Trans Equatorial Propagation events, were be able to add many points and multipliers… For example Cuban contests stations scanning 10 meters to pick up signals from Argentina, Uruguay, Paraguay and Chile had good results. Contest operators that use the 10 meters band have learned how to monitor the many automatic beacons operating on the segment from 28 point two to 28 point three megaHertz.
This is Dxers Unlimited’s weekend edition coming to you via short wave transmitters, the Hispasat one D satellite, transponder 79 vertical polarization and our streaming audio feed to the Internet.
Here is now our next radio hobby related topic. The popular ASK ARNIE section of the show is now on the air… Today I will answer a question sent by listener Henry Carol from the Stuttgart, Germany. Henry is listening on a professional Rohde and Schawartz communications receiver he was able to buy at a hamfest and he is asking for advice about what type of antenna will be a good option.
Amigo Henry is a long time RHC listener using a Sony ICF7600 D portable radio, but now he expects much better reception with his new professional receiver… Henry sent the layout of his property so I was able to recommend him to try a variant of the W4RNL multi band dipole fed using 450 ohms open wire feedline, connected via a remote switch to three balun transformers.. a 1 to 1 , a 4 to 1 and a 9 to 1, broadband transfomers… In a few seconds more details about my modified version of the W4RNL dipole now in use at my home amateur radio station CO2KK here in sunny Havana , Cuba.
This is Radio Havana Cuba , the name of the show is Dxers Unlimited and here is now part of my answer to German listener Henry K, who after buying a professional receiver at a hamfest asked for advice about what antenna type he could homebrew and install within the area of his property.
I recommended a variation of the W4RNL dipole, fed using via three remotely selected baluns,,, a classic one to one, an also classic four to one and a less frequently used nine to one balanced to unbalanced broadband transformers…. You will need a remotely operated coaxial switch to select the optimum balun for the frequency range you will want to use…
The wire dipole legs are exactly 13 and a half meters in length, with the antenna fed at the center using high quality 450 ohms open wire transmission line that ends at the junction box were the three baluns and the remote switch are installed. From the junction box a high quality RG213 coaxial cable goes to the antenna tuner located right next to the radio receiver. Several amateur radio operators that have built the CO2KK version of the W4RNL antenna, known in the USA as the 88 feet dipole, have added two more wires to each leg to improve the broadband response of the antenna, that works very well on the 80, 60, 40, 30, 20, 17, 15, 12 and 10 meters amateur bands by choosing the optimum balun transformer and finding the lowest possible standing wave ratio using a well designed antenna tuner…
My advice is that the CO2KK version of the W4RNL dipole using the balanced to unbalanced transformers will provide excellent performance, and here at CO2KK at present , due to the lack of the coaxial three position remotely operated switch, I am using just a 4 to 1 home brew balun with excellent matching achieved on 80, 60, 40 , 30 and 20 meters together with my broadband PI NETWORK antenna tuner…At present it is my only HF bands antenna, due to space limitations, and it does a good job with the dipole installed between two 9 meters high towers,,,
Yes amigos it is already happening right now to those of us that live North of the Equator, above 10 to 15 degrees north latitude,,, one of the most interesting effects of winter propagation now taking place is a consequence of the contraction of the ionosphere… that causes a decrease at night of the maximum usable frequency for any given path after local sunset…
One can witness the maximum usable frequency nose diving below even the seven megaHertz or 40 meters amateur band, and on some occasions the ionograms will show that the lower layer of the ionosphere will not support communications on frequencies above 6 megaHertz. Yes , let me warn you again that at times during solar minimum years, during the winter season the maximum usable frequency at night may drop even below the six megaHertz band amigos !!! Yes amigos , I continue to run my QRP very low power amateur radio station within the power range of one to five watts, with my favorite setting at the three watts level making good use of a short propagation peak window just around my local sunset.
Now the short form version of Arnie Coro’s HF propagation update and forecast… Solar microwave flux at 10,7 centimeters wavelengh, the currently accepted yardstick for measuring solar activity is at rock bottom figures or around 68 to 69 units, and no sunpots in sight for many days in a row, so expect a slow rise in the maximum usable frequency curve and poor propagation above 15 megaHertz….
See you all at the middle of the week edition of Dxers Unlimited, that will be on the air just after the half hour news service. Send your signal reports and comments about this and other Radio Havana Cuba programs to inforhc at enet dot cu, again inforhc at enet cu and Via Air Mail to Arnie Coro, Radio Havana Cuba, Havana Cuba….