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Hi amigos radioaficionados ! 


Welcome to the mid week edition of your favorite radio hobby program, the one and only offering complete, total , integrated coverage of all the many ways that you and I enjoy this wonderful hobby... from attempting to contact the International Space Station's radio amateurs from your backyard to preparing to relay emergency communications messages coming out of an area where a major earthquake has just happened... and of course that I should also mention the efforts in progress by many Dxers Unlimited listeners around the world to obtain their amateur radio licenses that will allow them to operate their own ham radio stations. 


Yes amigos, I am very enthusiastic about our hobby, because in contrast with other hobbies, radio has always a challenge to offer 

For example, during the past weekend QRP Amateur Radio Club International low power contest, I was able to contact several stations while running less than 2 watts and a very simple wire antenna. 


On the 15 meters band QRP frequency of 21.060 kiloHertz several stations were running 1 Watt power input and making nice two way CWradiotelegraphy contacts. 


The challenge of low power operation will put your operating skills under test, but once you become familiar with the very nice people that like you enjoy QRP or low power amateur radio transmitters , you will learn how to develop techniques that increase your chances of making a solid two way QSO or amateur radio contact .


Item two: Geomagnetic storm in progress as you will probably noticed when tuning around the short wave bands... the A index, or planetary geomagnetic disturbance indicator went as high as 64 during Tuesday UTC day, and that was surely felt at latitudes above 40 degrees North. 

Even here in the tropics, our 40 meters morning single side band net on 7045 kiloHertz that connects Cuba, Mexico, Haiti, the Dominican Republic , Venezuela and Central America was totally disrupted Tuesday morning by what looked like aSudden Ionospheric Disturbance. 


According to Napoleon, Charlie Oscar eight India Bravo, was the alternate net control at that moment, the 40 meters band suddenly died, and he could hear no one. 


It was just noise coming out of the loudspeaker Napoleon told me about half an hour later, when the band recovered from the disturbance. 

The daily sunspot count Monday was 41, up from the 40 recorded on Sunday... More about HF propagation conditions later at the end of the program, when you will be able to hear Arnie Coro's Dxers Unlimited's HF plus low band VHF propagation update and forecast. 

Now stay tuned or connected to our world wide web streaming audio … In a few seconds the program will continue after a short break for station ID.


You are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited, and it is on the air twice weekly, covering the more than 85 ways that you and I enjoy this wonderful hobby. 

Now here is item three: Monday April 5 UTC day we completed implementing the registered at the ITU Geneva RadioHavana Cuba's A10 schedule, that will be effective until October, although it may require some minor changes during the middle of the summer according to my analysis.

You will now be able to pick up RHC on several new frequencies , like for example 5970 kiloHertz, beaming to Central North America with our 4 by 4 curtain array. 

We are also now broadcasting on 12030 kiloHertz in Spanish , and we may soon be testing a daytime frequency on the 21 megaHertz or 13 meters band. 

We also added two more hours to our domestic Tropical Band service on 5040 kiloHertz, that from now on will be starting at 21 Hours UTC with our Spanish language magazine show . 


Your reception reports will be most appreciated amigos, and as always we will be sending back a nice QSL card confirming the reception of Radio Havana Cuba programs.. 


Send your reports via e-mail to inforhc at enet dot cu, again, inforhc at enet dot cu, or VIA AIR MAIL to Arnie Coro , Radio Havana Cuba, Havana Cuba.



This is the mid week edition of Dxers Unlimited, and here is item four...spring is here, and with it radio amateurs go out to enjoy field day operations of their receivers , transmitters and antennas. 


It is a lot of fun when you can combine a day or two hiking or camping while taking along your ham radio gear. 

Here in Havana we usually organize a one day event at the city's Metropolitan Park, where we hide a small 2 meters band beacon transmitter that most be found by the participants in the fox hunt. Our national amateur radio organization the Federacion de RadioAficionados de Cuba, encourages those meetings and provides several nice prizes for the winners. 


This is a family holiday, and while the radio amateurs are running around the park to find the hidden beacon, the children enjoy the day out by the Almendares river. 


Si amigos, yes my friends, oui mes amis, amateur radio blends nicely with family life when radio clubs know how to organize events like our yearly spring fox hunting day out at the Parque Metropolitano, Havana's second largest city park. 


By the way, if you ever want to see in use strange looking antennas, attending the fox hunt will make possible for you to see really odd looking antennas, all aiming at providing the best possible nulls that will lead to finding the hidden beacon transmitter. 


You will see from regular two element Yagi antennas to smaller Moxon rectangles and an ultra small magnetic loop claimed to provide almost perfect nulls. 


Those antennas are all homebrew by the participants , using recycled materials, and some of them have proven to be very effective when the need has come to handle emergency communications. 


Among last years spring fox hunt participants, the antenna that drew the highest attention was a Moxon rectangle, that showed a fantastic front to back ratio. 


According to those who saw the tests done after the beacon transmitter was finally spotted by one of the participants, the Moxon rectangle 2 meters band 2 elements beam must have had no less than 25 or maybe 30 decibels of front to back ratio, making it ideal for the fox hunting contest, and also an excellent choice for installing it at a location where the standard HT or handie talkie's short vertical antenna would not provide a link to an emergency net control station. 


So, as you may realize, the spring fox hunting game was very productive , as it lead to many more local hams learning about the Moxon rectangle antenna and details on how to build a practical version with locally available materials.



 Si amigos, even if you can not install an external antenna to receive short wave broadcasts, you can still enjoy listening to at least the more powerful stations by using a magnetic loop antenna. 


Sometimes I hear comments from people saying that magnetic loops require special highly insulated variable capacitors, and YES, that is true if you are going to TRANSMIT with a magnetic loop. 


But RO receive only magnetic loops do not need those special air spaced or vacuum variable capacitors. 


My prototype magnetic loop antenna used for receiving only applications is made in less than two hours, using a child's toy known as the HULA HOOP. 


This is just a circle made of half inch PVC pipe...and the only thing you will need to do is prepare a suitable mounting to keep the HULA HOOP standing in a vertical position right next to our radio. 


Yes, it MUST be right next to your short wave receiver, because the magnetic loop requires constant retuning every time you change your receiver's frequency even by just a few kiloHertz. 





My HULA HOOP MAGNETIC LOOP, is made using a length of RG58U lightweight coaxial cable , a short length of number 12 or number 14 PVC insulated copper wire, and an air spaced variable capacitor that was recycled from an old radio. 

The RG58U cable is used to actually make the loop, while another length connects the small loop to your radio. You need to add the antenna connector to the end of the coaxial cable, taking into account the type of antenna jack that your radio uses

I have changed my radio's antenna connectors to just two types, BNC and SO239. In the case of the prototype magnetic loop, it is used with the Sony ICF7600GR, that as explained was modified by adding a BNC female antenna connector.                                                                                                                                        By Sean Gilbert (see below for credits)


The HULA HOOP MAGNETIC LOOP has a diameter of 80 centimeters , close to 31 inches, and it is supported in a vertical position by a frame made of PVC thick wall water pipe. 

The antenna can be turned to find the best position for reception of the desired signal, or to null out interference. 

 When using right next to the receiver, it is possible to optimize reception by cancelling noise coming from nearby computers and TV sets. 

Again, let me underscore that RO or receive only magnetic loops DO NOT require large size air spaced variable capacitors, and that the materials used are not as critical as those required when your magnetic loops are going to be used for transmitting .


Using a standard dual section 365 picofarads maximum capacity variable capacitor, the tuning range of the 80 centimeters diameter magnetic loop made using RG58U coaxial cable is really impressive, and because Roxana my wife doesn't like the looks of the loop in our multi-purpose room where I keep a pair of radios for casual monitoring . 


I keep the loop in a nearby closet, and only take it out when actually using it !!! It is a very lightweight antenna, although it is NOT a small size antenna !!!


And now amigos, as always at the end of the program here is Arnie Coro's Dxers Unlimited's HF plus low band propagation update and forecast. 


It's in the public domain so it can be reproduced freely to help fellow short wave listeners and amateur radio operators to enjoy our hobby !!! Solar activity is expected to be very low for the next two UTC days (7 and 8 April). There is, however a chance for an isolated C-class event from Solar active sunspot Region 1061. It is also expected that yet another increase to unsettled levels with a chance for active periods is expected will happen on the 7th of April due to the onset of a high speed stream of particles flowing from a favorably positioned coronal hole. 


Activity levels are expected to decline to mostly unsettled levels by Thursday April 8 UTC day.... Don't forget that abnormal propagation conditions sometimes bring in unsual stations that you will not be able to pick under normal conditions !!! 


Amigos, don't forget to set aside a little time and tell me your impressions about this program , send your radio hobby related questions and any ideas you may have on how to improve it !!! Send mail to inforhc at enet dot cu or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana , Cuba.


*Arnie Coro´s  DXers Unlimited host

* Hula Loop photo by Sea Gilbert

Cortesy of Hard-Core DX

Via Yimber Gaviria, Colombia

Download a full Hula Loop PDF file

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