Dxers Unlimited, Tuesday 26 February

Radio Havana Cuba

Dxers Unlimited - for Tuesday 26 February 2019 

Arnie Coro, CO2KK

  

The Cuban CW Group of amateur radio operators is promoting a project that will help both beginners and experts operate on CW Morse Code Radiotelegraphy mode using a simple low power transmitter... Two versions of the low power rigs are now in the early design stages, one using all solid state devices recycled from retired computer CRT monitors and TV sets, and the other a hybrid transmitter using low power transistors and a pair of also recycled vacuum tubes operating as the driver and final RF amplifier stages. 

But, Jav, CO3JK, charlie oscar three Juliet Kilo, the Secretary of the Cuban CW Group wrote an e'mail explaining that the first part of the project aims at building a rugged, reliable power supply for the transmitters.

More radio hobby related information coming direct and from the source... in a few seconds after a short break for a station ID, I am your host Arnie Coro, CO 2 KILO KILO in sunny La Habana, Cuba enjoying wonderful early spring weather...

Si amigos this is Radio Havana Cuba... the name of the show is Dxers Unlimited and here is now more radio hobby related information... a few days ago I decided to dismantle an old hybrid amateur radio transceiver that had broken down many times , making each time more and more difficult to repair. 

It was not an easy decision, but when I started to take the rig apart, it proved to be the correct thing to do, when after testing the first ten electrolytic capacitors removed from the Kenwood TS820S using an equivalent series resistance meter, they all proved to be totally out of the minimum parameters... Attempting to revive that rig without a supply of high quality fully tested electrolytic capacitors for both the high voltage and low voltages power supplies would be simply an impossible task and it will also require a tremendous amount of time. 

Another finding that came out during the first steps of the dismantling process was related to the type of wrap around solderless connections used by Kenwood, that in my opinion was a very poor choice by the designers... The rest of the story is that so far I have carefully removed the VFO assembly, and the big power transformer that will soon be used for other home brew projects... Other small parts will need to be removed by first extracting printed circuit boards where valuable parts like the single side band filter and many quartz crystals can be recovered for recycling. 

Needless to say the Kenwood TS820 S had provided a useful service life of several decades that could had extended further more  if a different method of assembly had been used...  An before I forget the radio frequency driver stage and the two beam power tubes power amplifier were also neatly removed and could be used for a simple single band rig, making good use of a power supply built using the big transformer recovered from the transceiver.

ASK ARNIE, la numero uno, the most popular section of Dxers Unlimited is now on the air... answering a question sent by listener Salvatore from Romen , Italy... Amigo Salvatoreo wants to hear my opinion about the possibility of building self excited power oscillators for CW that use the Hartley – Hull circuit... Well amigo Salvatore, all I can say is that it can be done, but it does require the use of some hard to find parts, like wide spaced air variable capacitors , that are essential to achieve the required frequency stability, and you will also need a very stable fully regulated supply to feed the power oscillator.

My very good Italian friend Cris Greggio has built a prototype Hartley Hull single stage power oscillator that sounds very good on the air and does not drift at all. I remember many years ago building a similar CW rig using a single triode connected 807 type tube , fed from a professional high voltage regulated power supply... It provided about 15 watts output on the 40 meters band and was really stable ... Keying was excellent and no chirp was heard from that rig... Using an also home brew regenerative receiver, the 807 triode connected power oscillator made possible making some very nice DX contacts, but I must add that this happened many years ago during solar cycles 20, 21. 22 and 23 that were much more active than the present very weak cycle 24...

Soon, Radio Havana Cuba will be changing to the A19 transmissions schedule... and very few changes are expected to take place... The reason for not having to change many frequencies has to do with the very low solar activity expected for this season that starts during the spring and comes to an end during October.

.You can send your signal reports and comments about our short wave broadcasts to inforhc@enet.cu, again inforhc@enet.cu, and don't forget to include details of the programs heard so that we may verify your reception reports with a nice QSL card....

More radio hobby related information coming up: Recent radio noise measurements done at several of the world's most populated cities and also done at smaller towns and villages show something in common... The general background radio frequency noise levels within the frequency range from three to thirty megaHertz has increased dramatically during the past five years where ever measurements made five years ago were available... 

The results of those carefully done bandscans measuring the background noise demonstrate that services that once where capable of providing good quality coverage like the AM medium wave broadcast band have become, at some urban locations almost useless, even when the stations are using high power transmitters .... Add also that the FM broadcast band is also suffering from many electromagnetic incompatibility problems that reduce the service area of many stations in a significant way....

And now just at the end of the show,here is Arnie Coro's Dxers Unlimited's HF propagation update and forecast, expect poor to very poor conditions during the next two days due to the likely to happen effects of a high speed solar wind stream coming from a coronal hole... All  I will recommend is to monitor the lower frequencies for possible propagation anomalies... 

Send your signal reports and comments via AIR MAIL to Arnie Coro, Radio Havana Cuba, and use our primary e'mail address inforhc@enet.cu .See you at the weekend edition of Dxers Unlimited on the air next Sunday and Monday UTC days,

(Arnie Coro) 

DXers Unlimited, weekend edition-20 January

Sunday 20 January 2019

Arnie Coro CO2KK

  

Hi amigos, welcome to the weekend edition of your favorite listener oriented, technically minded radio hobby program, coming today once again directly from  right next to my ham radio station CO2KK, exactly as it happened many years ago, on the 27th of October of 1998, when I was sending an advance warning to radio amateurs in the Caribbean and Central America as the huge Hurricane Mitch was approaching the area. As many of you that heard that program remember well, a great number of radio amateurs in the Caribbean participated in a large-scale communications effort related to one of the most powerful storms ever seen in the area ever.

Amateurs in Canada, the United States of America, South America and even from Europe helped by providing relays on the 40 meters band when long skip made it impossible to work on that band, and as expected practically all the 2 meters band repeaters in the affected areas were damaged or totally destroyed by the hurricane force winds, landslides and the lack or commercial power. The availability of the 80 and 40 meter band amateur equipment that can operate using small generators or even car batteries has proven to be a great asset when weather or earthquake emergencies destroy local telecommunication facilities, or make using them almost impossible due to excessive traffic generated during the emergency. The 40 meter bands long distance relays of weather data for stations located in the affected areas and the forecast centers is vitally important too.

Item Two: A detailed explanation of why emergency communications provided by amateur radio operators are essential during hurricanes and earthquakes, as well as large scale accidents. Hams using portable equipment that can be powered from standby power sources are able to keep vital links to the affected areas among the important information provided on those two way links are weather data taken at places that were there, are no official weather stations, advance warning from possible flooding and help during search and rescue operations, and later after the storm is over, the amateur radio links are used to help medical aid workers, to select landing sites for helicopters and planes and in general to keep things moving during the very complex post hurricane period.

  

Among the most interesting aspects of the way that hams provide emergency communications is how simple antenna systems, low power radios and good and very well-trained operators combine to keep communications flowing

Most of present-day amateur disaster area communications is done using single sideband voice, but the increasing availability of portable lower cost lap top and notebook and tablets computers are encouraging the use of digital radio links, which are much more reliable, use less power and are also less prone to interference. Computer to computer communication via a radio link is an ideal way of handling emergency traffic, but as a friend of mine likes to say it is a developed country approach, but lower priced computers that are now available are making possible implementing keyboard to keyboard emergency communication links by amateurs in less developed parts of the world.

More about emergency communications during natural disasters a little later in today's edition of Dxers Unlimited, coming to you directly from my home location, right next to CO2KK my amateur radio station that is now part of not one or two, but actually three emergency communications networks on the 20, 40 and 2 meter bands Now let's take a break  I'll be back in a few seconds Short musical intercut

You may nowadays download from many public free access Internet sites a large number of very interesting files dealing with antennas, shortwave propagation, solar activity etc, that will help you to optimize your amateur radio station and make it much more useful for handling emergency communications whenever required. 

You can also request our QSL card, by just sending an e-mail directly to me send mail to inforhc@enet.cu

Item Three: Each edition of the big worldwide ham radio contests like the CQ World Wide SSB or the WPX prefix contest help quite a few newcomers to the amateur radio hobby to increase their total number of countries, or DX entities as they are now called... worked. Many Cuban radio amateurs both old and new participate in those challenging and interesting events and some of them have achieved very good results too.

Item Four:Transatlantic medium wave AM band DX season is now in full swing, something that happens has another peak time spanning from December to the end of March, because of the expected decrease in ionospheric absorption caused by the lower solar activity. Those AM band Dxes with good receivers, and the special antennas required are able to pull several of the most powerful stations from Europe and the Middle East quite easily during solar minimum years , by using narrow filters that let those stations come in between the 10 kilohertz channel spacing used by AM broadcasters in the America's.

  

Among the easy ones from the other side of the Atlantic, are several super power stations operating at the high end of the band, from about 1400 to 1620 kilohertz. Don't be surprised if at around your local midnight, when the sun is just rising in Europe, at least two or three of those megawatt stations make themselves heard via powerful heterodynes or whistles between the AM stations on this side of the Atlantic.

The super simple 2 element 2 meter band Yagi beam antenna which is ideal for emergency work it is built using either standard TV antenna elements, or heavy gauge copper wire The support for the antenna is made from one of my favorite antenna building materials-you guessed right amigos broomsticks. 

This is a very compact antenna that will provide about four or maybe a little more dB gain over a standard half wave dipole, but of course, many more db's above the typical rubber duck antenna used by hand held radios or handie- talkies The dimensions for this antenna are very easy to remember, if you choose to do your homework in metric. The reflector element is 101 centimeters long and the dipole driven element is 98 centimeters long  The two are separated by 50 centimeters of broomstick boom, and the antenna's driven element is fed using standard 50 ohm coaxial cable I leave about 30 of 40 more centimeters of broomstick behind the reflector element, so that I can tie the antenna to any available supporting structure This is a portable emergency antenna system, so it is made with low cost materials. The elements can be taken from an old TV antenna, or you may buy aluminum tubing of about 10 millimeters or 1-centimeter diameter.

The dipole element is fed at the center, so the two sides should be mounted on a piece of insulating material like acrylic plastic, polyethylene or PVC, you should use good insulation if you want the antenna to work well even when it is raining or snowing This is about the lowest cost "amplifier" that you can think off. See by the numbers... a rubber duck antenna used on a typical two-meter handie-talkie has a loss of no less than 6 db relative to a half wave dipole.

The Ultra-Low Cost 2 meter Broomstick Yagi antenna, has a 4 dB gain over a dipole in other words, if you replace the rubber duckie with my two element makeshift antenna, your signal will be a whopping 10 db more powerful, or 10 times louder than when you used the little rubber duck antenna

See you all at the middle of the week edition of Dxers Unlimited next Tuesday and Wednesday UTC days... Send your signal reports to inforhc@enet.cu or via Air Mail to Arnie Coro, Radio Havana Cuba, Havana, Cuba.

Dxers Unlimited weekend edition, 16 December

Hola amigos radioaficionados now listening to the weekend edition of Dxers Unlimited, I am your host Arnaldo, Arnie, Coro, radio amateur CO2KK wishing you all good reception of the week end editiom of this radio hobby show . QSL . QSL , YES.... QSL on the air to the many listeners that have sent signal reports and comments to inforhc@enet.cu Some of the reports have also included  mp3 audio files attached to the email messages. Those audio files allow our engineers to appreciate exactly how the station is heard by listeners using our short wave broadcasts.. No doubts that an mp3 audio files  is the most objetive form of reperting the quality of reception amigos !

QSL on the air to listener Claudio Galaz who sent a very interesting report from his location in Chile. Claudio tuned in to the 60 meters tropical band frequency of 5040 kilohertz and he tells us  that the signal, although weak, was easy to listen to because the 5040 kilohertz is on a very clear channel..

By the way I am going too ask Claudio to also monitor Radio Rebelde on 5025 kilhHertz and compare the two signals that originate with the same power of 50 kiloWatts from the Bauta Radio Cuba transmitting station.

Claudio also compared the reception of the RHC frequencies beamed to South America on 11700 kilohertz, with 250 kiloWatts and 11840 kilohertz, also using 250 kiloWatts and identical HR 4 dash 4 dash 1 dot zero high gain curtain arrays...sent from the San Felipe transmitting station located in Mayabeque province, south of the city of Havana....

Item one :  Solar activity update...yes MORE, bad news, because more than 60 percent of the days of this year 2018 went by without a single sunspot IN SIGHT...From January first of this year and up to December 14, sunspots have been missing for 206 days... and this for sure a fact that continues to sustain the point of view shared by many heliophysicists that solar cycle 24 minimum is now reaching the lowest expected number of sunspots. A monthly update reminder comes from Belgium., where the Royal Observatory confirms the Provisional International monthly mean Sunspot Number for November 2018 : 5.9 (five point nine) , again 5.9  ie the provisional international monthly mean Sunspot number for the month of November.

This very accurate data about solar activity confirms that cycle 24 is very near  its minimum and I may add that more small reverse polarity sunspots are expected from now on, the should appear at higher latitudes of the northern hemisphere of the Sun and show a reverse magnetic polarity that identifies them from solar cycle 24 sunspots that are located now near the solar equator.

Cuban radio amateurs are enjoying now the use of three antennas manufactured in Cuba and sold at a not for profit price by the Cuban Federation of Radio Amateurs... The most popular model is a zero db gain omnidirecional J pole antenna that has proven to provide excellent service as well as supporting hurricane force winds last year. The other two Cuban designed and built antennas are a three elements 6 dB gain yagi, and the other one a six elements Yagi optimized for maximum forward gain that is the favorite antenna among FM 2 meters Dxers.

Yes amigos, two meters band FM mode Dxing is becoming popular in some parts of the world where the availability of multi mode transceivers is simply zero. But, FM mobile units and handie talkies are plentiful, something that makes possible to install better antennas and attempt to try to work far away stations that are not normally available using low gain omnidirectional antennas.

Here in Cuba the 2 meters band is the most used, due to the availability of transceivers used by the professional users within the frequency range between 140 and 160 megaHertz that can be rather easily reprogrammed using a computer to radio interface and the proper software. Some handie talkies are also good candidates for the software conversion making it possible to operate on the 144 to 148 megaHertz frequency range. When connected to a vertically polarized Yagi antenna of at least three elements, the operating range achieved extends well past the typical area that is normally  used for effective communications with  the FM narrowband voice mode.

The main use of the 2 meters band here in Cuba is for local and semi-local contacts, with many radio clubs holding weekly round tables on previously announced frequencies, something that has proven  to be very useful to keep club members informed about relevant activities and also to provide excellent practice for emergency communications

Requests about the circuit diagrams and building instructions the ever popular Arnie Coro's regenerodyne receiver radio keep coming. There are two versions of my  regenerodyne receiver, one is built using vacuum tubes and the one is a hybrid circuit that uses vacuum tubes and solid state devices. The current circuit diagrams also include a design that uses a quartz crystal to feed the mixer with a high stability injection frequency, while another version uses a Franklyn type of self excited local oscillator that is very stable.Send your request for any of the circuits diagrams in our collection to inforhc@enet.cu.

Also receiving requests and questions related to my Super Islander Mark Six  direct conversion short wave receiver keep coming in to my email inforhc@enet.cu And as soon as they are received, it takes just a few seconds to send the electronic reply via the Internet. By the way listeners that have built the different versions of my regenerodyne radio have used them to  form part of a more complex amateur bands transceiver tell me that the project was an easy going task that could be built using standard available parts.

Here is now ASK ARNIE, the most popular section of this program with the reply to the question sent by listener Hugo from Hamburg , Germany, who listens to this show via the streaming audio available from www.radiohc.cu He wants to know more about how to test recycled parts that he has collected from several sources for the past several years. ANSWER: Well amigo Hugo, for testing resistors you only need a good quality digital multimeter.

For testing capacitors you will need not one but several different test instruments, testing electrolytic capacitors requires the use of a special instrument that measures the capacitor's equivalent series resistance, so by using a table of normal values of the electrolytic capacitors of different capacity and voltage ratings, you can discard the bad ones easily.... For measuring inductances now it is possible to buy a new type of digital instrument that provides very accurate measurements of inductances of a very wide range of values.


See you all at the middle of the week  edition on the airTuesday and Wednesday UTC amigos, just after the half hour news bulletin here at Radio Havana Cuba . Send your signal reports, QSL requests and radio hobby related questions to inforhc at enet dot cu or Via Air Mail to Arnie Coro Radio Havana Cuba, Havana, Cuba

DXers Unlimited, weekend edition Sunday 21 October

Arnie Coro, CO2KK

Radio Havana Cuba

Hola amigos... this is Dxers Unlimited's weekend edition... I am your host Arnie Coro, Radio Amateur CO2KK, and here is item one.

# One - one of the amateur radio most important contests will take place next week, and it is going to happen under somewhat better HF bands propagation conditions.

Here are some of the stations that have already announced their participation in the CQ World Wide SSB contest.

From the Caribbean SAINT BARTHELEMY, prefix FJ. Thierry, F6CUK plans to be QRV as F6CUK/FJ from October 21 to November 1.  Activity will be holiday style on the HF bands using CW and SSB. This may also include being an entry in the upcoming 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 will be QRV as PY0F from October 23 to 29. Activity will be on 160 to 10 meters using SSB and FT8. This includes being an entry in the upcoming CQ World Wide DX SSB contest. QSL direct to PY7RP.

Another South American station is going to be active during the upcoming CQ World Wide SSB Contest SURINAME, call prefix PZ. A group of operators will be QRV as PZ5K from October 23 to 30. Activity is on the HF bands using CW and RTTY.  This includes being an entry in the upcoming CQ World Wide DX SSB contest.  QSL via G3NKC.

Si amigos, thousands of amateur radio stations from all around the world are expected to be active during the CQ Worldwide SSB Contest, including several well experienced teams of operators from Cuba, that will be using the T4, tango four prefix, preserved here for special events stations.

Due to the expected bands conditions my forecast is that activity will be concentrated on the 20, 40 and 80 meters bands, with less contacts possible 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 are expected to be better than during last year's contest. Stations located inside the areas covered by TEP, Trans Equatorial Propagation events will be able to add many points and multipliers.

For example, Cuban contests stations will be scanning 10 meters to pick up signals from Argentina, Uruguay, Paraguay and Chile. 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 MHz.

This is Dxers Unlimited's weekend edition, coming to you via shortwave transmitters, the Hispasat one D satellite, 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, and today, I will answer a question sent by listener Carol from the US state of California. Carol owns a small portable shortwave receiver, and she wants to know if adding an external antenna to the telescopic whip will improve reception of our 6100 kHz transmissions beamed to the West Coast of the USA and Canada. 

Amiga Carol, my advice is to try to buy a commercial version of a magnetic loop antenna, that can be connected to your small portable. The magnetic loop requires continuous tuning every time you change frequencies, but it also provides a very useful additional filtering action that removes unwanted noise from the input of the radio.

A one meter diameter magnetic loop built using coaxial cable  can be supported with a light weight PVC pipe assembly that can be taken apart when not in use. Placing the magnetic loop near a window or with a length of coaxial cable it can be deployed at a sun deck or a garden.

The typical low cost magnetic loop used as a receive only antenna is tuned by hand, while higher cost ones are provided with a remote control feature. As a matter of fact, you can build your own magnetic loop for receiving, by running an Internet search using the words Magnetic Loop Antennas.

Our next radio hobby related information. For those of us that live north of the Equator, one of the most interesting effects of winter propagation 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 MHz 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 MHz.

Yes, let me warn you that at times during solar minimum years, during the winter season, the maximum usable frequency at night may drop even below the six MHz band amigos !!!

And talking about shortwave radio propagation conditions, let me tell you that I continue to enjoy very much the use of the very original application that runs on practically any computer and  makes possible to see the results of the REVERSE BEACON NETWORK.

This is certainly an amazing achievement accomplished by volunteer amateur radio operators from many countries around the world. I would not attempt to describe here how the receiving stations that are known as “skimmers,”  that automatically pick up amateur CW morse code radiotelegraphy signals that are calling CQ, and then also by means of an automated  computer program subrutine measure the CW transmission speed and the signal to noise ratio.

If it sounds to you like science fiction, but it is certainly not, and the now very reliable Reverse Beacon Network is adding yet another tool to learn more about the extremely complex phenomena that make possible ionospheric shortwave propagation.

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.

Again, I want to repeat this valuable information for those of you interested in knowing more about short wave propagation. You may want to visit the home page of the Reverse Beacon Network after calling CQ on CW if you already are an amateur radio station operator, and just learn, for example, what is happening when your friend Arnie Coro called CQ on the ham bands the last time he was on the air.

 Just type the following URL on your Internet browser search line:

http://www.reversebeacon.net/srch.php  Then when the site opens and asks for whom you are looking for, type COKK,  and you will see the latest spots on each of the ham bands where I called CQ.

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@enet.cu or postal airmail at: Arnie Coro, Radio Havana Cuba, Havana Cuba.

(Arnie Coco/R Havana Cuba)

Dxers Unlimited mid-week edition, September 11

By Arnie Coro

Hola amigos… more reasons for the very poor propagation conditions on the MF and HF bands.

Geomagnetic conditions have reached moderate storm levels on a planetary level (NOAA Kp 6 for the 6-9UT period today, 11 September 2018). The storm is due to the enhanced solar wind parameters associated with a coronal hole high speed stream, while the solar wind speed gradually increased from 370 km/s at noon 10 September to values near 610 km/s at 10UT today.

DXCC COUNTRY/ENTITY REPORT

According to the AR-Cluster Network for the week of Sunday, September 2-9,  they were 206 DX countries or entities on the air on the monitored amateur bands.

I am Arnaldo, Arnie, Coro your host here at the middle of the week edition of Dxers Unlimited. Now our next news item...

A number of hand-held FM transceivers capable of transmitting on frequencies beyond the 2 meters and 70 centimeters band are being banned by several frequency management authorities around the world. The usually very low-cost dual band FM handie talkies are considered a menace because they can easily be reprogrammed to operate on the public services frequencies. Banning those radios is achieved by placing them in black lists kept by Customs on the countries were they are no longer allowed to be imported.

QSL on the air to Dxers Unlimited's. Listeners that have asked to keep the HF bands propagation updates at the end of the show on every program. Don't worry, from now on whenever possible Arnie Coro's HF plus low band, HF propagation update will be on the air at the end of the show.

Next News Item: Sponsored by the International Telecommunications Union, ITU, the specialized oldest United Nations agency, a worldwide research project that is measuring the radio frequency spectrum noise levels will provide valuable information about this severe problem that has a negative impact on the use of radio telecommunications systems that are vital in today's world.

By the way some of the worst radio broadband noise levels measured at several megalopolis, like Mexico City, New York, London, Shanghai, Tokio, Moscow and Paris are showing that the AM broadcast band services are becoming useless at the present transmitting stations power levels. The actual effective service area originally planned for many AM broadcast stations since 1959 have proven to be practically useless due to the poor signal to noise ratios prevailing on the 530 to 1700 kHz frequency range.

Hurricane Florence now is in an almost fixed track, and is going to impact the US East Coast as a category 4 or even category 5 storm. The most powerful storm to reach that part of the continental United States, in more than 60 years.

Amateur radio operators located in the affected areas as well as others around the first skip HF coverage area are already deploying their emergency communications stations. 

It is expected that the record-breaking winds will produce considerable damage to the telecommunications and broadcasting facilities. As it happened last year in Texas, the cellphones networks went down before the full blast of hurricane Harvey had hit the area, making the use of amateur radio emergency systems essential for responding to live saving operations requiring air evacuations from flooded isolated areas.

Number 94 is here. Yes amigos, the number 94 way of enjoying our spare time by means of our radio and television hobby is here: It is known as amateur digital television, capable of high definition transmissions.

For delivery of television signals, there are several methods in use that include: cable (C), satellite (S), terrestrial (T), internet streaming (www), DVD, etc.

Each delivery system has its own advantages and disadvantages. As a result, different digital encoding mechanisms are used for each method. The cable, satellite and terrestrial all use RF carriers, while satellite and terrestrial are truly over the air rf paths. As radio amateurs, we use over the air rf transmission paths.

In the early days of DTV (early 2000s), some DTV hams were experimenting with using satellite TV equipment, mainly due to the low cost (? $25) of free-to-air (FTA) satellite, L-band (1-2GHz) receivers. Their work was primarily on the 23cm (1.2GHz) band.

Other early adopter, DTV hams experimented using cable TV equipment for the same lowcost reasons. The normal amateur radio environment is really the over the air, terrestrial, rf transmission with radio waves being transmitted horizontally over the surface of the earth.

The major issues encountered with such radio waves is the presence of multi-path, RFI and weak signals. Multi-path refers to multiple rf signals bouncing off of various reflectors, such as hills, buildings, etc. and arriving at the receiving antenna with various time delays. In the days of analog TV, this was readily evidenced by the presence of "ghost" signals on the TV screen.

DTV transmission in a cable TV environment is rf transmission in an almost  perfect environment. It is almost a perfect, echo free environment due to the efforts made to maintain very low VSWR in the cable TV system.   Signal strengths can also be kept up to relatively high levels. Thus, the digital modulation method for cable TV does not need to make many corrections for its good environment.

DTV transmission from broadcast TV satellites, is again in a relatively clean  rf environment. Because of the high gain and directivity of the receive antennas, there is essentially no multi-path to contend with from satellites. The main issue for satellite rf signals is very low signal strength at the receive antennas. Terrestrial rf transmission is the worst possible rf environment. It must deal with multi-path, RFI, and weak signals and still deliver a perfect DTV picture.

Here in Cuba our national television uses the highly efficient DTMB'T that has proven to be more reliable than the ATSC systems variants used in the USA. So far, Cuban radio amateurs have used analog television transmissions using several slow scan TV modes that proved to be very effective sending still photos of hurricane affected areas to the Civil Defense command posts using both 2 meters FM and HF single side band transmissions.

This is Radio Havana Cuba, the name of the show is Dxers Unlimited. I am your host Arnaldo, Arnie Coro and here is our next radio hobby related item for today...it is about the really amazing results achieved by minimalist amateur radio stations, using minimum parts counts receivers and transmitters.

Starting with a dual triode tubes in a glass envelope the regenerative receiver was designed to work on the 40 meters amateur band, using high impedance headphones.

The first triode is the detector and the second one works as an audio amplifier. The radio tunes from 7000 to 7150 kHz only. It has good sensitivity and uses very common electronic parts that you can find by recycling equipment. It uses a low voltage power supply that is also easy to build.

The transmitter first option uses quartz crystal control and a single power tetrode or pentode vacuum tube, that when fed from a voltage doubler power supply will easily provide between two and five watts into the simple half wave coaxial fed dipole antenna.

When a local amateur that is a QRP low power radios enthusiast saw the minimalist station he said and I agreed with him that it a simplified version of the famous World War II Paraset !!! He took the circuit diagrams and photos to duplicate the set.

And now at the end of the show.... Arnie Coro's HF propagation update.... Zero sunspots ... a blank solar disc with very low solar activity ...AND A GEOMAGNETIC STORM IN PROGRESS: As predicted, a moderately strong G2-class geomagnetic storm was underway on Sept. 11th as a stream of high-speed solar wind buffets Earth's magnetic field. This morning in Alaska, "amazing auroras covered all of the sky," reports Ayumi Bakken from just outside Fairbanks:

Send your signal reports and comments about this program to inforhc@enet.cu or postal mail to: Arnie Coro , Radio Havana Cuba, Havana, Cuba.

(Arnie Coro/R Havana Cuba)

Dxers Unlimited mid-week edition, Tuesday 4 Sept 2018

By Arnie Coro amateur CO2KK

Hola amigos radioaficionados all around the world...this is Dxers Unlimited's middle of the week edition with yours truly Arnie Coro as your host.  

Item # 1

DXCC COUNTRY/ENTITY REPORT: According to the AR-Cluster Network for the week of Sunday, 26, August, through Sunday, 2, September, there were 213 countries active and I guess that the good results have something to do with the FT8 digital communications mode now in use around the world making possible two way contacts under extremely poor propagation conditions.

The South African Radio League (SARL) said the past weekend, radio amateurs reported that they experienced periods of radio black-out which lasted 24 hours.

When a strong enough solar flare occurs, ionization is produced in the lower, more dense layers of the ionosphere (the D-layer), and radio waves that interact with electrons in layers lose energy due to the more frequent collisions that occur in the higher density environment of the D-layer. This can cause HF radio signals to become degraded or completely absorbed. This results in a radio blackout, the absence of HF communication, primarily impacting the 3 to 30 MHz band.

HamSci (Hamradio Science Citizen Investigation) is a USA based group of radio amateurs and scientists who work together to study various aspects of radio science. During this weekend's event they found that the solar and the planetary field united and created a hole that let plasma inside the magnetosphere of the planet create severe auroras.

The fast-growing sunspot (AR270) has reversed polarity which would link it as the first sunspot of the next solar cycle. The solar cycle is an average of 11 years. The current cycle (cycle 24) still has approximate two years to go before it is expected to reach its minimum and cycle 25 to begin. The question HamSCI is asking was this just a single event or are we truly entering cycle 25?

Whatever hit Earth was not proton flux which is associated with CMEs and coronal holes. The storm was created by fast compression of earth's magnetic field and the sudden release of magnetic pressure from the Sun.

This whiplash created a vacuum which sucked in the plasma surrounding the planet and at the same time caused the geomagnetic activity to rise to a G3 strong storm level.

Other sources are forecasting a much earlier than expected solar minimum, making cycle 24 one of the shortest on record.

Espeleologists, the scientists that do research about caves and caverns make use of a transceiver known as the HeyPhone that is a 17-year-old designer from British radio amateur John Hey, G3TDZ who passed away some time ago so he didn’t get to see his design play a role in the most recent high profile cave rescue that took place in Thailand, although it has apparently been a part of many others in the past.

The HeyPhone is considered obsolete but is still in service with some espeleology teams. The radio uses USB upper sideband voice operating a the very low frequency of  87 kHz. The low frequency can penetrate deep into the ground using either induction loop antennas like the older Mole- phone, or — more commonly — with electrodes driven into the ground to inject RF energy directly into the surrounding area.

What is interesting is that in today’s world, people take wireless communications for granted and don’t realize that cell phones don’t work underground or in the face of wide-spread disasters when the cell towers fail or the cell system is overloaded with traffic that it cannot handle.

More solar cycles predictions and forecast now circulating .... one of the latest ones says that cycle 25 is now coming to an end, after only 10 years of evolution...

Another source assures that reverse magnetic polarity sunspots located at the  less-active hemisphere of the Sun during cycle 24 are almost surely the precursor of solar cycle 25.

Here is the latest report from the very reliable Spaceweather site:

www.spaceweather.com  reported new sunspot group 2720 is the first large spot of the next solar cycle, Cycle 25. The magnetic polarity is reversed from the polarity of sunspots in Cycle 24.

Whatever is happening 93 million miles away from Earth will going to be quite clear as time goes by.

In the mean-time adjust your radio hobby operating habits and technologies for monthly sunspots counts of less than 10 for quite some time ahead.

Dxers Unlimited the radio hobby program covering the more than 93 ways of enjoying our spare time playing with radios, antennas and software.

Amateur radio satellites use frequencies that are supposed to be dedicated to that service.Recently On August 27, AMSAT Vice President of Operations Drew Glasbrenner, callsign KO4MA, noted: "Recently there has been a DMR signal QRM'ing the AO-92 satellite uplink on 435.350 or close by.” Hotspots, repeaters, terrestrial simplex (anything not satellite) should not be in 145.8-146.0 or 435-438 by international band-plan. He requests ground stations using those frequencies to please QSY, move these away from the satellites uplink frequencies. Possible sources of those signal include ease share to DMR, D-star, Fusion, P25 groups and similar terrestrial amateur radio activities.

Again the segments of two meters and seventy centimeters that are to be protected from ground based stations not intended to communicate via satellite are in the 145.8-146.0 segment of two meters and 435-438 MHz amateur satellite sub-bands.

It happened 159 years ago…and scientists are talking about the extraordinary geomagnetic storm that it caused known as the Carrington Event. Exactly 159 years ago, planet Earth was git by geomagnetic megastorm On Sept. 2, 1859, a powerful CME rocked Earth's magnetic field, causing a geomagnetic storm that set fire to Victorian telegraph offices and sparked auroras as far south as Mexico and Cuba.

Now known as the Carrington Event, that mega storm 159 years ago is a touchstone of modern extreme space weather research.

What are the odds it could happen again? The cause of all this was an extraordinary solar flare witnessed the day before by British astronomer Richard Carrington. His sighting on Sept. 1, 1859, marked the discovery of solar flares and foreshadowed a new field of study: space weather.

According to a study by the National Academy of Sciences, if a similar Carrington Event, occurred today, it could cause substantial damage to society's high-tech infrastructure and require years for complete recovery.

Could it happen again?

The answer is: Almost certainly! In a paper published just a few months ago, researchers from the University of Birmingham used Extreme Value Theory to estimate the average time between "Carrington-like solar flares." Their best answer: approximately every 100 years. In other words, we may be overdue for a really big storm.

AM medium wave broadcast band Dxing propagation conditions will see an improvement as we approach the autumn equinox.Look for stations from the  Bahamas, there are just three AM stations operating from the Bahamas.

The three are rather easy to log all along the East Coast of North America starting with station, ZNS3, on 810 kHz from Freeport, Grand Bahama.

Described as the Northern Bahamas Service.On 1540 kHz, ZNS'1 from Freeport Grand Bahama Island runs higher power, while ZNS'2 from Nassau, New Providence Island operates on 1240 kHz.

And now amigos, at the end of the show, here is Arnie Coro's HF propagation update and forecast.

Solar activity is at very low levels with daily solar flux figures near the minimum values ever registered since 1947, when solar radio astronomists started to monitor the Sun's solar flux on the 10,7 centimeters wavelength.

As all you familiar with the close ties between solar flux and HF bands propagation conditions, it is quite evident that we are going through a period of very poor propagation within the 3 to 30 MHz range.

See you all at the weekend edition of Dxers Unlimited and don't forget to send me your signal reports and comments to inforhc@enet.cu or via air mail to Arnie Coro Radio Havana Cuba, Havana, Cuba.

(Arnie Coro/R Havana Cuba)

Dxers Unlimited – midweek edition, 28 August 2018

By Arnie Coro CO2KK

Hola amigos radioaficionados, this is the mid-week edition of Dxers Unlimited your favorite radio hobby program. I am your host Arnie Coro, my ham radio callsign is CO2KK and yes, I certainly enjoy having this unique opportunity to share with you and others information about our wonderful hobby, yours and mine¨RADIO

By the way the most recent G3 class geomagnetic storm really took a big toll on the short wave propagation conditions, but I expect that they will make a comeback in the next several hours The information starts with a briefing about solar activity… or should I say solar lack of activity, with only very small sunspots active regions seen by observers and the daily international sunspot number was down to one point five, yes, you heard it right just less than two sunspots average associated with the also extremely low solar flux figures below 69 unitsn.

Looking at my archives I found that the month of August of 2008 went down to the history of solar monitoring with absolutely ZERO sunspot number, something that didn´t happen for many, many years of meticulous optical observations carried out by the most experienced astronomers.

And that was of course, during  solar cycle´s 23 tail end.Yes, we must no deal with another extended period of very low solar activity that during the next winter seasons will send the maximum usable frequency curve way down, as a matter of fact it may go as low as four or five MHz, during the local evening hours.

Now let me share with our radio amateur listeners and those of you that enjoy listening to hams communicating with each other on the short wave bands, information about hams that defy the bad propagation forecasts and call CQ into an otherwise absolutely empty band, only to be rewarded by a DX station coming back to the call.

It happens quite often, especially on the 17, 15, 12 and 10 meters amateur bands during periods of very low solar activity. Just to provide you with an example – a few days ago I was monitoring the 12 meters band, that spans from 24.890 to 24.990 MHz. It is one of the amateur bands that was granted to us radio hobby enthusiasts by the 1979 World Administrative Radio Conference, and unfortunately it is among the least used of the HF amateur bands.

Well, to make the story short, I found a station from Colombia handling a pile up, working one station after the other and giving them nice reports. I scanned the entire 100 kHz of the band several times, and the Colombian station was the only one heard here in Havana.

Obviously, he was reaching the United States quite well because all stations that he was working where from that country. Then I prepared by QRP or very low power station, tested it about 10 kHz, up from the Colombian station, retuned back to his frequency and gave him a quick call when he ended a QSO,

and sure enough amigo, my four watts received a five-seven report of the single side band voice signal, while running a center fed dipole up at around 10 meters above the roof.

Yes, even when apparently the higher frequency amateur bands are closed, it is very often not the case. What happens is that no one is using them at that given time, and that is why it is so important to call CQ on the well-known spot frequencies for the different transmission modes.

Nowadays if you have the possibility of using the FT8 digital communications mode, by all means, use it and you will be surprised by the amazing results. As it happened to me you may be rewarded with a nice two-way contact.

Yes, you are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited and get ready to listen to something really amazing, I have named it the DUMMY LOAD antenna system… and that will be explained in detail here at our technical topics section of the program.

Amazing, hard to believe, surprising, those are the words I hear when doing a practical demonstration of the antenna I am about to describe, but the fact is that despite all the odds, it does work.

Are you puzzled with what I am talking about? Want to know what it is?

Well, it is yet another version of what is known by engineers as a resistive loaded antenna system, which can be easily improvised with just a standard 50 or 75ohm dummy load, a coaxial T connector and a length of antenna wire.

I have named it the WONDER DUMMY LOAD ANTENNA The idea of using a dummy load as part of an antenna system can be traced to the very early days of radio. Our grandfathers used light bulbs as dummy loads to test their vacuum tube transmitters, and they soon found out, quite by accident  that even when their AM and CW transmitter was hooked to a 100 or 200 watt light bulb via a length of the then popular twisted pair feed line, their signals  sometimes could be heard across town, and surprisingly, they could also be heard at far away locations, while using the light bulb dummy load instead of an antenna, especially on the 10 meters band.

As many of you know well, one of the best compromise antennas, and I always  will insist in that it is a compromise antenna, the TTFD, or Tilted Terminated Folded Dipole, uses a terminating non inductive resistor and although it has losses that may amount up to 10 dB and even higher at the lower frequencies, many users install them for the convenience of not having to invest in an antenna farm. 

The real advantage of the resistive loaded antenna is that you can change frequencies fast, and if the antenna is well designed, the standing wave ratio will be reasonably low, so that the automatic antenna tuners used at those professional installations really don’t have to work very hard to bring the radio to maximum power output.

Now with the antenna I am describing here at Dxers Unlimited today, the concept of a resistive loaded antenna is carried a step further, by using a terminating resistor that is a perfect match to the coaxial line.

That means that a 50 ohm dummy load resistor is connected to the coaxial cable coming from the rig using a T type coaxial fitting, then to the free end of the T type fitting, you simply connect a random length of wire and start testing !!!

Amazing as this may seem, it works! And to test the concept you will only need a coaxial T fitting, a length of coaxial cable and a dummy load resistor capable of dissipating whatever power you want the transmitter to deliver to this rather unique antenna system... NOW, this is not an April’s fool joke, … remember we are in August ... and all what has been described so far about this unique antenna is absolutely field tested by yours truly, under the most diverse circumstances. .

The incentive behind using this dummy load plus wire unique radiating system is no other than experimenting, and at the same time, this might be a useful approach if you want to avoid problems with your solid-state rig’s final output transistors while using a stealth antenna!

During the recent Hurricane Irma emergency, I installed a DUMMY LOAD PLUS WIRE ANTENNA, that consisted of a 50 ohms dummy load rated for 100 Watts continuous service and 15 meters of number 10 copper wire, and of course a T coaxial connector… The length of the coaxial cable from the transceiver to the dummy load was 10 meters, and the dummy load was located below the 500 gallons water tank on my reinforced concrete roof top.

The wire was extended from there and tied to one of my towers…. the antenna worked very well on both the 20 and 40 meters band. As expected the standing wave ratio reading was a perfect one to one, and all stations to which I contacted were surprised to hear about the extremely rare type of antenna that I was using.

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

I expect that soon we will see the appearance of the yet to be fully explained by scientists trans equatorial propagation openings that bring VHF signals across the equator with amazing regularity every year and without any connection to the solar cycle.

Send your signal reports and comments to inforhc@enet.cu and via Air Mail to Arnie Coro, Radio Havana Cuba, Havana Cuba.

(Arnie Corro CO2KK) 

Dxers Unlimited – midweek edition, August 21

By Arnie Coro CO2KK

 Hi amigos, I am Arnie Coro, radio amateur CO2KK, and your host at the middle of the week edition of Dxers Unlimited on the air and on the web from beautiful La Habana Cuba where we are experiencing thunderstorms every afternoon and early evening, with the most powerful ones lasting until late at night.

Cuban radio amateurs are well aware of the dangers of lightning, so it has become a ritual to disconnect all equipment after operating, and when on the air, at the slightest hint of an approaching thunderstorm you stop and disconnect everything, including your wires that go to the physical ground.

Since 1990 when they were recorded by on board cameras operating on the now retired Space Shuttles, sprites and elves have captured a lot of interests by geophysicists and space scientist. The most recent event recorded are:

  

Giant 'ELVE' over Russia 

On Aug. 16, high above a thunderstorm in central Russia, an enormous ring of light appeared in the night sky. Using a low-light video camera in the town of Irbit, amateur astronomer Ilya Jankowsky photographed the 300 km-wide donut hovering near the edge of space.

"It appeared for just a split second, surrounding the horns of the constellation Taurus," said Jankowsky.

This is an example of an ELVE (Emissions of Light and Very Low Frequency Perturbations due to Electromagnetic Pulse Sources). First seen by cameras on the space shuttle in 1990, ELVEs appear when a pulse of electromagnetic radiation from cloud-to-ground lightning propagates up toward space and hits the base of Earth's ionosphere. A faint ring of deep-red light marks the broad 'spot' where the Electromagnetic high intensity pulse hits.

"For this to happen, the lightning needs to be very strong-typically 150-350 kilo-Ampères," that is from one hundred and fifty thousand to three hundred thousand Amperes, says Oscar van der Velde, a member of the Lightning Research Group at the Universitat Politècnica de Catalunya. "For comparison, normal cloud-to-ground flashes only reach from 10 to 30 kiloAmperes."

ELVEs often appear alongside red sprites, which are also sparked by strong lightning and are under scrutiny by ionosphere researchers because they may be the cause of some particular form of Sporadic E layer clouds. By the way, during the ELVE event over Russia, Jankowsky's camera caught at least two clusters of sprites dancing nearby.

ELVEs are elusive, and that's an understatement. Blinking in and out of existence in only a millisecond, they are completely invisible to the human eye. For comparison, red sprites tend to last for hundredths of a second and regular lightning can scintillate for a second or more. Their brevity explains why ELVEs are a more recent discovery than other lightning-related phenomenon.

Despite the poor propagation conditions during the weekend, the international event dedicated to lighthouses and lightships was a success, and I think that all participants did enjoyed the relaxed atmosphere prevailing while operating their stations because of the non-contest nature of the event. It did provide a nice opportunity for newcomers to the Dxing world to work the rarely used T4 prefix, authorized for the special occasion to several Cuban radio club stations that operated from lighthouses. Among them, at the Santiago de Cuba Morro Castle Lighthouse T48SC, tango forty-eight sierra charlie accumulated a good number of contacts.

Now we must wait for the final report from the organizers of the ILLW International event to see the results. Let me add that to calculate the short propagation conditions for the weekend I had to use the number 1, yes 01 Sunspot Number feeding the forecasting software, that I regularly use because its simplicity and accuracy, the nice job of W6EL, who made it freely available. W6EL HF propagation forecasting software runs fast and when I compare results with other much more sophisticated programs, the results achieved, are good indeed.

The non-conversational digital communications mode FT8 has already brought a lot of controversy, and the saga goes on and on, something that, in my opinion, has benefitted amateur radio during this extended period of extremely low solar activity and its associated very poor HF bands propagation conditions.

  

Item # 2 - of special interest to short wave listeners that enjoy catching DX on the tropical broadcasts bands and good news coming from Brazil. A new station on 90 meters, Rádio Cultura de Araraquara is on 3365 kHz in the   tropical band.

The station has just announced that starting last Friday, August 17, it began transmitting, using 3365 kHz, and running one kW, but not specifying the type of antenna in use. The broadcast schedule will be from 2100-0300 UTC and to make the best possible use of both greyline and night-time propagation at that location of Brazil.

As anyone monitoring the HF bands on a day to day basis, will easily find out, the low solar activity continues to limit the chances of shortwave propagation on frequencies above 20 megahertz, even during the best times of the day at any given location. The exception comes when sporadic E layer openings move the maximum usable frequency up past the 25 MHz range.

Recent observations confirm that solar cycle 24 continues to show very weak activity as compared with any of the previous five solar cycles and some scientists are calling for an extended tail end of the cycle to last even two more years, while other solar researchers are telling us that we are now already well into solar minimum.

Si amigos, I receive many radio related questions coming to the ASK ARNIE section of Dxers Unlimited ... and they have helped me to learn more about the radio hobby, making possible to share with my listeners some very interesting findings.

Peter, from Birmingham in the United Kingdom, wrote asking about how he could replace worn out vacuum tubes on a nice 1950's vintage radio receiver that he is bringing back to life. Peter explains that the wooden cabinet is simply beautiful, and the radio was kept in a dry place for storage after it broke down.

After exploring the circuit diagram, Peter found out that the valve or vacuum tube marked ECH81 showed a whitish dust inside the glass bulb, indicating the loss of vacuum, fortunately the ECH81 tube is still available from Russia where it was manufactured in large quantities under the designation 6 INDIA ONE P.

This is Radio Havana Cuba, the name of the show is Dxers Unlimited and here is news about a little known amateur radio satellite the first Phase 5 amateur payload is already operational in an elliptical orbit around the Moon.

Yes, you heard it right ... there is a Chinese satellite carrying amateur radio transponders that is orbiting around the Moon...The last transmissions from LongJiang 2 were on 2018-08-05 from 00:30 to 02:30 UTC and from 07:30 to 09:30 UTC on 435.400 MHz and 436.400 MHz.

Various experiments are being carried out with GMSK and JT4G downlink signals. Stations with 'normal' amateur equipment can receive the downlinks quite well. Downlink signals have even been received with no more than an Arrow antenna, no preamp.

DK5LA was the first to have his signals relayed through LongJiang 2 on 2018-07-15. On August 4, the first picture of an onboard camera was downlinked with SSDV. Other experiments will follow later. Why not give LongJiang 2 a try?

Thanks to Nico, PA0DLO for the above information.

See you all at the weekend edition of Dxers Unlimited next Sunday and early Monday UTC days just after the top of the hour news...send your signal reports and comments about this and other Radio Havana Cuba's programs as well as your radio hobby related questions to inforhc@enet.cu and via air mail postage to: Arnie Coro, Radio Havana Cuba. Havana, Cuba

(Arnie Coro)

Dxers Unlimited – weekend edition, August 19, 2018

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

(GVH)

 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 inforhc@enet.cu, and via air mail to: Arnie Coro, Radio Havana Cuba, Havana, Cuba.

(Arnie Coro/R Havana)

DXers Unlimited - midweek edition, August 14, 2018

Arnie Coro, CO2KK

Hi amigos all around the world, I am Arnie Coro your host here at the middle of the week edition of Dxers Unlimited on the air and on the web from beautiful La Habana Cuba.

The “non-conversational” digital communications mode FT8 is providing many city dwellers with a viable option to make contacts otherwise impossible with SSB or CW. It has also brought a lot of controversy that in my opinion has benefitted amateur radio during this extended period of extremely low solar activity and its associated very poor HF bands propagation conditions. Here is a very nice comment about the FT 8 digital mode

It is a fact that FT8 is extremely popular right now. Even when band conditions are good, there are times when few or no CW or PSK signals are present on a particular band, yet the band has lots of FT8 signals, with many stations easily workable with QRP and a simple antenna.

It is also a fact that FT8 is the easiest ham mode to use, and simply make contacts, barring none. Especially with QRP power. Under favorable conditions, you can work and log a station, exchanging call signs, signal reports, and Grid Locations, in under two minutes, by a couple of mouse clicks. The data is formatted and exchanged totally automatically. Another mouse click confirms the entry for logging.

But let me make it quite clear amigos, for all practical purposes, this mode is totally "non-conversational."

Yes, you can compose and send a station a 13-character message, but you can't ask that ham if he also operates on six meters or the type of antenna in use.

FT8 gives no chance for person to person dinamic exchange of information other than the data provided by the 13 characters messages!

Item # Two: Special interest to radio amateurs who are now using the sensational FT8 digital communications mode.

Si amigos, I receive many radio related questions coming to the ASK ARNIE section of Dxers Unlimited...and they have helped me to learn more about the radio hobby, making possible to share with my listeners some very interesting findings.

Amigo Randall, from Utah, USA and yours truly have exchanged ideas about regenerative receivers we have built, that make possible excellent reception of the HF bands spanning from 4 to 12 megahertz.

So when I received a question asking about what could be considered to be the most rugged, reliable, easy to homebrew, that can be made from electronic components not hard to find, and even using recycled parts, I immediately started to work on the project, that has kept me busy all along the weekend reviewing my notebooks and going to the workshop to pick up half-finished receivers projects.

The new CO2KK shortwave receiver already has a  name, an acronymn, coming from the words RUGGED RELIABLE EASY TO BUILD RADIO.... RRETOBUILD...Sunday evening, I was already drawing by hand the schematic diagram and the parts list for the front end....

Yes, it is true that the worst HF bands propagation conditions of the past ten years are happening right now as day after day, one after the other the Sun shows no sunspots, and the solar flux stays hovering barely above the lowest ever recorded value of sixty six units.

You must look back to the tail end of cycle 23 between 2008 and 2009 to see a similar long spell of a blank Sun and solar flux levels at the baseline readings.

Again, it is confirmed that according to well-known heliophysicists that keep a close watch on the Sun, some new solar cycle sunspots have been seen, something that indicated we are nearing the transition between the very weak cycle 24 and what may be another also very weak cycle 25.

For some reason or other August seems to have become the international weekend for lighthouses. Countries all over the world have become involved in one or another of lighthouse activity.

In Britain the Association of Lighthouse Keepers, ALK, conducts International Lighthouse Heritage Weekend on the third full weekend in August. Their objective is to encourage Lighthouse managers, keepers and owners to open their lighthouse or light-station and related visitors centers, to the public with a view to raising the profile of lighthouses, light vessels and other navigational aids, and preserving the world's treasured maritime heritage.

The major event which takes place in August is the International Lighthouse Lightship Weekend, ILLW, which came into being in 1998 as the Scottish Northern Lights Award run by the Ayr Amateur Radio Group.

The ILLW takes place on the 3rd full weekend in August each year and attracts over 500 lighthouse entries located in over 40 countries including Cuban stations that will use the T4 prefix for the special event stations.

QSL on the air to the listeners that have recently sent e-mail messages to inforhc@enet.cu

Yes amigos, send your reports, comments and your radio hobby related questions to inforhc@enet.cu Catch those elusive, now rare, F2 layer propagation events during solar minimum years that occur during your local daytime hours.

Here is how to catch MORE of those band openings by using the scanning functions of digital radios to search for 10 meters amateur band beacons, operating from 28.2 to 28.3 megahertz. Plus, you can do like-wise by programming the 40 citizens bands channels and leave your radio connected to a quarter wave vertical ground plane omnidirectional antenna, ready to pick up any DX signals that may reach your location.

The bad news that continues to worry shortwave listener’s and amateur radio operators, is that there are no signs for improvement of shortwave propagation conditions ... and this, is WHY it is happening.

Solar flux is holding at very low 70 flux unit levels and zero sunspots in sight. Let me repeat the following:

SOLAR MINIMUM UPDATE: The sun has been without sunspots for more than 50 percent of the days of this year 2018. To find a similar stretch of blank suns, you have to go back to 2009, when the sun was experiencing the deepest solar minimum in a century. Solar minimum has returned, bringing with it extra cosmic rays entering into the Earth's upper atmosphere, long-lasting holes in the sun's atmosphere, and strangely pink auroras. And as expected the worst propagation conditions on the HF

bands above 10 megahertz in more than nine years.

Current propagation Conditions: 

Solar-terrestrial indices for 13 August. Solar flux 68 and estimated planetary A-index 5. The estimated planetary K-index at 1200 UTC on 14 August was 1. No space weather storms were observed for the past 24 hours. No space weather storms are predicted for the next 24 hours. 225 Issued Tuesday August 14, 2018 at 1345 UTC

Solar activity was very low.

The daily solar flux index numbers (DSFI) were 67.9 67.8 66.4

There had been eight consecutive days with a 2000 UTC daily solar flux index number (DSFI) less than 70.

The official daily sunspot number (DSSN) was 0.

There had been 45 of the past 48 days with an official daily sunspot number (DSSN) of 0.

In 2018 there had been 132 days with an official daily sunspot number (DSSN) of 0.

New sunspot may be showing up On Tuesday August 14, 2018 a new plage rose around the eastern limb of the sun located at approximately S08E55. There may be one tiny sunspot associated with the plage and it could be numbered later today if it survives.

 See you all at the weekend edition of Dxers Unlimited next Sunday and early Monday UTC days just after the top of the hour news...send your signal reports and comments about this and other Radio Havana Cuba's programs as well as your radio hobby related questions to inforhc@enet.dot.cu or via air mail. Send your postcards and letters to Arnie Coro, Radio Havana Cuba. Havana, Cuba.

(Arnie Coro/R Havana Cuba)