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 09 December

Radio Havana Cuba
By Arnie Coro CO2KK

Hola amigos radioaficionados now listening to the weekend edition of Dxers Unlimited, I am your host Arnaldo, Arnie, Coro, radio amateur CO2KK wishing you excellent reception of this the week end edition of this program .

QSL on the air to the many listeners that have sent signal reports and comments to inforh@enet.cu We do appreciate the recent reports that have also included mp3 audio files attached to the email messages... That is the most objective form of reporting the quality of reception amigos !

QSL on the air to Paul Brown from Canada who sent an mp3 file and a photo of the screen of his transceiver that show excellent reception of our 6000 kHz - 49 meters band frequency using our 010 degrees azimuth curtain antenna array.

Solar activity update....sixty percent of the days of this year 2018 went by without a single sunspot... 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 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

Yes amigos , there are more than 91 well documented different ways of enjoying the radio hobby, and here I am to tell you about some of them today.

The 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 MHz, 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 MHz 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. anUsing advanced complex Yagi antenna arrays of between 10 and 40 elements , FM 2 meter band

Dxers participate in many contests, and are able to link up via far away repeaters.....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 are very useful to keep club members informed about relevant activities and also provide excellent practice for emergency communications

Requests about the circuit diagrams and building instructions the ever popular Australian regenerative solid state radio keep coming... The name of that simple receiver is the MOORABIN--- Send your request for any of the circuits diagram in our collection to inforhc@enet.cu. Also receiving  requests and questions relate to or 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 this receiver, that forms part as a module 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

More tips about operating simple home brew receivers like the MOORABIN thee Super Islander Mark Six  Yes amigos, I do insist about the fact that using a battery power supply is essential for optimum performance  of any solid state receiver and there are no exceptions.

Here is now ASK ARNIE , the most popular section of this program with the reply to the question sent by listener Michael from Edimburg , Scotland.....he wants to know more about how to find the sources of radio frequency noise that are making his reception of the AM medium wave band simply impossible .

Well amigo Michael you are just one more of the millions of listeners that are having difficulties picking up stations operating within the frequency range of 530 to 1700 kHz, and that is assigned for the AM medium wave broadcast band... In the Americas stations use 10 kiloHertz channel spacing, while other parts of the world use 9 kHz for separation between stations.

With the advent of many different home electronics and electrical equipment using the switched mode power supplies, the situation regarding the baseline noise level between 100 kHz and 10 MHz  has increased significantly .

So my number one advice for you amigo Michael is to check for the presence of any electronic or electrical device that may be the source of harmful interference....because it may be using a switched mode power supply.
 
This can be done by exploring your house using a portable AM receiver tuned to the low frequency region, listening to an empty channel as you move around each room In actual practice you may also just disconnect the electricity circuit breakers one by one while listening to the AM sniffer radio.... You do not need to be a radio Sherlock Holmes to locate at least a few of the interference makers.... that are within the affected area, including computers, cellphone chargers, automatic furnaces controls, TV sets and even a fish tank pump...

Helping a local radio amateur to find what was making his 40 meters band full of very intense signal, we found that the ADSL modem was the culprit.
In an upcoming program, I will give advice on how to deal with today's most impacting problem affecting our radio hobby .... dealing with devices that generate radio frequency interference.

Send your signal reports, QSL requests and radio hobby related questions to inforhc@enet.cu or via airmail: Arnie Coro CO2KK, 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, October 9

Radio Havana Cuba

Dxers Unlimited midweek edition for Tuesday 9 October 2018 Hola amigos radioaficionados all around the world ... I am Arnie Coro, radio amateur CO2KK, your host here at this the middle of the week edition of  Dxers Unlimited, your favorite radio hobby program....coming to you on the air and on the world wide web streaming audio , PLUS also on four FM broadcast band frequencies here in Cuba.

Here is Item One...hurricane Michael impacted the western part of Cuba with sustained winds exceeding 114 kilometers per hour and torrential rains.

According to Cuban weather expert Miguel Angel Hernandez, the north right quadrant of the storm will be slowly moving across the Yucatan Straight that separates Cuba from Mexico. As soon as the Cuban Civil Defense issued its first tropical storm alert, radio amateurs of the Pinar del Rio branch of the Cuban Federation of Radio Amateurs started to set up the emergency communications systems planned for the bad weather conditions.

They will be operating on the two meters band on frequencies from 144.300  MHz to 145.8 MHz for simplex FM mode operation, and they will also make use of several FM two meters band repeaters operating from 145.110 and 10 to 145.490 MHz.

The long range FM repeater at the Loma de Salon mountain is on 145,110 MHz and covers the eastern part of Pinar del Rio province, it has full coverage of Artemisa province and also provides service to fixed stations with external antennas located in Mayabeque and La Habana provinces of western Cuba.

Si amigos, this is the middle of the week edition of Dxers Unlimited. I was writing this script Monday afternoon when the first rain bands of tropical hurricane Michael were already producing constant rain fall over La Habana.  

Further to the west and south west, it was already raining heavily, as the storm was approaching western Cuba. For this particular hurricane related emergency, I will keep a close watch on the use of our 40 meters National Emergency Nets due to the very poor HF propagation conditions via the Near Vertical Incidence Skywave propagation mode.

Again, most emergency related traffic is expected to be on two meters FM, making the best possible use of the already existing repeaters located at TV stations towers and mountain top sites.

This is Dxers Unlimited, and here is now the very popular ASK ARNIE section of the show.... Today I am answering a request by several newcomers to amateur radio that want to know what equipment is needed to provide emergency communications.... first of all, you must understand that providing to your community back up emergency communications is a very complex matter It must be understood that the real strength of amateur radio comes from the commitment to provide volunteer services by operators that usually will form part of a radio club. EMCOMMS as they are known require to own and have ready to operate transceivers, antennas, batteries, generators and supplies to keep those stations operational.

Even the most simple low cost two meters, and seventy centimeters dual band FM handie talkie is capable of providing vital links between disaster areas and government authorities, that have lost contact when the cellphone systems and the fiber optic cables networks collapse, like in the case of an earthquake or a hurricane.

Yes, a less than fifty US dollars 2 meters and 70 centimers handheld FM radio can become a most useful link, especially if you add to it the following three items.

# Number One: at least one, or better yet two more additional batteries.

# Number Two: a flexible battery charger that can be connected to a generator or to a car or truck, yacht or aircraft electric system.

# Number Three: at least one omnidirectional antenna that can replace the handie talkie's small stub helically wound low efficiency unit provided with the radio. Better yet add a second portable YAGI antenna of at least three elements that can be easily transported, assembled in a few minutes and that will come with a portable telescopic mast capable of placing the vertically polarized YAGI at no less than three meters above any surrounding objects.

Si amigos, yes my friends, as you hear this program there are more than

50 Cuban radio amateurs that have activated the National Emergency Net to provide alternative communications in the areas of western Cuba that received the impact of category 1 Hurricane Michael expected to reach the southern USA starting on Tuesday.

Many of them use their handheld FM two meters band transceivers as part of the equipment used for local communications, and standard SSB transceivers for operating on the 40 and 80 meters bands.

This is Radio Havana Cuba, the name of the show is Dxers Unlimited and here is our popular technical topics section, devoted today to providing protection against wrong battery polarity connections that can produce very serious damages to radio equipment.

This is especially important during emergencies, when you may need to connect your radios to an external high ampere hours capacity battery. You would not mind to loose around three quarters of a volt on the feed voltage that will happen when a high current silicon diode is inserted into the positive wire of your radio and the battery.

If by mistake the battery is connected with the wrong polarity, the big silicon diode will provide protection, as no current will flow. This is my ultra-simple solution against wrong battery polarity mistakes, that I have incorporated as part of the emergency communications kit.

In the case of some two meters band FM hand held transceivers of the older generation, some of them have enough space inside to include the required three-amperes rated reverse polarity protection diode, but this approach is impossible with the latest generation of low cost dual band two-meters and 70 centimeters hand held, that are extremely compact. For those radios I use a connection to the external battery that incorporates the high current protection diode.

Using a recycled three to five amperes rating silicon diode will provide all the required protection, but if you are a perfectionist and want to spend the extra money, then using a very low voltage drop MOSFET device or a SCHOTTKY diode, will reduce the voltage drop from about seven hundred millivolts to just two hundred millivolts.

See amigos, yes my friends, if you ever use external batteries to provide power to your radios, follow my advice and add reverse polarity protection to all of them...the cost is minimal and preventing wrong polarity connections is vital for the survival of your radios.

The reports keep coming in as the autumn Trans Equatorial Propagation season peak is now in progress.Every day I keep receiving advisories about TEP openings from radio amateurs in the Caribbean and South America.

Most frequent reports make reference to 10 meters band QSO's, while less number of them report 6 meters band openings across the equator. So, my advice for you is, to keep a close watch at the way the maximum usable frequency curve moves up especially during the afternoon and early evening hours, local time when chances of TEP openings are more likely to happen..

And now amigos at the end of the show a short form space weather and solar activity report PREDICTIONS FOR 10 Oct 2018, 10CM FLUX: 071 / AP: 011 PREDICTIONS FOR 11 Oct 2018, 10CM FLUX: 071 / AP: 007

COMMENT: There were no sunspots nor flares on the visible solar disc of the Sun in the past 24 hours.

Amigos see you at the weekend edition of Dxers Unlimited next Sunday and Monday UTC days just after the top of the hour news bulletin.

(Arnie Coro)

Dxers Unlimited program, Sunday edition 16 September

Radio Havana Cuba

Dxers Unlimited weekend edition - Sunday 16 September 2018

Arnie Coro CO2KK

Hi amigos radioaficionados now enjoying slightly better shortwave propagation conditions as we approach the autumn equinox.

I am Arnaldo, Arnie, Coro your host here at the weekend edition of Dxers Unlimited your favorite radio hobby program coming to you from sunny La Habana Cuba, and here is now our first news item.

For a change, another broadcast station is going back to use shortwave transmissions, to provide better service to its listeners.

Radio Nepal is now back on short-wave.

Victor Goonetilleke just wrote on the Union of Asian DXers Facebook page on  13 September 2018:

Radio Nepal is back on short-wave after six years off the air on the 60 meters tropical band, by adding 5005 kHz to augment its national transmission grid broadcasting on MW and FM. According to a station official, Radio Nepal resumed short wave broadcasts from 02.00–5.00 p m Nepali time using a 10 kw transmitter at Khumaltar, Lalitpur in Kathmandu.

The same source said the station is using very low power. By all accounts, 5005 kHz is a difficult Dx catch for listeners outside of Nepal. Nepal is 5 hours and 45 minutes ahead of UTC.

  Even though the station is running its old 10kW power at present it can`t be more than a 1 kw or so. However, the greater news is that Nepal is now available on shortwave for Dxers.

Radio amateurs in the states of North and South Carolina continue to provide much needed emergency communications after hurricane Florence impacted the east coast of the United States. This one was a large diameter event, that affected a large area with very heavy rains and storm surges.

The American Radio Relay League sent several portable multi band stations to the area ahead of the arrival of the hurricane, while local radio clubs implemented the emergency plans to provide much needed alternate communications after damages to the cell phone and wired systems required the use of amateur radio stations.

Fixing broken down present day high technology radio equipment is extremely difficult, even when full information is available and the required test instruments can be used. Attempts to repair receivers, transmitters and transceivers using sophisticated solid-state high-density components is next to impossible nowadays, except when very simple problems are causing the failures... One good example is the typical battery contacts corrosion problems that often are the cause of intermittent operation... But once again, attempting to change springs that contact the negative side of batteries and small metal plates used for the positive terminals can prove to be very difficult if you don't have the proper tools and the vitally important instructions on how to disassemble the equipment so that you can access the affected areas.

One vitally important reminder is to never leave batteries inside radios and accessories in storage, and check frequently the batteries for any signs of leaks that can cause permanent corrosion damages to equipment.

Make a check list of all your equipment that uses batteries and once a month open the batteries compartment and be sure that everything is okay. If you have any doubts about possible leaks, discard the batteries immediately and do it in the most ecologically friendly way as possible.

QSL on the air, to the many Radio Havana Cuba listeners that are reporting our 15140 kilohertz frequency that is now starting at eleven AM Cuban time, that is fifteen hours UTC with the full two hours of the Cuba Online magazine show that ends at 18 hours UTC. Then 15140 kilohertz stays on the air with the same central North America 340 degrees azimuth beam with several languages feeds.

The English slot is on from three to four PM local time, that is from 19 to 20 hours UTC.  

Send your reports of the 15140 kilohertz 19 meters band frequency to inforhc @enet.cu and do include your postal mailing address so that we can send you a nice Radio Havana Cuba QSL card.

The best time of the year for AM medium wave Dxing is just around the corner.  Starting around the third week of September and lasting until the end of November the autumn and very early winter AM band Dx season this year should be at least as good as last year's one that started when the number of sunspots went below 20.

Listeners who asked why the autumn DX season for the AM broadcast band is typically better than the spring season, the answer is that during the months of March and early April atmospheric noise levels are higher than during September, and October.

By the way, I am using a recently repaired very old Grundig Yacht Boy 220 Long Wave , Medium Wave, shortwave and FM radio for late evening AM band Dxing with very good results.

Using the built in ferrite rod antenna on the AM Broadcast band during the daytime, I am able to pick up ground wave signals from stations located up to 250 miles away, thanks to the low local noise level prevailing in the neighborhood where I live.

A recent trip for a short vacation at the end of August to beautiful Varadero beach at a seaside location, brought daytime signals from more than 350 miles away coming from Cuban stations located to the east of our main island and operating on the 1200 to 1620 frequency range.

Yes amigos, even an old analog receiver can prove to be an excellent tool for AM medium wave band Dxing, among other highlights because the old radios do not use noisy frequency synthetizers.

This is Radio Havana Cuba, the name of the show is Dxers Unlimited, I am your host Arnie Coro radio amateur CO2KK and now here is ASK ARNIE, the most popular section of this program... just slightly ahead of the HF plus low band VHF propagation updates and forecasts featured whenever possible at the end of the show.

Today I will be answering a question by listener Alberto who listens from Buenos Aires Argentina to our Internet streaming audio. He wants to know why it is not possible for him to pick up our English language programs using his nice shortwave radio and external antenna.

Well amigo Alberto the reason why it is quite difficult to pick our English transmissions via shortwave at your location, is that we use directional antennas to beam the programs to North America, Central America, the Caribbean, and to the Mediterranean area of Europe. The highly directional antenna systems have what is known as a high front to back ratio, so, for example when we use the 6165 kilohertz beam to Central North America, an azimuth of 340 degrees, the reverse of the beam is on 160 degrees, but the passive reflector used on that curtain array cancels the backward lobe so that very little signal is sent in that azimuth.

By the way we do broadcast in Spanish and Portuguese to South America using identical antenna arrays that beam the signals to azimuths of 130, 160 and 172 degrees from Havana to provide full coverage of all of South America.

No need to use high power to enjoy amateur radio, even with simple equipment that do not need the assistance of sophisticate computer software digital communications programs like JT 65 and the most recent widely used FT8.

The unique joy of achieving a successful two way amateur radio contact with a DX station while running very low power, and simple radios is second to none amigos, and by the way here is a partial list of the most popular CW operating frequencies for QRP or very low power amateur stations are 7030 and 7040 on the 40 meters band, 10 dot 106 on the 30 meters band 14060 on 20 meters, 21060 on 15 meters and 28060 on the 10 meters band....Calling CQ using CW on those frequencies will in many instances bring back stations that regularly monitor them for QRP signals.

(Arnie Coro/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, 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)