Dxers Unlimited's weekend edition for Sunday June 3 2018

Radio Havana Cuba

Dxers Unlimited's weekend edition for Sunday June 3 2018 By Arnie Coro radio amateur CO2KK

Hola amigos... its really nice to have the opportunity of sharing with you about ten minutes of all radio hobby related information. I am your host Arnaldo, Arnie, Coro, radio amateur CO2KK  at the microphone, and here is item one of this show.
Several days in a row with at least one sunspots active region have had a positive effect on the levels of ionization, with the solar flux moving up to around 75 units... Nevertheless we continue to go through the tail end of solar cycle 24, the weakest one since mankind began to use radio waves for communications....

This is Dxers Unlimited's weekend edition coming to you from Havana, the capital city of Cuba.... Now item two: The history of radio is fascinating... every country in the world uses radio broadcasting facilities of some type, to provide vital services to its population.
Many of those sites are now part of the world's heritage.
Some of those facilities involve extremely complex engineering , using a lot of electricity to power up transmitters and having to perform regular expensive maintenance work.
In Europe we find a very interesting story around the so called Warsaw , Poland, radio mast, that when it went into operation on May 18 of 1974 for long wave AM band transmissions  as it was certified to be the tallest man made construction ever built.
The two one thousand kilowatts Brown Boveri transmitters operated in parallel to feed the huge tower with two thousand kilowatts of one hundred percent modulated long wave signals at first on 227 kiloHertz and at a latter date on 225 kiloHertz.
The huge steel structure  collapsed on August 8, 1991 due to a mistake by the crew doing maitenance work changing one of the the guy wire on the highest part of the structure.
Designed by  polish engineer Jan Polak, its height of 2,120.7 feet , that is equivalent to 646 dot 38 meters and it was chosen in order to make the mast function as a half-wavelength vertical radiator antenna, fed at the bottom,  a design parameter that was widely critiziced because of the radio frequency current distribution along the tall mast at the broadcasting frequency.

Located in Gabin, Poland, it was the world's tallest structure until August 8th 1991 when an error was made in exchanging the guy-wire on the highest part and that led to its collapse. Witnesses say it bent first then snapped at roughly half height.
During the solar minimum years , the Polish Long Wave Super High Power
225 kiloHertz AM broadcast signal could be heard half way around the world, due to the prevalent very low ionospheric absorption, typical of the solar minimum years..

Si amigos, although the Long wave AM broadcast facilities are closing down as a logical consequence of the expansion of FM and digital transmissions , plus the extremely high operating costs of the super power transmitters used at those stations, at least a few of them will probably remain on the air until the transmitting equipment life time comes to an end....
But, let me add that AM Medium Wave and AM Long wave transmitting facilities using the solid state technology will probably enjoy a lifetime well into the middle of this century....
So, Dxing on the Long wave and Medium wave AM bands will provide many more years of enjoyment, especially after 2020 when solar cycle 24 comes to an end...

The radio hobby is fully enjoyed by people with poor eyesight or totally blind... And now the availability of screen characters to voice generators is making possible for blind persons to use the digital communications modes, like PSK31, PSK63, MFSK, and the more recent JT 65 and FT 8 modes...On Thursday I received an air mail letter from radio amateu Charles Von Sant, callsign K9HIO that I would like to share with Dxers Unlimited's listeners... Charles , who live in Lawrenceburg, Indiana says he has listened to Radio Havana Cuba broadcasts for many years, finding our transmissions interesting to him He adds that he is helping an audio reading service by radio run by the Cincinnnati Association for the blind and visually impaired persons.The service is provided 24 hours a day on a sub carrier of station WGUC-FM 90,9 megaHertz FM, that operates on 67 kiloHertz. Charles add that the group provides users with receiving adapters that decode the sub carrier.
He adds that they are always looking for interesting radio programs, and that he would like to start up broadcasting a program similar to Dxers Unlimited...
Amigo Charles I wish you good luck with that project to provide a radio hobby program as part of the services to blind persons , and you can count on us for any help of advice needed....

Here in Cuba there are many blind persons that are licensed radio amateurs, having passed the Ministry of Communications tests required to obtain a license to operate their own amateur radio stations.

This is Radio Havana Cuba broadcasting via satellite on Hispasat I D transponder 79 vertical polarization, that has a nice footprint making reception possible at many locations in the USA and Canada, as well as over most of the Caribbean...
We are also on the streaming audio service from www.radiohc.cu And now here is one of Dxers Unlimited's most popular sections.... A visit to Arnie Coro's radio and electronics workshop. Si amigos, with just a few handtools, a soldering iron and a digital multimeter you can start to make your own workshop, where simple projects may be built, and also repairs could be made to electrical appliances and electronic equipment. I am not saying that you can find and fix complex faults, but you can certainly repair a desoldered audio plug, or build a simple reverse polarity protection device that will prevent damages done to electronic equipment when an external power supply is connected with the polarity reversed...
SI amigos, yes my friends, you can learn a lot about this wonderful hobby by reading tutorials devoted to teaching how to solder electronic equipment, how to follow a circuit diagram, and last but not least how to slowly go through the learning curve that makes possible to do more sophisticated homebrewing of radios and accesories ...

Amazing as it may sound, two meters band FM hand held transceivers are now available from many suppliers at rock bottom prices, and some ot those gems are also capable of operating on the 70 centimeters amateur band....Connecting one those FM transceivers now sold in many countries for less than 75 dollars or its equivalent, to an external antenna will make possible to communicate at much longer distances and establish links using the 2 meters and 70 centimeter bands repeaters.... The availability of this new generation of low cost handy talkies for the 2 meters and 70 centimeters band makes possible to enjoy amateur radio at a start up level without having to spend a lot of money.... phase two will be to learn how to build your first QRP transceiver kit, and go on the air on one of the HF amateur bands...

Listen next Tuesday and Wednesday UTC days, after the half hour news bulletin to the middle of the week edition of Dxers Unlimited, and set aside a little time to send me a signal report and comments about today's show... send mail to inforhc at enet dot cu, and Via Air Mail to Arnie Coro, Radio Havana Cuba, Havana, Cuba...
(Arnie Coro/Radio Havana Cuba)

DXers Unlimited, March 13, 2018

Radio Havana Cuba

Dxers Unlimited's middle of the week program for Tuesday 13 March 2018 By Arnie Coro radio amateur CO2KK

Hola amigos radioaficionados... hi my radio hobby friends all around the world... YES, it is time, right for you to enjoy  about ten minutes of all radio hobby related information coming to you from Havana, Cuba. I am your host, Arnaldo, Arnie , Coro and here is item one of today's

High frequency HF bands propagation will show a slight improvement only if solar activity increases during the next several days .... at this moment no new sunspot active region in sight , and the low solar flux is hovering at rock bottom levels around 70 units and even less..

By the way let me tell you that the sudden upsurge in the daily sunspot count and solar flux levels  is something that may happen at anytime during the bottom of the solar cycle ...

Yes,  This is typical of the tail end of a solar cycle, nothing abnormal at all... but it is certainly quite disgusting, due to the long prevailing minimum solar activity  to tune around the short wave spectrum and hear nothing or just very weak signals !!!

According to the most recent forecasts, next year, 2019 is going to be worse  with extended periods of much lower solar activity, that may combine with solar events that will further disrupt propagation conditions. 

Now, as we move into the  spring equinox here in the Northern Hemisphere and autumn equinox below the Equator,the beginning of summer, the propagation conditions on the HF bands from 10 to 20 megaHertz will  improve as soon as more energy reaches the ionosphere from the Sun. 

For those of us that live North of the Equator, one of the most interesting effects of late spring and summer propagation is a consequence of the daytime expansion of  the ionosphere... that causes an increase at night  of the maximum usable frequency for any given path after local sunset...

At times during solar minimum years, during the winter season  the maximum usable frequency at night may drop even below the six megaHertz band amigos !!!

 Now here is item two at the middle of the week edition of Dxers

Unlimited: I continue to enjoy very much the use of the very original software 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 quote skimmers unquote, automatically pick up amateur CW Morse radiotelegraphy signals that are calling CQ, and then also by means of an automated subroutine measure the CW transmission speed and the signal to noise ratio...

If it sounds to you as 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 short wave 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. On Sunday's afternoons I spend some of my leisure time operating on CW , on , twenty and my CQ calls at speeds between 13 and 16 words per minute and see how my signals are picked up by several skimmers and posted at the Reverse Beacon Network site so that they could be seen by just typing CO2KK, the call sign of my amateur radio station...

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

http://www.reversebeacon.net/srch.php

Then when the site opens and asks for whom you are looking for, type co2kk and you will see the latest spots on each of the ham bands where I called CQ...

Here is now ASK ARNIE, la numero uno, the most popular section of the show... answering today a question sent by listeners from the United States, Canada, Mexico, India, and South Africa, ... they all wanted to know what is the most economical type of antenna that can be used to optimize long distance amateur radio communications on the HF bands.......

That is a really challenging question amigos... but I will try to provide you with information about one of my favorite low cost DX capable antennas for the 20, 17, 15, 12 and 10 meter bands... It is not a multi-band antenna, it must be made for the specific band you want to operate... Results achieved with it are really good, if you are able to install the antenna in the clear...

It is made using locally available and low cost materials... The one third of a wavelength vertical antenna , using four quarter wave elevated radials produces a low take off angle vertical radiation pattern, and is a perfect match for 50 ohms coaxial cables feed line...

I used the 20 meters band version for many years, and my signal was many times as good or even better as the signal delivered by a local amateur operator that used a three elements multi band YAGI... Not to say that he was very upset when we compared signals with a distant station...

He even made a surprise visit to my home because he thought I had installed a three element YAGI ... I took my friend to the rooftop ands showed him the very simple vertical and the elevated ground radials. Then we went down to the station and measured the standing wave ratio , that indicated a 1 point one to one ratio...

That is of course an almost perfect match !!! I had to explain to him that there was no secret linear amplifier feeding the antenna,so what was actually happening was that the 120 electrical degrees height of the vertical monopole was concentrating the signal at low take off angles...

Needless to say that two weeks later he had improved his station by raising the Tribander YAGI to about 15 meters above his roof, and had also installed a perfect copy of my 20 meters band one third of a wavelength high 20 meters antenna. Now more valuable radio hobby related information to keep in mind when you decide to go on the air...

 AGAIN, BE ASSURED THAT I AM A FULL TIME ADVOCATE OF QRP or low power amateur radio operation although it is  quite a challenge, and that is why so many ham radio operators around the world are becoming more and more involved in building or buying CW rigs that are within the power range from 1 Watt all the way up to 5 Watt.... and some of us have installed calibrated signal attenuators that can turn a one watt rig into a one hundred milli watt transmitter at the flip of a switch that places a 50 ohms 10 decibels  attenuator between the rig and the antenna , cutting the power output to just one hundred milli watts...

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 band14060 on 20 meters, 21060 0n 15 meters and 28060 on the 10 meters band....

 Calling CQ on those frequencies will, in many instances, bring back stations that regularly monitor them for QRP signals. You can always go and check if any of the skimmers at the Reverse Beacon Network is picking up your CQ call And by the way before I forget... QRP transmitters running no more than

5 Watts into a half wave dipole fed with coaxial cable by means of a one to one balun and installed at a good height will provide really amazing results.

Send your signal reports and comments to inforhc at enet dot cu or via Air Mail to Arnie Coro, Radio Havana Cuba, Havana Cuba

(Arnei Coro/R Havana Cuba)

DXers Unlimited - January 22 edition

Radio Havana Cuba
Dxers Unlimited's weekend edition for Sunday 22 January 2017
By Arnie Coro/CO2KK

Hola amigos radioaficionados all around the world.. I am Arnaldo, Arnie,  Coro your host here at the weekend edition of Dxers Unlimited, the one  and only radio hobby program covering almost all of the 91 different  ways we can enjoy playing with our radios and accessories...

First news item... the Sun making a come back of sorts, after stalling  for about 10 days at the beginning of 2017... Sunspots are back in sight and the daily 10.7 centimeters solar radiation flux has moved up to around 85 units...  Correspondingly the next few days will see better propagation conditions on the short wave bands, especially between 10 a 21 megaHertz...

Item two.... good news coming from the European Broadcasting Union...
They are announcing a New dot radio Internet Domain The EBU is launching a new Top Level Domain (TLD) name -dot .radio - aimed at the radio community including Radio Amateurs. The launch is planned for September 2017 and the EBU says this which will progressively change the way people are reaching internet resources linked to radio.

These categories will be accepted for the use of a dot .radio domain:
• Radio Amateurs
• Radio broadcasting stations
• Unions of Broadcasters
• Internet radios
• Radio professionals (journalists, radio hosts, DJs, …)
• Radio-related companies selling radio goods and services
Item three: More and more radio amateurs around the world are learning standard electronic workshop procedures, like soldering , measuring  circuit parameters, reading circuit diagrams , also learning how to  visually identify electronic components, and all that new knowledge opens the way to start building the new generation of user friendly  radio kits... Yes I am very pleased to say that several of the most recently advertised via Internet amateur radio transceivers kits intended to be assembled at home using simple hand tools and standard measuring equipment like the now classic digital multimeters have proven  to be very reliable after proper assembly.

One recent example is the Bayou Jumper solid state QRP transmitter receiver rig, that was derived from the World War II Paraset rig used by paratroopers launched behind enemy lines and by freedom fighters in countries occupied by the Nazis to communicate vital information.  The twenty first century version uses all solid state components for the regenerative detector receiver and the power transistors transmitters...

Limiting the coverage to a narrow segment of the 40 meters band has proven to be a very wise decision, because it has helped to create more activity on the 40 meters band segment between 7100 and 7125 kHz.. Of course that this little rig is a CW only transmitter...  and it is able to receive also single side band voice signals as well as digital modes. Among the bright ideas brought forward by the radio club that is promoting this kit of parts we must include the use of coils that are part of the printed circuit board supplied with the kit of parts. Coil winding to exact specifications has proven to be a long time  problem for home builders. The Bayou Jumper, spelled B A Y O U  J U M P E R uses a single easy to wind toroid coil for the receiver...

The Bayou Jumper Transceiver was designed by two American radio amateurs Jim Giammanco N5 IB and David Cripe N M Zero S---- Here are now some
Specifications and Design Features of this very interesting amateur radio 40 meters band transmitter and receiver set General
     N5IB: Original prototype development, receiver development, PCB and
panel layouts, part sourcing.
     NMØS: Transmitter design, PCB, panel, parts sourcing, assembly manual.
     RXTX Design: Separate receiver and transmitter, built in RIT..
     T/R Switching: Hand switched with a chicken head knob, just as in the old days.
     Single Bander: 40M as supplied.
     Toroids: Only one toroid to wind in the receiver, and none in the transmitter. Only ONE for the whole rig!
     NO SMT: All parts are through hole, there are NO surface mount
devices in the kit.
     Current Requirements: Receiver 20ma, Transmitter 750ma
 
Enclosure: Beautiful silk screened panel and commercial wooden box,
for a very retro look. Dim. L x W x H, 7.75" x 5.5" x 3.25"

Here is more about how volunteer groups around the world are promoting the home assembly of ham radio equipment by designing rigs that can be successfully completed thanks to the use of high quality electronic components , extremely well designed and made printed circuit boards as well as excellent step by step instruction manuals.

The Bayou Jumper solves many of the problems found in previous attempts of making kits by addressing the most frequent failures of those projects, like for example the need to wind several toroidal ring inductances using very fine wires, a task that is quite a challenge for the older radio amateurs and also to younger less experienced home builders.

Now I am going to share with you the specifications of the performance achieved by the Bayou Jumper kit. Amazing as some them may seem to be, they were all fully verified with advanced electronic test instruments.
Receiver
     Tuning and Regeneration: Grounded front panel, and insulated shafts
on the controls, so hand effect detuning is minimized.
     Sensitivity: -120 dB (approx S1). Well below the typical rural band
noise level of approx. -100dB (approx. S4).
     Tuning Range: Tuning range approximately 120 to 150 kHz.
     One Knob tuning: No bandset/band spread needed.
     Varactor Tuning: Varactor tuning employing readily available
Schottky diodes as varactor diodes.
     RF Gain: Optional RF attenuator control, useful when employing
full-scale antennas.
     Audio: Plenty of headphone audio, and will drive a small speaker.
     Transmitter
     NS-40: Integrated into the PCB is Dave's famous NS-40 Class E
transmitter.  
More info here:
     Crystal Controlled: The rig has a socket for the old-style FT243 crystals, plus 7030 and 7122 kHz crystals and included crystal adapters. If you have old 7MHz Novice crystals, you can use them with this rig!
     Output Power: Solid 5 Watts.
     No Toroids: No toroids to wind, all inductors are etched on the pc board.
     Keying Options: Straight key built into the front panel, just like the original Paraset! Also includes a 1/8" jack so you can use it with your favorite mechanical key, or an electronic keyer with an interface, such as one of these.
     Spotting: You can activate the crystal oscillator at low power to allow zero beating the receiver to the transmit frequency.
     Final Amp: Cool running robust MOSFET.
     Spectral Purity: All harmonics and spurious emissions are 50dB or more below the carrier.
Using a half wave 40 meters band dipole antenna fed via a one o one balun with 50 ohms coaxial cable, my 5 Watts output QRP transceiver provides good two way contacts under normal propagation conditions. My daytime coverage reaches all over the Cuban archipelago, and at night I can work all over the Americas, Europe, Western Africa. Under very good propagation conditions early pre sunrise propagation of 40 meters makes possible DX contacts with Japan, Australia, New Zealand and many Pacific Islands nations--- Now at the end of the show... a short form HF bands propagation update::. Conditions have improved and will continue to improve due a slight but noticeable increase in solar activity... see you all at the middle of the week edition of Dxers Unlimited next Tuesday and Wednesday UTC days  just after the half hour newscast here
at Radio Havana Cuba.
(Arnie Coro/R Havana)