More Cuban Homebrew from the 80's and 90's -- A 160 Meter AM (Controlled Carrier) TX with Soviet 6P23s

 

160 Meter Transmitter

Jose CO6EC writes: 

I will be sending you some work of homebrew from the 80's and 90's when practically everything was manufactured by Cuban radio amateurs

The photos are of a Modulated Amplitude TX for the 160 Meter Band, about 25W of which several were made.  The final tube  was modulated in many cases by a 6DQ6, 2E26 or other similar ones that were very abundant at that time. 

This one in particular is  made with valves  6BH6 for the VFO, 6CL6 for the amplifier step and 6P23 Soviets in the final part, the modulator was made up of a 12Ax7 microphone preamplifier and a 6BM8 that came out through the cathode to the screen grid of the 6P23, in this way the carrier was controlled by modulation what we called  Carrier Control as there was no voltage on the grid at the ends there was practically no carrier  in the air which gave the impression of transmitting in SSB. hihihihihihi

For those who did not have a communications receiver, a conventional radio was adapted to receive that band, which in many cases was a VEF-206 of Soviet construction, to which an oscillator was adapted to beat the signal and get exactly on frequency. This was very popular here in the late 80's and early 90's. 

Thanks Jose.  We look forward to learning more about Cuban homebrew. The way in which radio amateurs got on the air with gear that they made themselves using the limited parts available to them is really interesting and admirable. 73  Bill 

Schematics for the Cuban Islander Double Sideband Transceiver (Please Send More Info)

 

Jose CO6EC has been digging up 30 year-old Islander schematics for us.  Thanks Jose.  This one shows a VFO for the Islander.   Note that it runs on 80 meters, but they select the second harmonic at 40 meters.  This was a smart move that surely helped with VFO frequency stability. 

Jose sent this printed circuit board pattern for the VFO.  Obviously they were making many of these rigs. 

Here is the power supply.  Jose reports that the transformer came out of a Soviet Krim 218 TV set.  As a kid, I also pulled a transformer out of an old TV -- I did it to build a power supply for a Heath HW-32A. 

Here is another version of the Islander.  Click on the image for  a better view.  Jose reports that this version was circulating during the time Islanders were being built.  He says this diagram many have been done by Arnie Coro CO2KK (SK), and may have been circulated on the internet. 

Here's the first schematic that Jose sent.  Again, click on the image for a better view. 

I will continue to gather information on the Islander and the Jaguey.  If you have any info please send it to me.  

Here are some earlier posts on these rigs: 

https://soldersmoke.blogspot.com/2023/03/the-islander-homebrew-dsb-rig-from-cuba.html

https://soldersmoke.blogspot.com/2023/03/needed-more-info-on-cuban-islander-or.html

Thanks to Jose CO6EC!  

Winterfest Loot: Who Can ID the Homebrew Receiver?

First a big congratulations to the Vienna Wireless Society and its President, Dean KK4DAS.  In spite of low temperatures that made the Winterfest Hamfest live up to its name, this year's 'fest was a big success with excellent turnout both by buyers and sellers.  There were a LOT of older rigs -- on one table I saw three HT-37s.   It was all great. Here is a video of the hamfest.  https://www.youtube.com/watch?v=oheht5jCuKE&t=619s  This was shot early on Sunday morning March 19, 2023, about 30 minutes after it opened.  An hour later there were a lot more customers. 

One of the first things I bought was the item pictured above.  I bought it mostly because we are currently building 40 meter receivers with the local high-school students.  I didn't have a screw driver, so I couldn't open up the box.   Something was rattling around in there.   I worried that the box might be mostly empty.  Or that it would have one PC board with a sad collection of ICs.  But in the hope that I would find something truly homebrew, I bought it.  

Below are pictures of what I found inside.  Can anyone tell us what this is?  ( I recognized it immediately.)  More on this device in due course. 

Other loot from the 'fest: 

The one on the left I've been using since around 1998!  It is getting beat up.  I bought the one on the right at the 'fest.  It is in much better condition.  5 bucks.  TRGHS. 

I always wanted one.  I had nice leather case, but I gave it to Dick Dillman years ago. I now feel like a real boatanchor guy.  I got for 15 bucks.  I see on Amazon they are selling for $466! 

I had one as a kid.  Will be useful in the DR.  In great shape. 

Eamon Skelton's book was a great find.  As were the early editions of SSB for the Radio Amateur.  Eight bucks for the whole lot.

I like homebrew speaker enclosures.  They add soul to the new machine. Perhaps a prize for the high-school project.  Three bucks. 

Finally, this thing.  Plagued by guilt for past cannibalizations of QF-1s,   I was going to pass on this one, but I realized that my friend Dean KK4DAS would be on his way, and if I didn't take it (and extract the variable capacitor) he would.  So I bought it.  But I may leave this one as is, for possible use as the The Radio Gods intended.  It could use some cleaning up.  It seems to have a coat of nicotine. Ten bucks. 

I also picked up a few larger knobs that may be of use with the high-school receivers. 

The Islander -- A Homebrew DSB Rig from Cuba

 

This article, the pictures, and the comments are all so cool. They really capture the spirit of homebrew. Obviously we still need more information on  the Islander and the Jaguey.  If you have it, please send it to me and I will disseminate it via this blog. 

From: https://www.frcuba.cu/filiales-grupos/villa-clara/contra-el-olvido.html  with translation by Google.  

I've been in touch by e-mail with Jose Campos CO6EC (the guy in the picture above).   He sent me this partial schematic of the Islander (we still need the VFO circuit and the RF amplifier) .  Thanks Jose! 

Published: 06 August 2018

Views: 2274

Comments: 6

Remembering

By José de Jesús Enríquez Campos (CO6EC)

Next 2019 will be the 30th anniversary of the first convention of radio amateurs in the province of Villa Clara, in Campismo de Ganuza, municipality of Corralillo, on the North coast, about 100 kilometers from Santa Clara, the provincial capital.

This convention was held on a national basis and colleagues from all the country's provinces participated at that time. We did not reach a thousand members throughout the national territory and most of the radio amateurs worked in the 40-meter Band in Amplitude Modulation Then the Lateral Side Band (SSB) was the privilege of a few and the 2 meters was something rare, which did not yet exist in our environment.

At that meeting, a project for a Tube Transceiver was presented, quite simple, with just six vacuum tubes and a BF310 transistor. It was possible to work in HF in Double Sideband, achieving a greater efficiency than the transmission in Modulated Amplitude (AM). This project became known as the Islander.

In only two printed plates, one for the VFO and another for the TX and RX part, which by the way were printed for distribution, in a company in Villa Clara, due to their easy construction and acquisition of the components (almost all of them came out of a Krin-218 TV), a large number of such equipment were manufactured by radio amateurs from all over the country. Like everything made at home, it always comes up with a little problem that later is necessary with tinkering, correcting it.

I remember listening to an old radio amateur from Havana (whose callsign I don't remember) in a pleasant QSO with another colleague, who jokingly said, "... some "Bugs" have now appeared in the band, called Islander, which is worse than the invasion of the Vikings…”, which gives an idea of ​​how many were built at that time, when if you wanted to make radio, you had to manufacture it, something unusual in these times.

As soon as we saw the project we decided to build it, because at that time we had an AM “transmitter” with modulation by “Carrier control” with four tubes, a 12AX7 preamplifier; an ECL82, as a modulator, with cathode output to the final tube Screen grid, a 6DQ6 and a 6BH6 as VFO; and to receive, an old Russian receiver from World War II.
 
 We got involved in the construction and improvements of the project and we managed, with some changes, to improve its performance and quality, because among the modifications to the original, we added: 

 -A switch, with which you could change the transmission mode to DSB -CW-AM.
-A "Pi" Filter at the input of the RX, which considerably improved its quality.
-An automatic volume control, because since it did not have AGC (Automatic Gain Control), when someone nearby came on, it would break your speaker.
-A filter for the microphone input, which improved the quality of the modulation.
-A final power stage, with a 6146B, with 750 V on the board, for about 70 W of  output, taking advantage of the 6P15P as Driver.
-The chassis was built from scratch using aluminum trays that were sold at the hardware store for “four pesos” each and that were special for making cabinets for these purposes.

After the construction was completed in one afternoon, with Reinaldo Martínez Domínguez (CO6UK), from Manicaragua, the balanced modulator was adjusted, since the good transmission of this type of equipment depends on the relationship between the amount of RF and audio that are mixed At that stage, it took us a long time to adjust, until Reinaldo with his expert ear told me, “leave it there, don't touch it, it's 99% complete”.

There were many international contacts that I was able to make with this very simple equipment, with very good reports, many of them with Europe, the American continent, that was very normal, since the propagation conditions in those years had nothing to do with the today, you could do half the world in AM, with about 100 W.
 
Many colleagues at that time asked me what equipment I was using.  When I told them it was an Islander, they asked me to send them the plans of the improvements made, they were many modified plans, mimeographed.
 
Perhaps the youngest do not know what that was and the photos taken by colleague Joel (CO6JC) that helped to illustrate the distribution of the components in the chassis, were sent to radio amateurs from the different provinces, in the interest of contributing modestly to migrate from AM to the Double Side Band, today it is a rarity to listen to someone on AM, there are already few who appear in Double Side Band, which shows that we have developed in these almost 30 years, despite the difficulties, which We went from just under a thousand to about 8,000 throughout the country today.

From time to time, a colleague in the 40 meter Band, from another province, has told me that he still keeps the plans and photos that were sent to him at that time, or as "Kike" (CO6GO) that he still has a Islander as a relic.

Ours passed away a long time ago and part of its components went to other projects, thanks to Joel (CO6JC) there is a graphic record of it, and that at that time I had hair, which I have lost in these bustles.
 
With this brief comment, we only want the new generations to know what radio amateurs were like in those days and the older ones to remember it.

Nothing, to remember is to live again.

Here he left you some images.

• (co6ec) Jose de Jesus Enriquez Campos

  Monday, 06 August 2018 19:30

  The first Image was the prototype presented at the Ganuza meeting, the rest of the photos were the ones we built with the improvements, and the photos and plans were sent to many colleagues, the colleagues who went to that meeting will remember, well, they still have to there are many left, because that was almost 30 years ago,
  greetings CO6EC

• (co8zz) Raul Verdecie

  Monday, August 06, 2018 23:12

  Magnificent photographs!!!... They seem to have been taken today with some digital "super camera"!!!
  Really, from what I can see now, the CO6EC Islander was the perfect example... mine (my first radio and built by me) was also made like this, with the plates that the FRC sold and it was good, but very ugly ...HI... The AGC worked wonderfully as it came, I don't know if Jose's improvements were later! With it I made my first hundred or so entities only in 40 meters / CW (between 7,100 and 7,150) when it was CL8ZZ. I gave it away so that someone would have their license and now I regret not having kept it... I would have liked to show it now to those who regret not having a radio!!!

• (co8zz) Raul Verdecie

  Monday, August 06, 2018 23:43

  Ah, I can never forget those headphones!!!... my external hearing aids (read ears) are much smaller today thanks to them, they exerted tons of force on the operators' skulls!!!

• (cm6vml) Vidal

  Tuesday, August 07, 2018 23:40

  Very good article, I hope that one day, with a good teacher, I can build my own team, congratulations Jose, regards Vidal.

• (co7wt) Pavel Milanes (CO7WT)

  Wednesday, August 08, 2018 09:52

  Sure...
  
  My first radio and with which I got my CL7WT license back in the 90's an ISLANDER, like that in capital letters.
  
  I remember that the CL only had a small 40m segment (like now) and that it was full of broadcasts as soon as the afternoon fell, it was an odyssey to speak on the radio... you had to find a "little hole" between the Broadcastings where it wouldn't bother you " a lot" to be able to talk.
  
  I remember that the old CO7OC (he is no longer a radio amateur) and CL7HU (now AC7HU) helped me build it with a board I bought at the radio club. I took almost all the valves from the deceased KRIM 218, then I found a store in Camagüey that sold idle things from the workshops...
  
  Turns out they had such a large inventory of "idle" tubes that they couldn't put it on the counter...they let me through to the warehouse...huge...stack of tubes, if I remember correctly I ended up with Chinese or Japanese tubes that they were more sensitive in the receiver... the driver went from a 6P14P to a more robust 6P9, by the end that was a humble 6P44 it became two 6P7s that were a Russian version of the RCA 607 if I remember correctly... in the end it had like 80W.
  
  It goes without saying that when I said on the radio that there were valves in that place "they flew"....
  
  The VFO was the one from the Jagüey, not the original from the Islander, I never knew about the AGC modifications.
  
  I would like if someone has the plans with the modifications to send them to me, just for nostalgia...
  
  My email pavelmc@gmail.com
  

• (co2jc) Carlos Alberto Santamaría González

  Monday, August 13, 2018 00:21

  Brother, your article is very good, because of the nostalgia and also because it talks about what we radio amateurs like: tinkering. I didn't have an Islander because what I started with in 2000 was a Polosa to which two colleagues helped me adapt it with VFO for 40 and 80 m. But I talked a lot with colleagues who did it with an Islander or a Jagüey and participated in the Rueda del Behique that I started in the 80 m. Others in the Hurricane Wheel that started a little later and were heard well. As you well say, the propagation at that time had nothing to do with what it is now, but it was very good to listen to the colleagues who came out with the equipment they had built. Thank you once again for your article. CO2JC

Needed: More Info on the Cuban Islander or Jaguey DSB Transceivers

CO6CBF: "I began operating on the HF bands using homebrewed radios. Mainly on CW running just 10 Watts. My very first phone transmitter was a controlled carrier AM modulator for the 160m band using tubes and components salvaged from an old TV set."

My good friend Dean KK4DAS has built a DSB rig for 10 meters and is working a lot of DX with it.  Peter Marks in Australia has also jumped into the DSB game.  A few of the students we are working with at the local high school may get their General Class licenses and convert their Direct Conversion receivers to Double Sideband transceivers. 

All of this has caused me to reminisce about the famous Cuban Double Sideband rigs. Homebrew Hero Arnie Coro CO2KK used to talk about these rigs on his "DXers Unlimited" program on Radio Havana Cuba.   But Arnie recently passed away, and with him I think a lot of the background info on the Cuban DSB rigs has also disappeared. I find very little about these rigs on the internet -- I have not been able find a single picture.  The Radio Havana Cuba archive of Arnie's shows has disappeared.  

Back in February I talked to Yulian CO6YI on 20 meters about the Cuban DSB rigs.  He said he had a lot of background info on them, and said he would try to send it to me.  I hope he is able to do this. 

The results of my initial Googling appear below.  There has to be more out there. I'm thinking that there must be a lot of background info on the Islander and Jaguey rigs sitting on the hard drives of radio amateurs.   It is time to give this info wider circulation.  Please send me any info you have on these rigs.  Of particular interest would be schematic diagrams and photos of the rigs.  

 

https://www.paara.org/newsletter/2000/graph200007.pdf

The Super Islander Mark VI: https://docplayer.net/24137256-Radio-havana-cuba-dxers-unlimited-s-weekend-edition-for-sunday-sunday-9-august-2015-by-arnie-coro-radio-amateur-co2kk.html

Date: Mon, 22 Mar 2004 17:48:59 -0500
From: "Prof. Arnaldo Coro Antich" 

Subject: Re: GB> 6EH7 vs. 6EJ7 as RF Amplifier

 Dear amigo Chris:
You are absolutely right !
EF184 is the best pentode for RF amplifier duty...
But, let me ask you something... have you thought
about the ECC88 and the even better ECC189 dual
triodes that were designed for TV tuner work, and
that incidentally were also about the last vacuum tubes
ever designed from ""scratch"" until Phillips and other
European manufacturers stopped from making
receiving type vacuum tubes.
The ECC189 is simply wonderful for a front end !!!
I am sure that you are aware of our limitations here at
my QTH regarding the possibility of obtaining solid
state modern devices... so we still make ""new"" ham radio rigs using mostly
vacuum tubes...
We even still make a version of "" The Islander"" a DSB transceiver with
direct conversion vacuum tube receiver...
Tube lineup is
EF184 RF amp
ECH81 product detector
ECH81 triode section not used
ECL82 triode audio preamp
ECL82 pentode audio output
6AH6  VFO ( Russian equivalent 6*5P )
Audio filter provided by good working brain of
operator !!!
Keep up the good work amigo !!!
73 and DX
YOur friend in Havana
Arnie Coro

CO2KK

http://ibiblio.org/modena/GLOWBUGSpiobaire/glowbugs.piobaire.weekly.html

Today’s first question came from a long time listener in India. Rajiv 
tells me that at this moment he is not able to pick up our station on 
the shortwave bands, and he rightly assumes that this is because of the 
very low solar activity… but Rajiv who lives in the garden city of 
India, Bangalore, the home of the nation’s electronic and other high 
tech industries, is able to read the scripts of the program that are 
made available to several short wave listeners clubs e-mail distribution 
lists. Rajiv tells me that he wants to obtain the electronic files of 
the Super Islander amateur radio transceiver to compare the circuit 
diagrams and design philosophy with a similar project that is becoming 
very popular among Indian radio amateurs.
Ok amigo Rajiv… I have already sent you all the files including some 
nice digital photos of the first prototype of the Super Islander, that 
as you will see, has two final amplifier options , one built using NPN 
RF power transistors, and the other one using two vacuum tubes that are 
very easy to find here in Cuba from recycled TV sets. The Super Islander 
is a single band transceiver that can be built for the 160, 80 or 40 
meter bands. Here in Cuba amigo Rajiv, the most popular amateur band 
nowadays is two meters, using the FM narrowband mode, and the second 
most popular band among Cuban radio amateurs is 40 meters, that’s why 
most of the Super Islanders are built for operating between 7.000 and 
7.150 kiloHertz.  The double sideband signal generated by the Super 
Islander simple circuit is very stable, and very few if any radio 
amateurs that contact stations using the Super Islander are able to 
detect that it is a double side band and not a single side band signal 
what they are hearing. One of the most outstanding features of the Super 
Islander single band amateur radio transceiver is that it is modular, so 
those who want to build it, are able to build and test each module as a 
single project, and after all the modules are fully tested, then they 
are easily wired together . The parts count, that is the number of 
components required to build a Super Islander was kept intentionally as 
low as possible, both to simplify its construction and to increase the 
reliability. I hope that amigo Rajiv in Bangolore , India will be able 
to make good use of the Super Islander’s files, and maybe even go ahead 
and build one , as the parts required are almost universally available, 
because that was one of the design requirements that I set when starting 
the  Super Islander project more than fifteen years ago….You can learn 
more about this simple amateur band transceiver by sending a request for 
the Super Islander files to arnie@xxxxxx … I will send it as a dot zip 
file and you will be able to see circuit diagrams, photos and full 
descriptions of the different modules of this nice little rig, that has 
proven itself under the most difficult circumstances, like handling 
emergency communications links during tropical storms.

http://www.hard-core-dx.com/hard-core-dx/2007/msg02587.html

https://studylibfr.com/doc/10070052/nmrevue-012008

Beginners generally build one of two radios; the vacuum tube Islander or the solid state Jaguey. The Islander is a DSB/CW Cuban design using a very clever low parts count circuit and a direct conversion receiver. The Jaguey, named for the Jaguey Grande Radio Club in Matanzas province, is a generic design, with a DC receiver, DSB and CW, using solid-state components. Many of its ideas are from Wes Hayward's W7ZOI's Solid State Design for the Radio Amateur. The lack of mechanical filters or quartz crystals to homebrew SSB filters made Cuban designers CO5GV, CO2JA and CO2KK choose a DSB and CW rig. Fitted with good quality capacitors for the VFO, it works quite well from a 12-volt car battery in hurricane emergencies.
https://web.archive.org/web/20140917014137/http://www.worldradiomagazine.com/old_wro/articles/features/cuba.html