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Showing posts with label Argentina. Show all posts
Showing posts with label Argentina. Show all posts

Thursday, October 5, 2023

A Cuban Knack Story, and a Pandemic (SITS!) SSB version of the DSB Jaguey Rig -- Viva el Cacharreo!

 

First, the Knack Story.  Andy CO2AFV clearly has The Dilbert Disease: 

Hello my name is Andy. I had an interest in Ham radio before knowing that existed.  While I was a child my entertainment was building quartz oscillators that later I tried to receive on neighbors' and friends' radios. One day I succeeded in modulating two of them and I finally established a conversation with a friend about 200 meters from my home!!!

Andy with his FB HB rig

Here's a description of a version of the 7 MHz Jaguey transceiver that Andy built during the pandemic.  It looks to me as if he took the Jaguey DSB rig and added a 455 kHz filter with an additional mixer to turn it into an SSB rig.  So he is generating the SSB at 455 kHz, and mixing it with a VFO running at around 6.8 MHz.  The sum output would put you in the 40 meter band; the difference output at around 6.35 MHz could (mostly) be knocked down by a bandpass filter.  I think the Cuban Radio Federation Web Site gets it a bit wrong -- the purpose of the filter is probably to eliminate the unneeded sideband, not really to suppress parasitics. 

Federation of Radio Amateurs of Cuba Published: September 17, 2020 Viewed: 2352 Comments: 12 

Radio Transceiver CO9BIA 455 A construction carried out in times of Pandemic by its author, Andy Fernández Valdespino (CO2AFV). 

Cuban radio amateurs continue to accept the challenge of isolation caused by the incidence of COVID-19, but this does not mean they paralyze their activities. Such is the case of Andy Fernández Valdespino (CO2AFV), who for more than four months has been working on the development and construction of a new transceiver, the CO9BIA 455, a device that already works perfectly in the 7 MHZ Band. 

Andy, who is technical secretary of one of the Havana Radio Clubs, has to his credit the construction of two Jagüey-type radio models, as well as several types of interfaces for programming and Digital Modes; and various prototypes of antennas, among other elements that make up its constant “cacharreo” activities, as we say in our language. 

He has now completed and tested a new model that he has named with the callsign of his Radio Club, CO9BIA, and the model 455 is due to the use in this prototype of a filter of the same capacity. Asked about the details and other construction bases of this radio, whose transmission and reception tests using only outputs from the driver were carried out on September 14, Fernández Valdespino pointed out that his objective was to build a portable QRP equipment, of very large proportions. small, that it would be capable of being operated in the 40 meter band on both sides, by incorporating an improved VFO from the traditional Jagüey, but this with some modifications, and that the radio in question would work powered by a 7-inch battery. .2 volt, the same ones that come with most of the “Handy” used by radio amateurs. 

To complete the “portability” characteristics of the new radio, the possibility of exchanging antennas has been incorporated, and a very light variant of the telescopic type can also be used, just over one and a half meters long. Andy explained that for the development of the new equipment, he was based on studies that he has been doing on some of the characteristics of the Jagüey, a direct conversion radio with very good sensitivity, but that does not have good selectivity, so in the conditions of the current solar cycle, its behavior is not optimal. In Jagüey, the signals, after being modulated, do not pass through any band-pass filter, which causes many “spurious” signals to be released into the ether, which represents an obstacle to be solved in order to incorporate a linear that can increase its output power. All of this, the creator assures, was taken into account for the construction of this new design. For example, in the transmission step, in the CO9BIA 455, the microphone signal is mixed, pre-amplified, filtered and re-amplified, until it is delivered to the 455 kHz filter, to finally be mixed with the VFO signal; and as a result of these steps, the sum and subtraction of these mixtures is obtained, which are in the order of 6 and 7 MHz. As a final result, after these signals are injected into the input bandpass filter, only one output is obtained of 7 MHz, whose operating segments are carried out through the use of the improved VFO. Given these characteristics, with which spurious signal outputs are reduced or eliminated, in this new radio it is feasible to add a linear that can raise the power to approximately 7 watts, which would adjust to the power conditions described above.

This experienced “clunker” says that for the development and construction of this transceiver, three fundamental aspects were combined: the first, applying the experiences of having built other radio models, to ensure that the new prototype could be built by any radio amateur. with minimal knowledge of electronics, using recycled components and materials. Secondly, he used and adapted parts of the construction schemes of a radio project called LU3DY, from the Argentine Radio Club “Almirante Brown”; and finally, the adaptation of some parts of the traditional Jagüey, such as the VFO board and circuit. Although, as already explained, the radio works, 

Andy Fernández is immersed in the construction of a small linear amplifier similar to the ARARIHNA project, by a Brazilian radio amateur, as well as making final adjustments to what is already a reality: the conclusion and final adjustments of the new CO9BIA 455 Transceiver, a portable QRP device for the 40 meter Band, developed in these times when we must all stay at home, to protect ourselves from COVID-19. 

By Luis Enrique Estrada Hernández (CO2BK) FRC Information System Coordinator 


Circuit details.  


The VFO Board

Here is the web site of the Federation of Cuban Radio Amateurs that describes Andy's work: 


And I learned a very useful Spanish word through this:  "Cacharreo" is a Spanish word that means to tinker with something in an attempt to fix, mend, or improve it. 


Thanks Andy!  And thanks to  Trevor for alerting me to this great project.  

Tuesday, April 18, 2023

A Request for Digital Help from a Ham in Argentina


Can someone out there help OM Martin LW9DTR? 

His e-mail is on his QRZ.com page: https://www.qrz.com/db/LW9DTR

MARTIN LW9DTR has left a new comment on your post " The JF3HZB Digital VFO Dial in the DJ7OO Direct Conversion Receiver (Who is JF3HZB?) ":

Technical support
Dear Klaus Kirschelmann
My name is Martin and my call sign is LW9DTR
I am writing to you from my hometown of Buenos Aires, Argentina.
I need your tech support because I'm trying to run the assembly you posted with the AD9850 + Arduino Mini + Oled to apply it in a QRP transceiver project and I've encountered two problems.
The first problem is that I can't find the code to program the Arduino on your website.
The second issue is that the QRP transceiver design I'm using requires an inverted DDS output, ie as the frequency on the display increases, the output frequency should decrease.
I lack programming skills, so I'm coming to you knowing you can guide me on what commands I can change in the program to make this happen.
I will be very grateful to you in advance for your tremendous support.
I say goodbye with all due respect and wish that this April 18th, International Amateur Radio Day, surprises you with joy and new projects.
A big and warm hug.
With respect:
Martin Silva, LW9DTR

Monday, December 6, 2021

Early Radio in New Zealand, and "The Knack"

 

Thanks to Thomas K4SWL of the SWLing Post for alerting us to this gem.  Listen to Sarah Johnston's program describing the origins and early years of broadcast radio in New Zealand. 


This wonderful recording and article reminded me of a bit of ham radio history involving New Zealand,  and someone who was involved who had a surname similar to mine.  The ARRL book "200 Meters and Down" by Clinton DeSoto reports on page 91 that on May 22, 1924, radio amateurs for the first time made a contact between New Zealand and South America.  Carlos Braggio operated rCB8 in Buenos Aires.  In New Zealand, J.H. O'Meara was at the key in Gisborne. 

Writing of the early amateurs,  DeSoto wrote (on page 92): 

 "Why did they do it?  None but one of them can know, and only he would know the feeling of driving ambition, the relentless call of work to be done, the gnawing discontent that hungers for accomplishment; it would be hard to put into words. The strange thing is that there were folk, everywhere on earth it seemed, who had that urge." 

"The gnawing discontent..."  That is what Jean Shepherd had when he couldn't get his Heising Modulator to work properly.  We've all been there. 

The last line in the quote from DeSoto's book speaks to one of the major themes of this blog and of the SolderSmoke podcast:  the way in which people all around the world got interested in radio in much the same way.  So many of us, all around the world,  often at age 13 or 14, suddenly got interested in radio.  We all had (and have!) "The Knack."  This is really very nice -- it is something that we have in common, something that pulls us together. 

Saturday, April 17, 2021

Argentine SSB (BLU) Homebrew from Guillermo LW3DYL



Really nice work.  BLU is Spanish for SSB.  (Juliano BLU?)

But I think Guillermo needs to build ONE MORE BOARD!  A VFO or a VXO.  Analog. To finish the job.    Guillermo tells me this is in the works -- he selected an IF of 11.0592 MHz specifically so that he can use a variable oscillator built around a 4 MHz ceramic resonator.  

Complete schematic and PC board patterns on his site: 

https://qrplw3dyl.blogspot.com/2021/04/transceptor-blu-para-40-metros.html?fbclid=IwAR0BLMVfVTxMlVy1WyUovVJ0FVrrkMulFxeuu24lkjdkW8j-6QX5g_yV05o




Click on the Bloc Diagram for a Better View:

Monday, October 12, 2020

Quino, The Creator of Mafalda ("BASTA!") RIP


Putting "Basta" in the SolderSmoke search box yields many blog posts.  The cry of ENOUGH! from six year-old Mafalda has been part of the podcast for many years and is now part of the SolderSmoke lexicon.   

https://soldersmoke.blogspot.com/search?q=Basta

We don't do a lot of obits on this blog (we try to keep it all upbeat) but the passing of Mafalda's creator Quino is news that many of you may have missed, and that I think merits mention here.  This link has a nice 3 minute report from NPR: 

https://www.npr.org/2020/10/04/920038792/mafalda-cartoonist-quino-dies-at-88

Adios Quino. Gracias por todo. 


Monday, April 8, 2019

Congratulations to Farhan on New Amateur Satellite Launched 1 April



This is not an April 1 trick.  Farhan and Exseed Sat have put another bird in orbit.  
Details here: 
http://amsatindia.org/

This site in Argentina gives pass information: 
http://amsat.org.ar/pass?satx=aisa1

I will be listening tonight! 

Congratulations Farhan! 

More info: 



Wednesday, September 7, 2016

ZL2BMI @ AA7EE -- Possibly the Most Beautiful DSB Rig Ever Built

Dave AA7EE has a very cool blog post on his version of the famed ZL2BMI DSB transceiver (seen above).  As usual, Dave puts most of us to shame with his excellent non-ugly construction and enviable in-focus macrophotography.

Check it out:
https://aa7ee.wordpress.com/2012/07/29/half-of-the-zl2bmi-dsb-transceiver-a-simple-80m-direct-conversion-receiver/

I especially liked Dave's discussion of how and why .1 uF caps are used in the coupling and bypass network between the two chips.

Of course, the only thing I don't like about this rig is the, well, the chips.  Can we persuade Dave to build the earlier discrete component version of this rig?

Be sure to read the many comments on Dave's post.   Our friend Rogier comments on the beauty of it all.  Edgardo LU1AR (the Argentine wizard with the gyrocopter) chimes in.  And we see  feedback from Eric Sears ZL2BMI himself.  FB. 

VIVA DSB! 


Wednesday, October 7, 2015

The Coolest Guy on 17 Meters


In our last podcast I mentioned that I had a very interesting contact on 17 meters with Raul Midon AE3RM.  This morning Raul's song "Tembererana" popped up on my Pandora feed.  The song is great, but is was the album cover that attracted my attention. 

Raul has an amazing personal history.  Born in Argentina, he and his twin brother have been blind since birth.  They have both obviously triumphed -- his brother is a NASA engineer.  

You can watch OM Raul sing about technology in his TED Talk:
https://www.ted.com/talks/raul_midon_plays_all_the_answers_and_tembererana?language=en

Here is his Wikipedia page.  Check out the info about his home studio and his technology company:
https://en.wikipedia.org/wiki/Raul_Mid%C3%B3n

From the Wiki:
Midón's album State of Mind was released on May 10, 2005. The album features a guest performance with Stevie Wonder, one of his idols, another one with Jason Mraz, and a song written in tribute to Donny Hathaway entitled "Sittin' In The Middle." Midón is an avid amateur radio enthusiast,[2] and in this song he also incorporates his call sign (KB5ZOT) by using Morse code.

Here is his QRZ page:  http://www.qrz.com/db/KB5ZOT
In it he writes:  "He has been an amateur radio enthusiast since Mrs. Redmond introduced he and his brother to the hobby back when they both attended the New Mexico School for the Visually Handicapped."  Good work Mrs. Redmond!

Here is Raul's antenna in Maryland.  Maybe he was thinking of this when he designed the album cover!


    

Sunday, December 30, 2012

SolderSmoke Podcast #148


SolderSmoke Podcast #148 is available:
http://soldersmoke.com/soldersmoke148.mp3
December 30, 2012

SPONSORED BY usedradiomall.com

-- Hurricane Follow-up
-- Subliminal Mind Control to Encourage Homebrewing (beep-beep)
-- The Shortcomings of the All American Five Receiver
-- Solid-Stating a Heath SG-6 (with Farhan's circuit)
-- VK3YE's Beach DSB Rig
-- Tek 'scope connection to frequency counter
-- Mod to W7ZOI/W7PUA power meter
-- JBOTing my 20 meter DSB Rig -- A Tale of Woe
-- LU1AR "The Most Interesting Ham in the World"
-- Billy's Raspberry Pi
-- Latest QST, SPRAT, Hot Iron
-- Videos: Landfillharmonica,  Knack in Sierra Leone
-- Santa delivered a Soldering Station
-- MAILBAG

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Monday, December 24, 2012

A Christmas Present from Argentina


There is an old saying in Spanish:  "No hay mal que por bien no venga."   More or less this is the same idea as: "Every dark cloud has a silver lining."  Well, the dark cloud was my techno-agony with the parasitic oscillations (see below).  The silver lining was the e-mail from Edgardo, LU1AR, in Buenos Aires that helped me get rid of them.    Edgardo advised putting a resistor across the primaries of the JBOT amplifier stages.  This is an old "lower the Q" trick, the idea being that lowering the Q might help prevent the amp from self-oscillating.     I used 680 ohm resistors.   First I put one across the primary of Q1.  No joy. Then Q2.  No luck.  Then I put one right across the primary of that big output transformer.  That did it!  The parasitics disappeared.   And I still get a nice 4 watts of output.  Thanks Edgardo.  I hope to make a contact with this rig today. 

The real silver lining in this story comes, however, in the form of Edgardo's blog site.  Wow, what an inspiring example of Argentinian Knack.  Radios, telescopes, auto-giros.  This guy is also into homebrew DSB rigs.  Wonderful stuff.  Check it out.  (Google will translate it for you, if necessary, but even if you don't read Spanish, the pictures tell most of the story.) 
http://www.lu1ar.blogspot.com.ar/
Thanks to all who sent advice and encouragement.  Merry Christmas! 

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
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