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Showing posts with label India. Show all posts
Showing posts with label India. Show all posts

Sunday, June 1, 2025

Ashish N6ASD's Beautiful SolderSmoke Direct Conversion Receiver -- Built in Bangalore -- "This was such a fun project. This was my first direct conversion build, and I learned a lot along the way."


Ashish N6ASD is a really good guy.  We started watching his projects when he was in San Francisco.  He does a lot of fundamental radio building.  And he is a friend of Homebrew Hero Frank Harris K0IYE

When I spotted a "thumbs up" from an N6ASD on the SolderSmoke Discord channel, I knew that we would soon have yet another Bangalore Direct Conversion Receiver.  Ashish has been in contact with both Farhan and Ramakrishnan.  FB. 

Ashish writes:  I finally finished building the receiver! This was such a fun project. This was my first direct conversion build, and I learned a lot along the way. The biggest challenge was finding stable capacitors for the oscillator. In my first attempt, I used whatever I had in my junk box, but those capacitors drifted all over the place. Mica caps seemed expensive and difficult to get in Bangalore. I ended up buying surface-mount NP0 capacitors instead. Soldering them was a hassle, but they are much cheaper and easier to get here. Next step will be more mods and experimentation! The first improvement will be in the BPF. I will replace the regular ceramic caps with NP0 caps and re-tune it.

Here is Ashish's receiver inhaling CW:   


Congratulations Ashish -- Welcome to the Hall of Fame! 

Ashish N6ASD

The resemblance between Ashih's photo and the famous
1818 painting by Caspar David Friedrich is completely coincidental,  
but quite remarkable. 




 

Thursday, May 29, 2025

SolderSmoke Podcast #260 FDIM, Hollow State Design, Pete's Bench and the Shelf of Shame, Direct Conversion Project News, How Best to Preserve this Blog?, Dean's Bench and the Desk of Despair, Bill's Bench and the Garage of Grief, MAILBAG

SolderSmoke Podcast #260 is available: 

Audio version:  http://soldersmoke.com/soldersmoke260.mp3

Video version: https://www.youtube.com/watch?v=bZzHSjOTbSY

Quote from the Old Miltary Radio Net:  "Being on the leading edge is great, but sometimes being on the trailing edge is more fun."  Indeed. 

Heard from an Australian on the Southern Cross Net:  "My antenna needs a lot of Viagra!" 

News from Dayton/Xenia/FDIM: Dayton Xenia.   Again, we didn't go.  But Bob Crane W8SX was there and got a nice interview with Grayson,  Hans, and Farhan.  We are presenting these and more.  Michigan Mighty Mite Revival at FDIM!  Jeff W9TH. 

Farhan's review of Hollow State Design: I am compelled to set aside the future of my family and to orphan my cats to resume work on the 250v power supply that I built last year. Inshallah, Allah favors those who favor thermatrons!   Grayson's book is  imbued with deep experimental insights and littered with gems. You have to read it over and over to find new things each time.   It goes into my reference shelf in the lab."  Buy it here: https://www.ermag.com/product-category/books/ 

----------------------------

PETE'S BENCH:

Pete working on JF3HZB dial.  Send Pete a Heath mono-bander! 

MHST on shelf of shame? Even the great ones have to take a break every so often. On the importance of taking a break. Ernest Rutherford 1917 and all that:  https://soldersmoke.blogspot.com/2025/05/on-importance-of-taking-break.html 

Channelized 40 meter rig. Heard in Arizona by Andy KB7ZUT on a HOMEBREW SSB Reciever.  Very rare.   SWL HB2HB. 

Pete:  Thumb broken as a Novice?  Early episode of Fat Finger Syndrome? 

---------------------------

DC RX NEWS:  

Quote from N6QW:  "The radios do not build themselves!"  

Alan W2AEW finishes Direct Conversion Receiver. And even he worries about feedback! 

Phil W1PJE MIT receiver  (with cool MIT stuff).  Coming to see us! 

KN6FVK's Barkausen-Be-Gone Spray :https://soldersmoke.blogspot.com/2025/05/john-kn6fvks-fb-homebrew-soldersmoke.html

Indian hams working DC RX. VU2JXN Ramakrishnan, VU2TUM  Puneit Singh, Ashish N5ASD, building one in Bangalore with 3D printed form from Scott, KQ4AOP.  Ramakrishnan is planning on building a second receiver with his daughter. On June 22, 2008 in SolderSmoke #86 we reported on the birth of Ramakrishnan's daughter.  This is that same daughter! See: https://soldersmoke.blogspot.com/2024/01/long-time-soldersmoke-supporter.html    How to get a PTO form in India.  A tip from Ramakrishnan: "I got the 3d printing done via https://robu.in with 1:1 size. After uploading the stl, I received it by post in 5 days or so."

German students of Andreas DL1AJG.  and Canadian students of Daniel VE5DLD. 

Receiver built in Singapore!  9V1/KM7ABZ

John M0XJA reports 8 members of his club are building this receiver. 

Chuck N4AVC got his PTO coil form 3D printed at the local library. For free!  FB! 

Few admit to being fooled by April Fool story.  But still, inspirational. VK3HN was going for a few seconds -- SOTA AI chatbots? John West liked the 85th harmonic threat. 

What next after DC RX?  Choose carefully! Don't bite off more than you can chew. 
Do some mods!  Build something else!  And remember to be a homebrew Elmer.  Help someone else build the receiver. 

-----------------------------

SHAMELESS COMMERCE DIVISION: 

Check out the SolderSmoke blog on the WayBack Machine.  The blog, not the podcast.  www.soldersmoke.blogspot.com   Would this be a useful backup if Google were to pull the plug on blogspot?  Is the format OK?   Is the template recoverable?  How best should  we backup the SolderSmoke blog?  

Be a Patreon SolderSmoke Sponsor!   Please subscribe to the YouTube channel!  Buy your Amazon stuff through our link.  Buy stuff from Mostly DIY RF.  

-------------------------------

DEAN'S BENCH:

Dean has completed his Mythbuster: https://kk4das.blogspot.com/2025/05/kk4das-mb-20-transceiver-complete.html   Plexiglass top! 

Diode switching

Dean:  Build of the SDR receiver.  Microscope required? 

____________________

BILL'S BENCH:

VK6JDW and HCJB in the Kimberly. 

The stages of separation:  Shack, Garage, Car trunk:  HP-8640B and HAMEG scope saved from garage. HP-8640B repair.  HAMEG Modulation Monitor. 

=================

MAILBAG

-- Wouter ZS1KE.  Thinks Soviet spies COULD homebrew.  Hamilton KD0FNR concurs. Agent Sonya and Soviet Spy homebrew. Copacetic Flow. I dunno....I dunno... 

-- Hamilton KD0FNR grew up in New Mexico, supports my idea of Starlink deorbit. See : https://www.kallmorris.com/columns/goodness-gracious-green-balls-of-fire

-- Adam N0ZIB Heard my 10 meter beacon from the DR.  28,233.5 MHz  On now. 

-- Rick N3FJZ  Great memory Direct Conversion messages. 

-- John KN6FVK had fun with DC RX. Tattoos on Board. We need a high sign! Like the Little Rascals. 

-- Adrian M7EFO DC RX builder in GQRP.  FB.

-- Steve KW4H Kits not the same as homebrew, but old Boatanchor kits have value. 

-- Mike WU2D -- Old buddy Charles Kitchen SK. 

-- Craig -- Some really nice feedback on Hack-A-Day re DC RX and Dean's videos. 

-- Peter VK3TPM proposes a certificate for SolderSmoke DC RX Honor Roll. 

-- Michael WN2A used a 3 inch reflector from Northern New Jersey. Edmunds Scientific "Space Conqueror"  

-- Phil W1PJE and Mike WN2A lament that our eyes don't pick up radio frequencies.  This would be a great troubleshooting tool! I can SEE the IMD!  Perhaps some tin foil hats? 

-- John WPE9IRS SW listener! Heard my beacon.  Many SWLs switching to tuning in ham stations. 

-- Peter VK3YE found a homebrew 160 meter double-sideband transciever at a hamfest.  He also found "Solid State Basics for the Radio Amateur -- A QST Anthology"  NOT SSDRA.  But good!

-- Peter VK2EMU  From the Southern Cross (I took a picture of it in the DR!)  Building the DC RX!

 

Ramakrishnan VU2JXN

Friday, May 9, 2025

Ramakrishnan VU2JXN's FB SolderSmoke Direct Conversion Receiver: "Extremely thrilled! Hooked!"

This is a really important Hall of Fame entry for us.  This is our first completed SolderSmoke Direct Conversion Receiver from India (more will come).  

Most importantly, this receiver was built by our good friend Ramakrishnan VU2JXN (ex VU3RDD).  Ramakrishnan goes way back in SolderSmoke history.  He was the one who first suggested (in 2006!) that our podcast needed a blog to go with it.  This was the origin of the SolderSmoke Daily News.  A short time later we announced the birth of Ramakrishnan's daughter.  That same daughter now has her ham license and will build a second receiver with her dad.  

Ramakrishnan VU2JXN

The roots of this receiver are deep in India. When Dean and I first went to the local high school to talk about ham radio support, I carried with me a Direct Conversion Receiver inspired by Farhan VU2ESE.  In fact, that receiver had a picture of Farhan and quotes from him taped to the wooden base.  When Dean and I designed the receiver that we tried to build with the High School kids, we used an oscillator based on the DC receiver that Farhan was building with youngsters at Indian girl's schools.  That is the receiver design that we are using in this SolderSmoke Challenge. 

Ramakrishnan is in Bangalore now, which is where he built this receiver.  Ashish N6ASD is also there now, and is building a receiver. 

Ramakrishnan writes:  

This morning before I got ready to come to work, I got a few minutes 
to turn on the radio and catch the morning nets. Extremely thrilled to
 get this working. The PTO is very stable.

Needless to say, you folks convinced me to get back into homebrew
and you have hooked me into it with this project.

I am off to my ailing mother's place tonight. I don't have a station 
there, but I am carrying a copyof EMRFD with me (I have two!).

I want to listen with this receiver as you all always say 
and make simple modification to this receiver and improve it.
 
Again, couldn't turn off from it even though I am at work! The bug has
caught me.

Here is some more video of Ramakrishnan's receiver: 





Congratulations Ramakrishnan. Welcome to the Hall of Fame! 

--------------------------------

Join the discussion - SolderSmoke Discord Server:

https://discord.gg/Fu6B7yGxx2

 

Documentation on Hackaday:

https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver

 

SolderSmoke YouTube channel:

Tuesday, January 14, 2025

Shock and Awe: The Story of Electricity --- Wonderful Video by Jim Al-Khalili (sent to us by Ashish N6ASD)

From Ashish N6ASD -- Oil Lamps and Electronics

Here is the link to the video: 


First, thanks to Ashish Derhwagen N6ASD for alerting me to this video.  You should all check out his blog

This is a really important video.  It is the best I have seen about the history of electricity and electronics.  It is from 2011, but it is still very good. Jim Al-Khalili travels through the world and displays the actual devices developed by the likes of Heinrick Herz,  Guglielmo Marconi, and Jagadish Chandra Bose.  There is great discussion of Benjamin Franklin, Volta and Galvani.  The role of electricity in The Enlightment is discussed.
  

Jim talks about the early transatlantic cables, and why some of them didn't work. 

We see Jagadish Chandra Bose developing early point-contact semiconductors (because the iron filings of coherers tended to rust in the humid climate of Calcutta!) 

There is a video of Oliver Lodge making a speech.   There is a flip card video of William Crookes (one of the inventors of the cathode ray tube and the originator of the Crooke's cross).  

We see actual coherers.  

There is simply too much in this video for me to adequately summarize here.  Watch the series.  Watch it in chunks if you must.  But watch it.  It is really great.  

Thanks Ashish.  And thanks to Jim Al-Khalili.  

https://www.youtube.com/watch?v=Gtp51eZkwoI

Tuesday, June 25, 2024

Field Day with Farhan, his Family and an sBITX Near Hyderabad, India

Farhan and his son Rayyan with an sBITX

The SolderSmoke crew thought it had a tough time this Field Day:  Pete N6QW had hoped to do something, but was stymied by hot California weather.  Dean KK4DAS had even worse weather.  Bill HI7/N2CQR was at a remote QTH with an HW-8 and a wire antenna -- he managed just ONE contact (W7RN in Nevada on 15 CW).  But none of us had as much trouble as our friend Farhan had.   In  his account of Field Day in Hyderabad, we see an intrepid ham standing up against the slings and arrows of outrageous fortune that Field Day often throws at true radio amateurs.  Here is Farhan's Field Day story: 

-----------------------------

You asked for it, so here it goes...

I got the chance last evening to head out to our farmland. My daughter Ramsha had her friend were over. By the time we all got into the SUV, it was already 5:30 pm. I had loaded in the Spiderbeam fiberglass pole, the sbitx with LiPo battery and an EFHW ATU strapped on, into the back into my backpack,  the toolbox with a few hand tools.

On the way to the farm, rain begin to come down. Rayyan (son, VU3ECQ) started said as much, I turned up the volume on Bruno Mars...

By the time we got to the farm, the rain was over(Ha!). We immediately begin to set up the antenna. I chose an inverted V config for the antenna and to use a tree as the support. The spiderbeam, as any who has been taken in by it knows, is a telescoping 33 feet high mast made of fiberglass. A curious villager decided to help us too. The girls had already taken off to pick the Mulberries.

So, Rayyan, the curious fellow, and I tried to telescope out the mast. The curious fellow, having never read the manual, picked up the mast from the wrong end and all the pieces fall out the other end. (Censored @#$%...). Within 15 minutes, we had all the pieces put back in the order of their thicknesses. I scotchtaped the center of the 66 feet wire to tip of the mast and we all hauled it up vertical. For those who don't forget maths, you can figure that two section of 66 feet wire will be exactly 33 feet high and when you tie this to the high end of a 33 feet high pole -- they just hang down vertically in a straight line. I was trying hard to remember the math teacher's name when the telescoping mast decided to untelescope into a 5 feet, collapsed height. My son commented that it has worked as advertised. Now, I wanted to remember my son's Moral Lessons teacher's name...

Next, we scotch taped the center of the 66 feet wire to approximately 2/3rd height. The curious guy and I walked it up back and took it to the tree. Rather we tried to. The branches kept getting in the way. Finally, managed to get within 4 feet of the trunk and I declared that we could just tie it up with the packing nylon rope bundle we were carrying. We did and it held up. 

By now, the two ends of wire had gotten all twisted around each other. We all had an excellent arm workout trying unwind them. The techniques -- never mentioned in any antenna handbook -- is to hold both ends of the twisted pair in one hand each, spread out your arms and make overhead sweeping motion to flick one wire over the other. This method only adds more twists into the wire. I discovered that wires could be twisted around each other both ways. There is no untwisting them. I discovered this amazing feature!

After watching us for 10 minutes, Humera, my XYL, asked us to forgive the world and bring down the mast and untangle the wires on the ground. By now, a stray cow had also sauntered in on her way back home. I think our language attracted her. She was bellowing for her calf to come and watch.

Next, we, efficiently undid the wire twists. Rayyan and the curious fellow held the two ends away from each other and I raised the mast. Or rather I tried to. At 45 degree tilt, the mast sections add up huge amount of weight. I was tottering around with it when it thankfully  leaned onto the tree branches. At this time, I declared it done. We tied the mast at 6 feet height by the rope to the tree trunk. One end went to the a branch of a bush and the other we walked to the point where it was taunt and touched the ground. 

I brought out the radio, much to the curious fellow's surprised, who was looking forward to me doing more entertaining things with the mast rather than a radio. We switched it on, I quickly peaked the ATU to maximum noise and keyed up. The sbitx shut off. Our battery was discharged.

An intrepid ham is never dissuaded by the flings and arrows of time which, when taken at a tide, leads to Field Day. I decided to move the operations to the farm cottage where we had power. But there was no supporting tree nearby. I decided to use the SUV as support.

We packed the SUV at an approximately correct distance from the vernadah of the cottage. We carried the mast over to the SUV and strapped it at two points: on the foot rest and on the overhead luggage rock. At this point the Spiderbeam fiberglass collaspible mast took a commercial break and demonstrated rapid collapse, into the much vaunted 5 feet size. Rayyan was rolling in the grass with mirth. This divided my anger between two opposing directions: toward  my progeny and toward my antenna mast. I didn't move.

I thought like an engineer.  The curious fellow and I carried the mast to an illuminated part of the farm, laid it down, and scotch taped each section to the next as the spiderbeam folks had warned us to do. It is strange how memory works better when your blood pressure is up. 

The mast went up again, this time strapped to the SUV's rack, door column, and the footrest. I setup the radio on a table outside the cottage, running the extension cord from inside. The SUV and the antenna were too far for the EFHW  to reach the radio. 

We asked Humera (XYL) and the girls who were watching us while having their mulberries to DO SOMETHING and not just SIT THERE. So, Humera got inside the SUV and started to roll it towards the cottage. A loud crunching sound announced the sad departure of the sunflower plants we had tied the other end of EFHW from  mother Earth. The EFHW had unrooted its support as the SUV pulled it away. These minor inconviences never deter a determine man, remember Gandhiji! 

Finally everything was in place, and we fixed up the rig but the microphone wouldn't key up. So what? I can just operate from the in-built mic and the thoughfully provided on-screen keyboard for CW, right? Well I could but I needed to key CW contiuously to set the SWR. So I opened up the mic. The curious fellow who had carried the radio to the new operating position was new to radio etiquette. He had just picked up the radio and walked, dragging the mic through the slush and weeds. The mic connector had come out.

I took the matters into my hands, by now, Rayyan was trying to show empathy for the old man by making loud noise like Aww! Shucks! and other unmentionables. I cut the cable with teeth, unbraided a small section and wired it up on the connector so I could short it to key the rig. Why can't the imbecile radio designers think of providing a tune button on the screen??

Finally, everything was in place. I tuned up and AIR net was on. This is the national evening SSB net on 7150. I tried breaking in with SSB a few times but didn't get through. Finally, I changed to CW and called. The net control asked "the CW station to QSY, this is the AIR net....". Finally some other SSB station who could copy my CW translated my CW to the net control and we had a three way contact.

At this point the girls declared we had to head home now that I had had my contact.

I was about to let out my public school vocabulary when I heard them say that they were hungry and there was lamb curry at home. The idea of getting back home and drying out, and eating the hot lamb curry and mangoes was too much for me. We folded up. But the mast refused to collapse. The curious fellow who had taken charge of the mast engineering had finally gotten hang of it. With superhuman strength, he had pulled the section of the mast out so tightly that no power on earth could potentially loosen them. I decided to trick the mast into thinking that we wanted it to stay up, so we put it back up vertically and slammed it into the ground. It dutifully woke up and demonstrated the much vaunted ability to fit back into a 5 feet tube.

I looked into the darkness to find the EFHW winder but I couldn't locate it. The curious fellow had left, scared by the racket the radio was making. The cow and the calf had gone home. We too headed back home. 

In the picture, you can see Rayyan standing while I am checking into AIR net. In the background is the SUV with spiderbeam fiber mast that is easy to carry in a 5 feet size.

73, de Farhan VU2ESE with a little help from my friends and family.

Thursday, March 7, 2024

The Wizard of Schenectady -- Charles Proteus Steinmetz

Such a beautiful article.   Ramakrishnan VU2JXN sent it to me.  It reminded me of how puzzeled we were when we found "Schenectady" on old shortwave receiver dials, amidst truly exotic locations.  Rangoon!  Peking!  Cape Town!  Schenectady?   Obviously this was due to General Electric's location in that New York State city.  But reading this article, I am thinking that the presence of Charles Proteus Steinmetz had something to do with it. His informal title (The Wizard of Schenectady)  confirmed that we have been right in awarding similar titles to impressive homebrewers. 

Here is the Smithsonian article that Ramakrishnan sent. 

https://www.smithsonianmag.com/history/charles-proteus-steinmetz-the-wizard-of-schenectady-51912022/#ixzz2lRMjrfit

And here is a link to a PBS video on Steinmetz: 

https://www.pbs.org/video/wmht-specials-divine-discontent-charles-proteus-steinmetz/

Here is a SolderSmoke blog post about "Radio Schenectady":

https://soldersmoke.blogspot.com/2020/07/radio-schenectady.html


Tuesday, January 2, 2024

Long-time SolderSmoke supporter Ramakrishnan VU2JXN Interviewed on QSO Today

 

I think we got our first e-mail from Ramakrishnan way back in 2006.  At the time he was VU3RDD. On June 22, 2008 in SolderSmoke #86 we reported on the birth of Ramakrishnan's new harmonic.  In this interview with Eric 4Z1UG we hear of Ramakrishnan's daughter (the same harmonic) getting her ham license and working with her dad on electronic projects.  Ramakrishnan has been with us for a long time!  

It was very cool to hear Ramakrishnan talk about the Lamakaan convention, the BITX 40, and the book The Electronics of Radio.  There was a nice mention of SolderSmoke and Pete. 

Listen to the interview here:  https://www.qsotoday.com/podcasts/vu2jxn

Thanks Ramakrishnan!  Thanks Eric! 

Friday, December 15, 2023

Check out the Hyderabad, India Hamfest! LARC-6


This all looks very familiar.  It is very much like the hamfests and rallies I've seen in the US and UK. 

Note in the video above that we see the HF Signals table and our good friend Farhan VU2ESE.

I was privileged to speak to the convention about my Mythbuster transceiver: 
  
Joseph VU2JQE recorded and uploaded many short videos on the LARC-6 convention and hamfest.  You can see the on his YouTube page:  https://www.youtube.com/@VU2JQE  Thanks Joseph and thanks to the Lamakaan ARC. 


Thursday, December 14, 2023

Mythbuster Video for the Lamakaan Amateur Radio Club of Hyderabad, India


I was really pleased when Farhan asked me to speak at this year's Lamakaan Amateur Radio Club convention.  He asked me to talk about my Mythbuster 75 and 20 meter SSB rig.  It was especially nice to talk about this rig because so much of the inspiration and circuitry for it came from Farhan's BITX rigs.  

I recorded a video so that we could avoid WiFi trouble -- the video appears above.  Below you can see photos of the convention and the presentation of the video.  



Thanks Farhan and thanks to the Lamakaan ARC! 

Saturday, December 2, 2023

"My Radio My Life" A Film about Radio Enthusiasts

My Radio My Life | Trailer | 4K from Makarand Waikar on Vimeo.

Wow!  VU2DTR is presenting a film about radio made by her mom VU2RBI.  They are showing it in Bethesda, Maryland today.  

Trailer above, summary below:  This looks really great.  I hope we can see the whole film on-line soon! 

--------------------------------------------

Set in the 21st century, the film revisits the golden era of radio in, when it was the dominant, popular, and only source of entertainment, news, and knowledge.

Being a medium that is heard across national borders, the radio has been instrumental in expanding horizons and enriching the lives of generations. Besides giving companionship to individuals, the radio brought families together and inspired people to make life choices.

Radio continues to enthrall people with its evolving nature and the sentiments associated with it.

Wednesday, October 11, 2023

Sunburst and Luminary: Apollo "Rope" Memory, and other items of interest

 

Wow.  That is the method that they stored computer memory for the moon missions.  When they were satisfied with a program they would say it was time to "put it on the rope."  

Here's an article on the women who built the rope memory (and the integrated circuits used in Apollo). This reminded me of the women's collective in Hyderabad that "wove" the ferrite core transformers for Farhan's BITX rigs: 

https://www.sciencenews.org/article/core-memory-weavers-navajo-apollo-raytheon-computer-nasa#:~:text=Core%20memory%20used%20metal%20wires,to%20create%20a%20particular%20pattern.

Here is a Wikipedia article on core rope ROM memory with some great illustrations: 

https://en.wikipedia.org/wiki/Core_rope_memory

The Rope

Other stuff of interest that I have spotted so far in the book Sunburst and Luminary -- An Apollo Memoir by Don Eyles:  

-- Not long before the fatal Apollo 1 fire, an MIT colleague of Don Eyles had a drink with Astronaut Gus Grissom.  Grissom unloaded about the poor state of the spacecraft, saying that, "What we have here is a Heathkit."  Grissom died in the fire. 

-- Eyles mentions the use of 6L6 tubes in analog audio amplifiers. 

-- MIT's Doc Draper used a Minox camera.  

-- When the Apollo 11 astronauts came back and were living for two weeks in an isolation chamber, NASA had bulldozers on standby to bury the whole thing ("astronauts, staff and all") in case some dangerous moon bug was detected.  (Is that true?) 

-- At one point soon before an important missile test, engineers realized that they needed an isolation transformer.  They did not have enough time to order one.  So they took an isolation transformer out of one of their soldering stations and used it in the missile.  It worked. Sometimes you just use what you have on hand. 

Friday, September 15, 2023

HB2HB -- A Contact with Denny VU2DGR (video)

At first I didn't realize it was Denny.  On September 11, 2023 at about 2330Z I had walked back into the shack after dinner.  I think DX spots showed an Indian station on 20 meter SSB.  Without realizing who it was, I tuned him in on my Mythbuster rig, heard the other station sign off, and quickly threw in my call.  Denny came back to me right away, and I think both of us then realized that we recognized the call of the other station. Wow, it was Denny, VU2DGR, the Wizard of Kerala!   At the time of the QSO, I didn't have my phone with me; after we spoke, I went to get it,  so the video above captures part of Denny's subsequent contact. (You can also at one point hear Guapo barking.) 

Denny has been running a wonderful station that combines SDR gear with and HDR tube type amplifier and a homebrew Moxon.  

Here is Denny's station. The transceiver is a RadioBerry.  the amplifier and power supply are on the other table.  


Here is the homebrew tube-type amplifier.  This is the part of the station that really puts the HB in HB2HB! That's the power supply on the left and the amplifier itself on the right: 


That amplifier has three 807s in it, with a 6L6GC: 



Here's a video on the RadioBerry transceiver. 


Finally, here is Denny's magnificent homebrew 20 meter Moxon: 


Thanks Denny! 

Tuesday, August 15, 2023

The Wizard of Kerala (India) -- Denny VU2DGR -- SDR and HDR

 
His signal was just booming in on 20 meter SSB yesterday evening.  It was one of the strongest signals I've heard from India.  I wasn't able to get through the pileup, but I heard mention of a homebrew station at his end...  Sure enough a look at his QRZ.com site shows that a LOT of solder has been melted in his shack.  Both SDR and HDR stuff.  Tube projects including an 807 amplifier made from "components collected from the scrapyard." And a homebrew 20 meter Moxon.  Check it out: 


FB Denny!

Kerala is on the southwest tip of India.  It is something of a hotbed of technological innovation.  My only Indian contact using my current series of homebrew dual-banders was with VU3TPW -- Renju is also in Kerala. 

Thursday, June 8, 2023

Canadian Build of the Direct Conversion Receiver -- Do This in Your Town! (Video)


This is so cool.  We have been getting reports from Daniel VE5DLD up in Regina, Saskatchewan, Canada.  Daniel is a teacher and he has been building the receiver with a group of students.  

They have been doing very well.  They may end up having more success than we have had here.  

This morning Daniel fired up his build of the receiver and it was inhaling 40 meter signals.  You can hear the CW and the FT8 and you can also hear shortwave broadcast signals just above the 40 meter frequencies.  Congratulations to Daniel!  He is now one of very few radio amateurs who has homebrewed a receiver.  I think his students will soon do the same.  

Daniel's students have built several of the boards and appear to be on the brink of full success.  

Their PTOs look very nice. 

The AF amps were the most challenging of the boards.  Theirs look great.  Excellent soldering. 

We want the receiver project that we carried out at our local high school to serve has a model for others.  After all, we got our inspiration from Farhan in Hyderabad.  We want to see this kind of homebrewing continue.  All of the information on this receiver is on our Hack-A-Day.io page: 

We strongly encourage others around the world to find ways to use this project to teach analog electronics.   We think the circuit strikes the right balance between simplicity and usefulness -- when they are done, the students will have a useful receiver capable of worldwide reception.  

Please let us know if you are building this receiver; we are especially interested in the use of this receiver in student-focused group-build projects.  

Sunday, May 28, 2023

Jerry KI4IO (Wizard of Warrenton) Describes His ALL ANALOG Phasing Transceiver -- Bob Crane FDIM interview #3 (audio)

Wow, this one really resonated with me.  Jerry had me won over when, early in the interview, he described his decision to dispense with the Si5351/Arduino combo:  "I said the hell with this digital stuff!"  I hear you Jerry.  I feel your pain OM.  

Jerry then goes on to describe a rig with bits of circuitry from some legendary sources:  The Ugly Weekender transmitter.  SSDRA and EMRFD.  W7ZOI's 1968 Direct Conversion receiver.  

Jerry discusses the "presence" of the direct conversion receiver.  And he decries the pernicious effects of AGC.  (Indeed, real hams MANUALLY control the gain.) 

The Wizard of Warrenton then shares some important tribal wisdom:  After building that new piece of gear, leave it on the bench for a couple of weeks.  Beware of "radio infatuation" (what a great term -- we will have to include this in the lexicon).    Jerry points out that while at first, the new rig will seem just perfect, with time time the need for improvements and modifications will become apparent. 

Jerry also has connections to India and Nepal (where he helped Father Moran).  See: https://www.qrz.com/db/KI4IO

Here is W8SX's interview with Jerry: 

http://soldersmoke.com/KI4IO23.mp3

Thanks Jerry!  Thanks Bob! 

Friday, March 10, 2023

Troubleshooting an Intermittent with Mr. Carlson. And Troublesome Tube Re-Branding.


This is a really great video on how Mr. Carlson (VE7ZWZ) did troubleshooting on a tube-type receiver. The problem was an intermittent.  They can drive you nuts, but Mr. Carlson show us how to stay sane. 

-- His use of ordinary observation at the start of the process is very important.  He notices a flickering glow in the voltage regulator tube.  The flickering coincides with the intermittent noise that he is trying to fix.  That is an important clue. 

-- He also can see that the grid of one of the AF amplifier tubes is getting way too hot: grid emission.  That is another important clue.  

-- He checks the grid voltage on the AF amplifier and finds that it is way too low.  It is fine on the other side of the resistor that carries the voltage to the tube.  But it is close to zero at the grid.   This means that the mica capacitors on the grid are suspect. 

-- He uses some fairly esoteric test gear -- a homemade device and an an old Heathkit signal tester -- to check his diagnosis.  They confirm that the mica caps are the problem.  He replaces the caps and the problem is gone.  A very satisfying troubleshoot. 

Mr. Carlson presents us with a lot of good info: 

-- 6K6 tubes were often in fact 6V6 tubes.  And 12AX7s were often 6VJ8s!  Manufacturers were deliberately re-branding tubes. So we shouldn't be surprised if some of our solid state devices turn out to be a bit different from what was promised.  This practice goes way back. 

-- I liked Mr. Carlson's final sensitivity test on the receiver -- he just waved his hand near the antenna connection and we could hear the receiver respond.  Excellent. 

-- Mr. Carlson is very negative about the use of polystyrene caps in oscillator circuits.  But we these simple and cheap caps being used to good effect in oscillators in India.  

-- The leaky and bad micas were a bit surprising.  Carlson speculates that their proximity to heat-producing resistors might have caused the trouble. 

Finally, it is interesting to hear the Canadian pronunciation of radio words:  Solder with the L pronounced (as in the UK).  Farad with the second A long and the final D emphasized (I say it just as the first two syllables of Michael Faraday's last name). 

Thanks Mr. Carlson. 

Monday, March 6, 2023

Pictures from Farhan's Hyderabad High-School Direct Conversion Workshops

 
Farhan came up with the idea of having high school students build their own receivers. We followed his lead -- there are now several such projects underway around the world. 




The simple but effective Colpitts circuit that Farhan recommended. 
The PTO tuning idea came out of  his "Daylight Again" transceiver

Oscillation!  

Sunday, March 5, 2023

Farhan's High-School Direct Conversion Receiver Workshops in India


Farhan sent this picture yesterday.   If you look closely you can see the students holding their homebrew 40 meter Direct Conversion receivers.  You can even see that they are using the same kind of PTO coil forms that we are using here.  Farhan reports that 11 receivers were built by 33 students.  A few more are being finished and will soon be active in Hyderabad. 

I was really blown away by this picture.   We are doing the same things on different sides of the world.  Our students will like this.  It will be as if they are seeing people of the same age building the same receivers 7,500 miles away.  

In our last session I mentioned to our students that Farhan of Hyderabad had given us the toroidal transformers that they are putting into their mixers.  I told them that in ham radio, when we use parts given to us by a friend we add "soul to the new machine."   And I said that Farhan would be coming to see them in May.  They were really impressed. 

We are starting to see similar efforts in different parts of the world -- Andreas with university students in Germany,   Daniel with high school kids in Canada.   We hope there will be others. 

Saturday, February 25, 2023

Progress Report: High-School Students Build Diode Ring Mixers (Board #2 of 4). Hyderabad Soul Added to the New Machines

Dean KK4DAS works with students

A team from the Vienna Wireless Society was back in the local high school Thursday and Friday of this week, helping the students finish their variable frequency oscillators and build their diode ring mixers.  Club President Dean KK4DAS was in the lead, and did an amazing job working with the school and procuring all the needed parts.  Mike KD4MM  and Don KM4UDX provided patient and understanding help to the students. 

Students at work on the receiver

On the oscillators, the students  had to add about six parts to install a buffer circuit built around a J310 FET.  They also had to replace some of the 3D printed coil forms for the main-tuning variable inductor. (Dean KK4DAS made some really nice forms -- see below.)   Several teams of students experiences were very pleased to get their oscillators running. 

Manhattan Mixer Pads

Then it was on to the diode ring mixer.  We had planned on having the students wind their own trifilar toroids, but we realized that this might be too much -- it would add a lot of time to the build, and would introduce a lot opportunity for error.  

One of Farhan's transformers

I remembered that Farhan had given me a big supply of FT-37-43 trifilar toroids that had been assembled in Hyderabad.  We decided to use these transformers.  We reasoned that this was not a big deviation from our DIY ethos -- after all, we didn't ask the student to wind their audio transformers, nor did they wind the RF choke in the VFO buffer.  But we faced a problem:   the Hyderabad transformers were all wound with the same color wire on all three turns.  This would make it hard for the students to figure out which wire went where (there were 12 such wires on each mixer board!).   I figured out how to do this:  The night before, I soldered together the center tap wires, and I twisted together the input coil wires.  We told the students to first solder the center taps in place, then solder the two free wires to the diode ring, and finally untwist the input coil wires, soldering in these connections.  This worked.  

How the transformers were prepped

Before we started, I gave the students a quick class on the essentials of mixers. And I pointed out that we were using transformers made in Hyderabad India and donated by our friend Farhan.  I told the students that whenever we include parts given to us by a ham radio friend we are adding "soul to the new machine." Indeed, Farhan's toroids added a lot of soul. 


We have been insisting that the students have each stage tested before moving on to the next.  This week we used signal generators to put RF and VFO energy into the mixers, and oscilloscopes to make sure that audio was coming out.  

One of the test set-ups for the mixers

The students are making good progress.  After today's session we did an estimate of where each of the projects stand at this point: 

We are building 15 receivers. 
Oscillation without the buffer:   11
Oscillation with the buffer: 5 
Mixer built and tested (but no diplexer yet):  5 
Mixer working, diplexer built  2

During the next month or so the students will build the bandpass filter and the audio amplifier, and put all the boards together to complete the receiver. 
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column