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Showing posts with label Farhan. Show all posts
Showing posts with label Farhan. Show all posts

Tuesday, March 5, 2024

A Contact with my Old Azorean DSB Transceiver


I've been thinking about balanced modulators, and I wanted to see how some of my early circuits performed.  So I pulled this OLD Double Sideband rig off the shelf and fired it up. The balanced modulator -- and everything else! - worked fine,  and I soon made contact on 17 meter SSB with Gene, AB9GK. 

This was the first DSB transceiver that I ever built.  I made this out in the Azores, probably in 2000 or 2001.  Years later I had replaced the RF power amplifier with a "JBOT" (Just a Bunch of Transistors) designed by Farhan.  

Over on my YouTube channel a comment came in from my friend Jack:  

"Looking inside and seeing the o-scope probe in place while the radio was on the air reminded me of neurosurgery where the patient is awake and talking while the surgeon probes different brain regions soliciting feedback. Sure, ham radio isn't neurosurgery, but it's not too far at times. Also, you already have rocket science covered."


Here is an article about my build of that first rig:


I think the article captures well the trials and tribulations faced by new homebrewers, perhaps with the twist that comes from being out in the middle of the Atlantic ocean.  

Mike WU2D is having similar fun with his homebrew 10 meter DSB transceiver: 

I was struck by how similar Mike's early QSO experiences were with mine.  We both put our DSB transmitters on the air before they made their way into real cabinets or boxes. 

Here's mine from 2001 in the Azores: 


Sunday, February 25, 2024

Innovation and a Dual Band Sweep with Version 2 of the 15-10 Transceiver


Here are a couple of videos on Version 2 of my 15-10 SSB transceiver.  In the video above I try to show the advances and innovations that have been made since the start of my BITX construction adventure back in 2013.  

 The video below shows the receiver in action this morning on 15 and 10 meter SSB.  I think it sounds pretty good. 


Click on the image for a better look

Farhan asked what the passband of the 25 MHz crystal filter looked like.  I sent him this.  I think it looks very good, and shows that it is possible to use an IF this high.  This permits us to not only set up the transceiver for dual band coverage (in this case 15 and 10 meters), but it also allows for a lower frequency VFO (in this case around 3.5 MHz) with a resulting increase in VFO stability.  


Monday, February 12, 2024

Dean's Amazing Homebrew sBITX

 
I was kind of making fun of  it during SolderSmoke podcast #250, but later that same morning I had a chance to watch the KK4DAS homebrew sBITX in action, in person, and I must say, it was very impressive.  This may be the only homebrew sBITX in the world (please correct me if I'm wrong).  

In the picture above you can see the amalgamation of traditional superhet with modern DSP.  Even for an HDR guy like me, the result is really cool.  Once again, I experienced waterfall envy.  And the sBITX receiver sounds great. 

Dean has written up his experiences with this rig in a blog post.  Check it out for more info: 


Thanks Dean! 



Tuesday, February 6, 2024

Pine Boards, Analog VFOs, and Homebrew BITX Transceivers -- AG5VG's Magnificent Creations

Click in image for a better view

This is amazingly cool.  WE ARE NOT ALONE!  There are others out there breaking the tyranny of the Si5351, building BITXs with analog LC VFOs.  And using copper clad boards affixed to pine boards. Plywood cabinetry!  And medicine bottle coil forms.  Really great.  And what a wonderful workshop. Thanks Michael.     

Good Afternoon Bill,


This is Michael Sahn, AG5VG.

I hope your doing well, all is well here in south Texas. I have recently built a bitx20 receiver and bitx20 for 40 meters receiver.

I built it using the analog VFO and both of mine are stable. What an awesome feeling it is to have a stable homebrew VFO. I have attached pictures .

It’s been a fun journey to get to this step. I have just been enjoying the receiver as Farhan instructed us. Then I’m going to go through the transmit side.

Air core coils are great for VFO. On my bitx40 I used a medicine bottle bottom but I put the VFO in a tin can as you will see in the pictures.

The bitx20 is all out, hand capacitance is a slight issue but it’s all learning experience.
Going to be adjusting the pvc coil bandpass filter inductors, I think the value is a bit off so it’s not as loud as it should be, but everything else is set good.

Just wanted to check in and great job on the videos and podcasts. I really enjoy them

73s
Michael

Click on image for a better view

Click on image for a better view

Sunday, February 4, 2024

Scott KQ4AOP Successfully BUILDS a Receiver (Video) -- This is the Homebrew Spirit at its Maximum

This is just so cool.  Scott KQ4AOP has successfully homebrewed a ham radio receiver.  He used the circuit Dean and I developed (with a lot of input from Farhan and others) for the High School receiver project.  But Scott has had more success than any of our students.  And I think he has had -- in a certain sense -- more success than any of us.  After all, how many of us can say -- as Scott can -- that he used a homebrew receiver that he made to listen -- for the very first time -- to amateur radio signals?  Scott writes:  "Those first sounds were my first time ever hearing any Amateur Radio first hand!" 

In the email below, you can see Scott's deep commitment to homebrew: "I want to build my own gear for 40m. I want to learn morse code. I want my first contact to be on my own gear."  Wow Scott, the building of the receiver is the hard part, and you have already done that.  I think you are well on your way.  

In the video above you can watch Scott tune the entire 40 meter band and a bit beyond. You hear CW at the low end.  Then FT-8.  Then SSB.  Up just above the top of the band I think you can hear our old nemesis Radio Marti.  And this powerful broadcaster is NOT breaking through on the rest of the band.  FB Scott.  Congratulations.  

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

 Bill,


Thank you for the quick response, direction, and pointers. I won't give up, and I am not in a rush. 

I have wanted my amateur radio license since the early-to-mid-80s. I got my Technician and General in May of 2022 and completed my Extra in May 2023. I always wanted to understand how to design circuits, and I wanted to build them. I share that background to say that I have this impractical goal that I am stubborn enough to stick to (all due respect to you and Pete's advice on the topic of getting on the air). I want to build my own gear for 40m. I want to learn morse code. I want my first contact to be on my own gear. So, your blog and podcast really resonates with me. 

I am only teaching myself at this point. It was the perfect project for my goals. I thought that if all these high school kids in Virginia, Canada, and Germany can do it, it was the sweet spot I was looking for. 

The only transceiver I have was recently gifted to me. It is a Sommerkamp TS-788DX CB radio that allegedly works on 10m in addition to CB. I haven't connected it up because I wanted to stay focused on the HSR. I have a mentor who has gear that I can use to test the oscillator. I am not involved with the nearby ham club, but I know they would help if needed. 

Thanks again and I will keep you posted,

73 Scott KQ4AOP


Bill and Dean - Thank you for sharing and documenting this receiver. I greatly appreciate you publishing the circuit, class notes, and build videos. That got me 75% to completion.
I feel blessed that both of you chipped in and encouraged me through the troubleshooting to finally getting the receiver to start “breathing RF”.
Those first sounds were my first time ever hearing any Amateur Radio first hand!

Friday, February 2, 2024

First Light! First Signals received on Version II of Homebrew 15-10 Transceiver

Ianis S51DX in Slovenia was the first call sign heard. Some peaking and tweaking remains to be done, but the receiver is working.

Congratulations to Scott KQ4AOP who got his Direct Conversion receiver working yesterday, And congratulations to Armand WA1UQO who got his regen receiver working. I think all of us are following Farhan's advice and are taking some time to just listen to the receivers we have built ourselves.

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! 

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, June 30, 2023

SolderSmoke Podcast #247 -- Hating on the IC-7300, Pete Goes FT-8 with a KWM-1, Bill's 15-10 Rig, MAILBAG

Bill's 15-10 Rig -- Click on image 

SolderSmoke Podcast #247 is available: 

Audio Podcast:  http://soldersmoke.com/soldersmoke247.mp3

Video:  (482) SolderSmoke 247 -- Hating on the IC-7300, Pete goes FT8 (with a KWM-1), Bill's 15-10 rig, Mailbag - YouTube

Bill’s Bench:

The 15-10 Dual Bander.

n  10 pole crystal filter at 25 MHz.

n  G3UUR, Dishal, AADE and all that..

n  Testing woes.  Looked bad.  But it was a bad test cable. Duh.

n  VFO (Colpitts) at around 3.5 MHz.

n  Buffer blues:  Bad J-310s.  Beware!  

n  Variable cap from a Heath Q Multiplier

n  A bit of a black art – competing goals. Freq coverage, etc.

n  BFO needed an amp to turn on the diodes in the balanced modulator

n  TIA amps.   SIX dual direction TIAs.  18 transistors.

n  On a pine board (like Frank Jones)

n  Will use the N6QW all discrete AF amp.

n  Maybe an RD16 in the final?

n  Will build a second one for the DR.

 Shameless Commerce:  Mostly DIY RF and the PSSST kit.  Todd K7TFC reports:  “The P3ST is on track for Lee Deforest's birthday release (August 26th). I'm going to send out another newsletter on July 4th, and I'll give some details on P3ST development.” Results of Todd’s Survey.

Pete’s Bench

n  FT-8 on the KWM-1!

n  Presentation to the ham club.

n  Why the Icom 7300 is the anti-thesis of homebrew.

MMAILBAG:

-- SPRAT 195  Summer 2023, in the mailbox.  A happy day at N2CQR

-- Armand WA1UQO sent a wonderful book about Faraday and Maxwell… And told me Jim K8OI was heading to our area.  I met Jim at the VWS Field Day event.  FB.  Thanks Armand.

-- Tony G4WIF sent Father’s Day greetings.

-- Alvin N5VZH asking about electrolytics for his 2-B.  Hayseed Hamfest!

-- John AC2RL replacements for the IBEW.  We need to start over!

-- Steve “Snort Rosin” Smith WB6TNL was in the area.  Sorry I missed him.

-- Joh DL6ID helping us to track down origins of a homebrew receiver Grayson saw in Berlin.

-- Grayson KJ7UM was in Europe visiting his wife’s relatives.  But I think he is back in the USA.

-- Walter KA4KXX sent a QRP HB family portrait. 

-- Wouter ZS1KE sent info on surface mount soldering.

-- George Zaff KJ6VU Ham Radio Workbench – re-runs! Recommended audio processor.  Let me know how it sounds. 

-- Michael AA1TJ   Great to hear from him. 

-- Alan Wolke W2AEW on the toroids  he used in Diode Ring video.  Thanks Alan!

-- Dean KK4DAS, AI and SWR meter project  And new lexicon word:  Hamsplaining. 

-- Bob N7SUR --  Let me know we are semifinalists in the Hack-A-Day prize!  

The 15 - 10 rig from above -- Click on image


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.  

Wednesday, May 31, 2023

Farhan VU2ESE FDIM Interview (#6) by Bob Crane W8SX: VHF Rig, sBITX, and Good News on Raspberry Pi 4

It was great that Bob was able to catch up with Farhan and talk to him about his VHF rig and about the sBITX. 
    
Farhan said that the VHF rig (the BITX23) was presented at the homebrew show-and-tell as a project.  The idea was to encourage others to get into VHF homebrewing.  Farhan points out that many of us are reluctant to go into VHF building, thinking that we need special or exotic test gear. No true says Farhan.   He is trying, with this rig, to bust this myth.  FB.
    
On the sBITX, Farhan points out that he too -- coming as he does from the homebrew tradition -- finds some of the modern rigs quite intimidating.  So he designed the sBITX to be less intimidating.  It is, he says, a tinkerable rig that could be homebrewed. It is all open source.  
    
Farhan points out that the rig is built around the Raspberry Pi 4, a device that has recently been hard to obtain.  This has driven up the price of the sBITX a bit.   But good news:  Farhan says that the word on the street is that the Raspberry Pi 4 will be available in quantity starting at the end of June.  

Here us Bob's interview with Farhan: 

http://soldersmoke.com/VU2ESE23.mp3

BITX23 VHF Rig

And here is a video of Farhan describing the BITX23: 

Thanks Fathan!  Thanks Bob! 

Friday, May 26, 2023

Coffee with Farhan VU2ESE (video)


Early morning in the N2CQR shack, May 16, 2023

-- Propagation
-- Web sites (RBN, PSK Reporter, others)
-- CW
-- Homebrew rigs
-- VFOs

Saturday, May 20, 2023

Farhan and Bill Fire up the sBITX and (at the other end of the tech spectrum) a Direct Conversion Receiver (video)


At the high tech end: the sBITX.  At the low tech end: The high-school direct conversion receiver. 
Check out the frequency readout on the DC receiver!  

Farhan Describes his New 2 Meter SSB Transceiver (Video)


On May 16, 2023 Farhan gave us a look at his new BITX23 2 Meter Transceiver. Two days later he made a presentation on this rig at the Four Days in May event. Highlights: -- Use (and non-use) of the Cascade tool -- Cascade and the original BITXs -- ADE-1 -- SI570 -- Raspberry Pico -- Diplexer -- Different Grounds to get rid of digital noise -- Gimmick Capacitors (and gimmicks made from coax) -- Ugly SMD Capacitor Soldering -- Tombstoning! -- Melting RG-174 Coax -- No need to learn Arduino programming -- Dilbert! -- Bill and Pete -- Techie Tatts! Thanks Farhan!

Two days later, Farhan presenting the rig at FDIM


Wednesday, May 17, 2023

Farhan Visits Northern Virginia En Route to FDIM (Videos to Follow)


Mike KD4MM, Farhan VU2ESE and Dean KK4DAS

Farhan VU2ESE was in Northern Virginia this week, on his way to the Four Days in May Event at the Dayton Hamvention.   We had a great visit with Farhan.  We took him out to the Thomas Jefferson High School for Science and Technology where he shared with the students tribal wisdom about building CubeSats and about building simple direct conversion receivers.  Farhan's use of direct conversion receivers to teach homebrewing to students in Hyderabad inspired our efforts in Northern Virginia.  We often referred to Farhan when speaking to the students here, so it was really great to give them a chance to talk to him directly. 


From the high school we went to the local restaurant at which Vienna Wireless has its weekly lunch. Many of the people at this lunch are also members of the VWS makers group.  This was a lot of fun. 


Don KM4UDX even brought in his somewhat eccentric build of the uBITX transceiver designed by Farhan.  Don's rig is labeled "The uBITX of Life."  It has also been called "The Franken-uBITX." Whatever the name, Farhan was clearly pleased to see Don's handiwork. 

I shot a lot of video during Farhan's visit (last time I failed to do this and regretted it).  I will put these videos up on the SolderSmoke YouTube channel during the days ahead. 

Thanks Farhan! 

Wednesday, April 12, 2023

Farhan's sBITX -- Taking Orders! (Video)

It is really looking great.  Congratulations to Farhan for bringing yet another amazing rig to the amateur radio community.   

Order yours here: 

https://www.hfsignals.com/

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. 

Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column