A Tale of Two Old Analog VFOs -- Artificial Intelligence's Role. PLEASE COMMENT!

The Kenwood VFO under test, with 2 Yaesu VFOs Standing By 

I have sung the praises of the VFOs taken out of the old Yaesu FT-101s.  I am using them in two homebrew 20 meter SSB transcievers,  one in the Dominican Republic, the other here in Virginia.  We started buying these things just for the anti-backlash reduction drives. But the vendors would send along the reduction drives AND the entire VFO module.  These circuits were all analog, and all discrete component.  I understood them, and had completely homebrewed circuits very much like them.  So I felt comfortable using them. 

Somewhere along the line, I got the VFO from a Kenwood TS-820s.  My motivation was the same:  I wanted the anti-backlash reduction drive. But as with the Yaesus, the entire VFO box came with the purchase.    The frequency on this one was much lower than the Yaesu.  the Kenwood ran from 5-5.5 MHz, the Yeasu was up around 9 MHz.  On this alone, the Kenwood seemed better.  

I recently put the Kenwood on the bench and began testing it.  I used Artificial Intelligence (AI) in the tests.  The results were good and bad.  Sometimes AI helped, sometimes it made matters worse.  Mike WU2D recently used AI to look at the tubes of an old receiver he was working on.  He too was impressed by the usefullness of AI, but I think he too had some misgivings. Here are some of Mike's conclusions: 

Let's start with a fundamental question:  I asked Gemini which of the two "ages better."  Gemini said that the Kenwood was superior in this regard.  I disagree.  Here is why: 

-- Tuning on the Kenwood was very jumpy and very scratchy.  AI correctly said that this was probably due to corrosion over the years on the connections between the main tuning capacitor and ground.  Strike 1! AI recomended cleaning with DeOxit. As a last resort they recommended putting some solder wick between the rotator shaft and ground.  I did that and it fixed the problem (you can see the solder wick in the picture above), but I never had to do that with the Yaesu VFOs.   

-- The schematic of the VFO shows a .9 V RMS output from the VFO.  But it does not specify a 50 ohm load.  Here is the Yaesu schematic: 

AI kept insisting that I use a 50 ohm load.  When I did, the output was reduced down to 54 m V rms. I questioned AI about the load, but it kept insisting on 50 ohms.  Only later, did AI point out that in the Yaesu, the VFO would feed into a HIGH IMPEDANCE load.  Strike 2. 

-- Gemini kept warning about the Q3 and Q4 transistors. They were 2SC460 transistors with weird (ECB) pinouts.  And they were prone, it said, to a horrible sounding disease: "Original Hitachi 2SC460 transistors are infamous in vintage ham gear for silver migration ("black foot disease"), where the lead plating oxidizes, turns black, and causes severe noise, leakage, or intermittent oscillation failure." AI happily recommended replacing them with 2N3904s.  I did this, but the voltage on the emitter was way off.  AI blamed this on the new transistors (that it had recommended!) saying that their hfe was too high (so, uh, why did you recommend them?).  It then said that the direct coupling from Q3 to Q4  was at fault;  it recommented putting a .001 uF cap between these two transistors, along with two resistors for the biasing of Q4.  I did this.  I am not sure if it was necessary.  Strike 3. 

-- Gemini said I should check D3. It was germanium, you see, and "notorious"  for going open.  It was open.  I replaced it with a wire, but AI had a fit.  It worried that voltage from the follow-on circuits in the Yaesu with mess up the voltages on Q4.  I told AI not to worry about this -- all I had was the VFO!  Strike 4. 

-- I still wasn't getting good output.  Here AI was very useful.  First it told me to check the voltage on the emitter of Q4.  It was too high.  Then it told me to look at the resistance to ground from the emitter of Q4.  Uh oh.  It was open.  I quicky went through the connections to ground.  L6 was open.  I relaced it with 100 uH inductor. This corrected the situation.  I now had 1 volts AC rms at the output with no load and .8 V AC rms with a 1000 ohm resistor in the load.  SCORE ONE FOR AI. 

So, looking back, I came to several conclusions:  

-- Gemini was just wrong in saying that the Kenwood VFO ages better than the Yeasu VFO.  The Kenwood had Germanium diodes, weird transistors that get "Black Foot" disease, main tuning caps that get scratchy due to corrosion, inductors that go open.  Yuck.

-- You have to take the recommendations from AI with a grain of salt (see WU2D's conclusions above).  Sometimes they are right, sometimes they are wrong, and sometimes they recommend things that might not be necessary.  Dean KK4DAS points out that AI's seem to do better when you upload the schematic.  Maybe this lets AI analyse it using a simulator.  I had not done this.

-- I will probably use the Kenwood VFO in a 17 meter SSB transceiver.  I recently bought some 13 MHz crystals for the filter and the BFO/Carrier Oscillator from Mouser.  And AI confirms that this combination should not produce any problematic spurs.  We'll see.  The ultimate test is still real-world construction. 

What do you guys think about using AI in projects like this?  Will AI improve? 

What Happens Inside an AI Chip When You Ask a Question. PLEASE COMMENT

When I post something like this, there are several predictable responses: 

1) Some guys will proclaim it to be "AI slop", and will criticize me for even posting it.  

2) Some guys will just declare that I am "getting old" (as if they are not) and will assume that at my age, I just somehow can't understand these new machines (as if they can!).  

3) Many more sensible guys will put aside their feelings about AI and my age, and -- perhaps giving the devil his due -- be amazed by the complexity of these machines.   

I think it is pretty amazing.  

What do you guys think? 

CuriousMarc and Company Fix an Old Analog Device (an Apollo Hand Controller)

I really liked this repair video (above), not because I will ever fix an Apollo-era hand controller (I won't) but because it illustrates well what can go wrong with older, analog gear.  And how you fix it.  

You watch as Mark and Mike try to figure out what was wrong.  This brings us back to the diagnostic questions that Richard Feynman posed to his neighbors when, as a boy, as he fixed their AM radios back in Brooklyn.  "My God! He fixes radios just by thinking!" exclaimed one amazed customer. 

Once (well, several times) after they thought they had it figured out, they used simple test gear (a DMM) to find the short.  Then they fixed it, and brought the controller back to life. This wasn't easy.  It involved lots of digging (almost literal digging) and put at risk some irreplaceable parts.  But they did it.  Three cheers for the CuriousMarc team. 

BTW:  What was that liquid that Marc used to replace the insulation that had been scraped away to allow for testing? 

Margaret Hamilton, Apollo Computer Programmer, has Died

About the Guy Who Brought Us the AADE L/C Meter -- Neil W. Heckt

 

There it is.  The AADE L/C meter.  Many of us have been using these things for years.  I have two of them -- the one that I bought is here in my shack in Virginia.  The other was given to be by Todd VE7BPO and it is in my shack in the Dominican Republic. I sometimes wondered who was behind Almost All Digital Electonics.   Today I got the answer. 

Rishav is from Nepal,  He has been studying in Germany.   He is working on homebrewing the test meter (the company shut down when Neil passed away).  In the course of his research, Rishav gathered some very nice info about Neil W. Heckt, the fellow who created AADE and the meters that so many of us used.  Thanks Rishav! 

Memories of Neil W. Heckt

My work with Tobias (KK7BCO/2M0TFF) on a LC meter as the fifth build in Red Summit RF's Homebrew Workbench series for beginners introduced me to the clever LC meter design of Neil Heckt. As we celebrate his work by building one ourselves, in this post I hope to celebrate his life through the memories of those who knew him.

Neils's AADE L/C Meter IIB was a great hit, with thousands of units sold both as kits and as fully assembled instruments. It is not difficult to find praise for the meter. Many owners have written about its accuracy, usefullness, limitations, and clever design. Scattered among those reviews, however, are also small glimpses of Neil himself—stories from people who corresponded with him, asked him for help, or sent their meters back to him for repair. The reviews of the AADE L/C Meter IIB on eHam.net are particularly valuable in this respect. Many are written by people who dealt with Neil directly, and aongside their praise for the meter they remembered his kindness, honesty, and unusually generous customer service.

Memories

There is surprisingly little written about the man behind the instrument. While trying to learn more about him, I found most of the biographical information in his obituary. While searching further, I came across a moving remembrance titled Celebrate the Sun, written by Jill L. Ferguson, Neil's daughter-in-law. It offered something quite different from the technical accounts and product reviews: a glimpse of Neil as a husband, father, and person. One story in particular reveals a wonderfully personal side of him:

She (Kay) said her favorite book and life philosophy came from Celebrate the Sun. Back before she and Neil dated she had told him about this book. Not only did he borrow her copy and read it, but he photocopied the whole thing and pasted page by page into a photo album and intermixed the pages with his own photographs of the sun, of himself on hikes, and of the two of them walking in the woods. He decorated the front of the book with black electrical tape and two die-cut pelicans as they are key characters in the book. After Neil and Kay moved in together and married, she found this book he had created but had never told her about. She intimated that part of the way she knew he was the man for her was because he had taken her interest in this book so seriously. On his last night, she had the book Neil had created with them in hospice center and was reading the end of it to him shortly before his passed.

I was deeply moved by the story and wrote to Jill to ask whether she might be willing to share a few more memories of Neil, and perhaps a photograph. She kindly replied that she would speak with Kay, Neil's wife, and with Neil's son, her husband.

Two days later, I received a message containing a wonderful remembrance written by Kay herself, together with a photograph of Neil as a younger man. I have reproduced both here.

Photograph of Young Neil, thanks to Jill, sent to me by Kay.

Neil Heckt worked for the Boeing Company for more than 30 years. He was a member of their early air and space team. In his earliest years he worked on getting satellites into orbit and later getting men onto the moon. He developed his first inventions during those years which, of course, were owned by Boeing.

When we met he was a few short years from retirement. He was anxious to start his own business and create new products unrelated to his work at Boeing. He named his company Almost All Digital Electronics.

The inventions that followed seemed focused on developing ways to measure very, small units of...? He invented an atomic clock. It is my understanding that the Bureau of Weights and Standards in Colorado used it and that it was displayed there. Here I must state that I am woefully unknowledgable about any aspects of his work. I am neither a business woman or an inventor so, though I found him brilliant I rarely understood what his inventions really did. We were very different in many ways but genuinely admired each other's talents.

The last invention was an L/C Meter kit for hobbyists. He did very well with that product. The arrival of the internet and eBay made it a commercial success.

I thought his philosophy about not patenting his products was unusual. He told me that he developed a product, sold as many as he could and when someone copied his work he would stop production and leaveit to someone else to deal with it while he invented something else.

He had talents and ideas brewing in his brain that craved to be made real. He told me that whenever he needed money he would invent something that people would buy and then he paid his bills.

He wasn't like me and the people in my world who took on a second or third job when we needed money. I found his confidence and creativity to be amazing!

Neil was scrupulously honest in his business . Once he purchased two antique vacuum tubes for less than $100 from an eBay customer. When they arrived he discovered that they were quite valuable. He wrapped one tube up and sent it back to the customer with a note telling him what it was worth. Instead of selling it and making a good deal of money he sent it back. I asked him why. He said it wouldn't be fair to the seller for him to keep all of it for himself because the guy just didn't know what he had.

If anyone had a problem assembling one of his kits they sent them to him and he would fix their problems without charge.

Neil was sick for many years before his death. His brilliant mind was with him to the end.

I hope these memories help preserve not only Neil Heckt’s work, but also something of the thoughtful, generous, and inventive man remembered by those who knew him.

***

Some Useful Drake History from 15 years ago -- Thank you to Bob Crane W8SX

I stumbled upon this report on an interview that Bob Crane W8SX did with Bill Frost back in 2011.  Bill had been Service Manager for Drake, and knew a lot about the 2-B.  This interview is a reminder of the great info that Bob has brought to us over the years.  Thanks Bob! 

Especially interesting and useful were Bill's comments on crystal filters, the number of 2-Bs produced, and the rarity of the Q multiplier. 

Check it out: 

https://soldersmoke.blogspot.com/2011/05/w8sx-drake-interview.html

Are we alone in the universe? How well have we checked so far? PLEASE COMMENT

 I am a fan of Fraser Cain's.  I encourage SolderSmoke listeners, readers, and viewers to check out his work:  https://www.youtube.com/@frasercain  

Having grown up with a steady stream of Carl Sagan ("billions and billions") and Star Trek, I naturally accepted that there must be some other intelligent civilizations out there.  But maybe not.  Lately I have been hearing from some very well informed people that we may be alone. This video explains why.  It also has a lot of good information on how to carry our a Search for Extraterrestrial Intelligence.  

Please let me know what you think about all this. 

Helge LA6NCA Does It Again! This Time Homebrew CW Solid-State QRP.

This one is really cool, and reminds us what an intrepid and skilled radio amateur like Helge can do. 

I really liked the simple scheme he used to shift frequencies from transmit to receive. 

I liked the antenna that he used, and its origns.  FB. 

Finally I really liked the serendipitous source of the sidetone.  

Thank you very much Helge!