Thanks to Walter KA4KXX for alerting us to this gem of a book. L.B. Cebik is best known as an antenna guru. I did not know that he also did a book on the homebrewing of rigs.
I was a bit apprehensive when I saw "designing" in the title. We have talked about how, all too often, modern hams seem to challenge the homebrew nature of our rigs by asking if we had "designed" it ourself. "Well," I answer, "I did not invent the Colpitts oscillator, nor the common emitter amplifier, nor the superheterodyne receiver... But I did build this rig myself." I worried that OM Cebik might have been plunging us into this design debate way back in 1979.
But no need for worry. His definition of "design" is quite expansive:
I have not read the whole thing yet. I hope that others will go through it and highlight for the group the parts that they find to be the best. Please put your thoughts in the comments section below.
I used to say that at a hamfest, you should get three things: 1) some parts 2) a tool, and 3) a book. I thought I had maxed out on books. Until Bob KD4EBM sent me this one. I made room for it.
Just consider some of the chapter headings and sub-headings:
-- The Philosphy of Troubleshooting.
-- Quashing Spurious Oscillations
-- Oscillations Crop up
-- Roundup of "Floobydust:" Loose ends that don't fit elsewhere
-- Real circuits and real problems
-- Experts have no monopoly on good advice
-- Learn to recognize clues
-- When computers replace troubleshooters, Look Out
-- Understanding diodes and their problems
-- Identifying and avoiding transistor problems
Sadly Bob died in 2011. But his good advice and wisdom lives on:
This morning while looking to an old book that is still a favorite, I found a footnote to an even older book that is also one of my favorites: Terman's "Radio Engineer's Handbook" 1943. As I've said, Terman was, of course, right. Don't challenge Terman. The Radio Gods don't like that.
-- Grayson was also selling a Thermatron version of our beloved Michigan Mighty Mite transmitter. It is crystal controlled for the 40 meter band, but the Color Burst Liberation Army approves! Here is a wonderful video on this rig:
-- Asked why someone should build with tubes when so much good solid state stuff is available, Grayson makes some especially excellent points: The solid state gear is often filled with mysterious little black boxes -- we often don't really know what goes on in there. Thermatron construction provides a break from complicated SDR nonsense "that is not really radio." That last comment will generate some criticism, but not from here. I think Grayson is right, He earlier expressed admiration for complex circuitry, but he also rightly defends simple, understandable rigs.
Thomas K4SWL has a good post about the importance of taking a break from radio. Following up on this, I noted that "taking a break" is often a good way of finding a solution to a difficult problem. I noted that I have confirmed this -- it has worked for me. Pete Juliano N6QW recently announced that he is taking a break from the MHST project. That is a good idea. A solution will likely emerge.
I noted that there is some evidence backing up our suspicion about the benefits of breaks. I earlier shared some comments from Harry Cliff's excellent book, "How to make an Apple Pie from Scratch."
Harry also wrote about the usefullness of taking breaks. In 1917 Ernest Rutherford was having trouble understanding the presence of some hydrogen nuclei. Harry writes:
"Again, he was forced to put his work on hiatus to go on a mission to the United States in the summer of 1917, but it turned out to be one of those useful breaks when stepping away from a problem lets your mind slowly work out the problem in the background. When Rutherford got back to the lab in September he had the answer..."
A question this morning from Scott KQ4AOP caused me to Google this old book On page 59 I found the article about my first transmitter. Someone has put a copy of the entire book on the interenet. Here it is:
This book is especially important to the SolderSmoke community because its title has led to one of the most important concepts in our community and our lexicon: That we put "soul" in our new machines when we build them ourselves, when we make use of parts or circuits given to us by friends, or when we make use of parts (often older parts) in new applications. All of these things (and more) can be seen as adding "soul" to our new machines. With this in mind I pulled my copy of Tracy Kidder's book off my shelf and gave it a second read. Here are my notes:
-- On reading this book a second time, I found it kind of disappointing. This time, the protagonist Tom West does not seem like a great person nor a great leader. He seems to sit in his office, brood a lot, and be quite rude and cold to his subordinate engineers. Also, the book deals with a lot of the ordinary stupid minutia of organizational life: budgets, inter-office rivalry, office supplies, broken air conditioners. This all seemed interesting when I read this as a youngster. But having had bosses like West, and having lived through the boring minutia of organizational life, on re-reading the book I didn't find it interesting or uplifting.
-- The young engineers in the book seem to be easily manipulated by the company: They are cajoled into "signing up" for a dubious project, and to work long (unpaid) hours on a project that the company could cancel at any moment. They weren't promised stock options or raises; they were told that their reward might be the opportunity to do it all again. Oh joy. This may explain why West and Data General decided to hire new engineers straight our of college: only inexperienced youngsters would be foolish enough to do this. At one point someone finds the pay stub of a technician. The techs got paid overtime (the engineers did not), so the techs were making more money than the engineers (the company hid this fact from the engineers). The young engineer who quit probably made the right move.
-- The engineers use the word "kludge" a lot. Kidder picks up this term. (I'm guessing with the computer-land pronunciation that sounds like stooge.) They didn't want to build a kludge. There is one quote from West's office wall that I agree with: "Not everything worth doing is worth doing well." In other words, don't let the perfect be the enemy of the good. Sometimes a kludge will do.
-- Ham radio is mentioned. One of Wests lead subordinates was a ham as a kid. Kidder correctly connects this to the man having had a lonely childhood. Heathkit is also mentioned once, sarcastically.
-- The goal itself seems to be unworthy of all the effort: They are striving to build a 32 bit computer. But 32 bit machines were already on the market. The "New Machine" wasn't really new.
-- Kidder does an admirable job in describing the innards of the computer, but even as early as the 1978 models, I see these machines as being beyond human understanding. The book notes that there is only one engineer on the hardware team who has a grasp of all of the hardware. The software was probably even more inscrutable.
-- I found one thing that seemed to be a foreshadowing of the uBITX. The micro code team on this project maintained a log book of their instructions. They called it the UINSTR. The Micro Instruction Set. Kidder or the Microkids should have used a lower-case u.
-- The troubleshooting stories are interesting. But imagine the difficulties of putting the de-bugging effort in the hands of new college graduates with very little experience. I guess you can learn logic design in school, but troubleshooting and de-bugging seem to require real-world experience. We see this when they find a bug that turns out to be the result of a loose extender card -- a visiting VP jiggled the extender and the bug disappeared.
-- Kidder provides some insightful comments about engineers. For example: "Engineering is not necessarily a drab, drab world, but you do often sense that engineering teams aspire to a drab uniformity." I think we often see this in technical writing. Kidder also talks about the engineer's view of the world: He sees it as being very "binary," with only right or wrong answers to any technical question. He says that engineers seem to believe that any disagreement on technical issues can be resolved by simply finding the correct answer. Once that is found, the previously disagreeing engineers seem to think they should be able to proceed "with no enmity." Of course, in the real world things are not quite so binary.
-- This book won the Pulitzer prize, and there is no doubt about Kidder being a truly great writer, but in retrospect I don't think this is his best book. This may be due to weaknesses and shortcomings of the protagonist. I think that affects the whole book. In later books Kidder's protagonists are much better people, and the books are much better as a result: for example, Dr. Paul Farmer in Kidder's book Mountains Beyond Mountains.
-- Most of us read this book when we were younger. It is worth looking at again, just to see how much your attitudes change with time. It is important to remember that Tracy Kidder wrote this book when he was young -- I wonder how he would see the Data General project now.
-----------------------
Here is a book review from the New York Times in 1981:
I like Frank Harris K0IYE's book so much that I don't mind posting about it frequently. "From Crystal Sets to Sideband" is must-read material for all homebrewers.
The picture above is especially significant. I first came across it in the old pulp-style magazine called World Radio. The picture, like Frank's book, is truly inspiring.
This week I stumbled across a relatively new chapter in Frank's book. Chapter 3A deals with his approach to homebrewing (Luddite, analog, HDR) and his advice on how to set up a home ham-radio workshop. There is a lot of wisdom in this chapter.
The opening paragraph of Chapter 3A really grabbed me. Check it out here. Click on the text below for a better view:
Click on the image above for an easier read
Frank's advice on what to do when you get stuck on a problem is right on the mark, and a bit counterintuitive, but very true: Do something else for a while.
The above video appeared on Hack-A-Day this morning. ON THE SAME MORNING, Bruce KK0S happened to send me this version of Joe Walsh WB6ACU's song "Analog Man." This version has the lyrics. Thanks Bruce.
I am currently struggling with some DNS server problems. Dean KK4DAS is helping me. In spite of many years on the internet, this DNS problem has reminded me that, like Joe Walsh, I am an analog man. I mean, just take a look at my Mythbuster rig: (1382) Mythbuster for Lamakaan ARC - YouTube
But there are limits to my analog fanaticism. First, while Joe proclaims that he is looking for an analog girl, I very luckily found a digital girl. Elisa is quite digital. Second, even though digital tech is not my thing, I am willing to accept its usefulness. I mean, there is so much we wouldn't be doing if we were all "analog men." Like going to the moon.
This is a hobby -- it is all for fun. Whatever floats your boat, right? Still, Joe's song reminds me a bit of the old "SPARK FOREVER!" that you can still see on old QSL cards. That's kind of sad. I just recognize that my comfort zone is more analog than digital.
The impact of the CK722 on Pete Juliano, on ham radio, and eventually on SolderSmoke was quite profound. Back in 2015, I wrote about this on the blog:
I knew Pete had a lot of experience with transistors, but I didn't realize just how far back this experience reaches. Pete writes, "The March 2015 issue of QST had an article about a 1953 transistor transmitter project which was really advanced technology since the transistor was only invented about 5 years before that time... About 1953 at the age of 11, I built my first solid state audio amplifier using the venerable CK722 from Raytheon. The transistor did look a bit strange in that cool blue cube shape with a red dot on the side to identify the collector. What a joy and surprise to me that it worked the first time power was applied... It was the CK722 that in large measure started me on a life’s work and engagement in a wonderful hobby. That CK722 path also led me to designing and building a QRP solid state version of the Collins KWM2 which I call the KWM-4." I asked Pete why an 11 year-old kid in 1953 felt compelled to build a solid state audio amp. The answer is very cool: Pete's father had introduced him to crystal radios at age 8. Pete wanted an amplifier for his crystal set, but his dad was worried about him building high voltage tube gear. So that's how Pete got his VERY early start with transistors.
We are really lucky to have Pete Juliano sharing his vast tribal knowledge with us.
----------------
You can see a complete set of SolderSmoke posts about the CK722 here:
Wikipedia has a nice article on the CK722. The design contest Raytheon sponsored would be the kind of contest we could really get into! https://en.wikipedia.org/wiki/CK722
Mostly DIY RF:Work proceeds in the Oregon Silicon Forest on P3ST kit development. Todd is confident the P3ST will be released on December 18th.Many other kits available now: https://mostlydiyrf.com/
Armand WA1UQO has sent me two of Basil Mahon's books. They are both really great. He is a wonderful writer who has the rare ability to present not only the people who made the discoveries, but also the technical details of the discoveries themselves. There is so much to learn from Basil Mahon's books. I put a link to one of them on the column to the right >>>>>>>>>>>>>>>>>>>>>>
I bought his book on Maxwell so I can read it on a long flight our to California.
PERSONAL:
Born May 26, 1937, in Malta; married Ann Hardwick (a teacher of chemistry), April 1, 1961; children: Tim, Sara, Danny. Education: Attended Royal Military Academy, Sandhurst, 1955-57; Royal Military College of Science, B.Sc., 1960; Birkbeck College, London, M.Sc., 1971.
Check out his career:
British Army, career officer, serving with Royal Electrical and Mechanical Engineers in Germany, Aden, and United Kingdom, 1955-74, retiring as major; Government Statistical Office, civil servant, 1974-96. Consultant and trainer on censuses and statistics, including work for clients in Russia, Estonia, Croatia, and Republic of Georgia.
And his thoughts on writing:
Basil Mahon on writing: "To me, the joy of writing is simply the chance to give readers the joy of reading—to share one's thoughts and passions with them, hoping to leave them with a feeling of pleasure and well-being. By the time I came to write The Man Who Changed Everything: The Life of James Clerk Maxwell, careers in the army and the civil service had given me plenty of practice in writing instructions—where crispness and clarity were the cardinal virtues—so the big test was to try to hold fast to these qualities and to entertain the reader at the same time."
It was great to get a comment from Paul VK3HN -- this led to a re-establishment of contact. Apparently Google knows who I have been e-mailing, so this great video appeared on my YouTube screen. Thanks Google!
-- Great to hear Paul's shout out to Pete Juliano N6QW, and Pete's concept of noodling.
-- Paul's emphasis on testing each stage independently is really important.
-- Wow, ferric chloride! It is great to see someone doing this (instead of just sending Gerber files to China).
-- Books. This reminds me that I have to get Drew Diamond's books.
-- Paul's comment on the usefulness of a general coverage receiver. Right on target Paul.
-- On the test gear, we can now add the TinySA Ultra. And you don't have to win the Lotto!
-- Finally, Paul is absolutely right on the need to constantly update and publish changes to schematics. I am guilty of not doing this. (I hang my head in shame.) This became a problem in our simple High-School receiver project -- I would make changes to circuits and fail to communicate these changes to Dean KK4DAS. Paul's method would have solved this problem.
Buy the book from the Amazon link on the right side of the page >>>>>>>>>>>>>>>>>>>>>>>
There is so much great stuff in this 2018 video. I am definitely going to buy the book. This is another of those things that reminds me (a hardware guy) of the importance of software (Sunburst and Luimary were the names of two programs that Eyles wrote to enable the LEM to land on the moon).
-- Asked about one of the biggest ancillary contributions of the Apollo program, Eyles immediately says, "integrated circuits." They used three terminal NOR gates. Lots of them.
-- They never had a hardware failure in the Apollo computers. Demonstrating a classic troubleshooting technique, when they discovered what they thought was a hardware failure, they ran the program on another computer. The problem was also there, so they knew there had been no failure on the first machine.
-- The LEM simulator was very cool.
-- Eyles' ability -- in two hours -- to write the code for the automatic landing program that Astronaut John Young was asking for, then have it flown on an Apollo mission to the moon was very impressive.
Thanks to the MIT Museum for posting Don's talk. And thanks to HackADay for alerting us to it.
Oh man, this book is so good. You really just need to buy it now. I put it in the Amazon link to the right.
OVER HERE >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The Imsai guy reminded me of this book, and pointed out that earlier editions are more reasonably priced, so I got the second edition (looks like 1980, reprinted many times through 1988). Dean KK4DAS got one too (I think he also got the second edition).
Lest there be any doubt that this book is for us, first let me point to the pictures of Paul Horowitz and Winfield Hill. https://artofelectronics.net/about/
Winfield Hill
Just from the pictures, you can tell that these guys have THE KNACK. And -- get this -- THEY ARE BOTH PROFESSORS AT HARVARD. Wow.
Dean KK4DAS and I have already started sharing quotes from the book:
Referring to other books, H and H write: "Much of the favorite pedagogy of beginning textbooks is quite unnecessary, and, in fact, is not used by practicing engineers, while useful circuitry and analysis lies hidden in application notes, engineering journals, and hard-to-get data books."
"Thus, the treatment of this book reflect our philosophy that electronics, as currently practiced, is basically a simple art, a combination of some basic laws, rules of thumb, and a large bag of tricks. For these reasons we have omitted entirely the usual discussion of solid state physics, the h-parameter model of transistors, and complicated network theory, and reduced to the bare minimum the mention of load lines and the s-plane. The treatment is largely non-mathematical, with strong encouragement of circuit brainstorming, with mental (or, at most, back-of-the-envelope) calculation of circuit values and performance."
Stay tuned. There is a lot more coming about this wonderful book.
Here is a cool video about a very cool book. I wasn't going to buy it, but when I saw it in a book store, I opened it up to a random page and found myself looking at the 2N3904. TRGHS. So I bought it.
First a big congratulations to the Vienna Wireless Society and its President, Dean KK4DAS. In spite of low temperatures that made the Winterfest Hamfest live up to its name, this year's 'fest was a big success with excellent turnout both by buyers and sellers. There were a LOT of older rigs -- on one table I saw three HT-37s. It was all great. Here is a video of the hamfest. https://www.youtube.com/watch?v=oheht5jCuKE&t=619sThis was shot early on Sunday morning March 19, 2023, about 30 minutes after it opened. An hour later there were a lot more customers.
One of the first things I bought was the item pictured above. I bought it mostly because we are currently building 40 meter receivers with the local high-school students. I didn't have a screw driver, so I couldn't open up the box. Something was rattling around in there. I worried that the box might be mostly empty. Or that it would have one PC board with a sad collection of ICs. But in the hope that I would find something truly homebrew, I bought it.
Below are pictures of what I found inside. Can anyone tell us what this is? ( I recognized it immediately.) More on this device in due course.
Other loot from the 'fest:
The one on the left I've been using since around 1998! It is getting beat up. I bought the one on the right at the 'fest. It is in much better condition. 5 bucks. TRGHS.
I always wanted one. I had nice leather case, but I gave it to Dick Dillman years ago. I now feel like a real boatanchor guy. I got for 15 bucks. I see on Amazon they are selling for $466!
I had one as a kid. Will be useful in the DR. In great shape.
Eamon Skelton's book was a great find. As were the early editions of SSB for the Radio Amateur. Eight bucks for the whole lot.
I like homebrew speaker enclosures. They add soul to the new machine. Perhaps a prize for the high-school project. Three bucks.
Finally, this thing. Plagued by guilt for past cannibalizations of QF-1s, I was going to pass on this one, but I realized that my friend Dean KK4DAS would be on his way, and if I didn't take it (and extract the variable capacitor) he would. So I bought it. But I may leave this one as is, for possible use as the The Radio Gods intended. It could use some cleaning up. It seems to have a coat of nicotine. Ten bucks.
I also picked up a few larger knobs that may be of use with the high-school receivers.
I was not going to buy this book. But then, Elisa and I were in a book store and there it was. I decided to take a look. I opened it to a random page: 2N3904. TRGHS. Sold.
It is really interesting.
You can order yours through the Amazon Search block in the right side column of the blog.
Most of us grew up with the above diagram of how a receiver detects (demodulates) an AM signal. Here is how they say it works:
-- Because of the way the sidebands and the carrier in the transmitted signal interact, we end up with a signal whose "envelope" matches the frequency of modulation. And we just need one side of the envelope.
-- We used a simple diode to rectify the incoming signal.
-- A simple filter gets rid of the RF.
-- We pass the resulting signal through a capacitor and we get audio, which we listen to.
REASONS FOR SCEPTICISM
But recently, a member of my local radio club has questioned this explanation of AM detection. He maintained that "envelope detection" is not real, and that was actually happening was "square law" mixing. I guess there are reasons for skepticism about the envelope detection explanation: The envelope detection explanation does seem very (perhaps overly) simple. This does sound a bit like the kind of "dumbed down" explanation that is sometimes used to explain complex topics (like mixing). Envelope detection does seem consistent with the incorrect insistence from early AMers that "sidebands don't exist." (Of course, they do exist.) All the other detectors we use are really just mixers. We mix a local oscillator the incoming signal to produce audio. Envelope detection (as described in the diagram above) seems oddly different.
Denial of envelope detection can even be found in the ARRL handbook: On page 15.9 of the 2002 edition we find this: "That a diode demodulates an AM signal by allowing its carrier to multiply with its sidebands may jar those long accustomed to seeing diode detection ascribed merely to 'rectification.' But a diode is certainly non-linear. It passes current only in one direction and its output is (within limits) proportional to the square of its input voltage. These non-linearities allow it to multiply."
ISN'T THIS REALLY JUST MIXING, WITH THE CARRIER AS THE LO?
It is, I think, tempting to say -- as the ARRL and my fellow club member do -- that what really happens is that the AM signal's carrier becomes the substitute for the VFO signal in other mixers. Using the non-linearity of the square law portion of the diode's characteristic curve, the sidebands mix with the carrier and -- voila! -- get audio. In this view there is no need for the rectification-based explanation provided above.
But I don't think this "diode as a mixer, not a rectifier" explanation works:
In all of the mixers we work with, the LO (or VFO or PTO) does one of two things:
-- In non-switching mixers it moves the amplifier up and down along the non-linear characteristic curve of the device. This means the operating point of the device is changing as the LO moves through its cycle. A much weaker RF signal then moves through the device, facing a shifting operating point whose shift is set by the LO. This produces the complex repeating periodic wave that contains the sum and difference frequencies.
-- In a switching mixer, the device that passes the RF is turned on and off. This is extreme non-linearity. But here is the key: The device is being turned on and off AT THE FREQUENCY OF THE LO. The LO is turning it on and off. The RF is being chopped up at the rate of the LO. This is what produces the complex repeating wave that contains the sum and difference frequencies.
Neither of these things happen in the diode we are discussing. If you try to look at the diode as a non-switching mixer, well, the operating point would be set not by the carrier serving as the LO but by the envelope consisting of the carrier and the sidebands. And if you try to look at is as a switching mixer you see that the switching is being controlled not by the LO but by the envelope formed by the carrier and the sidebands.
Also, this "diode as a mixer" explanation would require the diode to be non-linear. That is the key requirement for mixing. I suppose you could make a good case for the non-linearity of solid state diodes, but the old vacuum tube diodes were quite linear. The rectifying diode mixer model goes back to vacuum tube days. The "diode as rectifier" model worked then. With tubes operating on the linear portion of the curve, the diodes were not -- could not -- have been working as mixers. We have just substituted solid state diodes for the tubes. The increased non-linearity of the solid state diodes does introduce more distortion, but the "detection by rectification" explanation remains valid.
Even in the "square law" region (see diagram below) an AM signal would not really be mixed in the same way as signals are mixed in a product detector. Even in the square law region, the diode would be responding to the envelope. Indeed, the Amateur Radio Encyclopedia defines "Square Law Detector" as "a form of envelope detector." And even in the square law region, the incoming signal would be rectified. It would be moving above and below zero, and only one side of this waveform would be making it through the diode. Indeed the crystal radio experts discuss "rectification in the square law region" (http://www.crystal-radio.eu/endiodes.htm ) So even in the square law region, this diode is a rectifying envelope detector.
Here is what I think is the best proof that the "envelope detection" explanation is real: In this video, we see someone build an envelope detector in a simulator. Watch as he then traces the signals as they move through the diode, the RC filter, and the coupling capacitor. He goes through it cycle-by-cycle. You can clearly see how the rectification of the AM leads to envelope detection.
The rectifying envelope detection model goes way back in radio history, back to when authors did not shy away from complex technical explanations. Terman knew how mixers worked, and his 1943 "Radio Engineers Handbook" went to 1019 pages. Terman presented it as a rectification-based detection of the envelope. I think envelope detection is real, and that Dr. Terman was right.
--------------------------------------
Some links that might help:
Analog Devices has a very good, rigorous site showing how envelope detectors work:
The crystal radio guys have a good take on square law detection (note, they just see it as rectification, but on a lower, more parabolic portion of the curve): http://www.crystal-radio.eu/endiodes.htm
“…. Eric Schlaepfer (@TubeTimeUS) andWindell Oskay(co-founder ofEvil Mad Scientist)’s latest book,Open Circuits, is a celebration of the electronic aesthetic, by literally opening circuits with mechanical cross-sections, accompanied by pithy explanations and illustrations. Their masterfully executed cross-sectioning process and meticulous photography blur the line between engineering and art, reminding us that any engineering task executed with soul and care results in something that can inspire feelings of awe (“wow!”) and reflection (“huh.”):thatis art. …”
.jpg)
