Sunburst and Luminary -- A Poem about Transistors and ICs

 

Sunburst and Luminary by Don Eyles has a lot of the kind of color that helps the reader understand what was going on technologically during the 1960s.  For example, there is this poem about integrated circuits (you don't get to use "poem" and "integrated circuits" in the same sentence very often): 

The transistor's a marvelous invention

Replaced the tube convention

        Found its niche

        To amplify or switch

Whatever the designer's intention. 

But the breakthrough was the IC

Integrated monolithically

        It became pivotal

        As computers went digital 

With increasing complexity. 

Eyles tells us that this poem was written by hardware designer Jayne Partridge, and appears in Eldon Hall's write-up of the Apollo Guidance Computer and the decision to use ICs in it: 

https://www.amazon.com/Journey-Moon-Guidance-Computer-1996-09-03/dp/B01F9FSN7C  

Another Evaluation of the TinySA Ultra (with Teardown) (Video)

More info on using the TinySA Ultra. 

-- Makes me wonder if it makes sense for me NOT to enable Ultra mode now.  I am not going into the UHF range.

-- Waterfall!  Sig Gen! 

-- Kerry got a lot of distortion when listening to FM broadcast signals.  I wonder if this is due to the Tiny SA detector being an AM detector? 

-- Teardown was very cool.  

-- Comparison to the HP spectrum analyser was very illuminating.  Bottom line:  TinySA Ultra gives you a lot of capability for $150.  

 

"Sunburst and Luminary" author Don Eyles was a Ham, a Hacker, and a user of Plywood who Understood Juju

-- As a kid, Eyles took a summertime shop class with W4LRO.  Eyles himself went on to get his ham license -- he was K4ZHF and was active for a while on the 40 meter and 6 meter bands. 

-- He writes of how the Apollo software acquired more "juju as labor and logic were poured into them." Juju. 

-- He describes the electronics lab in the MIT Instrumentation Laboratory: "If you had a private project you could sometimes get some simple milling done for a smile, and you could scrounge the odd resistor or capacitor... On the second floor there was a small "hackers shop" with a drill press, metal shear, a bending brake, and a few hand tools which was open to anyone, including software engineers. That was the first use of the term "hack" in a technical context, that I can recall hearing. I took the term as referring to the sometimes messy process by which perforations of suitable sizes were made in the aluminum boxes, or chassis, that were used for constructing electronic devices."  Indeed.  We hack.   

-- After describing the first integrated circuits, Eyles looks back at high school and notes that he and a friend, "after learning about truth tables, James Chambers and I had experimented with similar devices composed of relays mounted on a piece of plywood."  Plywood.  

  

More to follow on this book. 

Bezos Bucks! New Amazon Link Working Well! Please use it!

 

Click on image for a better view

In the graph above you can see the Amazon Associates stats for SolderSmoke.  While obviously I'm not going to get rich on this, it is nice to see that the new Amazon Associates link is working well.  Note the difference between early September and late September. 

The link is over here >>>>>>>>>>>>>>>>>>>>>>>>>>>>>

You can use it to buy anything on Amazon (not just the item that is advertised).  Just start your search from the Amazon link on the right hand column of this blog, and buy the item within 24 hours of entry into the Amazon system and -- CHA CHING for SolderSmoke!  Thanks.  

The TinySA Ultra Spectrum Analyser (video)

I got mine this week, and I've been playing with it.  When I spoke to Dean KK4DAS, I asked what he thought the first thing I did with it was.  He guessed that I tried out the greatly improved Resolution Bandwidth.  Good guess, but not quite:  I tried out the  "listening" feature on this SA.  You will recall that the plain-vanilla, non-Ultra TinySA required a hardware mod to allow for listening.  Dean had told me that the Ultra came with a headphone jack.  Indeed.  I fired it up and was able to listen to 1220 AM and also to the FM broadcast stations in the area.  With the FM stations, I'm guessing I was using a form of slope detection (IMSAI guy says it detects AM).   I tried to see if I could see/hear stations on the ham bands -- so far, no luck.  I'm not sure why, but I will work on this.  

The IMSAI guy video (above) does a great job in comparing the TinySA Ultra to a "real" spectrum analyser.   I think it compares very well.  

One note on where I got mine:  I ended up getting it from R&L Electronics, the recommended U.S. dealer for the device.  I had tried getting it (cheap) through AliExpress.  This didn't really work out.  The tracking info from AliExpress showed that the box had made it to my local post office, but I never got it.  It may have been that they just didn't take the complete mailing address from PayPal.  In any event, I was able to get a refund from PayPal, so no loss here.  R&L turned out to be a great source. 

Ultra, of course. 

"The Art of Electronics" #8 -- Why Not a Simple Emitter Follower as The AF Output Circuit?

Click on the image for an easier read

Back when Dean KK4DAS and I were trying to find a suitable AF amplifier circuit for our High School Direct Conversion receiver project, we were debating what to use as the final.  One option was the standard NPN-PNP push-push amplifier (like in Figure 2.53 above)  -- an advantage with this one was that it would not require an AF transformer.  But we decided that this circuit would add complexity to a project that we were hoping to keep very simple. 

Another option was a simple common emitter amplifier with a transformer in the collector circuit.  This worked, and was simpler.  We ordered the transformers.  

In the midst of all this, at the local radio club hams asked us why we just didn't put a single emitter follower at the output to handle the impedance transformation to an 8 ohm speaker (sort of as in Figure 2.52 above).  They were convinced this would work.  I was not so convinced and pointed out that we had never seen such a circuit in any of the ham radio literature.  If this could be done, why hadn't the likes of Doug DeMaw and others used this circuit in their many, many rigs?  

This discussion kind of ended there (we opted for the common emitter transformer circuit), but I have thought about it from time to time.  A couple of weeks ago, when I got the second edition of The Art of Electronics, I found the above discussion of the use of this kind of emitter follower circuit.  You can see why this circuit has not been used.  Just to be sure, I built one in LTSpice.  Sure enough, it takes way too much current.   

Thank you, Horowitz and Hill! 

A Look at Old Radios in Australia (video)

I thought you guys would like Peter Parker's latest video.  And in it, Dean KK4DAS might see a clue or two for his Halli restoration/repair project.  

What really struck me was the dial markings on the Australian radios.  They seem to be mostly oriented toward the reception of Australian AM or LW broadcasters -- not many exotic DX locations are marked.  Australia is big! 

Looks like a lot of crystal detectors in glass tubes.  At first I thought they might have been coherers, but I think they are crystal detectors. 

Many variometers visible. 

I saw one Geloso-Milano Communications 8 receiver.  Va bene! 

I also saw one "Tasma 780" Superhet.  Cool name! 

What is up with the "Green Theme"? 

I have some of the headphones they showed. 

Please note in the Comments section anything special that you noted in watching Peter's FB video. 

More on the coil winding machine here: 

https://hackaday.com/2023/08/30/all-mechanical-coil-winder-is-a-scrap-bin-delight/#more-612604

Ciprian YO6DXE Puts the Michigan Mighty Mite on AM! (video)

Excellent work Ciprian!  

Here we have a Michigan Mighty Mite being modified for AM in Romania, with input from Hungary, and inspiration from Melbourne, Australia (Peter Parker VK3YE).  With a very nice shout-out to SolderSmoke.  

I really like Ciprian's emphasis on having fun with the electronics. 

TRGHS! 

F6CRP's FB Homebrew Receiver

I like F6CRP's homebrew receiver.  I like the way he presents it (block by block) and I like the inclusion of the W7ZOI IF board. The JF3HZB VFO is quite cool (even though it is digital),   We have posted about this VFO several times: 

 https://soldersmoke.blogspot.com/2022/05/who-is-jf3hzb-creator-of-that-nice.html

Denis has a very nice station and workbench: https://www.qrz.com/db/F6CRP

He also has some very nice videos on his YouTube channel: 

https://www.youtube.com/@radiorider8249/featured

Thanks Denis! 

Crushing Spurs with Better Bandpass Filters

PA3AKE's passband (on screen) an mine (on NanoVNA) 

While I was away in the Dominican Republic (3-9 August 2023),  I was thinking about spurs.  While there I watched Nick M0NTV's video about mixers.  The video was all great, but I was especially taken by the way he used a spectrum analyser to evaluate the output of various mixers.  This made me think that I should do the same thing with the output of each of my dual-band BITX rigs. 

I was especially worried about the output from my 17-12 rig.  The IF is at 21.4 MHz.  The VFO runs around 3.5 MHz.   So if you add the IF and the carrier oscillator signal you get to 12 meters.  If you subtract them you get to 17 meters.  But you need some good bandpass filtering to sufficiently knock down the unwanted output from the mixer.  And the BP filter should be sufficiently narrow to take out any remnants of the carrier oscillator signal. I had taken the easy way out and had used simple dual-tuned-circuit (DTC) filters.  I started to wonder if these simple BP filters would be enough to knock down the 12 meter signal while on 17 and the 17 meter signal while on 12.  I pulled out my NanoVNA to look at the passbands: 

Here is what the 17 meter DTC filter passband looked like. The cursor is at 29.6 MHz and you can see that near the 12 meter band it is only providing about 21 db of attenuation.  That is not enough. 

And here is what the 12 meter filter looked like. Here the cursor is at 18.150 Mhz and shows about 25 db of attenuation at this frequency.  Again, not enough.  

The results are as you would expect: I could see 24.9 MHz signals in the output when I was on 17 meters, and I could see 18 MHz signals in the output when I was on 12 meters.  The spurs weren't strong, but they were there.  I knew that more robust BP filters would help.  

At first I used the circuits prescribed by Martein PA3AKE.  He used larger toroidal cores, I used smaller T-50-6 (yellow) cores.  The results were very similar.  See the first picture on this blog post. 

The results were really good.  See pictures below.  I was using a TinySA with the signal fed through a 50 ohm 30db attenuator.  I was putting a 1 kHz signal in to the mic input.  

This picture shows the 12 meter output and the now non-existent 17 meter spur.  The cursor is at 18.142 MHz:    

This picture shows the 17 meter signal and the now non-existent 12 meter spur. The cursor is at 24.993 MHz.   We can see some second harmonic signal getting past the LP filter -- I will fix this.  

Then Farhan commented on Martien's filters, noting that they are all in the "LSB" configuration.   You can see from the charts below how they would be really good when you are trying to use the "difference" output from your mixer while knocking down the sum output,  but not vice versa.     So I built new USB filters for 12 meters,  and for 10 meters in my nee 15-10 rig.  I got better results on the two "sum" bands in my rigs (10 and 12 meters) 

The Art of Electronics #7 -- Paul Horowitz on Ham Radio, and on SETI (audio)

Radio Contact · “We didn’t find anything, so the search goes on”

Above is a seven minute audio podcast in which Paul Horowitz talks about ham radio and SETI. 

See also:  https://radiocontact.org/portfolio/paulhorowitz/

and  https://en.m.wikipedia.org/wiki/Paul_Horowitz

Sunburst and Luminary -- An Apollo Memoir by Don Eyles (video)

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.

Also, take a look at this one: https://www.youtube.com/watch?v=oi4h04ZgQsQ

And this:  https://www.youtube.com/watch?v=cmAc7t7tAlc