Early Hacking with an IMSAI 8080 -- "War Games" (1983) Scene with Matthew Broderick and Ally Sheedy

Some computer history here, and it is old enough (1983) to fit into the SolderSmoke theme.  Plus it appears that the young fellow has a shack (of sorts) and uses it to impress a girl from his biology class.  Finally, we know the IMSAI guy has an important YouTube channel... 

Attempting 2 meter contact, Dominican Republic to Puerto Rico

It is about 100 miles across the Mona Channel.  That is a longshot on 2 meters, but I got the idea when, this past summer, I regularly heard WIDI 99.5 FM in the Dominican Republic from western Puerto Rico.  So over the fall I gathered 2 meter gear, and got a directional antenna and sent all of this gear to the DR.  

Here is the antenna.  Seven elements. I got it through Amazon.  It came kind of incomplete and without any written or on-line instructions.  AI told me to do exactly the WRONG thing with what they assumed was a reflector.  Fortunately I ran into this YouTube video and learned that it was in fact a "ZL Special" antenna, and that it has, in fact, TWO driven elements.  It was through that video that I learned how to assemble this thing.  

My "station" consists of a Heathkit HM-2109.  It is a VHF wattmeter/SWR meter that I bought by mistake.  But I kept it, and it proved very useful in this 2 meter Mona Channel project.  There is a Baofeng UV-5R (boo! hiss!) and a Yaesu FT-470 that KD4EBM gave me.  I have a Communication Concepts 2 meter amplifier -- I must have picked this up at a hamfest.  It promises 35 watts with 5 watts of drive.  The old CCI amp gives the rig good juju. 

This morning I wrote to the hams of western Puerto Rico: 

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

Saludos desde el otro lado del canal de la Mona! 

Soy radio aficionado:  Hi7/N2CQR.   Vivimos en República Dominicana en Cap Cana seis meses cada año.

He notado que puedo escuchar WIDI 99.5 FM aquí.  Parece que hay Tropospheric ducting. 

Como radioaficionado, me gustaría averiguar si podemos hacer contacto en 2 metros usando la misma propagación. 

Tengo: 

Dos transceptores de FM

Un amplificador a 35 vatios. \

Un antenna directional de 7 elementos con un gain de 11.5 db. 

Estoy a una elevación de 7 Pisos.  Puedo ver el canal de Mona. 

Hay alguien en la costa oeste de PR (tal vez cerca de Mayagüez) quien puede hacer un schedule para probarlo? 

O hay un repetidor en la zona que puede usar para averiguar si puedo -- por lo menos -- "kerchunk"  el repetidor?  

Gracias por su ayuda! 

73  Bill  Hi7/N2CQR

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

Greetings from the other side of the Mona channel!

I am a radio amateur: Hi7/N2CQR.   We live in the Dominican Republic in Cap Cana six months every year.

I've noticed that I can listen to WIDI 99.5 FM here.  There seems to be Tropospheric ducting.

 As a radio amateur, I would like to find out if we can make contact in 2 meters using the same propagation.

 I have:

Two FM transceivers

An amplifier at 35 watts. \

A 7-element directional antenna with a gain of 11.5 db.

I am at an elevation of 7 Stories.  I can see the Mona's channel.

 Is there someone on the west coast of PR (maybe near Mayagüez) who can make a schedule to try it out?

 Or is there a repeater in the area that you can use to find out if I can -- at least -- "kerchunk" the repeater?

 Thank you for your help!

 73  Bill  Hi7/N2CQR

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

Stay tuned! 

Watching the Hubble Space Telescope (an old friend) from the Dominican Republic

 

A recent article about the possibility of an early demise of the Hubble Space Telecope caught my eye.  I first saw HST as it came overhead (a lot) during my first stay in the Dominican Republic (1992-1996).  

Here is an entry from my observation log showing one of my first sightings of HST from the DR: 

2 February 1995: (message placed on COMPUSERVE board) I got a really nice look at the HST this morning (2 February) from my perch here in Santo Domingo. I woke up early and checked the computer for any satellites that might be in the neighborhood. (I'm a ham and have been trying to communicate through the new Russian Hamsat RS-15). I noticed that HST would be visible starting at around 0935 UTC (0535 local); I scrambled up onto my roof with binoculars in hand and began to scan the southern sky. There she was, right on time! I first spotted the satellite when it was in Centaurus (with the Southern Cross glimmering off to the right) and followed it through Scorpio, below Venus and Jupiter until it vanished in the east. Great way to start the day! Yet another benefit of southern latitudes! 73 and Clear Skies, Bill (N2CQR/HI8)

I am back in the DR now; I decided to look for it again.   

The Heavens-Above web site gave good info on the orbit.  So did the N2YO site.  There were a couple of morning passes in January that didn't work out because of local cloud cover,  but last night (January 20, 2026) I managed to see it on an evening pass. It was fainter than I remember, peobably because I saw it at 1930 Local, near  zenith, as it was getting ready to fly into the darkness.  But I saw it.  My old friend, HST.  

Here is the pass that I watched last night: 

There is another good pass tonight.  I will give it another try.  Stay tuned. 

He's Back! The Dos Equis Man -- The Most Interesting Man in the World -- RETURNS!

Memes with this guy appeared in many SolderSmoke posts.  

Examples: 

https://soldersmoke.blogspot.com/2022/10/worlds-most-interesting-man-on-ptos-and.html

https://soldersmoke.blogspot.com/2017/06/stary-thirsty-my-friends-very.html

https://soldersmoke.blogspot.com/2022/11/watching-shortwave-broadcast-stations.html

And now he is back!  

https://edition.cnn.com/2026/01/16/food/dos-equis-most-interesting-man-ads

Background info on The World's Most Interesting Man:  

https://www.politico.com/magazine/story/2017/06/02/most-interesting-man-world-friends-barack-obama-215215/ 

"His personality is so magnetic, he is unable to carry credit cards."

Stay thirsty my friends!  

Here is another new one: 

MIT Technology Review on Why AI LLMs are So Strange and So Alien

Until recently, I thought that the AI LLMs were just sort of fancy, souped-up search engines.  Google on steroids.   But then they started getting simple things wrong.  And they seemed to understand that that our April 1 stories were just sarcasm.  There seemed to be more to them than fancy search engines.  

This MIT article explains what is going on with the LLMs.  

https://www.technologyreview.com/2026/01/12/1129782/ai-large-language-models-biology-alien-autopsy/

What do you folks think of this?

Why is it that AI-provided electronic circuits often don't work in the real world?

Like many, I have turned to AI for circuit ideas.  And like many, I have been surprised by how many of these ideas just don't work.  I have found relatively simple circuits that don't work when built in the real world, and don't work when built in LTSpice. I have already described how AI failed when I asked it a simple question about how many 330 ohm resistors to put in parallel to get 50 ohms.  Mike WU2D had found that a lot of AI provided circuits just don't work.  (Go to the 10 minute point in his video. )

I was wondering why this is so.  So... I asked AI!  For those who are sure that their AI is smarter than my AI, let me specify:  I just wrote the question into the Google search box and looked at the "AI Overview" in the response.  

Here is what AI said: 

AI-recommended circuits often fail in the real world due to gaps between simulation and reality, such as a lack of real-world data (noise, rare conditions), AI's inability to grasp complex physical nuances like heat dissipation or component aging, and poor integration with physical prototyping, leading to brittle designs that don't account for manufacturing tolerances or environmental stresses, despite being mathematically sound. 

Key Reasons for Failure:

Data Limitations (Garbage-In, Garbage-Out): AI relies heavily on training data; if it's incomplete (missing extreme temperatures, noises, aging effects) or biased, the AI generates designs that work in simulation but not in messy real-world conditions.

• Brittleness & Lack of Context: AI struggles with "edge cases" or novel situations not in its training, leading to fragile designs, much like an AI failing to recognize a rotated bus. It lacks human intuition for subtle physical interactions.
• Physical Nuances Ignored: Simulations often miss crucial real-world physics like heat hotspots from component imperfections, electromagnetic interference, or subtle signal integrity issues, which become critical in physical prototypes.
• Manufacturing & Prototyping Gaps: AI designs might be theoretically optimal but impractical to build (e.g., impossible tolerances, complex layouts). The gap between virtual design and physical assembly (poor connections, wrong components) causes failures.
• Validation Challenges: AI-generated circuits need extensive, real-world testing (SPICE simulations, breadboarding, PCB builds) to catch issues, but AI can't perform physical troubleshooting like soldering a damping resistor or witnessing ground bounce in a lab.
• Probabilistic vs. Deterministic: AI works on probabilities, whereas electronics often need deterministic precision. A small error tolerable in some AI tasks can be catastrophic in sensitive circuits. 

How Engineers Address This:

• Iterative Feedback Loops: Combining AI's speed with human expertise and physical testing to refine designs.
• Hybrid Approaches: Using AI for creative exploration but relying on established physics models (like SPICE) and human judgment for final validation.
• Focus on Integration: Ensuring AI tools work seamlessly with existing engineering workflows and physical constraints. 

SolderSmoke Homebrew Direct Conversion Receiver Hall of Fame Update: 106 Completed + 7 Honorable Mentions: Total Receivers Built: 113 (As of February 1, 2026, 2238Z)

Please let us know if you spot any errors, or if we have inadvertently missed anyone.  Don't worry about being late to the game -- the challenge continues.  All of the info is still available. 

As of February 1, 2026 2238Z:

So far 106 completed receivers, and 7 honorable mentions.  Total Count:  113.       Receivers built in 17 countries.   

NE3U (KY4EOD)  Matt 

KQ4AOP       First ham signals ever heard! 

N9TD             Derek

AC3NG          Ryan

VK3TPM       Peter Marks  

W4KAC         Ken 

W4KAC         Ken built a second one! 

N2EPE           Erik

VA3NCA        Wayde    

KI5SRY          Mark -- Gears on PTO screw

 

KA1MUQ       Frying pan receiver

AA1N              Adam

ZL1AUN         Aaron -- Using SSB transmitter -- New Zealand

W8UC             Never before homebrewed. 

VK4PG           Phil -- Nice case, "really pleased"

G7LQX           Working well, video of CW and SSB.  -- England

KE2AMP        John     Spring on PTO screw -- great

N9SZ              Steve  nice receiver

KD9NHZ        Piotr  Nice one

KE8ICE          Calvin, Very cool receiver. 

 

WV3V              Jayson!  Got it done!

GM5JDG         Martin.   -- Scotland 

KF8BOG          Jim:  A long struggle, but success.  

Chris Wales    Fantastic video.  -- Wales

YD9BAX         Wayan! Homebrew transformer!  Indonesia

N0NQD         Jeff 

WN3F              Roy -- Made new stickers! 

AB5XQ            Bill  

KB7ZUT          Andy  

AA1OF            Jer

VictorKees        Holland

KC9OJV           John -- Manhattan-style convert

WZ5M              1, 2 or maybe even 3 receivers!

K1KJW             Jim in Vermont

KC5DI              Dallas -- friend of WZ5M

Gary                 Australian -- Wooden PTO form

LU2VJM          Juan in Argentina  -- Argentina

K1OA               Scott "Most fun in 50 years"

KC9DLM         Ben -- Had EFHW problems

PH2LB             Lex  Yellow, Glue Stick -- Netherlands

AI6WR             David

G6GEV            Dave (It was a blast!) 

KC1ONM        Wayne  MakerLabs NH

KB1OIQ          Andy    MakerLabs NH

KA1PQK         Jay       MakerLabs NH

W1TKO           Mike    MakerLabs NH

K5KHK            Karl

SM0TPW         Mikael  -- Sweden

KI7LKB           Brian (coat hanger tube)

M6CRD            Chris

W2DAB           Dave in NYC

W4JYK            Wes of VWS

KA4CDN          Mike of VWS

M7EFO             Adrian 

VK5RC             Rob

KD8KHP          Dave

VK1CHW         Chris

KA0PHJ           Brian

W0IT                Louis

W1PJE             Phil

W2AEW           Alan

KN6FVK          John (Barkhausen-Be-Gone Spray) 

VU2JXN           Ramakrishnan -- India

AA0MS            Doug 

9V1/KM7ABZ   Paul  --  Singapore

VK2BLQ          Stephen -- Australia

N3FJZ              Rick

Daniel               VE5DLD  -- Canada

Student 1          Student of VE5DLD

Student 2          Student of VE5DLD

Student 3         Student of VE5DLD

K7WXW          Bill 

NK3H               Mitch

KN4ZXG         Ted

WA1MAC        Paul

N4AVC             Chuck 

K3IY                 Kevin

N6ASD             Ashish in Bangalore

W1DSP             Rick

WD4CFN         Steve

KM5Z             Mike

KF5DAN         Dan

Fritz                 Fritz

N9OK              Joe

WA5DSS         Bill 

K0GDB           Grant

G0JNR            Shane Glow-in-Dark Coil Form

KK7BCO        Tobias

K2BVR            Bob

Robert              Sutton

K5YFO           Dave (Texas) 

KD4PBJ          Chris

KN4GAH        Chris -- EE perspective

F1GMA           Philippe  -- France

W2TEF            Todd

EI9ITB            Karl  -- Ireland

VU2TUM         Puneit Singh

AA7EE             Dave Richards

KI5VIR            Jay

CT7AXD       Graham -- Promoted from Honorable Mention!

G3MOT           Josh

KW4H             Steve

NJ7V                Charlie (RedSummit)

N2ETZ            Denny

AB9LM           James

W9XT              Gary

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

Honorable Mentions: 

*AA7U            Steve No PTO

*VK7IAN        Ian -- No Manhattan boards -- Tasmania

*KC1FSZ        Bruce's build on a PC board

* DL1AJG      Andreas -- Germany

* Matthew      Student of DL1AJG

* Arash           Student of DL1AJG 

*KA4KXX     Walter -- FB 20 Meter version

Artificial Intelligence Not So Intelligent! AI Flunks the Parallel Resistor Test!

So this morning I asked this of AI:      

How should I make a 50 ohm dummy load capable of handling 5 watts from 330 ohm 1/4 watt resistors?'

Here was the answer: 

Oops.  Nope.  That makes a load of about 20 ohms, not 50.   

Wow,  this seemed like a fairly simple request.  AI got it wrong.  If AI (LLM) can't get a simple question like this right, you have to wonder how many other things it is getting wrong. 

More on Spark Transmission and Reception -- From Germany. Spark Transmission using a Piezo Fire Starter

More spark today.  I really liked how Robert Dalby demonstrated spark transmission and reception.  He used a simple Piezoelectric flame starter (like the one that many of us have in our shacks) as the transmitter, with a homebrew coherer connected to an LED and some batteries as the receiver.  Ingenious.  As with CuriousMarcs video of yesterday, you can see how Marconi's system really worked.  Brilliant. 

This demo also shows how many devices can generate part of the noise we hear in our receivers.  We see and hear the noise generated by a nearby electric fence, and the noise made by a simple electric motor.  Many new builders have trouble accepting the reality of noise.  Noise happens. 

The entire YouTube channel is very interesting.  Check it out here: 

https://www.youtube.com/@deutscheavionik7211

It is based on the amazing collection of Dieter Beikirch (I think he is DJ5RS) and is presented by Robert Dalby. Here is how they describe the channel: 

German avionics in the era of the vacuum tube. Join us as we investigate the most critical period in the rapid development of electronics, especially airborne electronics, from the first spark-gap radios of WW1 to the advances in radar technology in WW2.

Spark Gaps and Coherers demonstrated and Measured by CuriousMarc

CuriousMarc provides a good demonstration of how spark transmitters work with coherer detectors.  His measurements are really illuminating.  His device just needed a "tapper" to de-cohere the metallic filings.  We see the tapper in this wonderful "Secret Life" video by Tim Hunkin: 

https://soldersmoke.blogspot.com/2021/06/remastered-secret-life-of-radio-with.html

Walter KA4KXX's Innovative 20-meter SolderSmoke Direct-Conversion Honorable-Mention Receiver

 

It is a thing of beauty.  We were really pleased to see our old friend Walter KA4KXX take on the SolderSmoke challenge, and we weren't a bit surprised to see him do so using some real twists in the design.  You see, Walter is a very experienced homebrewer.   He has built many, many rigs over the years.  Just check out his QRZ page and you will see what I mean: 

 https://www.qrz.com/db/KA4KXX

Walter supported our original high school effort by offering the students a $500 prize for any student who used our receiver (and a similar transmitter) to check in to the 40 meter Sunrise Net.  Sadly, there were no takers.  But we really appreciated the attempt. 

We have listed Walter's receiver in the Honorable Mention category, only because his build is so innovative:  20 meters instead of 40.  An IC in the audio amplifier.  There were differences, but even a quick look at the above picture above shows that Walter's receiver is very much a SolderSmoke Direct Conversion Receiver.  

Here are some additional photos from Walter. 

Congratulations Walter.  Welcome to the Hall of Fame!  

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

From Walter's QRZ page

Let's Start the New Year with... THE KNACK!

Happy New Year everyone!  Our friend Rogier PA1ZZ sent this to me. I'm sure there are parts of it that people will disagree with, but the overall message (BUILD THINGS!) is, I think, right for this group. Thanks Rogier!