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Showing posts with label radio history. Show all posts
Showing posts with label radio history. Show all posts

Tuesday, January 14, 2025

Shock and Awe: The Story of Electricity --- Wonderful Video by Jim Al-Khalili (sent to us by Ashish N6ASD)

From Ashish N6ASD -- Oil Lamps and Electronics

Here is the link to the video: 


First, thanks to Ashish Derhwagen N6ASD for alerting me to this video.  You should all check out his blog

This is a really important video.  It is the best I have seen about the history of electricity and electronics.  It is from 2011, but it is still very good. Jim Al-Khalili travels through the world and displays the actual devices developed by the likes of Heinrick Herz,  Guglielmo Marconi, and Jagadish Chandra Bose.  There is great discussion of Benjamin Franklin, Volta and Galvani.  The role of electricity in The Enlightment is discussed.
  

Jim talks about the early transatlantic cables, and why some of them didn't work. 

We see Jagadish Chandra Bose developing early point-contact semiconductors (because the iron filings of coherers tended to rust in the humid climate of Calcutta!) 

There is a video of Oliver Lodge making a speech.   There is a flip card video of William Crookes (one of the inventors of the cathode ray tube and the originator of the Crooke's cross).  

We see actual coherers.  

There is simply too much in this video for me to adequately summarize here.  Watch the series.  Watch it in chunks if you must.  But watch it.  It is really great.  

Thanks Ashish.  And thanks to Jim Al-Khalili.  

https://www.youtube.com/watch?v=Gtp51eZkwoI

Sunday, January 12, 2025

Some History of Homebrew Ham Radio -- From Wikipedia and from K0IYE

Frank Harris K0IYE's Homebrew Station

From Wikipedia:  https://en.wikipedia.org/wiki/Amateur_radio_homebrew 

In the early years of amateur radio, long before factory-built gear was easily available, hams built their own transmitting and receiving equipment, known as homebrewing.[2] In the 1930s, 40s, and 50s, hams handcrafted reasonable-quality vacuum tube-based transmitters and receivers which were often housed in their basements, and it was common for a well-built "homebrew rig" to cover all the high frequency bands (1.8 to 30 MHz). After WWII ended, surplus material (transmitters/receivers, etc.), was readily available, providing previously unavailable material at costs low enough for amateur experimental use.[3]

Homebrewing was often encouraged by amateur radio publications. In 1950, CQ Amateur Radio Magazine announced a ‘‘$1000 Cash Prize ‘Home Brew’ Contest’’ and called independently-built equipment ‘‘the type of gear which has helped to make amateur radio our greatest reservoir of technical proficiency.’’ The magazine tried to steer hams back into building by sponsoring such competitions and by publishing more construction plans, saying that homebrewing imparted a powerful technical mastery to hams. In 1958, a CQ editorial opined that if ham radio lost status as a technical activity, it might also lose the privilege of operating on the public airwaves, saying, ‘‘As our ranks of home constructors thin we also fall to a lower technical level as a group’’.[4]

In the 1950s and 60s, some hams turned to constructing their stations from kits sold by HeathkitEicoEF JohnsonAllied Radio's Knight-KitWorld Radio Laboratories and other suppliers.[5]

From "From Crystal Sets to Sideband" by Frank Harris K0IYE https://www.qsl.net/k0iye/

Dear Radio Amateur,

 I began writing this book when I realized that my homebuilt station seemed to be almost unique on the air. For me, the education and fun of building radios is one of the best parts of ham radio. It appeared to me that homebrewing was rapidly disappearing, so I wrote articles about it for my local radio club newsletter. My ham friends liked the articles, but they rarely built anything. I realized that most modern hams lack the basic skills and knowledge to build radios usable on the air today. My articles were too brief to help them, but perhaps a detailed guide might help revive homebuilding. I have tried to write the book that I wish had been available when I was a novice operator back in 1957. I knew that rejuvenating homebuilding was probably unrealistic, but I enjoy writing. This project has been satisfying and extremely educational for me. I hope you'll find the book useful...

...My personal definition of “homebuilding” is that I build my own equipment starting from simple components that (I hope) I understand. I try not to buy equipment or subassemblies specifically designed for amateur radio. I am proud to be the bane of most of the advertisers in ham radio magazines. I still buy individual electrical components, of course. I just pretend that the electronics industry never got around to inventing radio communications. 

An irony of our hobby is that, when the few remaining homebrewers retire from their day jobs, they often build and sell ham radio equipment. These industrious guys manufacture and sell every imaginable ham gizmo. I doubt any of them have noticed that, by making everything readily available, they have discouraged homebuilding.

Tuesday, October 8, 2024

The Transistor that Changed the World -- the MOSFET


Another great video from Asianometry.  

My only quibble is that it kind of left unclear the differences between JFETs and MOSFETs.  After all, we still use both.  Note our beloved J310 JFET.  And the IRF510 is a MOSFET.  

Google's AI explains: 

A JFET (Junction Field-Effect Transistor) and a MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) are both types of field-effect transistors, but the key difference is that in a JFET, the channel conductivity is controlled by a reverse-biased PN junction, while in a MOSFET, it's controlled by an electric field across an insulating layer between the gate and the channel, allowing for a much higher input impedance and greater design flexibility in MOSFETs; essentially, MOSFETs are considered a more advanced version of JFETs with superior performance in many applications like high-speed switching and integration into complex circuits. 

Saturday, September 7, 2024

Sony and the Transistor


I found the comment about Sony's belief that NPN transistors are superior to PNP very interesting. 


Tuesday, August 20, 2024

"The Far Sound" -- Bell System Video from 1961 -- Good Radio History (video)


This is a really OLD video, but there is a lot of great material here: 

-- Tubes.  (Valves or Thermatrons)
-- Coax.  
-- Frequency Division Multiplexing. 
-- Negative Feedback and the fight against distortion. 
-- Transistors and early experiments with semiconductors.
-- Fiber optics and Masers.
-- Satellite communications.
-- Early hopes for video communications.

The video is, by today's standards, extremely misogynist.  And the sound experiment with the poor woman wearing a male head was just weird.   But still, an interesting film. 

Thanks to Mark KM4GML for reminding us of this wonderful Bell Labs (AT&T) video archive. 

 

Saturday, May 11, 2024

Jens OZ1GEO's AMAZING Radio Museum



Brace yourselves.  This is just too much, too much radio history, too much cool stuff.  We are into ham radio sensory overload territory here. The rigs, the radios, the radioactive stuff (including tubes!).  Lots of Whermact stuff.  A Chinese receiver.  Tesla coils and Faraday shields.  Much more. 

Thanks to Helge LA6NCA for alerting us to this and for shooting these videos.  And thanks to Jens OZ1GEO for putting this magnificent collection together.  I hope they find sometplace to keep this all together so that future generations can benefit from it. 

George WB5OYP points out there is more from Jens here: 

Thursday, March 7, 2024

The Wizard of Schenectady -- Charles Proteus Steinmetz

Such a beautiful article.   Ramakrishnan VU2JXN sent it to me.  It reminded me of how puzzeled we were when we found "Schenectady" on old shortwave receiver dials, amidst truly exotic locations.  Rangoon!  Peking!  Cape Town!  Schenectady?   Obviously this was due to General Electric's location in that New York State city.  But reading this article, I am thinking that the presence of Charles Proteus Steinmetz had something to do with it. His informal title (The Wizard of Schenectady)  confirmed that we have been right in awarding similar titles to impressive homebrewers. 

Here is the Smithsonian article that Ramakrishnan sent. 

https://www.smithsonianmag.com/history/charles-proteus-steinmetz-the-wizard-of-schenectady-51912022/#ixzz2lRMjrfit

And here is a link to a PBS video on Steinmetz: 

https://www.pbs.org/video/wmht-specials-divine-discontent-charles-proteus-steinmetz/

Here is a SolderSmoke blog post about "Radio Schenectady":

https://soldersmoke.blogspot.com/2020/07/radio-schenectady.html


Wednesday, March 6, 2024

N6ASD Builds a Zinc-Oxide Negative Resistance Transmitter (and a Spark/Coherer rig)


I saw this video and post on Hackaday this morning:


I got the fellow's callsign from  his Morse CQ.  
It is N6ASD in San Francisco. 

Check this out from his QRZ page: https://www.qrz.com/db/N6ASD

My journey into the world of amateur radio began in a very primitive way. My first "rig" comprised of a spark-gap transmitter and a coherer based receiver. A coherer is a primitive radio signal detector that consists of iron filings placed between two electrodes. It was popular in the early days of wireless telegraphy.

Spark transmitter (using a car's ignition coil to generate high-voltage sparks):

Coherer based receiver (using a doorbell for the "decoherer" mechanism):

When I keyed the transmitter, a high voltage arc would appear at the spark-gap and this produced (noisy) radio waves. The signal would be received by the iron-filings coherer on the other side of the room. A coherer is (usually) a one-shot receiver. You have to physically hit it to shake the filings and bring the detector back to its original state. That's what the doorbell hammer did. It would hit the coherer every time it received a signal. It amazed me to no end. A spark created in one room of my house could make the hammer move in another room. Magic!

Soon after this project, I started experimenting with *slightly more refined* crystal detectors and crystal radio circuits. As most of you would know, these amazing radios don't require any batteries and work by harnessing energy from radio waves. I guess these simple experiments instilled a sense of awe and wonder regarding electromagnetic waves, and eventually, this brought me into the world of amateur radio in 2015.

My main HF rig is an old ICOM IC-735. The only modification on this is radio is that it uses LED backlights (instead of bulbs):

Icom IC 735

With space at a premium in San Francisco, the antenna that I have settled for is an inverted vee installed in my backyard (and it just barely fits). I made the mast by lashing together wooden planks. For this city dweller, it works FB:

I have recently gotten into CW, and it has definitely become my mode of choice.

I'm a self-taught electronics enthusiast and I love homebrewing radio circuits. I'll be sharing more info about them soon.

Thanks for checking out my page. I hope to meet you on the air!

73,
N6ASD

 

Monday, February 19, 2024

Jean Shepherd has Trouble with his Heising Modulator (and his date)


This is probably Jean Shepherd's best program about homebrew ham radio.  It is about how we can become obsessed with the problems that arise with equipment that we have built ourselves, and how normal people cannot understand our obsessions.   

I posted about this back in 2008, but I was listening to it again today, and quickly realized that it is worth re-posting.   Realize that Shepherd's Heising modulation problems happened almost 90 years ago.  But the same kind of obsession affect the homebrewers of today.  

Note too how Shepherd talks about "Heising" in Heising modulation.  Heising has an entire circuit named for him, just like Hartley, Colpitts, and Pierce of oscillator fame.  Sometimes, when I tell another ham that my rig is homebrew, I get a kind of snide, snarky, loaded question:  "Well, did you DESIGN it yourself?"  This seems to be a way for appliance operators to deal with the fact that while they never build anything, someone else out there does melt solder.  They seem to think that the fact that you did not design the rig yourself makes your accomplishment less impressive, less threatening.  This week I responded to this question with Shepherd's observation -- I told the enquiring ham that my rig is in fact homebrewed, but that I had not invented the Colpitts oscillator, nor the common emitter amplifier, not the diode ring mixer, nor the low-pass filter.  But yes, the rig is homebrew, as was Shepherd's Heising modulator.    

Guys, stop what you are doing. Put down that soldering iron, or that cold Miller High Life ("the champagne of bottled beer") and click on the link below. You will be transported back to 1965 (and 1934!), and will hear master story-teller Jean Shepherd (K2ORS) describing his teenage case of The Knack. He discusses his efforts to build a Heising modulated transmitter for 160 meters. He had trouble getting it working, and became obsessed with the problem, obsessed to the point that a girl he was dating concluded that there was "something wrong with him" and that his mother "should take him to a doctor."

This one is REALLY good. It takes him a few minutes to get to the radio stuff, but it is worth the wait. More to follow. EXCELSIOR! FLICK LIVES!

Thursday, January 18, 2024

Some Great Reading Material -- Links to Radio Publications

 


My fellow Hambassador Dave WA1LBP sent this to me today (from Taiwan, I think).  Lots of great  ham radio and SWL info in these many publications.  The one that caught my eye was "The Modulator,"  an ARRL publication done by the 2nd District in the 1920s.  Really interesting.  I will sent this to Lyle, W7QCU who has an interest in radio from this era.   


Thanks Dave!  73! 

Sunday, January 14, 2024

QRP Trigger Warning! 500 kW from WLW (great video)


Wow, this video will make you appreciate the simplicity of QRP! 

My favorite part was when they required the use of "dark welding goggles" for whoever was charged with a visual check of  the tube filaments.  

Thanks to Hack-A-Day for alerting me to this wonderful video. 

Friday, November 24, 2023

A FREE Book from the Early Days of Ham Projects with Transistors: The CK722 -- The Device that Got Pete Juliano Started in Homebrew

 
Pete N6QW sent this amazing book to me this morning.  Pete wrote: 

"The book was the size of a Notebook and had a gray cover. I built some of the projects like the CPO. If you had a CK722 then you were there."

You can get the book for free here: 


 http://n4trb.com/AmateurRadio/RaytheonTransistorApplications/Raytheon%20Transistor%20Applications.pdf 



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

Thanks Pete.  And thank you Raytheon! 

Thursday, November 16, 2023

The Grid Leak Detector -- Follow-up from Yesterday's Post on the Whole Earth Catalog's "Hippy" One Tube Receiver

Click on image for a better view
When I first looked at it in the Whole Earth catalog circuit, I thought it was a regen.  But a commenter correctly questioned this conclusion.  I remembered the grid leak circuit (WN2A provided more info in the comments).  This morning I found a Wikipedia page that explains it all very well.  I especially like the description of how this detector works both with small signals in the "square law" range of the tube, and with larger signals in the linear range of the tube.  The history of the discovery of the need for the large resistor is also very interesting.  I remember building FET amplifiers and finding that they would -- after time -- shut down.  This would happen as charge built up on the gate.  I had neglected to include the normal 100k ohm resistor (that would "leak" this charge to ground).  Once I put this resistor in, the amp worked fine.  

Here is the Wikipedia article:  


Sunday, October 15, 2023

Spy Rigs, Para Sets, Bugs, and Enigma Machines -- Dr. Tom Perera W1TP (video)


This is a really amazing presentation by Tom Perera W1TP to the Fairlawn (NJ) Amateur Radio Club. 

There is so much great info in this presentation.  Some of the highlights for me: 

-- The U.S. Civil War telegraphic (wired) spy set was just mind blowing.  I had never heard of this.  

-- The way the Nazis transmitted a signal 1 kc off the BBC frequency, so that Germans who tuned their Nazi-issued receivers to the BBC could be detected by neighbors (from the resulting 1 kc tone!) and turned in to the Gestapo.  

-- "Things don't land gently when dropped by parachute." Indeed.  This was a reminder of the courage of the young women who parachuted into Nazi-held territory during WWII.  Like Paulette.  It was great to see her with her Paratrooper wings on.  AIRBORNE!  And the picture of the operator with the bicycle generator was of Virginia Hall.  See: https://www.npr.org/2019/04/18/711356336/a-woman-of-no-importance-finally-gets-her-due  That portrait hangs in the hallway of the National War College. 

-- How they put the schematic of the PRC-5 right into the box.  Great idea.  But it had a terrible receiver.  One of the schematics showed a 455 kc IF and a BFO.  So they sent in superhets, not just regens. 

N2CQR operating the Para Set of G3ROO around 2009

This video makes me want to build a Para Set. 

Thanks a lot to Tom W1TP and the Fairlawn ARC. 

Saturday, August 19, 2023

Valveman -- The Story of Gerald Wells


Don't be deterred by the annoying test patterns at the start of this video.  Just skip past them.  The rest of the video is quite good.  Or you could just click on this link and avoid the first 83 seconds of test pattern:  https://youtu.be/Y8w6iwaAGJ4?t=83

Gerald Wells has been mentioned on this blog before, but I don't think we've ever presented the full documentary on this fellow.  Here it is.  Gerry is clearly one of us: a radio fiend, obsessed (as he admitted!) with wireless, a victim of THE KNACK.   

George WB5OYP of the Vienna Wireless Society got to meet Gerald Wells and visit his museum. George alerted me to this video.  Tony G4WIF also was able to visit Gerry and his museum. 

The documentary is full of interesting stuff, and is, in itself, a Knack Story.  Wells mentions the Crippens murder so well described by Eric Larson in "Thunderstruck."  It was this crime that brought radio to the center of public attention.  

Thursday, April 20, 2023

Artie Moore and the Titanic


I had never heard of Artie Moore, but his is a very interesting story from the earliest days of radio. 

 https://en.wikipedia.org/wiki/Artie_Moore

https://www.facebook.com/groups/118053768802799



Thursday, February 23, 2023

Early (1912?) Ham Station

 
Perhaps a bit overdressed by today's standards, but he's got a familiar look on his face.  Confidence and pride in his rig, and a steely determination to make contacts with it.  

If you zoom in you can see the crystal and the cat's whisker. 

More on this here: 

http://uv201.com/Photo%20Pages/ham_3.htm?fbclid=IwAR10Lbi2CAsYeiBDUjWb5KIQrh1SJVGwDyL2_1ZrkPk1VbllAUbeahwxsAI

Wednesday, February 22, 2023

The Transistor at 75, and the Raytheon CK722 (Pete's First Transistor)

 

https://www.eejournal.com/article/the-transistor-at-75-the-first-makers-part-1/

Part 4 is especially interesting to us because of the N6QW-CK722 connection: 

     Raytheon: Raytheon started making vacuum tubes in 1922. During World War II, the company made magnetron tubes and radar systems. Raytheon started making germanium-based semiconductor diodes in the 1940s and, just months after BTL announced the development of the transistor in late 1947, started making its own point-contact transistors using germanium salvaged from Sylvania diodes. After attending the 1952 BTL transistor symposium and licensing the alloy junction transistor patents from GE, the company quickly started making germanium transistors including one of the most famous transistors of that generation, the CK722, which was simply a rejected commercial CK718 transistor with downgraded specs for the hobby market. (Jack Ward has created an entire museum around the Raytheon CK722 PNP transistor.) Raytheon exited the semiconductor business in 1962.

Here are all of our blog posts on the CK722: 

https://soldersmoke.blogspot.com/search?q=CK722

Here is our post on Pete Juliano's CK722: 

https://soldersmoke.blogspot.com/2015/03/pete-juliano-homebrwing-with.html


Is this the Origin of the Term "Ham" Radio?

Click on the image for a better view

The timing (1895) and the context (railroad telegraphy) seem about right.  But other etymologies are out there.  Lexicographer Steve Silverman KB3SII is on the case.  What do you guys think?  Are the roots of "ham" radio in railroad telegraphy? 


Monday, February 13, 2023

The Infinite Impedance Envelope Detector (done with an FET)


Recently a fellow ham claimed that "envelope detection" doesn't really exist, and that the standard "rectification and filtering" explanation of how envelope detectors work (going back to Terman and beyond) is wrong.  But here is a good demonstration of the envelope detection of an AM signal.  It uses an infinite impedance detector built around an FET.  As Baltic Lab notes in the video above, the action is essentially the same as what happens with a vacuum tube:  The device is biased at cut-off.  The negative portion of the ENVELOPE is discarded.  The positive portion of the ENVELOPE is passed through the device and filtered.  What remains is the audio -- the same audio frequency that modulated the carrier.  ENVELOPE DETECTION.  

I was thinking about how fortunate we were that this form of detection was possible. Fessenden used what were in effect diode detectors to envelope detect very early transmissions of radiotelephony. If simple envelope detection via rectification had not been possible, radiotelephony might not have been invented as early as it was. 

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