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.
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 Heathkit, Eico, EF Johnson, Allied Radio's Knight-Kit, World 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.
I found the comment about Sony's belief that NPN transistors are superior to PNP very interesting.
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.
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
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):
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
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!
You can get the book for free here:
https://www.facebook.com/groups/118053768802799
If you zoom in you can see the crystal and the cat's whisker.
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
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?
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