As the electrons travel down the tube, they interact with the RF signal. The electrons are attracted to areas with maximum positive bias and repelled from negative areas. This causes the electrons to bunch up as they are repelled or attracted along the length of the tube, a process known as velocity modulation. This process makes the electron beam take on the same general structure as the original signal; the density of the electrons in the beam matches the relative amplitude of the RF signal in the induction system. The electron current is a function of the details of the gun, and is generally orders of magnitude more powerful than the input RF signal. The result is a signal in the electron beam that is an amplified version of the original RF signal.
Bench Grass is a blog about the history of technology by the former student of a student of Lynn White. The main focus is a month-by-month retrospective series, covering the technology news, broadly construed, of seventy years ago, framed by fictional narrators. The author is Erik Lund, an "independent scholar" in Vancouver, British Columbia. Last post will be 24 July 2039.
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Sunday, March 15, 2026
Line Scanning: A Technical Appendix to Postblogging Technology, November 1955
Sunday, September 7, 2025
Postblogging Technnology, May 1955, II: It Sure Better Not Be 99 Balloons Going By!
Shaughnessy,
Vancouver,
Canada
Dear Father:
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| @Ferry Life: https://ferriesbc.proboards.com/thread/9490/bc-ferries-memories |
Your Loving Daughter,
Ronnie
Sunday, August 10, 2025
Postblogging Technology, April 1955, II: Streaming and Peppermint Bombs
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| Fortune is going to get you Philistines into abstract art even if it takes another 25 years |
R_.C_.,
Shaughnessy,
Vancouver,
Canada
Dear Father:
Your Loving Daughter,
Ronnie
Friday, July 19, 2024
A Technological Appendx to Postblogging Technology, March 1954: Noise About the Type 2001
Saturday, July 13, 2024
A Technological Appendix to Postblogging Technology, March 1954, II: Revisiting the Nuclear Submarine Question
The story here is that the United Kingdom is a rich, first world country and a Great Power. It fought the Second World War in alliance with the United States, now a superpower. At the time the metropolitan British Isles had 34% the population of the continental United States, compared with 20% today. It is fashionable to compare and contrast the technological achievements of the two states across a wide range of warmaking capabilities in WWII, and after, and to attempt to draw larger conclusions. It is particularly interesting to ask whether the steady decline in creditable comparisons over this period (or longer ones going back into the Nineteenth Century) is consequence or, perhaps to some extent, cause of the increasing disparity in national power (and, of increasing relevance, population). One such comparison is between the first nuclear submarine launched by the United States, Nautilus, commissioned on 30 September 1954, and the first British nuclear submarine, Dreadnought, commissioned 17 April 1963.
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| Sea power is submarine power now |
What I didn't have was a contemporary view in the form of a leading article in The Engineer explaining what a mid-century British technocrat would deem important research questions needing to be worked out before the nuclear submarine could take the sea as the lynchpin of modern strategic power. So in this short week, I am going to take another dive.
Sunday, September 24, 2023
A Technological But Also Inevitably Political and Medical Appendix to Postblogging Technology, June 1953, I: Diagnosing Presidents
Sunday, June 11, 2023
Gathering the Bones, XXVIII: Devil Take the Tobacco People
Who knew that I'd need the "Drug Humour" tag again the week after I created it?
Since I, personally, have this rigorously scholarly background in the literature, it occurs to me to wonder whether, given that producing tobacco is evidently quite hard, there isn't more to say.
Sunday, June 4, 2023
Postblogging Technology, February 1953, II: Too Good To Be Forgotten
Shaugnhessy,
Vancouver,
Canada
Dear Father:
I think I would be on and on about either feminine complaints or politics if I spent overlong with this, so best wishes, my love, and what a complete shambles the Eisenhower Administration has been! "Car dealers for New Dealers."
Hah! Also, oops. Sorry. Like I said, better not to spend too long on this.
Your Loving Daughter,
Ronnie





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