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
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.
Popular Posts
- Gathering the Bones, 18: Hew Down the Bridge!
- Postblogging Technology, October, I: Forest for the Trees
- The Bishop's Sea, III: The Real Presence
- Postblogging Technology, November, 1943: Caesar's New Clothes
- Postblogging Technology, November 1950, II: Platypus Time
- Postblogging Technology, December 1950, II: Christmas Corps
- Postblogging Technology, March 1944, I: Pulling In the Horns
- I Would Run Away to the Air: The British Economy, Montgolfier to 727, Part 1
- A Techno-Pastoral Appendix to Postblogging Technology, October 1950: The Chestnut Plague
- The Bishop's Sea: Fine Corinthian Leather
Sunday, March 15, 2026
Line Scanning: A Technical Appendix to Postblogging Technology, November 1955
Sunday, March 8, 2026
Postblogging Technology, November 1955: Even the Moderate Adlai Stevenson
Shaughnessy,
Vancouver,
Canada
Dear Father:
![]() |
| The idea was good, but the material wasn't up to it and they took it too far. |
Your Loving Daughter,
Ronnie
Sunday, March 1, 2026
Jordan River Is Deep and Wide: A Technical Appendix to Postblogging Technology, November 1956
So we are sorted at work about how this humble blogger is going to be plugged into our current workplace "the retail emergency is forever" scheme:
Saturday: 6-230; Sunday, 10-6:30 "Need experienced people in the mid shift on our busiest day," until Saturday at 3PM, at which time it was changed by text message to 6-2:30: Monday, 6-2:30: Tuesday: 6-2:30: Wednesday, 1:30-10 "The DM will visit tomorrow, we need the department in good shape." It's good to be wanted at work, but if I asked you to guess what I did on Thursday, and you answered, "Managed to sleep for six hours, then sat on the couch eating stale chips and watching Youtube clips, taking a break every hour to nap," you would be right! As it turns out, I wouldn't have been able to finish it on Sunday morning, either.
And this is why this post is largely in response to things Newsweek will cover in our next installment of postblogging, which was about one quarter done Saturday afternoon when I gave up and went out for dinner.
Math time:
+
=
The point of this week's technical appendix is that some people say that British Airways ruined the British aviation industry by rejecting British planes, and some people say that British aviation ruined British aviation by forcing the Britannia on British Airways. In the spirit of the Internet these days, I'm going to present the case that it's actually "both"! And along the way I'm going to drag in some infrastructure projects of the mid-Fifties that are also having a continuing impact in a little part of the world that I like to call "the Middle East," which you probably haven't heard of. We're very geographically educational around this blog!Thursday, February 19, 2026
Postblogging Technology, November 1955, I: The Path of Duty
Shaughnessy,
Vancouver,
Canada
Dear Father:
After the excitement of playing secret agent for a few weeks, I am afraid that my life has turned into that of a junior associate doing her best to get her billable hours up and having to watch her children being raised by someone else.
Your Loving Daughter,
Ronnie
Saturday, February 14, 2026
Fiasco: A Technical Appendix to Postblogging Technology, October 1955
i)
ii)iii)Sunday, February 8, 2026
Postblogging Technology, October 1955, II: Boom boom!
![]() |
| According to Reddit User WeirdWings, this is the Bartini A-57, a supersonic V/STOL delta wing flying boat nuclear bomber, with a supersonic recon plane piggyback. "It was never put into production" says Wikipedia, which proceeds to speculate on why it was cancelled in 1957. |
R_.C_.,
Shaughnessy,
Vancouver,
Canada
Dear Father:
Your Loving Daughter,
Ronnie





