I became interested in VHF, UHF, and eventually the generation and transmission of microwaves, as a youth, and had constructed a lot of homemade experimental apparatus when in 1959 I happened to talk with a couple of engineers from Stanford Research who were working on an apparatus to generate 100 GHz signals.? After some research and a lot of thought, this inspired me to obtain a WW-II surplus, 25 GHz range klystron tube and to purchase necessary waveguide and flanges to construct 4X frequency multipliers.? A little later, I was able to obtain a better, 33.3 GHz post-war klystron tube and develope suitable X3 multipliers that proved more efficient.? Internal dimensions of the WR-8 100 GHz waveguide are 0.04” by 0.08”.? This is a worldwide standard.? A brief account of this work is found in an older account on the Netherlands amateur microwave site at .

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A ?hobby group centered on constructing and operating equipment at these higher frequencies is found at ; although it has not been very active lately because much of the interest has shifted to /g/The122GProject/topics , a group centered around adaption of automotive radar chips to function as transceivers in the 122 GHz amateur radio band.? A brilliant Australian engineer and his fellow amateurs have designed and arranged for manufacture of these transceiver boards at an affordable price, allowing amateurs around the world to experience and investigate the peculiarities of transmission and reception at these frequencies.

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Various complexities are encountered in fabricating apparatus for these frequencies.? Now in my late 80’s I’ve not accomplished anything of note; however, those interested in exploring further might enjoy the work of Neil Smith, G4DBN, an exceptionally talented British engineer, machinist, radio amateur and presenter at .? Some of his interesting U-Tube videos can be viewed through links on this site.?

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Bruce, KG6OJI