Reply to post: Re: Concrete Tornado

Hell hath no fury like a radar engineer scorned

Alan Brown Silver badge

Re: Concrete Tornado

"It took a long time for solid state electronics to catch up with vacuum tubes for high (kilowatts) power, and high (gigahertz) frequency applications."

More or less, it took FETs to catch up - which isn't surprising considering their principles of operation are broadly similar, whilst junction transistors are playing with quantum mechanics and Heisenberg's uncertainty principle (which is why they're noisy, you're hearing quantum variations as things jump the junction)

Mind you, one of the reasons that tubes _could_ operate at such high powers/frequencies was simply that their size and heat meant they were easier to cool despite being inefficient as hell(*). After all, all you really had to do was prevent them getting so hot the vacuum could be breached (softened glass or metal), vs keeping FETs under 100C or so.

(*) One of my lecturers used to regale us with stories of UK TV broadcast sites (powered by klystron-fed transmitters) which radiated so much waste heat that the end of the nights broadcast was the signal for folk in a nearby caravan park to put on shirts and go to bed - even in early winter.

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