“As long ago as 1960, I listened to a well-respected engineer confidently forecast that 150-watt HF power transistors at prices comparable to valves of equivalent dissipation were but two years or so distant”, wrote Pat Hawker in the October 25th 1972 edition of Electronics Weekly.
“Today it is possible to buy an HF 159-watt transistor or a pair of devices which will provide an output of 140 watts at 175MHz – but they will cost much , much more than equivalent thermionic devices and require significantly more engineering expertise to design them into good, reliable amplifiers,” continued Hawker.
The article continued: “RF power amplifiers long remained the Achilles heel of fully-transistorised communications and broadcasting equipment , despite the periodic announcements that the troubles of the past had been overcome in new generations of devices.”
“Engineers who had come to think of the RF power transistor as the fastest fuse on three legs remain a little cynical,” commented Hawker.
“A year ago”, continued the article, “one well-known journal ran a piece entitled: ‘You can depend on today’s RF power transistors’ with the revealing addendum: ‘Designers no longer face unrealistic power claims , unreliable multichips, and stringent circuit parameters; present devices give up to 150 watts of reliable RF poler and they’re steadily getting better.”
“But fortunately this time it was true”, wrote Hawker, “well, almost true.”
In the same 1972 edition of EW the cartoon ‘Electroon’ shows a car which had swerved onto the grass verge of a road as it passed an on-coming vehicle with the caption: ‘Your radar collision avoidance system certainly works, Popkiss, but at present I feel it tends to exaggerate.”
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