CELEBRATING THE 50TH ANNIVERSARY OF Microwaves & RF has inspired us to pull our old volumes off the shelf and take a trip down the proverbial memory lane. For folks who are newer to the industry, such issues offer a history lesson. For microwave veterans, they provide a chance to indulge in nostalgia as one sees faces, company names, and developments of the past. The advertisements, in particular, provide a snapshot of a respective timeframe's stylistic sense while highlighting the then cutting-edge product and technology trends. The ads' style in terms of fonts, color, and general graphic design are vastly different from todaynot to mention their content, which has dramatically changed.

In today's world, for example, knobs most often remind engineers of test and measurement equipment. With more commands and capabilities being handled by touchscreen prompts, though, even those knobs are starting to seem "vintage" if not antiquated. In an ad from November 1962, however, Westinghouse proudly touts its knob-based accurate klystron tuning: "No more wrestling around with a screwdriver!"

According to the ad, this "exclusive" Westinghouse tuning knob added precision and ease to klystron tuning. It was especially suitable for bench oscillators in the laboratory, the school, and on the production floor. (Today, of course, we would say that it served applications from research and development through manufacturing.)

The tuning adapter, dubbed the WX-5079, had a tuning rate of 60 mc per turn of the tuning knob at X-band. Five tubes covering a "wide" frequency range could be supplied with this tuning knob. In this case, "wide" meant a total of 7.5 to 17.5 GHz (gc). Power could be varied in each tube, helping the knobs satisfy a range of applications. Depending on the tube type, they put out anywhere from 120 to 220 mW and provided an electronic tuning range from 25 to 50 MHz (mc). Beam voltage also was important enough to mention in the ad, being either 500 or 600 V, depending on the model.

In terms of visual cues, this one is pretty cute. We especially admire the way a large man's hand is shown holding the screwdriver in the "old way" photograph while a nicely manicured woman's hand is shown tuning the knob in the "new way" photo!

Hands seem to be a rather common theme in the early 1960s, as an ad from Texas Instruments, Inc. focuses on a man's hand as he palms a newly released circuit. Compared to today's ICs, these discrete, "subminiature" gallium-arsenide (GaAs) pill varactors offered no integration benefits. They did, however, provide a minimum cutoff frequency of 90 to 150 gc at -2 V. They offered junction capacitance of CJ at 0 bias from 0.15 to 0.75 pF.

These varactor diodes targeted low-noise parametric amplifiers, harmonic generators, microwave switches, subharmonic oscillators, phase shifters, and parametric limiters. Given the size of this varactor diode, we can certainly envision how large those end components were. This picture is quite a contrast to today's chip photos, which are compared to items like pennies and paper clips. Things have changed, to say the least.

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