in the late 1980s, freshly out of engineering school, I was working as an RF engineer at the General
Electric Aerospace Electronics Division (GEASD) in Utica, NY. I was tasked with designing a small switched
filter/amplifier for part of an airborne electronic countermeasures system. At the time, I was new to
the RF design world, even though I had spent a lot of years working on RF systems. So, I set about researching
components from MIL-qualified vendors.
Johnson, Narda, Amplifonix, and many other companies published really nice catalogs in those days that
were chock full of application note. Most app notes are found today on the Internet rather than in data
books, which is of course not only more convenient, but saves a lot of cost for printing and distributing.
Up until the mid-to-late 1990s, manufacturer's catalogs were actually used rather than just being tossed
into the recycle bin when they arrive in the mail.
As anyone who has been in the RF business for a while knows, jokes are always made about how anything
and everything can - and will - affect the performance of high frequency circuits if proper precautions
are not taken. Statements like, "Gain will be 10 dB nominal, with variations depending on the time of
day, stock market levels, and the phase of the moon." Well, the engineers at Watkins Johnson actually
managed to pull off getting a gag plot into the 1989 catalog for their WJ-G1/SMG1 voltage-controlled
attenuator. It is shown below. Do you remember seeing it?
Thanks to Joe Cahak, of Sunshine
Design (click logo at right) for providing a scan of the catalog page. Joe worked for WJ at the time,
and is now a independent consultant with 25 years of experience.
Watkins-Johnson WJ-G1/SMG1 Voltage-Controlled Attenuator Datasheet with Phase vs.
VCTL vs. Frequency vs. Phase of the Moon Chart.
Also, don't forget the Signetics 25120 Fully Encoded, 9046 n N, Random Access
Write-Only Memory datasheet.
While you're wasting time, you might as well see the "slightly tentative data" for
WEMAC- The One Zed
Two Zed Vacuum Tube that was purportedly the inspiration for the Signetics 25120.
Posted September 15, 2015
The inventions and products featured on these pages were chosen either for their uniqueness in the RF engineering realm, or are simply awesome
(or ridiculous) enough to warrant an appearance.
All Featured Product Archive Pages:
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