back 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
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 voltage-controlled attenuator. It is shown
below. Do you remember seeing it?
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.