WJ-G1 Phase vs. VCTL vs. Frequency vs. Phase of the Moon
Watkins 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?
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.