HP 8662A 1.3 GHZ Signal Generator
HP 8662A Synthesized Signal Generator
Released in 1980, HP 8662A would become the low noise RF oscillator standard against which all others would be compared. Usually you can have either frequency accuracy, large tuning range, fast sweeping, or low noise. Pick one, or at most two in the list. But the HP 8662 gives you all of them, from 10 kHz to 1.28Ghz, with an astounding 0.1 Hz frequency resolution. It accomplishes this by an intricate arrangement of PLL loops within PLL loops and remarkable RF engineering quality, down to triple gold shielded cabling.
Learn more about the story of the HP 8662A from the HP memory project: http://hpmemoryproject.org/timeline/bob_devries/hp8662a_01.htm
HP 8662A Repair
With its complex nest of many PLL loops, one is bound to go bad and ruin your day, or more exactly, your oscillator lock. This is the dreaded error 99-04. Without lock, the high performance HP 8662 becomes a mundane imprecise, noisy run of the mill oscillator. Mine fell prey to error 99-04, but was repaired in a series of 8 videos with a PLL and VCO deep dive.
Mythical HP 8662A picture by Kevin Twomey
The HP 8662 was part of the items photographed by San Francisco photographer Kevin Twomey. We ended up making a "mythical HP 8662" photoshop montage of the device by combining a shot of the front panel with a top view of the RF drawers.
Here is a video of the photoshoot at Kevin's studio