[time-nuts] Old Crystal.

[ed breya]

I have some similar, that came from some old HP OCXOs. They look like 
they were built inside octal tube envelopes, without the pin bases. I'm 
pretty sure they are 1 MHz, and came from some HP51110 (I think ?) 
reference generators, part of one of their ancient synthesizers - it was 
a two-piece rack mount beast, with bundles of coax between. I junked 
them out long ago, and saved the ovens and crystals and some other stuff 
for possible reuse. I also have some others from ancient, unidentified gear.

One thing I recall is that at least in one, or maybe all, the crystal 
itself is shaped like a double-convex optical lens, not a flat disc.

Ed