[time-nuts] OXCO Spurious Output at Line Frequencies
dk4xp at arcor.de
Thu Jul 14 03:09:22 EDT 2016
Am 13.07.2016 um 04:38 schrieb Mark Sims:
> A friend on mine once worked on projects to build very sensitive magnetometers (submarine detection and space probes). Their test lab was in the middle of a square mile of land selected for its low magnetic residue properties. The building was made completely (of carefully selected) wood... no nails, etc. Everything that went into the construction was scanned.
> You had to hike into or be ferried into the lab... no cars allowed anywhere near the place. You also had to wear specially selected clothes (no metallic fasteners, residue, dyes, etc). No metal eyeglasses, etc allowed. No wallets (credit cards) or currency allowed (magnetic ink, the things could detect a dollar bill across the room). No amalgam dental fillings or medical implants allowed. I always wondered how they allowed any test equipment, electricity, etc into the place...
Wonder how they dealt with the variable magnetic field of the earth?
I've been in an ultra-shielded room at the PTB in Berlin where they did
things with SQUIDS and contactless EEGs. I was there with a geo-physicist
who also had interest in sensitive magnetometers.
Aah, google finds it:
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