[time-nuts] Some More questions
time.bandit at btinternet.com
Thu Jan 19 09:24:53 EST 2006
I visited an MoD microwave lab many years ago, and they used to run all
their temperature sensitive stuff on a huge steel table about 3 inches
thick, apparently to minimise the effects of ambient temperature change.
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Poul-Henning Kamp
Sent: 19 January 2006 14:08
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Some More questions
In message <43CF928D.4030101 at erols.com>, Chuck Harris writes:
>It would be interesting to see how such an oven performs compared to
>the traditional double oven.
According to a guy at the danish metrology lab, the optimal strategy is
moving as little heat as you can get away with.
They keep most of their stuff in a basement room where the air condition is
set "hysterically" to 21 C.
Temperature sensitive things then get a layer of insulation, for instance
their resistance standards are mounted inside a huge aluminium block
(roughly 50x50x25 cm) which acts as a buffer for any fluctuations the
aircondition / open doors etc may cause.
Their suggestion for a cheap environmental chamber is an old fridge where
you keep the door closed. After some weeks it will have reached a stable
temperature relative to the room.
If your room temperature is not stable, run temperature controlled water
through the loop of the fridge.
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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