[time-nuts] PTTI 2012, part 2

Bob Camp lists at rtty.us
Tue Dec 4 14:34:48 UTC 2012


Indeed, you likely won't get USNO grade with a shoe box sized part. You can
get one to work and do quite good ADEV. No, I haven't done it, I'm just
going on what I've been told. The main point being that for a basement
project - smaller is probably lower cost.


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Poul-Henning Kamp
Sent: Tuesday, December 04, 2012 9:19 AM
To: Discussion of precise time and frequency measurement; Bill Dailey
Subject: Re: [time-nuts] PTTI 2012, part 2

In message
<CAMPhiorJihW9z6-q0+Qfd+GPLjs6e8_ovWrDxQoxV=92Hgjo8A at mail.gmail.com>
, Bill Dailey writes:

>If you look at the papers on portable rubidium fountains
>they are significantly bigger than a shoebox (65 cm).

Diameter is controlled by dispersion of the launched atoms (=recovery rate)
and the layers of shielding.

65cm looked like close to a minimum for USNO grade, amateurs could probably
make do with less shielding.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
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Never attribute to malice what can adequately be explained by incompetence.

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