[time-nuts] PTTI 2012, part 2
EWKehren at aol.com
EWKehren at aol.com
Tue Dec 4 22:25:14 UTC 2012
Paul
Frankly I do not think I will live long enough to see a time nut build a
fountain Rb. Over the four years I have watched many smoke and mirror
projects with nothing coming out of is. In German we have a saying: paper is
patient. We should walk before we run.
Many members did buy a FE 5680, how many do you think are in operation, if,
there would be discussions about its temperature performance. take a close
look on page 7 figure 5 of the brochure, I also see it. Personally I use a
Shera loop. But that is an overkill and for some to complex since it
requires direct analog C field control. My real focus is on controlling FRK-H,
M100 and HP 5065.
What is needed is a coordinated effort to start with temperature control, a
simple GPSDO only taking care of aging using RS232 interface an analog
loop for controlling something like a Morion. Stability and accuracy could be
in the 1 E-12 range, low cost able to be assembled by 90% of list members,
but then I proposed it once before looking for some one to develop the
filter. No response, it is clear that very few are willing or able to actually
build something.
When Corby wrote about his experience with the dual mixer / counter, large
response and we will have a complete documentation set, but when I asked
for a few that would be willing to build one right away, I would make
complete kits, I got one response. Sad, but that is the reality.
How many FE 5680A door stops do you think are out there? How many
PICTICII's do you think are in use?
Bert Kehren Miami.
In a message dated 12/4/2012 9:49:29 A.M. Eastern Standard Time,
paulswedb at gmail.com writes:
Basements the key. So for me bigger is better. Heck if its a rack thats ok.
It gets interesting in what types of components you can use if you are
willing to go larger.
Great point on the laser and optics. Funny thing is for small change you
can actually get used optics bench components at least at the last MIT flea
I ran across the items. They were snapped up by the way.
>From what I have seen of time-nuttery and Hydrogen masers I am actually not
all that sure its beyond this group.
Regards
Paul
On Tue, Dec 4, 2012 at 9:34 AM, Bob Camp <lists at rtty.us> wrote:
> Hi
>
> 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.
>
> Bob
>
> -----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
> FreeBSD committer | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by
incompetence.
>
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