[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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