Hi
Fountain's don't work very well in zero G….:)
Bob
On May 6, 2013, at 12:23 AM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
On 05/06/2013 02:29 AM, Mike S wrote:
On 5/4/2013 2:40 PM, Attila Kinali wrote:
Can anyone shed some light on why the GPS Cs beams have a worse stability
Rather the opposit. They will be really compact and can have long
observationtime.
Cheers
Magnus
Originalmeddelande
Från: Bob Camp li...@rtty.us
Datum:
Till: Discussion of precise time and frequency measurement time-nuts@febo.com
Rubrik: Re: [time-nuts] GSP clock stabilitiy
On Sat, 4 May 2013 16:31:42 -0700 (PDT)
Mark Spencer mspencer12...@yahoo.ca wrote:
The article available for download via this URL contains some history
about development issues with Rb and Cs Clocks for GPS. It seems at
one point after the GPS system was placed into service a development
On Sat, 04 May 2013 21:53:00 -0700
Hal Murray hmur...@megapathdsl.net wrote:
Radio astronomers use H-masers. Can I assume that they are mid-term and that
H-masers are better than Rb (at mid-term)?
Disclaimer: I'm not into astronomy. What i write below is solely based
on what i've stumbled
Hi
All the data is in an adev plot. In this case short is 100 seconds, and long
is 10,000 seconds. Those are rough numbers, since a really good Rb (like
Corby's) may cross over a bit earlier. A really crummy Cs (low beam current)
might not cross over for a couple of days against a well
All the data is in an adev plot... The cross overs will happen... you have
to measure them.
True, but then what do you do?
It is not quite as simple or easy as it may sound.
Although it is a good place to start,
for best results in a GPSDO you can not just compare the ADEV crossover
points of
On 5/4/2013 2:40 PM, Attila Kinali wrote:
Can anyone shed some light on why the GPS Cs beams have a worse stability
than the Rb vapor clocks?
I don't know, but it makes me wonder about things like
1) How sensitive is each to C-field tuning - i.e. for the same change in
C-field, by how much
On 05/06/2013 02:29 AM, Mike S wrote:
On 5/4/2013 2:40 PM, Attila Kinali wrote:
Can anyone shed some light on why the GPS Cs beams have a worse stability
than the Rb vapor clocks?
I don't know, but it makes me wonder about things like
1) How sensitive is each to C-field tuning - i.e. for the
Hi,
Bruce recently mentioned [1], where Fig. 2 shows that the Cs clocks
of the old II and IIA birds are less stable than the Rb clocks of the
newer birds. This struck me as odd and i tried to find out why
a Cs beam had worse stability than a Rb vabor cell. The only paper comparing
both clocks
Rule of thumb: quartz is best short term, Rb or H-maser mid-term, and Cs by far
the best long-term.
For GPS clocks the long-term doesn't matter that much since each space clock is
monitored and updated against the GPS master clock(s) on the ground.
/tvb (iPhone4)
On May 4, 2013, at 11:40 AM,
In message bb05041d-f03a-42ac-85c6-467110fc3...@leapsecond.com, Tom Van Baak
(lab) writes:
Rule of thumb: quartz is best short term, Rb or H-maser mid-term,
and Cs by far the best long-term.
I have never seen a technical description of the Cs used in the
early GPS satellites, but I have seen
Note also Galileo uses Rb and H-maser only; no Cs.
/tvb (iPhone4)
On May 4, 2013, at 1:53 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message bb05041d-f03a-42ac-85c6-467110fc3...@leapsecond.com, Tom Van
Baak
(lab) writes:
Rule of thumb: quartz is best short term, Rb or H-maser
The article available for download via this URL contains some history about
development issues with Rb and Cs Clocks for GPS. It seems at one point after
the GPS system was placed into service a development program for new Cs GPS
clocks failed and by necessity there was a shift towards Rb (at
Hi
In a ground servo'd system, there is very little need for a Cs beam clock. The
medium term stability of the Rb's is plenty good enough to allow the ground
segment to keep up with / correct for what ever the space clocks are doing.
Bob
On May 4, 2013, at 7:31 PM, Mark Spencer
On 05/05/2013 01:31 AM, Mark Spencer wrote:
The article available for download via this URL contains some history about
development issues with Rb and Cs Clocks for GPS. It seems at one point after
the GPS system was placed into service a development program for new Cs GPS
clocks failed and
t...@leapsecond.com said:
Rule of thumb: quartz is best short term, Rb or H-maser mid-term, and Cs by
far the best long-term.
What is short, medium, and long?
Radio astronomers use H-masers. Can I assume that they are mid-term and that
H-masers are better than Rb (at mid-term)?
Does the
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