Rick Harold wrote:
> All,
>
> I'm planning doing some experiments in distance measurement. They don't
> deal with atomic time directly but with extreme short periods of time.
>
> I need to determine the position of a instrument with a 1mm accuracy or
> less.
> The instrument is not connected to a
> In order for cesium beam standards to even work, one must apply
> a slight magnetic field, the so-called C-field, which rather strongly
> distorts the shape of the resonance peak.
Tom (and all),
do you think that a Cs clock, having a not-well-adjusted
C field, might have a shape of the resona
Tom,
The conceptual deadlock that I would overcome is whether adjusting the C-field
the Cs resonance varies, as this would impact the defition of the "second".
Thanks,
Antonio I8IOV
> > What is the reference used to measure stability and accuracy
> > of H Masers?
>
> Antonio,
>
> Good questio
What is the reference used to measure stability and accuracy
of H Masers?
Do Caesium clocks have something like a C field adjustment
(as Rb clocks have), and in the case, what it acts upon?
Thanks in advance,
Antonio I8IOV
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Time-nuts,
I was wrong with my interpretation.
The clocks were all working ok.
Thanks.
Antonio I8IOV
> I got some private answers.
> Sorry, I've been concise not to bias your thoughts.
> Only, I would precise that for "unlocked" I mean a clock in
> which the crystal is free running not locked to R
I got some private answers.
Sorry, I've been concise not to bias your thoughts.
Only, I would precise that for "unlocked" I mean a clock in
which the crystal is free running not locked to Rb or Cs, and not to lock
between clocks,
Antonio I8IOV
> Time-nuts,
>
> I have to admit that I have an inte
Time-nuts,
I have to admit that I have an interest in gravitational
anomalies.
If anybody out there has nothing better to do, here is the
stuff to spend some minutes.
In early 90's a Chinese researcher (Zhou) opened a debate
claiming to have observed anomalous behaviour on atomic
clocks durin
Thanks Magnus and Tom, you clarified more than enough.
73,
Antonio I8IOV
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Hi all,
I'm planning to use a HP 53131A for phase measurements.
In a limit case, just to understand, suppose that I'm
reading, say, 100 degrees, and the next reading gives again
100 degrees, but meanwhile the signal under test jumped 360
degrees. Is there any way to detect such a case?
Thank
Hi Neville,
inspecting the lamp is a quite easy job.
Yes, it is in the smaller housing.
Unlock the check nut just enough, and unscrew the lamp (along
with the check nut) using a point shaped tool (a toothpick).
It is easy.
Don't touch it with fingers.
Before doing this, take note of how much th
Yuri,
as a rule of thumb, read my message posted here last month:
http://www.febo.com/pipermail/time-nuts/2008-October/033926.html
I have 10 EFRATOM LPRO, and only one came with a faulty lamp.
I think it lost vacuum, and the glass looks clear but with
small white pigments. I inspected some of th
On Fri, 31 Oct 2008 13:59:06 EDT SAIDJACK wrote:
> Hi Antonio,
>
> wow, that's amazing. Your prediction was pretty accurate!!
>
> So I wonder if we have one of the most sensitive gravitational sensors out
> there :)
You know that the issue is reproducibility.
> How did you correlate the j
On Oct 30 SAIDJACK wrote:
> Hi guys,
>
> there is a very nice Crystal jump visible online today:
>
>_http://resco.ucol.mx/Fury/gpsstat.htm_
> (http://resco.ucol.mx/Fury/gpsstat.htm)
>
> Has anyone else seen a similar effect today?
>
> This jump will be visible online for a couple mor
Thanks, Said.
What seldom happens to my tuning forks is similar to your
brown line, of course.
Do you have date and time of this beatiful jump?
Have you observed, by chance, a negative (restoring) jump at any time after
this jump?
(the sense of the latter question is that, if you observed a
res
Hi all,
Thanks for your comments, info, ideas and references.
I've found the plots that Tim Shoppa pointed me to, and they
are a good response to my original question.
It has been interesting hearing about the jumps of pendulums
too, this was new to me.
Also I argue from the discussion that, wh
Neville,
> Hi Antonio,
>
> precise pendulum clocks also suffer rate jumps, the process
> of rate jumping seems to be common to most time counting
> systems.
I have an interest in this. May you point me to any references?
73,
Antonio I8IOV
___
tim
> Are you sure it is the tuning fork and not the reference
> for your counter? -
> 73 - Mike
Hi Mike,
the tuning fork jumps were in the order of e-7, while the references were a HP
10811 and a Racal Opt 04E both in the range of e-10.
Thanks and 73,
ANtonio
__
Hi Rick
> I'm not quite sure what the question is here
>
The question is:
may anybody tell me (date and time) when a crystal jumped?
(a sample response could be: my crystal jumped on January 22, 2006 12:25 UT).
I would like to map in time as many jumps as possible.
I hope someone in th
> Hi Antonio,
>
> precise pendulum clocks also suffer rate jumps, the process
> of rate jumping seems to be common to most time counting
> systems.
Thanks, I was missing this info.
> I have an LPRO rubidium oscillator. I mounted it on a heat
> sink with fins and placed it in an insulated box. A
I would be very pleased to know when (date and time) anybody
out there happened to record jumps in frequency of crystals.
I have stable (e-07) tuning forks which happen to jump too,
and I don't understand why, even having under control
temperature and air pressure. Sometimes they return to their
Maybe this could be of interest.
I have an LPRO continuously running since ending last January. Lamp volt was
7.92V.
As of October 22 (today, 9 months later) the voltage is 7.7V.
The voltage dropped by 0.22V.
The VCXO Volt was 6.7V, and now is 6.8V.
It is powered at 24V, and the temperature at th
You heard the Russian station RWM (.-. .-- --) which transmits on 4996,
9996, 14996 and maybe 19996. It is the easiest to receive station in Europe,
quite strong signal.
73,
Antonio I8IOV
> Hi,
>
> I listened today the WWW station and I've found it on 9.996 Mhz instead of
> 10.000Mhz and
A good LPRO works both with cover on or off.
> Q703 voltages look good (with cover off and unit working).
Lamp color seems good (slightly pinkish violet). The room
that I am in is lit by DC halogen lamps so not rippley light
to worry about.
If the power to the halogen lamp comes from battery,
Sometimes trying to fix a faulty unit is simply a challenge.
Some more tips.
The LPRO with cover removed cannot work in the presence of artificial light
coming from AC powered sources!! It locks randomly to the light ripples.
My definition of the normal color of the rubidium light would be pink
I suggest not touching any of the adjustment points.
Check the rb light. If it gets too reddish, then probably the lamp gets too
hot. There is a resistor in the heater circuitry that may be faulty. I'm away
at the moment, and don't have my notes on hand, but the resistor is on the
bottom side of
Hello Martyn,
Martyn Smith <[EMAIL PROTECTED]> wrote:
Despite the AGC we still achieve good phase noise (-135 dBc/Hz @ 1 Hz
with
a -168 dBc noise floor) together with 130 dB isolation and 10 ps/C phase
stability.
I have problems to understand, how your amplifier can achieve phase
noise o
I want one. Where to send the request?
Antonio I8IOV
> 2) Those of you newcomers to Time-Nuts should expect
>to wait until the first batch has been shipped and
>TAPR is ready for you. There should be enough for
>everyone; so don't panic.
>
__
Any sources for an MRF160 power mosfet? Or any suggestions for a replacement?
Thanks in advance.
Antonio I8IOV
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Rainer,
I presume your Power Supply has a fan which may absorb 2 to 4
Watt. Given the low consumption of Thunderbolt, you could try
disconnecting the fan to save a few Watts.
The Meanwell T-30B has no fan. I' ve not yet measured its
idling consumption (no load), but to answer your question it
sh
Thanks to all for the interesting discussion. I understand that,
having a thunderbolt, I might feel free to delay a bit (or even cancel)
my Rb disciplining project.
A last question to tvb. You said that
6) Turn-over -- if you flip the black box upside down, the Rb
version will show little or
More precisely, if I had two black boxes, one containing a GPS-Rb-XTAL setup
and another containing GPS-XTAL, what measurement would you make from outside
the boxes to distinguish from one another?
Antonio I8IOV
> Tom Duckworth wrote:
>
> > Antonio,
> >
> > Absolutely! With a good XTAL you ha
Tom Duckworth wrote:
> Antonio,
>
> Absolutely! With a good XTAL you have parts in the 9th, short term. With a
> XTAL controlled by a Rubidium, in the phase-lock feedback loop, you have
> parts in the 12th, short term. With the Rubidium disciplined by the GPS,
> with its on-board Rubidium/Cesium
Does it make any sense "GPS disciplining" a rubidium oscillator?
In such a case we have a chain made of
GPS - Rubidium - XTAL
as opposed to the simpler case of
GPS - XTAL
(assume that XTALs are of the same quality, and so the control loops).
Does the addition of Rb in the middle of the chain add
> Alternatively since you only need 25mA @ +12V, 25mA @ -12V and 300mA
> @+5V (if I'm reading the right datasheet) you can use a much lower
> voltage output transformer suited to the 5V regulator and use a pair of
> voltage doublers or triplers to feed your 12V regulators.
> A 7.5- 0 - 7.5V tra
> I have 2 different Racal Dana 1992 frequency counters:
> The first one (kept for spares because the display is broken) has a
> GPIB interface of type 19-1146:
> this interface has NOT the SK4 jumper (see
> RACAL-DANA-1991-1992-ServiceManualSch.pdf pages 16/17 in my archive).
> The other one, in
Ulrich Bangert, DF6JB wrote:
> So a better phrase would be that the lamps voltage is an indicator of
> the lamp's health IF and ONLY IF everything else is sane. Don't blame
> the lamp before you have checked the temperature and the exciting
> field's frequency.
Agreed completely. I'm not yet con
Dan Rae wrote:
> In my original copy of the 1992 manual, there is only one jumper
> indicated on the GPIB board. It is at the front of the board. Pages
> 7-34 and 7-35 show it. On the first page it says : "Make certain the
> jumper plug is installed in the upper two pins of SK4 as shown".
>
> Antonio I8IOV ([EMAIL PROTECTED]) wrote:
>
> "The unconvenience with the 02M version is that it uses a military
> GPIB language (MATE/CIIL), and I had to get familiar with it."
>
> The Racal units that I have (with no button problems) have a
> jumper for mil
I purchased on ebay four rubidium LPRO and I'm quite satisfied with them.
The lamp-Volt parameter (which is an indication of the lamp's health) was
respectively 8.4, 7.95, 6.8 and 5.1 Volt.
When an LPRO leaves the factory its lamp-V is around 12V. A drop of up to 3 V
would be expected in the firs
It should be 58540A, not 58450A. Look at:
http://www.leapsecond.com/museum/hp58540a/ds-58540a.pdf
Antonio I8IOV
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I learn from this discussion that the aging rate claimed by manufacturers would
refer to the
aging of the whole assembly, not the crystal alone. And for practical purposes
that is correct.
And even in the case of sealed assemblies, components other than the crystal
itself may affect
the overa
Thanks Rick.
I will study the matter a bit more. Meantime I would tell where my question
originated from.
I was referring to a condition where temperature is assumed to be constant.
In the article at http://www.agilent.com/metrology/xtal-policy.shtml (fig. 1)
Agilent
doesn't refer to temperatur
Hi all,
the aging rate of crystals is known to be not constant.
Is there any known external cause affecting the rate, or it is only a matter of
casuality?
Thanks,
Antonio I8IOV
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Brian,
your problem sounds different of mine. Anyway, what I wanted to mean is that
the control voltage is monitored not actually at the varactor, but much more
near to
the sweeping circuit. That indication might be misleading because there are
other
components between the point where the volt
I would report my experience with an EFRATOM LPRO with a similar problem,
maybe this could help.
The sweept frequency was always below 10 MHz, so missing the opportunity to
lock.
The sweept VCXO control voltage at the monitor pin was correct, but at the
varactor it was too low. The problem was in
Whether or not the rate of atomic clocks may be affected by a solar eclipse is
a controversial matter.
NATURE magazine published the article "Chronometry: Effect of the 1999 solar
eclipse on atomic clocks",
see:
http://www.nature.com/nature/journal/v402/n6763/abs/402749a0.html
but the full text
Tom,
for your archive of tuning fork oscillators pictures, look at my Bryans
Aeroquipment (later a Negretti & Zambra division) 50 Hz fork at
http://xoomer.alice.it/iovane
and click on fork.htm -
This appeared to be quite stable.
Antonio
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time-nuts
Just speaking of 10811 clones, I have one made by Piezo Systems, model #
2810007-1. It fits electrically and mechanically HP boards, and looks like a
10811. But I miss the specs. Does anybody have any info?
Thanks,
Antonio
> Geoff Blake wrote:
> > Hi,
> >
> > I know this has been asked before -
od success
Bernd
DK1AG
Original-Nachricht
Betreff: [time-nuts] HP10811 problem - wrong frequency
Datum: Sun, 13 Jan 2008 19:37:48 +0100
Von: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Antwort an: Discussion of precise time and frequency measurement
had.
Hello Jim,
thanks for your remarks, but i dont think that the oven fails. The power
consumtion is about 3W and the unit is gettuing warm on the outside. I guess
this is okay ?
[EMAIL PROTECTED]
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To
. Can anyone help me ?
Thanks a lot...
Best regards
[EMAIL PROTECTED]
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Hi all,
I have some Qualcomm "RF/SYNTH W/GPS" boards which are programmable
synthesizers for the 750-1000 MHz band. They bear a 10 MHz TCXO as a reference.
Based on the above mentioned lettering on the PCB, I guess the oscillator could
be GPS disciplined supplying some GPS derived signal somewher
Hi Frank,
in fact Symmetricom states that LPRO is not field-repairable, and I suspect
that disassembly would be destructive of the delicate mechanical/thermal
coupling between the lamp assembly and the outer case. Anyway, as my unit
doesn't work, I will try to repair it, and even in the case of
Hi all,
I've just joined this list today, and have found that the archive is full of
interesting stuff.
So I would ask, is there any possibility to search the
archive by keywords?
Thanks in advance.
Antonio I8IOV
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Hi all,
does anybody out there have any experience in replacing the lamp on an LPRO
rubidium oscillator?
I have two LPROs, one working and another which reads "lamp volt" = zero. I
feel it is not a matter of lamp, as the lamp housing doesn't heat (it should).
I would try swapping the lamps bet
Certainly we use UTC in Britain, although the Government are keen to try
and keep the Greenwich link, so the term GMT is erroniously used more often
than not (especially by the BBC!).
> Yes, there are people who want to stop this irritating leap
> second business until well after they are dead, b
Further to my previous reply, the HP Archive website has an Operating &
Service Manual for the 10811A/B at:
http://www.hparchive.com/Manuals/HP-10811AB-Manual.pdf
In section 2.20 on the page numbered 8 (actually the sixteenth page in the
PDF), a 15-pin Cinch connector is described.
Agilent have a "Product Overview" PDF for the 10811E/D on their website:
http://cp.literature.agilent.com/litweb/pdf/5091-1639E.pdf
which has a pinout. Hopefully they will have stuck to the same pinout.
Peter
> Hello,
>
> I purchased one of the HP 10811-60155 standards on ebay one m
to: John,KE5FX
Hi John
I read your question on the THUNDERBOLT look-alike sold by 'accelium'. Since
I have bought this unit (for 500$!!!), I can answer some of it:
The hp58533a has a similar form factor as the Thunderbolt but it's an
entirely different design. I made the following notes when tryi
Mit freundlichen Grüssen
Paul Klöckler
Coral links Gmbh
Postfach 6955
CH-3001 Bern
Schweiz
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Randy Warner
Sent: Mittwoch, 13. Dezember 2006 19:27
To: Discussion of precise time and frequency measurement
Dear colleagues
When I lately visited the research facility where I had worked in the
80ies*) I was told that the local timescale is still generated by the two
BVA oscillators I had installed back then. One is free running and the other
one is daily corrected against GPS time-scale. (The place is
I'll gladly pay what ever (within reason of course) some one wants to
sell me a operating/service/schematic of the Tracor 892 hopefully with
the antenna info as well.
Any help would be appreciated.
Thank You
Mike Harrison
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John
You might also look at http://www.qsl.net/zl1bpu/PRECISION/Reference1.htm
Peter
ZL2AYX
On Wed, 18 Jan 2006 11:27:31 -0500, Neon John <[EMAIL PROTECTED]> wrote:
> On Wed, 18 Jan 2006 00:03:37 -0800, "Christopher Hoover"
> <[EMAIL PROTECTED]> wrote:
>
>>J
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