Dear Krishna
You should probably check with the manufacturer exactly how one should
interpret eg SYNC:FEE?
The manual says:
"This query returns the Frequency Error Estimate."
but is this a offset due to eg a DAC resolution limitation, or is it
the uncertainty in the frequency?
I am guessing it is
Dear Attila
We have clock comparison data going back 25 years so you could DIY.
But I thought I sent that to you a couple of years ago?
Cheers
Michael
On Fri, 26 Mar 2021 at 3:34 am, Attila Kinali wrote:
> Moin,
>
> Does someone of those who own a 5071 have long-term ADEV data?
> I'm looking f
Typical L1 antenna delays range from 20 to 70 ns.
I know of only one antenna for which a delay is given by the vendor and the
technique used was just to measure the electronic delay ie by injecting a
signal into the circuit. To do it properly, you need a setup in a microwave
anechoic chamber with t
Hello Gilles
There's a reasonable way of treating data with gaps in it:
https://iopscience.iop.org/article/10.1088/0026-1394/45/6/S19
Essentially, any averaging interval with missing data is dropped from
the ADEV summation.
This reduces the number of intervals averaged over and increases the
unc
Dear Jim
These, in conjunction with some M6 nylon washers, work OK for
isolating an SMA bulkhead feedthrough from the case:
https://www.minikits.com.au/components/hardware/washers/Metric-M6-Washers
(the nylon shoulder washers down the bottom)
The connector will rotate though if you try to torque u
Hello Ole
Have you looked at dynamic Allan variance ? Patrizia Tavella wrote a few
papers about this.
Cheers
Michael
On Wed, 16 Sep 2020 at 7:28 pm, Ole Petter Ronningen
wrote:
> Hi, All
>
>
>
> I am currently working on some lather long time-series, and I find myself a
>
> little unsure of ho
Dear Tom,
A one year, single device licence to access the signal cost about AUD10K
when I asked about a year ago. The plugin card for a commercial timing box
was about AUD3K.
Cheers
Michael
On Mon, 10 Aug 2020 at 9:05 am, Tom Van Baak wrote:
> Hi Stu,
>
> There's no problem with a semi-commer
Hello Tom,
(and thanks everyone for your advice)
I want to do the same as you: rack mount the oscillators. Elaborate
vibration isolation solutions are not possible in the available space viz 3
to 4 RU.
I have the manufacturer’s test data for the oscillators, plus my own test
data, so I think I wi
I have three Oscilloquartz 8607-Bs that I'm rehousing.
In their former life they were part of the frequency synthesis chains
for H-masers and they hung vertically from a rubber suspension that was
presumably intended to provide vibration isolation. Unfortunately, the
person responsible for this ha
Hello Jim
>How does a CSO compare with a Mercury Ion clock - the latter does fit in
>a satellite and is intended to replace the USO kind of function.
The current CSOs can be surprisingly compact. I was visiting a university
colleague who had recently bought one from Cryoclock for use in quantum
Hello Tim,
There’s a TDEV plot here:
http://www.openttp.org/scripts/blog.php
PPS measurements were post -processed using the sawtooth corrections.
Cheers
Michael
On Tue, 7 Jan 2020 at 1:07 pm, Tim S wrote:
> Hi, first time poster, just getting into the time rabbit-hole.
>
> I'm looking at
In Australia, fixed vehicle speed measurement devices, such as
piezoelectric loops buried in the road surface, are operated by the
state road transport authorities (the police operate mobile devices
such as handheld LIDARs). These have to be checked with some
(typically) purpose-built device which
I think you are missing the key selling point of this device, namely
it's long term stability and accuracy of a few parts in 10^15. From my
point of view as a national timekeeper, this is much more useful than
good short term stability. UTC reporting is at 5 day intervals so what
the clock does at
The atoms are laser cooled and held in a magneto-optical trap. It’s
basically a short, one-way fountain.
Cooling the microwave cavity would be useful for reducing the black body
radiation shift, but without checking the numbers, this would not be so
useful at the relatively low accuracy claimed fo
Hello Dana
The prototype system I built used an E1 digital telephony card with 30
lines. I think it cost about $12000/year to lease the associated 2
megabits per second data capacity but we didn't do that; we just
commandeered a few lines from our site's capacity.
I believe the live system needed
I designed the hardware and wrote the software for the now defunct
Australian speaking clock.
The prototype pieced together the audio from fragments and it did
indeed take quite a bit of effort to get this to sound clean.
Mismatches in sound levels at the boundaries caused 'pops', for
example. I sp
I have uploaded the paper that appears in the conference proceedings:
http://www.openttp.org/downloads/Multi-GNSS_IFCS-EFTF_2019_paper.pdf
Cheers
Michael
On Sun, Sep 22, 2019 at 9:49 AM Michael Wouters
wrote:
>
> Hello Anders,
>
> We did some work on single-frequency time-transfer
Hello Ragnar
Mktimetx uses the receiver-provided sawtooth correction in the TP message.
The TDEV plots in the presentation I linked show its effectiveness.
Cheers
Michael
On Mon, 23 Sep 2019 at 4:21 pm, Ragnar Sundblad wrote:
>
> Hello Michael,
>
> > On 22 Sep 2019, at 23:54,
descriptive words, I would love to see that.
>
> Might I ask why you didn't use the F9P in dual-frequency mode, as I
> understood that gives a much better result, being able to (almost?)
> eliminate ionospheric effects?
>
> Regards,
>
> Peter
>
>
n the same TIC-based sawtooth correction work for 30s RINEX data instead?
> If gpsd can produce dual-frequency RINEX from the F9T, then the new
> (software)part needed is the sawtooth-correction at 30s intervals applied
> to the raw RINEX from the F9T.
> https://gpsd.gitlab.io/gpsd/ppp-howt
Hello Anders,
We did some work on single-frequency time-transfer with the F9P earlier
this year which we presented at IFCS-EFTF in April.
http://www.openttp.org/downloads/Multi-GNSS_IFCS-EFTF_2019.pdf
There's a paper too, which I should upload.
In short, the F9P is very suitable for code-based tim
Hello Kevin
There is a Perl script to configure and log the ublox that is
available as part of OpenTTP
https://github.com/openttp/openttp/tree/master/software/gpscv/ublox
Cheers
Michael
On Sun, Jul 14, 2019 at 8:03 AM Kevin Croissant
wrote:
>
> This is the library I am using:
> https://github.c
We monitor GNSS timing in this way ie with common, single-frequency
receivers configured to track a single GNSS system only, measured with
respect to UTC(AUS). The plan was to make the data publicly available
but that's still on the TODO. Currently we monitor GPS, GLONASS and
BeiDou.
Over the two
The Galileo outage is being attributed to problems at the Precise Timing
Facility in Italy
https://insidegnss.com/update-galileo-service-degraded-on-all-satellites-precise-timing-facility-problems-cited/
Cheers
Michael
On Sun, 14 Jul 2019 at 7:06 am, Mark Sims wrote:
> The satellite tracking
I recently got some prices on Russian masers. The passive masers are about
$us90K and the active masers are about $US250K. There’s apparently quite a
bit of paperwork to do with the export licensing but it just needs a bit of
patience :-)
Cheers
Michael
On Thu, 11 Jul 2019 at 3:01 am, Bob kb8tq
about 20 years ago, JPL was operating a Hg ion clock at the Tidbinbilla
tracking station just outside Canberra, Australia. I think they installed a
few at various nodes in the Deep Space Network at the time. It operated for
a few years but never reliably enough to be a useful UTC clock ( we were
s
Hello Luiz,
(Did we meet at IFCS-EFTF in Orlando? If so, my apologies for not
remembering your name, and for repeating here what you know). I presented
some preliminary time-transfer data for the F9P at IFCS and wrote a short
paper for the proceedings; if you’d like a copy, I am happy to send you
>A cable run from your rack in the middle of the datacenter, through to the
>roof, is either impossible or thousands of dollars and weeks of planning.
I've done this 4 times now for GPS antennas connected to NTP servers.
I agree with the thousands of dollars (2K to 4K for cable runs of
around 50 m)
e is
limited to at most tens of seconds because of atmospheric turbulence.
Table 3 is worth a look too.
Cheers
Michael
On Fri, Jun 7, 2019 at 7:17 AM Michael Wouters
wrote:
>
> My radio astronomer colleagues tell me that there is about a 20 minute limit
> to VLBI observing run
My radio astronomer colleagues tell me that there is about a 20 minute
limit to VLBI observing runs because of atmospheric instability so this
limits improvements to be had from better clocks. My recollection is that a
maser is still sufficient out to 100 GHz. There is a paper about this that
I wil
Some older ResTs with v1.2 firmware stopped tracking 15 minutes after the
rollover but recovered trackingafter a hard reset. UTC time of day in the
8FAB message has stepped back 20 years, unsurprisingly.
Cheers
Michael
___
time-nuts mailing list -- time-
A multichannel, L1 GPS-only simulator/recorder costs about US5k. We have
one of these that we used to test for rollover problems with some older
receivers that we use (none found). The software with this lower cost
device is not very sophisticated. As Bob hints though, a top of the line
simulator i
Oops, units for TDEV are seconds, not nanoseconds!
On Wed, 20 Mar 2019 at 7:41 pm, Michael Wouters
wrote:
> Hello Dan,
>
>
> As promised here is a comparison of the ZED-F9P and NEO-M8T
> sawtooth-corrected PPS. The PPS is measured against a 5071 with standard
> tube. Three
Hello Dan,
As promised here is a comparison of the ZED-F9P and NEO-M8T
sawtooth-corrected PPS. The PPS is measured against a 5071 with standard
tube. Three days of data were used. The 5071 was measured against another
5071 and I divided the TDEV by sqrt(2). The 5071 data at shorter than 300s
is li
The f9p is about 3 times better than the ublox m8t. Will post a plot
later..
Cheers
Michael
On Tue, 19 Mar 2019 at 9:00 am, Bob kb8tq wrote:
> Hi
>
> ….. and here I was wondering if it had ever gone out :) Glad it made it.
>
> No, I did not run any single frequency units beside it. It is much
This project www.openttp.org provides software for post-processing of raw
data for time-transfer from some currently available single frequency
receivers. It provides CGGTTS and RINEX, the latter for use with the
various PPP services. There are some tools in there too for doing eg common
view and a
We have operated about 40 PRS10s over the past 20 years or so. These are
all run continuously in benign environments and monitored via GPS
time-transfer . Some have died after just over a year; others have operated
for more than 12 years. A new one generally takes a few months to burn in,
before i
Fwiw, I have been evaluating the F9P for post-processed time transfer
(code-based) and it's looking significantly better than the NEOM8T. Tdev is
about 3 times better, mainly due to a reduction in the tdev of the
sawtooth-corrected pps. Zero baseline performance is getting close to that
of a top of
Hello Rodger,
We have one of these still operating in the lab and I have a manual. Please
contact me off list.
Cheers
Michael
On Tue, 26 Feb 2019 at 3:00 am, Rodger via time-nuts <
time-nuts@lists.febo.com> wrote:
> Thanks but that manual is for the slave clock displays. I'm looking for
> the
>
BeiDou, Galileo and GLONASS all broadcast UTC time of day (or thereabouts
for GLONASS - it's offset by the timezone for Moscow) so any multi-GNSS
receiver has a sanity check on UTC calculated from GPS.
Michael
On Wed, 6 Feb 2019 at 11:03 am, Bob kb8tq wrote:
> Hi
>
> From what I can see, you ca
If you scroll down to the bottom of the product pages for the zed-f9x
modules, you'll see the 'ANN-MB', a L1/L2/E5b antenna that ublox is
presumably making to go with the ZED-F9. It's still marked 'preorder'
Cheers
Michael
On Tue, 22 Jan 2019 at 6:00 am, Bob kb8tq wrote:
> Hi
>
> To be more
m operate with several satellites ? I haven't
> seen any mention (quick overlook in the data sheet) neither in the
> Septentrio nor in the NVS...
>
> Cheers.
>
> JF
> --------
> On Mon, 12/3/18, Michael Wouters wrote:
>
> Subj
Hello
There are many alternatives to the Z12T. It all depends on your budget. I
am guessing that you want to establish legal traceability to your local
UTC, is that right?
Starting at the top end, you can buy complete systems from Dicom and
Piktime. These cost about $25K and $40K respectively. Th
In Australia, the legal reference for standards of measurement is defined
by the National Measurement Act:
https://www.legislation.gov.au/Details/C2016C00085
This also defines the legal source of time of day UTC(AUS), the Australian
realisation of UTC. State legislation then defines local time as
I've done some experiments with the NV08C and NEO8MT recently. Both of
these receivers report L1 carrier phase. Using the CSRS-PPP service, I
don't get quite as good results as Mark. The errors are more like 0.5 m
(95% confidence interval) in X,Y,Z. However, there is a systematic error
too of about
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