Re: [time-nuts] Thunderbolt code phase measurement

Hello Mark By "hosing" do you mean that you lose messages for the next second? That was a problem with the Resolution T too. I wanted to get ephemerides from the receiver so I ended up minimising lost messages by tracking satellites as they popped into view, and then requesting an ephemeris after

Re: [time-nuts] nuts about position

The US-based services work fine with non-local data. I've used them with Australian locations. The IGS network is global so nearby stations in the IGS network are used for the solution. There are non-US services too, like AusPos. The topic of better antenna coordinates seems to come up now and

Re: [time-nuts] RINEX for Android

Hello Jim, There's a Perl script here https://github.com/openttp/openttp/blob/develop/software/gpscv/ublox/ubloxlog.pl that's for configuring and logging a ublox NEO-8MT. The caveat is that it uses a custom file format. However, the associated processing software, mktimetx, will read this and

Re: [time-nuts] new longwave time service planned in India

India has IRNSS, their own GNSS augmentation system. FWIW, S Korea is about to start testing its own radio time signal but the range is only 500 km or so as I remember. Cheers Michael On Thu, 5 Apr 2018 at 12:23 am, Bob kb8tq wrote: > Hi > > It’s also *way* cheaper than putting

Re: [time-nuts] PRS10 Information and help needed

Hello Arnold, A frequency offset of a part in 10E-11 still sounds healthy to me. I wonder whether there is some kind of electronic problem? I have run 40 or so PRs10s and the lamp is the usual bit that dies. If you hook up a computer to the RS232 port, there are lots of diagnostics available.

Re: [time-nuts] Team of physicists repeats tvb Project GREAT

Sorry, missed the last character in the URL: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.073601 On Thu, 15 Feb 2018 at 4:42 pm, Michael Wouters <michaeljwout...@gmail.com> wrote: > There's a photo here: > > https://journals.aps.org/prl/abstract/10.1103/PhysRe

Re: [time-nuts] Team of physicists repeats tvb Project GREAT

There's a photo here: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.07360 Cheers Michael On Thu, 15 Feb 2018 at 1:47 pm, Chris Caudle wrote: > On Wed, February 14, 2018 7:06 pm, jimlux wrote: > > At substantially more expense, and with an experimental

Re: [time-nuts] Anyone have experience with this antenna?

your worst > case path has a foot or so of PVC in it compared to a best case path with > well under > a tenth of an inch. That’s going to give you a bit of variation ….. Add > some dirt or water > or ice to the equation and who knows what the result might be. > > Bob &

Re: [time-nuts] Anyone have experience with this antenna?

I can see why the geodetic community would worry about antenna phase centre variation when a radome is installed but is it really an issue in timing applications? The few papers I've read suggest PCVs of less than 10 mm, or equivalently, 30 ps. This is at the level of precision available from

Re: [time-nuts] Trimble thunderbolt accuracy expectations

If UTC accuracy is your goal then the practical limits are well-established. National labs operating clock ensembles (multiple Cs , H-masers) with calibrated time links ( GPS, two way satellite time- transfer) and steering them to UTC with predictive algorithms typically achieve 5 to 10 ns

Re: [time-nuts] inexpensive, black box, GPS or NTP based TTL time capture?

Hello Jim We are using BeagleBone Black + GPS 1 pps etc in our time-transfer system You can see the overlays in https://github.com/openttp/openttp/tree/develop/software/system/device-tree-overlays Best regards Michael On Wed, Oct 25, 2017 at 11:43 AM, jimlux wrote: > On

Re: [time-nuts] Power connectors continued

I've been caught by that one. Someone used 240V IEC inlets as convenient 10A DC inputs to an oven in an ion trap. Fiddling around in the back of the racks, I made the inevitable mistake and Poof! there went $1000 worth of isotopically separated Yb 171. A few years later, someone else did the same

Re: [time-nuts] GPS Antenna on Tower.

Try again ..., Since 1cm of motion is equivalent to 30 ps, there's probably not much point in putting your GNSS antenna on a geodetic monument if all you care about is timing. But it does matter if you're trying to track continental drift. Michael On Tue, 20 Jun 2017 at 10:44 pm, Michael

Re: [time-nuts] GPS Antenna on Tower.

Since 1cm of motion is equivalent to 30ps, there's probably not On Tue, 20 Jun 2017 at 10:11 pm, Didier Juges wrote: > If that is not time-nutty, I do not know what will :) > > On Jun 20, 2017 7:04 AM, "jimlux" wrote: > > > > > for geodetic

Re: [time-nuts] Next Aug 21 eclipse and time flow

Apologies, I didn't read the paper carefully enough. The original claim does appear to be for a comparison of like clocks eg Cs vs Cs, with a claim of greater effects for a comparison of clocks in and out of the eclipse path. Cheers Michael On Mon, 29 May 2017 at 8:20 am, iovane--- via time-nuts

Re: [time-nuts] Next Aug 21 eclipse and time flow

The effect you're looking for depends on a comparison of two different kinds of atomic clocks eg Cs vs H-maser so the maser comparison presumably will be a null measurement. But I see the path of totality passes a bit north of NIST Boulder and I'm pretty sure they will notice if there is an

Re: [time-nuts] calculating stats with gaps in the data

There are 'better' ways of handling gaps when calculating ADEV and siblings. Patrizia Tavela has a nice method: you pad out the time series, tagging missing points with NaNs say, and then if a difference contains a missing data point, you drop it. It works very well. I expect this is in Stable32.

Re: [time-nuts] Time Dilation tinkering

Hmm, it appears that Symmetricom has an interpretation from IATA which classifies their rubidium-containing products as non-hazardous. I went through all of this some time ago because we were shipping rubidiums about domestically (Australia) and there was no permissible maximum qty of rubidium

Re: [time-nuts] Time Dilation tinkering

Dear Chris, I believe IATA prohibits the carriage of any quantity of rubidium on passenger aircraft. You have to complete a "Dangerous Goods Declaration" and it then has to go by cargo aircraft. Cheers Michael On Wed, Mar 22, 2017 at 1:12 PM, Chris Albertson wrote:

Re: [time-nuts] Time Dilation tinkering

7 1:40 PM, Michael Wouters wrote: > > These are less stable than a rubidium eg tau=10e-11@1000s and monthly > > ageing of 9e-10. > > The price of these has gone up too- they're now about US5000. > > > > Really? That's a big increase. I bought some last year (well, in

Re: [time-nuts] Time Dilation tinkering

These are less stable than a rubidium eg tau=10e-11@1000s and monthly ageing of 9e-10. The price of these has gone up too- they're now about US5000. Cheers Michael On Wed, 22 Mar 2017 at 7:03 am, Scott McGrath wrote: > Or perhaps use the Symmetricom CSAC ... > >

Re: [time-nuts] Coming to a drive-way near you: Optical Lattice clocks

that means it's not very useful for time comparisons. Cheers Michael On Sat, 25 Feb 2017 at 1:00 am, Bob Camp <kb...@n1k.org> wrote: > Hi > > > On Feb 24, 2017, at 5:02 AM, Michael Wouters <michaeljwout...@gmail.com> > wrote: > > > > On Fri, Feb 24, 2017 at 1

Re: [time-nuts] Coming to a drive-way near you: Optical Lattice clocks

On Fri, 24 Feb 2017 at 9:00 am, Poul-Henning Kamp wrote: > Have we talked about this yet ? > > https://arxiv.org/abs/1609.06183 > > https://arxiv.org/abs/1607.03731 > > > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org | TCP/IP since

Re: [time-nuts] Coming to a drive-way near you: Optical Lattice clocks

On Fri, Feb 24, 2017 at 10:27 AM, Bob Camp wrote: > Hi > > I agree with their premise that to be useful you need transportable clocks. > I’m not quite sure > that something the size (and weight) of a pickup truck is really > transportable. Yes one can > move it around (unlike a

Re: [time-nuts] 1PPS users?

One application is advanced network diagnostics eg cards like this: https://www.endace.com/endace-dag-high-speed-packet-capture-cards.html So for a 40 GbE card, time-stamping 1 kilobyte packets demands sub-microsecond accuracy, if you want to compare at different points in your network. Cheers

Re: [time-nuts] Sapphire oscillators

Dear Attila You don't need a cryo-cooler, you can just use a cryostat if a break in operation (when you top up the helium) is not a problem. We operated one of the UWA CSOs like this as the flywheel for our Yb trapped ion frequency standard. A few other national standards labs use the CSOs - one

Re: [time-nuts] Cs tube pics

other lab. The price was US 2 million and I'm guessing that was "mates' rates". Cheers Michael On Thu, Nov 3, 2016 at 8:13 AM, Attila Kinali <att...@kinali.ch> wrote: > On Thu, 3 Nov 2016 07:42:13 +1100 > Michael Wouters <michaeljwout...@gmail.com> wrote: > >

Re: [time-nuts] 12.6GhZ Yb clock - was Cs tube pics

time to do it. > > Bob - AE6RV -- > --- > AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/neo/groups/GFS-GPSDOs/info > > From: Michael Wouters <michaeljwout...@gmail.com <javascript:;>> >

Re: [time-nuts] Cs tube pics

I worked on a trapped ion frequency standard 20 years ago, a 12.6Ghz Yb clock. It's still in the lab across from me and looking at it, and the electronics, I think it is the sort of thing that a physicist might contemplate building in his/her garage but ... Building it took about 10 man years of

Re: [time-nuts] theoretical Allan Variance question

Dear Stewart FWIW, if you do the experiment I suggested (TI measurement on identical 10 MHZ etc) on a HP53132A counter, you get ADEV = 2.0x10^-10 at 1 second. The manual says the LSD is 150 ps; when you include trigger errors, it specifies a resolution of 300 ps. The 200 ps implied by the

Re: [time-nuts] theoretical Allan Variance question

Dear Stuart In a perfect world, your TI measurements would have a uniform probability distribution function with amplitude 0.5 ns and mean value 0 ns. At least, this is the kind of PDF you would assume for "resolution error". For this distribution, ADEV is 0.5 ns. I don't know the HP5334B,

Re: [time-nuts] Inexpensive Alternative to a 5120A

The Red Pitaya is a lower cost (but lower performance) alternative to the USRP boxes. I've implemented a RF phase meter using the RP and get about 1 ps time resolution at an averaging time of 1 s. The RP analog input side seems to be a bit noisy so loses a few bits. There was some discussion

[time-nuts] NVS NV08C

(Restarting the thread with a more apposite topic name) On Sun, Aug 14, 2016 at 12:47 PM, Mark Sims wrote: > The NVS NV08C GPS receiver module is a rather nice little 32 channel > GPS/GLONASS/SBAS receiver that has an output message that gives you the raw > satellite bit

Re: [time-nuts] NUT4NT: Four-channel All-frequency GNSS RF-to-Bits

This board just seems to be the RF front end for a GNSS receiver. You then have to do the whole business of acquiring and tracking the code, and then do the PVT solution, at which point you can make your own 1 PPS. Cheers Michael On Sunday, 14 August 2016, Gregory Maxwell

Re: [time-nuts] Shera revisted

The Red Pitaya uses a Zynq, and there's an (unofficial) SDR application available to experiment with. Cheers Michael On Thursday, 11 August 2016, Chris Albertson wrote: > Thanks for pointing out the Zynq. Wow you get a dual core ARM and an > FPGA all in one package.

Re: [time-nuts] Oscillator Phase Noise: A 50-Year Review

On Sat, Aug 6, 2016 at 9:34 AM, KA2WEU--- via time-nuts wrote: > Leeson produced a somewhat random selection of papers , omitting important > things like the sapphire based best in the word . This was not even > referenced . The reference [145] at the end of the sentence

Re: [time-nuts] Using the HP 58503a to correct your PC clock

On Sat, Aug 6, 2016 at 6:41 AM, Attila Kinali wrote: > So, best you can hope for is an jitter of ~50us rms within the same > city with _good_ network connections. Once the distance increases > and especially if you get routers with conquestion inbetween, then > the delay and

Re: [time-nuts] Q/noise of Earth as an oscillator

On Wed, Jul 27, 2016 at 8:08 AM, Attila Kinali wrote: "I am not sure you can apply this definition of Q onto earth." It doesn't make sense to me either. If you mark a point on the surface of a sphere then you can observe that point as the sphere rotates and count rotations

Re: [time-nuts] [LEAPSECS] Leap second to be introduced at midnight UTC December 31 this year

I'd be interested to know how 10ns less latency is useful. AFAIK, a high speed trading system consists of multiple processing nodes, which certainly could have a 10ns accurate time reference eg via PTP, but latency and jitter would limit time stamping of transactions to the microsecond level.

Re: [time-nuts] LSEM (Leap Second Every Month)

Apropos Bob's comments, the problem of ambiguous timestamps during a leap second, at least with current operating systems, is only made worse by more frequent leap seconds. Making critical systems run on a leap second free time scale like TAI, for example, just shifts the problem to the interface

Re: [time-nuts] How does sawtooth compensation work?

Hello Michael > Thinking out loud, I wonder how bad L1-only, post-processed, would be for > time-nuts use? Especially with a timing-grade antenna (e.g. the common > Trimble Bullet). Dual frequency is great when your receiver has the potential > to move, you have to resolve carrier phase

Re: [time-nuts] Good GPSDO on eBay?

"Full tested by Agilent 53132A with US-012 option and Ex-ref from trimble thunderbolt GPSDO." I think what the seller saying is that the counter was externally referenced to the Thunderbolt for the frequency measurements that they state. Cheers Michael On Sun, Jul 10, 2016 at 10:58 AM, Charles

Re: [time-nuts] Cable length calibration

As a practical matter, in the lab we seldom need a cable delay measured to better than +/- 0.5 ns, which we usually do as a time interval measurement, with a 1 pps into a tee on channel A of a TIC and then the cable from the tee to channel B. For cables up to 40 m or so, just measuring the

[time-nuts] GNSS antenna delays

The discussion about antenna cable delays made me think of the issue of the antenna delay. An antenna typically has a bandpass filter and amplifier so there clearly is some non-negligible delay associated with this. The issue is usually sidestepped by calibrating the delay of receiver+antenna

Re: [time-nuts] Impact of GPS antenna height measurments

Tom Van Baak said: "This note is just a plea not to apply the speed-of-light number or the "nanosecond a foot" rule-of-thumb out of context." It works reasonably well as a rule of thumb. It's an upper limit but if you wanted to refine it a bit, divide by two. The average value of sin(x) on

Re: [time-nuts] Impact of GPS antenna height measurments

Poor coordinates for the antenna couple into the apparent distance to a satellite in such a way that the error in the distance tracks a parabola-shape as the satellite rises and descends, with a corresponding error in the apparent satellite time. At any instant, the combination of N satellites

Re: [time-nuts] Improving on basic L1 timing

big to get a relatively modest improvement. Hope this helps. Cheers Michael On Wed, Jun 15, 2016 at 4:21 PM, Michael Wouters <michaeljwout...@gmail.com> wrote: > I should have added, if you do all of the above, the improvement in > stability over just using a sawtooth-corrected PPS

Re: [time-nuts] Improving on basic L1 timing

I should have added, if you do all of the above, the improvement in stability over just using a sawtooth-corrected PPS is not all that spectacular, a factor of two or three. I'll post a plot of some data tomorrow. Cheers Michael. On Wednesday, 15 June 2016, Michael Wouters <michaeljw

Re: [time-nuts] Improving on basic L1 timing

If you followed the link to www.openttp.org and are wondering where the software is, follow the link on the home page to GitHub and then look in the Develop branch. The ublox branch is for the new '8' series receivers. Cheers Michael On Tuesday, 14 June 2016, Michael Wouters <michaeljw

Re: [time-nuts] Improving on basic L1 timing

Hello Angus If you have 3 rubidiums of similar stability + 3 counters, you could do a 3-cornered hat. Otherwise, GPS common view to a better clock may be an option. If you are reasonably close to a national standards lab, you might be able to use their time-transfer files to compare your

Re: [time-nuts] Ublox Neo-6M time error.

The local clock bias value reported by the Res T is the difference between the receiver's clock and the reference time scale ( GPS or UTC). You need it to correct the raw pseudo ranges reported by the receiver, which are with respect to the receiver's clock. Cheers Michael On Wednesday, 1 June

Re: [time-nuts] Commercial software defined radio for clock metrology

rable. So for other applications eg a 10 MHz phase comparison where frequency differences are quite small, the data width could be dropped significantly. Cheers Michael On Sat, May 28, 2016 at 3:11 PM, Attila Kinali <att...@kinali.ch> wrote: > On Sat, 28 May 2016 12:08:18 +1000 > Michael Wou

Re: [time-nuts] Commercial software defined radio for clock metrology

The following may be of interest to those playing with low-cost SDR hardware: I also have been looking at low-cost SDR hardware for T measurements and have made an RF phase meter based on the Red Pitaya. The performance of this was not as good as I was hoping for: the fractional frequency

[time-nuts] GPS week rollover and time of day

Earlier this year, a venerable VP Oncore in one of our systems started outputting a time of day which was 1024 weeks in the past. This was presumably because it had some reference time in its firmware which it was using to resolve the n*1024 weeks ambiguity in broadcast GPS time, and it was now

Re: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)

> Multipath on GPS normally requires a couple of things: > > 3) The signal path length has to be close enough that the normal firmware > does not reject > the solution. > Expanding on this a bit, because it's relevant to the "aircraft causing multipath" question, the pseudo random noise

Re: [time-nuts] laser as clock source

. Cheers Michael On Sat, May 7, 2016 at 6:05 PM, Michael Wouters <michaeljwout...@gmail.com> wrote: > Dear Ilia > > Emission of light is a quantum mechanical process. It is fundamentally > statistical in nature and as someone commented earlier, makes a good > random number

Re: [time-nuts] laser as clock source

Dear Ilia Emission of light is a quantum mechanical process. It is fundamentally statistical in nature and as someone commented earlier, makes a good random number generator. Here's one, for example: http://www.nature.com/articles/srep10214 If you attenuate any light source, lasers included, to

Re: [time-nuts] synchronization for telescopes

On Thu, May 5, 2016 at 4:53 AM, jimlux wrote: > On 5/4/16 11:52 AM, Ilia Platone wrote: >> >> You got it, however: It only matters relative time. Start and Stop times >> will be known, and that is solved. >> Someone has proposed using TV or other broadcasting carrier as

Re: [time-nuts] Optical transfer of time and frequency

Not stable enough unfortunately. An ageing rate of a few parts in 10^12 per day is typical, which translates to 100 ns. You could be brave and model that as linear frequency drift to predict the time offset to the required 0.5 ns or so but I suspect that it could be a very frustrating exercise. We

Re: [time-nuts] synchronization for telescopes

Dear Attila On Tue, May 3, 2016 at 10:05 PM, Attila Kinali wrote: >I have some numbers of an project of the ETH that did use standard >LEA-6T recording the phase data and got in the post processing >to an uncertainty of <4mm averaging over several hours. Translating >that to

Re: [time-nuts] Fw: Optical transfer of time and frequency

One other possibility occurs to me that might be doable with surplus gear and sticks to the budget. Instead of using WR, give up on getting time of day and just send a 1 kHz pulse stream in each direction. Each station then measures against its own GPSDO clock using a standard/homebrew TIC and

Re: [time-nuts] synchronization for telescopes

ween the modules local oscillator to the satellites > and from there to the other locations. > > This should bring you at least down to a 1ns uncertainty level > (after calibration). Judging from Michael Wouters said, probably > close to 200-300ps. > The number I quoted is for h

Re: [time-nuts] Using lasers for data transmission

Dear Ilia On Sun, May 1, 2016 at 6:40 PM, Ilia Platone wrote: > The problem would be modulating a 10GBASE-T signals into a single laser > beam, and demodulating it using (I think) an APD. > The White Rabbit cards use SFP (small form-factor pluggable) lasers that plug into

Re: [time-nuts] Optical transfer of time and frequency

On Sat, Apr 30, 2016 at 6:14 AM, Magnus Danielson wrote: > Well, giving the conditions mentioned, doing ranging codes such as those > used by GPS is very easy and cheap. Doing this in bidirectional isn't too > hard. Doing a suitably high chip-rate should cost very

Re: [time-nuts] Optical transfer of time and frequency

So why not do White Rabbit free space ? Cheers Michael On Sat, Apr 30, 2016 at 4:04 AM, Paul Boven wrote: > Hi everyone, > > On 04/29/2016 03:28 PM, Magnus Danielson wrote: >> >> Phase/time transfer over fiber is shaping up, but White Rabbit is >> starting to grow up and more

Re: [time-nuts] Optical transfer of time and frequency

On Fri, Apr 29, 2016 at 1:18 PM, Bruce Griffiths <bruce.griffi...@xtra.co.nz> wrote: > Quoting Michael Wouters: "According to this, > > http://www.nist.gov/manuscript-publication-search.cfm?pub_id=912449 > > there are many practical challenges with a one way free-space o

Re: [time-nuts] SE880 GPSDO

According to this, http://www.nist.gov/manuscript-publication-search.cfm?pub_id=912449 there are many practical challenges with a one way free-space optical link. They were, however, aiming for much higher stability than is needed here. There are a lot of ideas being tossed around here. It

Re: [time-nuts] SE880 GPSDO

On Wed, Apr 27, 2016 at 7:21 PM, Bruce Griffiths wrote: > Stabilising the GPS receiver antenna temperature is probably a good idea > particularly if it has bandpass filter(s). It's not so clear that temperature stabilization of the antenna is necessary. There have

Re: [time-nuts] SE880 GPSDO

On Wed, Apr 27, 2016 at 7:51 AM, Attila Kinali wrote: > > > > Another way would be to use L1/L2 receivers with calibrated antennas. > I know that BIPM has a GPS station that can deliver time transfer > accuracy <2ns over a distance of several 100km. It could be possible > to use

Re: [time-nuts] suitable statistics for measurements with gaps

The technique used for dealing with gaps is really about handling random gaps in an otherwise uniformly sampled sequence. The idea is that you take your sequence, pad it out with the missing data (tagging those points with a NaN or whatever) and then when you're computing ADEV, if a data triplet

Re: [time-nuts] Lady Heather coming soon to a Linux box near you...

One simple trick I have used many times is to split the TX pin from the GPS receiver - ntpd really only needs to receive. Some ntpd refclock drivers will attempt to configure the receiver but if you can ensure that ntpd is getting the messages it needs, then all should be fine. Otherwise, hack the

Re: [time-nuts] Trimble SMT 360

gt; “thinks” are > >> correct. Another possibility is a position hold situation with a very > low > >> satellite count. > >> As a single observed satellite goes in and out of multi path, the > solution > >> goes all over the place. > >> Again, you ne

Re: [time-nuts] Trimble SMT 360

ch all > of this > would be apparent from the normal messages out of the part. > > Bob > > > > > On Apr 18, 2016, at 10:13 PM, Michael Wouters <michaeljwout...@gmail.com > <javascript:;>> wrote: > > > > Does anyone have experience with the Trimble

[time-nuts] Trimble SMT 360

Does anyone have experience with the Trimble SMT 360 ? I bought some of these four or five months after they were released. During testing, the 1 pps output evidenced a problem, as shown in the attached plot (the 1 pps is being measured against a Cs beam standard), which is not

Re: [time-nuts] Where does the source time for GPS come from?

Dear Sean, The USNO is the main source of precise time in the US via the GPS system. It has an ensemble of caesium clocks and hydrogen masers in Washington that it uses as the reference to provide corrections for the clocks that are onboard each of the GPS satellites. These corrections are

Re: [time-nuts] Precise Time transfer and relative position over a short baseline

Dear Bruce Posted too hastily ... Since you don't care about absolute time, maybe using identical receivers you might be able to get a few hundred ps synchronization using a PPP solution, for example. Attached is 6 months of data for two Javad receivers, with daily PPP solutions. The antennas

Re: [time-nuts] Precise Time transfer and relative position over a short baseline

Dear Bruce I think it will be very difficult to achieve synchronization at the level you want using GNSS signals. The BIPM would only claim 2 ns accuracy for calibration of the delays in a GNSS receiver plus antenna. When you process carrier phase data, you typically see jumps at the day boundary

Re: [time-nuts] Unix equivalent of Windows RbMon app for PRS10 monitoring

Dear Mike, I have a Perl script and a C++ application that may be of use. The Perl script logs continuously, but is mainly for logging TT? responses. The C++ application is used interactively. Either could be modified to do what you want. Take a look at:

Re: [time-nuts] Reliability of atomic clocks

Dear Paul, You are probably thinking of one of these: Chadsey et al “Maintenance of HP5071A frequency standards at USNO” in Proc. 29th PTTI, p49-60 (1997) Chadsey “An automated alarm program for HP5071A frequency standards” in Proc. 31st PTTI, p649-655 (1999) Brock et al “End-of-life

Re: [time-nuts] Standard Room Calibration Procedure

Dear Luciano I run a T calibration laboratory. It sounds like what you're after is a Test Method (TM), which we use as part of our quality system. Any accredited calibration laboratory will have documents like this. They vary greatly in their detail according to the needs of each laboratory, and