Re: [time-nuts] Tektronix FCA3103 ADEV measurement tau setting problem

[Azelio Boriani]

The now freely available Stable32 has Hadamard, overlap Hadamard,
Hadamard total.

On Mon, May 28, 2018 at 9:17 PM, Richard (Rick) Karlquist
 wrote:
> I have a Tek FCA3103 300 MHz counter that measures ADEV
> as a built in function.  When I bring up the settings
> menu for the measurement, it has an entry window for
> "tau" (the averaging time, IE "sigma sub y of tau").
> It defaults to 200 ms.  I can enter larger values and
> ADEV gives reasonably results.  However, if I enter
> smaller values, even 199 ms, I don't get any error
> on the display, but I get clearly erroneous
> results for ADEV. I read the manual and cannot find
> anything to the effect that the instrument doesn't work
> for less than 200 ms.
>
> BTW, I asked Tek "customer no support" about it and
> they were clueless.
>
> 1.  Is this pilot error?  Can anyone tell me the trick?
>
> 2.  Can anyone recommend a 300 MHz counter that measures
> ADEV, correctly :-)?  Bonus question:  a counter that
> measures Hadamard variance?
>
> 3.  Can anyone recommend a 300 MHz counter that can
> measure ADEV and Hadamard using off the shelf software
> that runs on a PC?  I don't write software :-)
> Bonus question:  software to make these measurements
> that works with the FCA3103 that I already have?
>
> I have an NI GPIB-USB-HS to interface the counter
> to the PC running the software if that helps.
>
>
>
> Thanks
>
> Rick N6RK
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Re: [time-nuts] Antenna cable delay compensation

[Azelio Boriani]

In the uBlox protocol specifications there is an antCableDelay, an
rfGroupDelay, a userConfigDelay, all are 2's complement quantities, no
bounds given in the manual.

On Tue, May 22, 2018 at 4:55 AM, Mark Sims  wrote:
> A related question is:  Do you use positive or negative numbers to set the 
> antenna cable delay value?  Again, most GPS receiver documentation does not 
> say.I think that I've only seen it explicitly mentioned in the Trimble 
> documentation and the Oscilloquartz Star-4 documentation.
>
> Also there is the question of does the receiver time message come out before 
> or after the 1PPS and what is the message offset time from the 1PPS?   Again, 
> rarely documented by the receiver manufacturer.   Lady Heather can measure 
> those (if the operating system clock is accurately set)  Heather uses the 
> message time offset to adjust the displayed time or get the audible "tick 
> clock" aligned to true time.
>
> Heather has a table of typical message offsets for the supported receivers, 
> but measuring and setting the value for your receiver/computer/serial port 
> can improve things.
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Re: [time-nuts] Improving ocxo temp control

[Azelio Boriani]

First, be sure not to measure your  HP52132A stability with the OCXO.
What is your reference source?

On Mon, May 21, 2018 at 7:12 PM, Bob kb8tq  wrote:
> Hi
>
> There are a lot of reasons an OCXO drifts. Temperature control is rarely the 
> issue.
> More likely you are looking at the drift / wander characteristics of the 
> crystal ( and
> components) in the OCXO. The simple answer is to leave it on for a while ( 
> like weeks)
> to allow things to settle out a bit.
>
> The paper that Rick tossed up last week is a pretty good one in terms of 
> temperature
> control issues in an OCXO and what the issues are.
>
> This all assumes you are in a fairly benign environment. If you have lots of 
> drafts, put a
> cardboard box over the unit to shield it. If you room temperature is all over 
> the place, then
> there are a lot of ways to get to ~ 1 or 2C sort of stability in a lab. What 
> you do depends
> a *lot* on what your situation is.
>
> =
>
> So, assuming you *do* want to improve the temperature control:
>
> First you need to take out what’s in there now. If it’s wandering around get 
> rid of it. This
> involves tearing apart the OCXO.
>
> Now take a look at Rick’s paper and redesign the thermal enclosure. Get the 
> heater placement
> and sensor placement right and feed that into a simple controller.
>
> Run some tests over temperature and check out the data. It’s likely your 
> first guess at things
> is not going to be correct.
>
> Try to optimize the heat sources and sensors and re-test the result. 
> Everything interacts so
> this is not a quick process.
>
> Once you are reasonably happy with where things are, start looking at a more 
> fancy controller.
> A simple approach would be feeding thermistor voltage into some 24 bit ADC’s 
> and then
> processing the result with an MCU.
>
> Ok so that’s all a bit much.
>
> =
>
> What happens if you mess with the OCXO from the outside of the package?
>
> You change the heat loss out of the package. This increases the thermal gain. 
> ( less power
> to increase the oven temperature by 1 C ). Assuming the original circuit was 
> balanced
> out, you have made things worse rather than better.
>
> Ok so you do an enclosure with a fan it it so the heat loss doesn’t get less.
>
> You now have more heat loss and the same issue applies. In addition the fan 
> and it’s
> nonsense probably haven’t done the poor little OCXO any good.
>
> When one designs a double oven, the inner oven is optimized for performance 
> *with*
> the outer oven present. Equally, the outer oven is optimized for performance 
> with the
> heat load (and dynamics) of the inner oven.
>
> =
>
> Assuming you still want to head down this road, temperature controllers are 
> no different
> than any control loop. The first place to start is a textbook on control 
> loops and control
> theory. The basics of what a loop does and the terminology are what you are 
> after. Anything
> advanced will assume you understand this part first.
>
> Next up are temperature sensors. Simple answer here is that a glass bead 
> thermistor is
> the way to go. For heat, transistors are the normal go-to device. The 
> controls loop takes
> in the thermistor output and spits out a voltage to change the current 
> through the transistor.
>
> If you have the money for software licenses, the next stop is some good 
> mechanical CAD
> that will feed into thermal modeling. From that you can work out a proper 
> heat flow and
> gradient design. Assuming that is a bit to expensive, you are back to trial 
> and error. There
> are no “just duplicate this” designs that I know of.
>
> Once you have the structure, sensors, heaters, and control you toss it into a 
> temperature
> test chamber. That may be something fancy or something you put together. You 
> run the
> gizmo over temperature and observe what it does. You then optimize the P,I,D 
> coefficients
> in your control loop. Indeed you may not have all of them or you may have an 
> extra one.
>
> ===
>
> Of course one could simply shop for a $20 OCXO on eBay. Even if you have to 
> buy a
> dozen before you find a good one, it’s still cheaper / faster / easier / more 
> likely to succeed
> than all the nonsense above. If this is a commercial design for a product you 
> are going
> to sell, that does not work very well. The same fundamental answer applies. 
> If you need
> better performance, shop for a better oscillator.
>
>
> Lots of fun 
>
>
>
>> On May 21, 2018, at 12:23 PM, Club-Internet Clemgill 
>>  wrote:
>>
>> Thanks for your interesting replies.
>> What I am actually trying to do is the following:
>> I bough a small ocxo (size of half a ping-pong ball) that performs well 
>> (Abracon / AOCJY3_B 10Mhz)
>> Reaching about 5*10E-11 kind of MDEV at low point ("kind of"… because a I 
>> use an HP52132a as input to Timelab)
>> But it’s frequency is slowly drifting with time, with a quasi linear slope.
>> I wondered if placing it in a third ovenized enclosur

Re: [time-nuts] lecture on PLL and phase noise and verilog

[Azelio Boriani]

Maybe that such a technique can be applied to the simulation of
counters and interpolators, an actual topic on this list.

On Mon, May 14, 2018 at 2:47 PM, jimlux  wrote:
> If you're in California southern Central Coast area (Ventura, Santa Barbara,
> Thousand Oaks, etc.) the local IEEE chapter is sponsoring a talk on phase
> noise and Verilog
>
> https://events.vtools.ieee.org/m/172159
>
> PLL'S AND PHASE NOISE MODELING IN VERILOG
> Verilog is the accepted language of choice for modeling and simulating
> digital designs. For analog blocks the tool choice is a low level circuit
> simulator like HSPICE or Spectre. For PLL’s a common misconception is that
> you can use Verilog to model a PLL if you don't care about accuracy, but if
> you do care about precision, you'll need an analog circuit simulator like
> HSPICE or Spectre. Various options like Verilog-A and Verilog-AMS are
> attempts to achieve the best of both worlds, but in this talk, we propose
> that the tool of choice for modeling and studying PLL’s and is plain
> “digital” Verilog. It's the right tool, but almost always used the wrong way
> for modeling PLL's. Understanding how the underlying simulation engine in
> Verilog works enables us to set up our models in a very precise, yet very
> simple manner. The efficiency and speed of Verilog allows us to literally
> watch our PLL designs come alive in the time domain with timing accuracy
> that can't be achieved in an analog circuit simulator. Watching designs
> operate in the time domain crystalizes our understanding of them, and
> enables us to study and quantify transient and other non-linear phenomena.
>
>
> Biography:
>
> Greg Warwar received a master’s degree in electrical engineering from Rice
> University in 1989. Following graduation, he joined Texas Instruments in
> Dallas, TX as a member of the technical staff where he worked on ΣΔ analog
> to digital converters for precision audio applications. In 1992, he joined
> Vitesse Semiconductor in Camarillo, CA where he worked for 23 years on high
> speed serial communications IC’s, focusing on many areas of analog and
> mixed-signal design including VCO’s, phase locked loops, clock recovery,
> frequency synthesizers, and adaptive equalization. Since 2015, Greg has been
> a principal engineer in the mixed-signal ASICs design group at Teradyne,
> Inc. in Agoura Hills, CA. Greg holds six U.S. patents in the area of CMOS
> mixed-signal IC design.
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Re: [time-nuts] GPS Timing Antenna Failure - Long

[Azelio Boriani]

Usually GPS antennas are patch antennas. The PROCOM GPS4 (I have 2 of
them) should be a real QFH (I haven't opened it to verify), the
Vaisala radiosonde RS92 has a real QFH. The Sarantel SL series seem is
a double helix not a classic QFH with the two different-size loops.
They name their series GeoHelix.





On Sun, May 13, 2018 at 1:25 PM, Clint Jay  wrote:
> I'm all for anything that encourages whisky growth
>
> On Sun, 13 May 2018 12:16 pm Dana Whitlow,  wrote:
>
>> Flux can provide just the right kind of ionic leakage path that leads to
>> whisky growth
>> and eventual sudden shorts.
>>
>> Dana
>>
>>
>> On Sun, May 13, 2018 at 12:23 AM, Hal Murray 
>> wrote:
>>
>> >
>> > lmcda...@lmceng.com said:
>> > > To make this very long story into a short one, I learned that the  HP/
>> > > Symmetricom 58532A GPS Reference (timing) antennas use a simple patch
>> > > antenna instead of a quadrafilar antenna and that old solder flux
>> > residue
>> > > will attenuate the even amplified GPS signal out of this antenna.
>> >
>> > Flux seems unlikely to produce a sudden failure.
>> >
>> > If flux was the problem, I'd expect it to work poorly when first
>> > installed,
>> > or maybe decay slowly over time as something changed.
>> >
>> >
>> >
>> >
>> > --
>> > These are my opinions.  I hate spam.
>> >
>> >
>> >
>> > ___
>> > time-nuts mailing list -- time-nuts@febo.com
>> > To unsubscribe, go to https://www.febo.com/cgi-bin/
>> > mailman/listinfo/time-nuts
>> > and follow the instructions there.
>> >
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Re: [time-nuts] Question about frequency counter testing

[Azelio Boriani]

You can measure your clocks down to the ps averaged resolution you
want only if they are worse than your one-shot base resolution one WRT
the other. In a resonable time, that is how many transitions in your
2.5ns sampling interval you have in 1 second to have a n-digit/second
counter.

On Fri, Apr 27, 2018 at 4:32 PM, Azelio Boriani
 wrote:
> Yes, this is the problem when trying to enhance the resolution from a
> low one-shot resolution. Averaging 2.5ns resolution samples can give
> data only if clocks move one with respect to the other and "cross the
> boundary" of the 2.5ns sampling interval. You can measure your clocks
> down to the ps averaged resolution you want only if they are worse
> than your one-shot base resolution one WRT the other.
>
> On Fri, Apr 27, 2018 at 3:38 PM, Bob kb8tq  wrote:
>> Hi
>>
>> Consider a case where the clocks and signals are all clean and stable:
>>
>> Both are within 2.5 ppb of an integer relationship. ( let’s say one is 10
>> MHz and the other is 400 MHz ). The amount of information in your
>> data stream collapses. Over a 1 second period, you get a bit better than
>> 9 digits per second.  Put another way, the data set is the same regardless
>> of where you are in the 2.5 ppb “space”.
>>
>> Bob
>>
>>
>>
>>> On Apr 27, 2018, at 5:30 AM, Hal Murray  wrote:
>>>
>>>
>>> olegsky...@gmail.com said:
>>>> No, it is much simpler. The hardware saves time-stamps to the memory at 
>>>> each
>>>> (event) rise of the input signal (let's consider we have digital logic 
>>>> input
>>>> signal for simplicity). So after some time we have many pairs of {event
>>>> number, time-stamp}. We can plot those pairs with event number on X-axis 
>>>> and
>>>> time on Y-axis, now if we fit the line on that dataset the inverse slope of
>>>> the line will correspond to the estimated frequency.
>>>
>>> I like it.  Thanks.
>>>
>>> If you flip the X-Y axis, then you don't have to invert the slope.
>>>
>>> That might be an interesting way to analyze TICC data.  It would work
>>> better/faster if you used a custom divider to trigger the TICC as fast as it
>>> can print rather than using the typical PPS.
>>>
>>> --
>>>
>>> Another way to look at things is that you have a fast 1 bit A/D.
>>>
>>> If you need results in a second, FFTing that might fit into memory.  (Or you
>>> could rent a big-memory cloud server.  A quick sample found 128GB for
>>> $1/hour.)  That's with 1 second of data.  I don't know how long it would 
>>> take
>>> to process.
>>>
>>> What's the clock frequency?  Handwave.  At 1 GHz, 1 second of samples fits
>>> into a 4 byte integer even if all the energy ends up in one bin.  4 bytes, 
>>> *2
>>> for complex, *2 for input and output is 16 GB.
>>>
>>>
>>> --
>>> These are my opinions.  I hate spam.
>>>
>>>
>>>
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>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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>>
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Re: [time-nuts] Question about frequency counter testing

[Azelio Boriani]

Yes, this is the problem when trying to enhance the resolution from a
low one-shot resolution. Averaging 2.5ns resolution samples can give
data only if clocks move one with respect to the other and "cross the
boundary" of the 2.5ns sampling interval. You can measure your clocks
down to the ps averaged resolution you want only if they are worse
than your one-shot base resolution one WRT the other.

On Fri, Apr 27, 2018 at 3:38 PM, Bob kb8tq  wrote:
> Hi
>
> Consider a case where the clocks and signals are all clean and stable:
>
> Both are within 2.5 ppb of an integer relationship. ( let’s say one is 10
> MHz and the other is 400 MHz ). The amount of information in your
> data stream collapses. Over a 1 second period, you get a bit better than
> 9 digits per second.  Put another way, the data set is the same regardless
> of where you are in the 2.5 ppb “space”.
>
> Bob
>
>
>
>> On Apr 27, 2018, at 5:30 AM, Hal Murray  wrote:
>>
>>
>> olegsky...@gmail.com said:
>>> No, it is much simpler. The hardware saves time-stamps to the memory at each
>>> (event) rise of the input signal (let's consider we have digital logic input
>>> signal for simplicity). So after some time we have many pairs of {event
>>> number, time-stamp}. We can plot those pairs with event number on X-axis and
>>> time on Y-axis, now if we fit the line on that dataset the inverse slope of
>>> the line will correspond to the estimated frequency.
>>
>> I like it.  Thanks.
>>
>> If you flip the X-Y axis, then you don't have to invert the slope.
>>
>> That might be an interesting way to analyze TICC data.  It would work
>> better/faster if you used a custom divider to trigger the TICC as fast as it
>> can print rather than using the typical PPS.
>>
>> --
>>
>> Another way to look at things is that you have a fast 1 bit A/D.
>>
>> If you need results in a second, FFTing that might fit into memory.  (Or you
>> could rent a big-memory cloud server.  A quick sample found 128GB for
>> $1/hour.)  That's with 1 second of data.  I don't know how long it would take
>> to process.
>>
>> What's the clock frequency?  Handwave.  At 1 GHz, 1 second of samples fits
>> into a 4 byte integer even if all the energy ends up in one bin.  4 bytes, *2
>> for complex, *2 for input and output is 16 GB.
>>
>>
>> --
>> These are my opinions.  I hate spam.
>>
>>
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
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Re: [time-nuts] Question about frequency counter testing

[Azelio Boriani]

If your hardware is capable of capturing up to 10 millions of
timestamps per second and calculating LR "on the fly", it is not a so
simple hardware, unless you consider simple hardware a 5megagates
Spartan3 (maybe more is needed). Moreover: if your clock is, say, at
most in an FPGA, 300MHz, your timestamps will have a one-shot
resolution of few nanoseconds. Where have you found a detailed
description of the CNT91 counting method? The only detailed
description I have found is the CNT90 (not 91) service manual and it
uses interpolators (page 4-13 of the service manual).

On Thu, Apr 26, 2018 at 2:45 PM, Bob kb8tq  wrote:
> Hi
>
> Even with a fast counter, there are going to be questions about clock jitter 
> and just
> how well that last digit performs in the logic. It’s never easy to squeeze 
> the very last
> bit of performance out …..
>
> Bob
>
>> On Apr 26, 2018, at 3:06 AM, Azelio Boriani  wrote:
>>
>> Very fast time-stamping like a stable 5GHz counter? The resolution of
>> a 200ps (one shot) interpolator can be replaced by a 5GHz
>> time-stamping counter.
>>
>> On Thu, Apr 26, 2018 at 12:28 AM, Bob kb8tq  wrote:
>>> Hi
>>>
>>> Unfortunately there is no “quick and dirty” way to come up with an accurate 
>>> “number of digits” for a
>>> math intensive counter. There are a *lot* of examples of various counter 
>>> architectures that have specific
>>> weak points in what they do. One sort of signal works one way, another 
>>> signal works very differently.
>>>
>>> All that said, the data you show suggests you are in the 10 digits per 
>>> second range.
>>>
>>> Bob
>>>
>>>> On Apr 25, 2018, at 3:01 PM, Oleg Skydan  wrote:
>>>>
>>>> Dear Ladies and Gentlemen,
>>>>
>>>> Let me tell a little story so you will be able to better understand what 
>>>> my question and what I am doing.
>>>>
>>>> I needed to check frequency in several GHz range from time to time. I do 
>>>> not need high absolute precision (anyway this is a reference oscillator 
>>>> problem, not a counter), but I need fast high resolution instrument (at 
>>>> least 10 digits in one second). I have only a very old slow unit so, I 
>>>> constructed a frequency counter (yes, yet another frequency counter 
>>>> project :-). I is a bit unusual - I decided not to use interpolators and 
>>>> maximally simplify hardware and provide the necessary resolution by very 
>>>> fast timestamping and heavy math processing. In the current configuration 
>>>> I should get 11+ digits in one second, for input frequencies more then 
>>>> 5MHz.
>>>>
>>>> But this is theoretical number and it does not count for some factors. Now 
>>>> I have an ugly build prototype with insanely simple hardware running the 
>>>> counter core. And I need to check how well it performs.
>>>>
>>>> I have already done some checks and even found and fixed some FW bugs :). 
>>>> Now it works pretty well and I enjoyed looking how one OCXO drifts against 
>>>> the other one in the mHz range. I would like to check how many significant 
>>>> digits I am getting in reality.
>>>>
>>>> The test setup now comprises of two 5MHz OCXO (those are very old units 
>>>> and far from the perfect oscillators - the 1sec and 10sec stability is 
>>>> claimed to be 1e-10, but they are the best I have now). I measure the 
>>>> frequency of the first OCXO using the second one as counter reference. The 
>>>> frequency counter processes data in real time and sends the continuous one 
>>>> second frequency stamps to the PC. Here are experiment results - plots 
>>>> from the Timelab. The frequency difference (the oscillators are being on 
>>>> for more than 36hours now, but still drift against each other) and ADEV 
>>>> plots. There are three measurements and six traces - two for each 
>>>> measurement. One for the simple reciprocal frequency counting (with R 
>>>> letter in the title) and one with the math processing (LR in the title). 
>>>> As far as I understand I am getting 10+ significant digits of frequency in 
>>>> one second and it is questionable if I see counter noise or oscillators 
>>>> one.
>>>>
>>>> I also calculated the usual standard deviation for the measurements 
>>>> results (and tried to remove the drift before the calculations), I got STD 
>>>> in the 3e-4..4e-4Hz (

Re: [time-nuts] Question about frequency counter testing

[Azelio Boriani]

Very fast time-stamping like a stable 5GHz counter? The resolution of
a 200ps (one shot) interpolator can be replaced by a 5GHz
time-stamping counter.

On Thu, Apr 26, 2018 at 12:28 AM, Bob kb8tq  wrote:
> Hi
>
> Unfortunately there is no “quick and dirty” way to come up with an accurate 
> “number of digits” for a
> math intensive counter. There are a *lot* of examples of various counter 
> architectures that have specific
> weak points in what they do. One sort of signal works one way, another signal 
> works very differently.
>
> All that said, the data you show suggests you are in the 10 digits per second 
> range.
>
> Bob
>
>> On Apr 25, 2018, at 3:01 PM, Oleg Skydan  wrote:
>>
>> Dear Ladies and Gentlemen,
>>
>> Let me tell a little story so you will be able to better understand what my 
>> question and what I am doing.
>>
>> I needed to check frequency in several GHz range from time to time. I do not 
>> need high absolute precision (anyway this is a reference oscillator problem, 
>> not a counter), but I need fast high resolution instrument (at least 10 
>> digits in one second). I have only a very old slow unit so, I constructed a 
>> frequency counter (yes, yet another frequency counter project :-). I is a 
>> bit unusual - I decided not to use interpolators and maximally simplify 
>> hardware and provide the necessary resolution by very fast timestamping and 
>> heavy math processing. In the current configuration I should get 11+ digits 
>> in one second, for input frequencies more then 5MHz.
>>
>> But this is theoretical number and it does not count for some factors. Now I 
>> have an ugly build prototype with insanely simple hardware running the 
>> counter core. And I need to check how well it performs.
>>
>> I have already done some checks and even found and fixed some FW bugs :). 
>> Now it works pretty well and I enjoyed looking how one OCXO drifts against 
>> the other one in the mHz range. I would like to check how many significant 
>> digits I am getting in reality.
>>
>> The test setup now comprises of two 5MHz OCXO (those are very old units and 
>> far from the perfect oscillators - the 1sec and 10sec stability is claimed 
>> to be 1e-10, but they are the best I have now). I measure the frequency of 
>> the first OCXO using the second one as counter reference. The frequency 
>> counter processes data in real time and sends the continuous one second 
>> frequency stamps to the PC. Here are experiment results - plots from the 
>> Timelab. The frequency difference (the oscillators are being on for more 
>> than 36hours now, but still drift against each other) and ADEV plots. There 
>> are three measurements and six traces - two for each measurement. One for 
>> the simple reciprocal frequency counting (with R letter in the title) and 
>> one with the math processing (LR in the title). As far as I understand I am 
>> getting 10+ significant digits of frequency in one second and it is 
>> questionable if I see counter noise or oscillators one.
>>
>> I also calculated the usual standard deviation for the measurements results 
>> (and tried to remove the drift before the calculations), I got STD in the 
>> 3e-4..4e-4Hz (or 6e-11..8e-11) range in many experiments.
>>
>> Now the questions:
>> 1. Are there any testing methods that will allow to determine if I see 
>> oscillators noise or counter does not perform in accordance with the theory 
>> (11+ digits)? I know this can be done with better OCXO, but currently I 
>> cannot get better ones.
>> 2. Is my interpretation of the ADEV value at tau=1sec (that I have 10+ 
>> significant digits) right?
>>
>> As far as I understand the situation I need better OCXO's to check if HW/SW 
>> really can do 11+ significant digits frequency measurement in one second.
>>
>> Your comments are greatly appreciated!
>>
>> P.S. If I feed the counter reference to its input I got 13 absolutely stable 
>> and correct digits and can get more, but this test method is not very useful 
>> for the used counter architecture.
>>
>> Thanks!
>> Oleg
>> 73 de UR3IQO
>> <1124.png><1127.png>___
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Re: [time-nuts] GPS coordinate differences between APRS.FI and Google Maps

[Azelio Boriani]

aprs.fi uses google maps... have you taken a look to your raw packets?

On Sat, Apr 21, 2018 at 12:34 AM, Scott McGrath  wrote:
> DATUM perhaps?
>
> Content by Scott
> Typos by Siri
>
> On Apr 20, 2018, at 5:20 PM, Russ Ramirez  wrote:
>
> This has probably been mentioned before, but there is a significant
> discrepancy between APRS.FI locations for DMR hotspots for example, and
> what my Trimble receiver and Google Maps says when I use my address to
> lookup the coordinates.
>
> On APRS.FI my location has to be 45.15 N, -93.39 W for the icon to be in
> the right location on the map.
>
> On regular Google Maps, my QTH is correct and matches what my Trimble says
> via Lady Heather within a few seconds. 45.2586 N, -93.6554 W.
>
> Do any of you know what causes this, and did I do anything wrong possibly?
> TIA
>
> Russ
> K0WFS
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Re: [time-nuts] Weird Stuff Warehouse shutting down

[Azelio Boriani]

For those of us (like me) that can travel to the US less than once in
a lifetime, there is an EEVblog #124 - A Tour of Apex Electronics:




On Sun, Apr 8, 2018 at 2:25 AM, Alexander Pummer  wrote:
> other surplus:
> https://www.google.com/search?client=firefox-b-1&tbm=lcl&ei=qGDJWrDzBuXm5gKB3bmQDw&q=electronic+surplus+bay+area+ca&oq=electronic+surplus+bay+area+ca&gs_l=psy-ab.12...16142.25972.0.28698.14.12.2.0.0.0.228.1752.0j11j1.12.00...1c.1.64.psy-ab..0.0.00.qHdPqOyu4I8#rlfi=hd:;si:;mv:!1m3!1d406993.57669817575!2d-122.07998499435485!3d37.551234775823595!3m2!1i636!2i386!4f13.1
>
> 73
>
> KJ6UHN
>
> Alex
>
>
> On 4/7/2018 4:03 PM, paul swed wrote:
>>
>> Like most of you I also visited these places and have dragged back and
>> shipped lots of "Weird stuff". Even smaller parts through airport
>> security.
>> The oddest thing was 3/4" cable TV hardline connectors and there was no
>> issue at all.
>> It always made it fun to go on a business trip to the area and always slip
>> a bit of time into visit the places.
>> There may still be two left at this point. Electronic Surplus Sales or ESS
>> and do not recall the name of the other. But do know its location be
>> heart.
>> I can say that in the 70s they really had an effect on my overall career.
>> Piles of computer stuff and much else. Buy it by the pound. Think it was
>> Mikes surplus by the Oakland airport. Long gone and one up in Berkley.
>>
>> There is one crazy place down in northern LA. Some what hard to get to but
>> my god the stuff. Overwhelming. They dicker also. Nothing like a tough
>> bargain was there 3 years ago.
>>
>>
>> On Sat, Apr 7, 2018 at 10:36 AM, Bob kb8tq  wrote:
>>
>>> Hi
>>>
>>> Over the years, this has been the fate of a *lot* of surplus / goodie
>>> outfits. They have
>>> a “deal” on some property and that runs out. Sometimes it’s a sale with
>>> the neighborhood
>>> improving. Other times it’s the roof needing repairs and nobody sees the
>>> need to do them
>>> until it is way to late ….
>>>
>>> Bob
>>>
 On Apr 6, 2018, at 11:24 PM, Bruce Lane 
>>>
>>> wrote:

 Fellow techies,

I'm sorry to report we're losing another surplus place. Weird
 Stuff
 Warehouse, in Sunnyvale, CA, is closing its doors as of Monday,
 9-Apr-18.

It seems we have Google to blame. Here's Weird Stuff's final
 newsletter, verbatim.

 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

 April 6, 2018

 To Weirdstuff Customers,

 Sadly, after 32 years in business, Weirdstuff Warehouse will be closing
 its doors as of April 9, 2018. If you have been following the real
 estate news for Sunnyvale you know that Google purchased a large amount
 of real estate in the area including the building we have been leasing
 for the past 22 years. We have been asked to vacate the building as soon
 as possible, and in order to accomplish that task we are selling our
 inventory and many of our assets to Outback Equipment of Morgan Hill.
 The transfer of inventory and assets will take place on April 9, 2018;
 at that time Weirdstuff Warehouse will cease to do business.

 Even though Weirdstuff is closing we will retain ownership of the
 Corporation, trademark, and domain names. We hope to handle these
 entities and wind down the corporation before year end.

 Many of you have been loyal customers for many years, and we have
 enjoyed working with you. We thank you for your loyalty and business.

 For more information, check out our website after Monday, April 9, 2018.

 WeirdStuff Warehouse
 384 W. Caribbean Dr.
 Sunnyvale, CA 94089
 (408) 743-5650
 --

Heh... So much for Google's favorite "Don't Be Evil" motto

 ---
 Bruce Lane, ARS KC7GR
 http://www.bluefeathertech.com
 kyrrin (at) bluefeathertech dot com
 "Quando Omni Flunkus Moritati" (Red Green)
 ___
 time-nuts mailing list -- time-nuts@febo.com
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Re: [time-nuts] Meinberg (Rode & Schwartz), ED170MP GPS Receiver

[Azelio Boriani]

I think you can use the GPSMON32 with the ED170

I have an ED167MP, it works only with its downconverter antenna and
the rear panel has 2 serial ports and a network connection (a
Lantronix serial_port/telnet adapter, a simple serial port over
ethernet).

On Sun, Apr 8, 2018 at 1:23 PM, Martin Burnicki
 wrote:
> Time wrote:
>> Does anyone have any information for the Meinberg (Rode & Schwartz), ED170MP
>> GPS Receiver?
>
> If you send email to techsupp...@meinberg.de then I'm sure my colleagues
> of the support group can help. It would be good if you specify a little
> bit more detailed which information you're interested in.
>
> Martin
> (working @Meinberg)
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Re: [time-nuts] TS2100: List of root commands?

[Azelio Boriani]

Try this:



On Thu, Apr 5, 2018 at 2:29 AM, Bruce Lane  wrote:
> Fellow time-tickers,
>
> I just finished conversion of one of my TS2100's to OCXO, and I'm now
> in the process of tweaking the EEPROM settings.
>
> During my research, I came across (and, foolishly, didn't bookmark)
> either a web page or a mailing list post which listed the 'root eng'
> commands, and exactly how to enter them. I've been successful with 'root
> eng ee gain' and 'root eng ee filter,' but I can't seem to get the
> syntax down to set the D/A value.
>
> Does this sound at all familiar?
>
> Thanks much.
>
> --
> ---
> Bruce Lane, ARS KC7GR
> http://www.bluefeathertech.com
> kyrrin (at) bluefeathertech dot com
> "Quando Omni Flunkus Moritati" (Red Green)
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Re: [time-nuts] GPS ANTENNA

[Azelio Boriani]

An unusual attenuator with a DC pass.

On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge
 wrote:
> Or use a choke ring survey antenna and an attenuator :)
>
> Dave
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob kb8tq
> Sent: 01 April 2018 14:43
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS ANTENNA
>
> Hi
>
> Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
> receiver. These beasts are trying to dig out a signal that you can’t even see 
> with a spectrum analyzer.
> It’s way to far below the noise floor to detect that way. They optimize 
> things pretty tightly to get that done (and to hit a price target ….). Put to 
> much gain in front of them and they get unhappy.
>
> Making this even more crazy, the survey industry standard antenna *does* have 
> a lot of gain. Survey receivers need way more gain in front of them than 
> timing receivers. Put a survey antenna directly on a timing device and 
> trouble will likely be the outcome. Equally, a survey instrument probably 
> will not be happy with a timing receiver.
>
> Why all this nonsense? As far as I can tell, it goes back to how the very 
> early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. 
> They made a basic decision to put a lot of gain at the antenna. Motorola came 
> along with their GPS modules later on. They made a *very* different decision 
> about how to distribute the gain. There are very good arguments on both sides 
> for why they did it this way.
> The bottom line is still - you need to match things up …
>
> Bob
>
>> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
>>
>> On Sat, 31 Mar 2018 10:58:19 -0500,
>> donandarline-Re5JQEeQqe8AvxtiuMwx3w
>> wrote:
>>
>>> I found a supplier for high quality GPS antennas at a very reasonable
>>> price. PCTEL GPSL1-TMG-SPI-40NCB.
>>
>> *** SNIP ***
>>
>> I had one of those on 25m cable, and it worked fine on a Tbolt , until
>> i got an active antenna splitter that also had some gain.
>> Then i had to replace it w. a 26dB version of same type, else the
>> "Jackson Lite" was loosing sync.
>>
>> What i mean here, is that you can get too much gain too.
>>
>> Btw: Good price.
>>
>> CFO
>> Denmark
>>
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Re: [time-nuts] WWVB Antenna revisited/Spectracom 8182

[Azelio Boriani]

The AM modulation stuff is not affected also by the new WWVB signal.
The WWVB problem affecting timing and frequency receivers is the
180deg phase modulation where the DFC77 is only 13deg and is
randomized so that the mean phase is zero.

On Fri, Mar 23, 2018 at 10:35 AM, Martin Burnicki
 wrote:
> paul swed write:
>> I'll add to the comments the spectracoms are phase tracking receivers and
>> do not work on the new BPSK  signal.
>
> When the German PTB made effort to increase the accuracy and reliability
> of the DCF77 long wave receiver in the 1980s, they implemented thus in a
> way that old receivers of the original AM modulation would not be affected:
> https://www.ptb.de/cms/en/ptb/fachabteilungen/abt4/fb-44/ag-442/dissemination-of-legal-time/dcf77/dcf77-phase-modulation.html
>
> If I remember correctly then there were some discussions with folks a
> NIST when they were going to introduce their new modulation scheme, but
> even though the guys at NIST knew that their approach would break
> existing receivers, they implemented it anyway that way, even though
> other (compatible) ways would have been available. :-(
>
> Martin
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Re: [time-nuts] Replacement A9 boards for the HP 5065A

[Azelio Boriani]

The part number BFC234421475, on 
seems to be a Philips product, 2500 available, for 49.28 UAH
(Ukrainian Hryvnia, that is 1.77 USD). A mysterious capacitor...

On Sun, Feb 25, 2018 at 12:35 PM, Charles Steinmetz
 wrote:
> Interesting.  I'm inclined to say I stand corrected, BUT:  (i) as Mark
> noted, the datasheet link points to the datasheet for Vishay FC Series HF
> thin-film resistors [which are really excellent low-reactance T/F resistors,
> if you need any]; (ii) I cannot find any reference to PC caps on the
> Vishay/BC web site; and (iii) other distributors do not list this cap (or
> any Vishay/BC PC caps, for that matter).
>
> I did discover Electronic Concepts (ECI) (https://www.ecicaps.com/), who
> claim to make their own PC film and do seem to supply three series of PC
> caps.  They seem mainly to make them to order, but they have small
> quantities of some parts in stock.  Prices are by quotation, so I don't know
> what they charge.  I assume they are pretty pricey, and if they run out of
> an in-stock cap there may be a minimum order to get more.
>
> So, I do stand corrected.
>
> All that said, PP and PPS are the best choices for the A9 integrator
> project.
>
> Best regards,
>
> Charles
>
>
>
> On 2/24/2018 9:35 PM, Mark Sims wrote:
>>
>> For a while, all makers of polycarbonate caps got out of the business.
>> The US government had to step in and get involved... apparently they are
>> used in a lot of explody thingies, etc.
>>
>> Mouser shows one (around $7 for a 4.7 uF cap):
>>
>> https://www.mouser.com/ProductDetail/Vishay-BC-Components/BFC234421475?qs=XPb5zkzE6%252bBS9mv3hRFZcw%3d%3d
>>
>> But, the datasheet link goes to a resistor...
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Re: [time-nuts] Furuno GT-8031 breakout board

[Azelio Boriani]

I see that Buerklin has also complete GPSDOs from Furuno, the GF-8701
seems the entry level model for 291 eur.

On Thu, Feb 15, 2018 at 7:55 PM, Bob Darlington  wrote:
> I bought some of the Furuno GT-8736 boards for $35 a pop, qty 1 (or 2 as
> was the case).  And was quoted at $26.91 a pop if I buy 100.   If there's
> interest, I'm happy to coordinate a group buy at cost.  Just paid off that
> credit card yesterday so why not?   If there are more desirable boards from
> Furuno, let me know and I'll see what I can do.
>
> -Bob
>
> On Thu, Feb 15, 2018 at 3:59 AM, ew via time-nuts 
> wrote:
>
>> Talking about Furuno has any one looked at the GT-87. I have known about
>> it for years but found no way to buy some now DigiKey has them for $ 100,
>> Buerklin in Germany for half that price. Saw tooth is +- 1.7 nsec we are
>> not going to bother with correction. We are in the process to lay out a
>> board any recommendations are appreciated
>> Bert Kehren
>>
>> In a message dated 2/15/2018 12:39:48 AM Eastern Standard Time,
>> hol...@hotmail.com writes:
>>
>>
>>  I just did a small adapter board that converts the 2x5 pin 2mm header on
>> the Furuno GT-8031 to a 1x9 pin 0.1" connector with the pinouts of the
>> Adafruit Ultimate GPS. There a couple of minor pin differences... the
>> Adafruit FIX pin is not used and the Adafriuit 3.3VREG output pin is used
>> as the Furuno antenna power connection. The Furuno can be soldered to the
>> board or a female connector could be installed.
>>
>> I'm getting ready to order a few boards. If interested, contact me off
>> list.___
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>>   1 Attached Images
>>
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Re: [time-nuts] Does a frequency counter locked to GPS need to "warm up"?

[Azelio Boriani]

No warmup needed if the counter switches to the external reference. If
the counter uses the external reference to lock the internal one then
it is better to wait until the internal one is stable, maybe the
counter has a standby mode where it appears powered off but the
internal reference is active (usually an ovenized reference). For the
best performance (stability of trigger levels, input amplifiers and so
on) it is better to warmup the whole counter always.

On Thu, Feb 8, 2018 at 8:33 AM, Chris Wilson  wrote:
>
>
>   08/02/2018 07:31
>
> Does  a  frequency  counter  connected  to a permanently running (Trimble 
> Thunderbolt) GPS
> disciplined frequency standard need to warm up after switch on before 
> readings settle?
> Just curious, thanks.
>
> --
>Best Regards,
>Chris Wilson.
> mailto: ch...@chriswilson.tv
>
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Re: [time-nuts] GPS Jamming

[Azelio Boriani]

Wasn't the selective availability an accuracy degradation system?

On Mon, Jan 29, 2018 at 10:55 AM, Adrian Godwin  wrote:
> What a pity nobody thought to include an accuracy degradation system into
> GPS itself, for use when you don't want the enemy to benefit from it.
>
> And how odd to show off your secret jamming technology in a major scheduled
> exercise, so the Bad Guys can study it.
>
>
> On Fri, Jan 26, 2018 at 2:57 PM, Gary Neilson  wrote:
>
>> Don't know if this has be posted before or not. Also don't know if this
>> will affect timing info.
>>
>> GPS Jamming > gps-in-the-western-u-s-for-largest-ever-red-flag-air-war-exercise>
>>
>> I am on the very edge of their coverage map.
>>
>> Gary
>>
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Re: [time-nuts] PBS, Tue evening, The Secret of Tuxedo Park

[Azelio Boriani]

>>...he would wear it on the outside of his wrist instead of the inside, so 
>>that gravity changed the rate of the tuning fork...
Sort of manual turbillon...

On Tue, Jan 16, 2018 at 4:04 PM, Tom Van Baak  wrote:
> I can't stress enough how important Loomis was to the history of precise 
> timekeeping in early radio, telephone, pendulum clock, quartz oscillator era. 
> And for those of us who still have Loran-C receivers can thank him (Loomis 
> Radio Navigation -> LRN -> Loran).
>
> So I highly recommend the 2003 book "Tuxedo Park" by Jennet Conant:
> http://www.simonandschuster.com/books/Tuxedo-Park/Jennet-Conant/9780684872889
>
> Our kind of guy. In the "Palace of Science" chapter she writes: Loomis would 
> remain a "time nut" for the rest of his life, according to Luis Alvarez, who 
> recalled that Loomis always wore "two Accutrons--one on his right wrist and 
> one on his left wrist." He would check them every day against WWV (the 
> standard frequency broadcasting station of the National Bureau of Standards), 
> and if one was gaining a half second on the other, he would wear it on the 
> outside of his wrist instead of the inside, so that gravity changed the rate 
> of the tuning fork and the two watches tracked each other, and WWV, "to 
> within less than a second a day."
>
>
>
> Some other Loomis links of interest:
>
> https://en.wikipedia.org/wiki/Alfred_Lee_Loomis
> https://en.wikipedia.org/wiki/LORAN
> https://timeandnavigation.si.edu/navigating-air/navigation-at-war/new-era-in-time-and-navigation/alfred-loomis
> http://www.ob-ultrasound.net/loomis.html
> http://leapsecond.com/pages/loomis/
>
>
> And the clever way to do time transfer and compare precision clocks to 1 ms 
> in the 1930's...
>
> http://leapsecond.com/pend/shortt/1931-RAS-Precise-Measurement-Time-Loomis.pdf
>
>
> Also the classic "The Evolution of the Quartz Crystal Clock" by Warren A. 
> Marrison:
>
> https://ieee-uffc.org/about-us/history/uffc-s-history/the-evolution-of-the-quartz-crystal-clock/
> via https://ieee-uffc.org/about-us/history/uffc-s-history/
> and original at https://archive.org/details/bstj27-3-510
>
>
> If someone knows how to record any time/clock/navigation parts of PBS show 
> for non-US viewers let me know, off-list.
>
> /tvb
>
>
> - Original Message -
> From: "Hal Murray" 
> To: 
> Cc: "Hal Murray" 
> Sent: Tuesday, January 16, 2018 1:42 AM
> Subject: [time-nuts] PBS, Tue evening, The Secret of Tuxedo Park
>
>
>> (Sorry for the clutter to those of you outside the US.)
>>
>> http://www.pbs.org/wgbh/americanexperience/films/secret-tuxedo-park/
>> Two of the shorts mentions time.
>>
>> Many thanks for the Tuxedo Park book suggestion many years ago.
>>
>>
>> --
>> These are my opinions.  I hate spam.
>>
>
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Re: [time-nuts] Oscilloquartz OSA-4350 GPSDO

[Azelio Boriani]

The GPS receiver featured in the picture at

is a Motorola UT+.
My OSA4351 has a Motorola GPS receiver.

On Sun, Dec 31, 2017 at 7:43 PM, Gregory Beat  wrote:
> Oscilloquartz OSA-4530 GPSDO : 2-page product brochure
> http://syncarchitect.com/downloads/PDF_0018_453X.pdf
>
> Magnus Danielson picked one up five years ago, but didn’t find the software.
> https://www.febo.com/pipermail/time-nuts/2012-December/073331.html
>
> The OSA 4530 is a three board design, with bottom board being power and 
> control board, middle board being OCXO, output buffer, PPS and time measure, 
> and third board the Navicom GPS receiver board.
>
> Features an OSA 8663-B6SG double-oven SC-cut, a Navicom GPcore Sync 15 GPS 
> receiver, based on the Zarlink GP4020 chip, and a RAKON 10 MHz reference.
>
> Are you going to swap out the DC-DC module?
>
> Oscilloquartz SA
> Avenue des Pâquiers 1
> 2072 Saint-Blaise
> Switzerland
>
> SyncView Plus
> http://oscilloquartz.com/files/1403600295-2014-06_DS_OSASyncViewPlus.pdf
>
> greg
> Sent from iPad Air
> ==
> From: Mark Sims 
> To: "time-nuts@febo.com" 
> Subject: [time-nuts] Oscilloquartz OSA-4530 GPSDO
>
> The 4530 GPSDO arrived, but was dead.   Looks like the DC-DC that makes 5V is 
> bad.   The seller sent a replacement unit that seems to be working.
>
> Also a list member sent me a copy of the 4531 manual.  The commands listed 
> are very similar to the Star-4 commands.  But sending any of the 4531 
> commands to the 4530 returns an "invalid command" response... strange, the 
> 4531 manual sort of implies most should work with the 4530.
>
> So, I'm still looking for a 4530 manual or the OSA control software...  does 
> anybody know where I can find it?
>
> --
>
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Re: [time-nuts] IEEE Spectrum - Dec 2017 - article on chip-scale atomic frequency reference

[Azelio Boriani]

Is that a Trimble Thunderbolt? Is there a way to compute the uncertainties?

On Sun, Dec 10, 2017 at 2:42 AM, Tom Holmes  wrote:
> Mark...
> You're place really moved a foot in 48 hours? Impressive and scary!
>
> From Tom Holmes, N8ZM
>
>> On Dec 9, 2017, at 8:19 PM, Mark Sims  wrote:
>>
>> Which gets real fun with things like solid earth tides getting involved.   
>> Lady Heather can now calculate and plot solid earth tides.   Over the last 
>> 48 hours my place moved up/down 315 mm and gravity changed 186  microgals... 
>> and that was a rather stable period.
>>
>> --
>>
>>> A 1 meter change in elevation corresponds to a frequency offset of about 
>>> 1e-16. So for 1e-18 levels of performance you "only" need to know g, or 
>>> your elevation to 1 cm accuracy.
>> 
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Re: [time-nuts] Next upgrade

[Azelio Boriani]

...and what about shrinking the 16bit over the fraction of the EFC
range that, for example, the OCXO will be using for the next 5 years?
16bit over 10V are as 20 (a little less, OK) over 1V, if I can use my
16bit over 1V for the next 5 years, when the DAC will be near full
scale I can "trim" the aging.

On Sun, Nov 26, 2017 at 6:25 PM, Bob kb8tq  wrote:
> Hi
>
> If you sum two DAC’s without any sort of feedback, you get problems when the
> “coarse” dac is changed. You have no way to know the step size of the coarse
> dac to (say) 20 bit precision.
>
> As an example : If you are after 20 “good” bits, you might overlap
> them at the 10 bit point on the coarse dac. That would give you 22 bits on the
> summed output. It would give you enough extra bits to take care of any odd
> things that might be going on. You only have 1/1024 of the total range before
> you must tune the coarse dac. Even with a good set of parts, you *will* be
> doing coarse tuning.
>
> Bob
>
>> On Nov 26, 2017, at 12:13 PM, Azelio Boriani  
>> wrote:
>>
>> Is summing a "fine tune" 16bit DAC and a "coarse tune" 16bit (or less)
>> DAC with an op-amp not good enough?
>>
>> On Sun, Nov 26, 2017 at 5:53 PM, Bob kb8tq  wrote:
>>> Hi
>>>
>>> Each time I’ve tried the method in the app note, there has been a tone in 
>>> the output
>>> spectrum at the sample rate of the ADC. I’ve never found a way to do the 
>>> grounding
>>> that eliminates it. The tone is large enough to show up as a spur on a 
>>> “typical” OCXO
>>> when it goes into the EFC port.
>>>
>>> Bob
>>>
>>>> On Nov 26, 2017, at 8:56 AM, Ole Petter Rønningen  
>>>> wrote:
>>>>
>>>> I guess everyone has seen this, but Linear has a nice appnote «A Standards 
>>>> Lab Grade 20-Bit DAC with 0.1ppm/°C Drift»
>>>>
>>>> http://cds.linear.com/docs/en/application-note/an86f.pdf
>>>>
>>>> Ole
>>>>
>>>>> 26. nov. 2017 kl. 13:50 skrev Magnus Danielson 
>>>>> :
>>>>>
>>>>> Hi
>>>>>
>>>>>> On 11/26/2017 02:26 PM, Attila Kinali wrote:
>>>>>> Though, if you have a decent 16bit DAC and want to get to 18bit,
>>>>>> that's fairly simple using delta-sigma modulation... if you can live
>>>>>> with a low pass fillter after the DAC. But the DNL will be the limiting
>>>>>> factor here (unless you use some special techniques) and the (absolute) 
>>>>>> INL
>>>>>> will not get better, for obvious reasons.
>>>>>
>>>>> I needed 19 bit rather than 16 bit, so I implemented an interpolation 
>>>>> scheme. A first degree sigma-delta would also be possible, but for low 
>>>>> ratios what I did was more efficient.
>>>>>
>>>>> A first degree sigma-delta is fairly simple thought.
>>>>>
>>>>> The trick is that you want to push the noise high up so it becomes 
>>>>> trivial to filter, then the filter will not be hard to design and won't 
>>>>> be low enough to cause PLL instability and implementation troubles.
>>>>>
>>>>> Cheers,
>>>>> Magnus
>>>>> ___
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Re: [time-nuts] Next upgrade

[Azelio Boriani]

Is summing a "fine tune" 16bit DAC and a "coarse tune" 16bit (or less)
DAC with an op-amp not good enough?

On Sun, Nov 26, 2017 at 5:53 PM, Bob kb8tq  wrote:
> Hi
>
> Each time I’ve tried the method in the app note, there has been a tone in the 
> output
> spectrum at the sample rate of the ADC. I’ve never found a way to do the 
> grounding
> that eliminates it. The tone is large enough to show up as a spur on a 
> “typical” OCXO
> when it goes into the EFC port.
>
> Bob
>
>> On Nov 26, 2017, at 8:56 AM, Ole Petter Rønningen  
>> wrote:
>>
>> I guess everyone has seen this, but Linear has a nice appnote «A Standards 
>> Lab Grade 20-Bit DAC with 0.1ppm/°C Drift»
>>
>> http://cds.linear.com/docs/en/application-note/an86f.pdf
>>
>> Ole
>>
>>> 26. nov. 2017 kl. 13:50 skrev Magnus Danielson :
>>>
>>> Hi
>>>
 On 11/26/2017 02:26 PM, Attila Kinali wrote:
 Though, if you have a decent 16bit DAC and want to get to 18bit,
 that's fairly simple using delta-sigma modulation... if you can live
 with a low pass fillter after the DAC. But the DNL will be the limiting
 factor here (unless you use some special techniques) and the (absolute) INL
 will not get better, for obvious reasons.
>>>
>>> I needed 19 bit rather than 16 bit, so I implemented an interpolation 
>>> scheme. A first degree sigma-delta would also be possible, but for low 
>>> ratios what I did was more efficient.
>>>
>>> A first degree sigma-delta is fairly simple thought.
>>>
>>> The trick is that you want to push the noise high up so it becomes trivial 
>>> to filter, then the filter will not be hard to design and won't be low 
>>> enough to cause PLL instability and implementation troubles.
>>>
>>> Cheers,
>>> Magnus
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
>>> To unsubscribe, go to 
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
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Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[Azelio Boriani]

With 197dB of path attenuation and, say, 1W or 2W of transmitter
power, I think that a modest antenna is insufficient. The usual yagi
array for this distance is made by 8 27-element antennas like this:


On Sat, Nov 18, 2017 at 12:54 AM, Bob kb8tq  wrote:
> Hi
>
>
>> On Nov 17, 2017, at 4:26 PM, Patrick Barthelow  wrote:
>>
>> From me, Pat a newbie, second post:
>>
>> A new project, STEM opportunity.   A STEM/CitizenScience/Ham Space Science
>> project. Kids welcome.
>> In formative stages so this is for internal discussion, not for public
>> announcements yet.
>> Will do a frequency measurement of a Cubesat at about 437 mhz that will
>> orbit the Moon in 2018.
>> Can be received by modest yagi antennas while orbiting the moon.
>
> That sounds like a pretty high ERP … Of course your definition of a modest 
> antenna
> may not be quite the same as mine :) Consider that there *are* SNR 
> implications
> when you get into your accuracy requirements below.
>
>> Challenge is to get/use/build precision frequency references and counters,
>> and measure the carrier frequency.Cesium, Rubidium,  MASER, GPS based,
>> commercial standards, and their derivations all welcome.
>> Have found 4 (and More)  more hydrogen line masers in diverse locations
>> around the world, who wish to participate.
>> USA, Netherlands, South Africa, Australia, Mexico, and other locations have
>> expressed interest.
>>
>> I am a member of  Team Alpha Cubesat.  We and some other teams are in the
>> NASA CUBEQUEST challenge.  Launching next year a 6u  cubesat to lunar
>> orbit.  I am not an expert at the freq measurement aspect of this, so, I am
>> a Newbie. With tons of questions, but  I was surprised how quickly a check
>> of the world's Hydrogen line MASERS got many to offer to come on board.
>> MASER is overkill, but that is OK.
>
> The MASER is a cute device. It is not an accurate device by it’s self. It is a
> very *stable* device. Yes, that is a subtle distinction. In this case I think 
> it is
> a pretty important one.
>
>>  The Chief Scientist of the project is
>> in the USA and wants to make measurements to the HZ level, at 437 mhz so
>> with MASERS and Cesium, Rubidium we are overkill but it could generate
>> STEM/Citizen Science participation.  That is what we are doing.  So the
>> satellite will be on 437.5 mhz  plus  minus doppler.  We have to measure
>> its received freq to 1 HZ or less.
>
> Ok, 1 Hz at 437.5 MHZ is roughly 2 ppb. That is pretty much “slam dunk” 
> accuracy
> with a GPSDO. Much easier to obtain and set up in a school environment. The
> key will be orbit estimation for the +/- doppler part of it.  Orbit 
> estimation is not
> quite a slam dunk sort of thing. The GPSDO would also give accurate location.
> Even with good orbit data, the solution still requires a good location 
> estimate.
>
>>   So I talked to the chief scientist,
>> and we decided to go with a public STEM related program
>
> I’ve been down the road (from scratch to running) on STEM competitions. The
> KISS principle is one to keep in mind. At the same time you *do* want a topic
> that presents a challenge.
>
>>  with it. [PLEASE
>> DO NOT GO PUBLIC YET
>
> This *is* a public list, it’s “out” now.
>
>> this is confidential for now.] Announcement of a
>> competition for anyone to measure the frequency of the sat as it is in moon
>> orbit.  So I decided to check with  about 5 geographically diverse located
>> MASERS. ( Australia,  South Africa, UK, Holland, Mexico and USA,  and got
>> or am getting buy-in from them to make the measurement.  I was surprised
>> they did not just say go away... a half million dollar MASER is, or should
>> be busy with similar but necessary measurements from paying customers.
>> Overkill, I admit, but it is a chance for Citizen Science publicity,
>> Popular Science, STEM, etc..
>>
>>
>> Anyway I got a bunch of MASERS  to participate and will develop a website
>> for people to measure the freq and send in their "answer".  We will have
>> (are looking for) sponsors that will pay prizes or wall paper awards,  for
>> very close accurate measurements.
>> This is like a modern day Frequency Measurement Test that ARRL did years
>> ago.  I will in fact call ARRL to see if they want to play in this.  I will
>> CC others to see if they want to play.  Other frequency references used may
>> be commercial variations of
>> Cesium Beam and Rubidium references.  But the King Kong in accuracy is the
>> MASER.  I got to learn a bit about the MASER they had at Arecibo when I was
>> there.   And now know a school in Europe a Technical Instrumentation
>> school, that offers a project to build a Hydrogen Line Maser using modern
>> simpler, cheaper methods and hardware.
>>
>> Arecibo may play on this event next year.   So, you only need modest yagis
>> to pick up the Sat at moon distances  on 437.5 mhz  should be fun...
>> The Goldstone MASER; above:
>>
>>>
>>> https://www.nist.gov/pml/time-and-frequency-

Re: [time-nuts] Interpreting and Understanding Allen Deviation Results

[Azelio Boriani]

If you have only one GPSDO, a coaxial cable is your best friend to
test the performance of the counter in time-interval mode. If you have
two GPSDOs, the Segal's law apply:
<https://en.wikipedia.org/wiki/Segal%27s_law>, better go directly for
three.

On Thu, Nov 16, 2017 at 7:18 PM, Bob kb8tq  wrote:
> Hi
>
> The exact software command used depends on the GPSDO you have. How you send 
> the command to
> the GPSDO depends a bit on the driver software you are running. Not all 
> GPSDO’s or modules have
> cable delay. All the ones I run do have the feature. Normally it comes set to 
> some random default setting
> like 60 ns. I typically take one GPSDO and deliberately make it the odd one 
> out of the group. By making
> the offset large (say a microsecond or two) it’s easy to spot the “false 
> ticker” in the group if things get
> mixed up.
>
> Assuming you set the odd GPSDO to be early (which could be cable delay + or 
> cable delay -) it would
> go to input A on the counter. That would be the start channel. Input B would 
> come from any normal
> pps signal and it would be the stop channel. You can of course do this other 
> ways that work just as
> well.
>
> Again - this is for looking at a pps relative to a GPSDO using a 5335 or 
> similar counter.
>
> Bob
>
>> On Nov 16, 2017, at 12:05 PM, Jerry  wrote:
>>
>> Bob,
>>
>> I am also a time newbie... how do you adjust this in software?  For time 
>> interval as discussed below, the unaltered GPSDO output goes to A and how do 
>> you create the GPSDO delay for B without a physical coax delay?  Any change 
>> in GPSDO cable delay setting will affect A and B the same.  Sorry if this is 
>> a stupid question
>>
>> Jerry, NY2KW
>>
>> -Original Message-
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob kb8tq
>> Sent: Thursday, November 16, 2017 11:15 AM
>> To: Discussion of precise time and frequency measurement 
>> Subject: Re: [time-nuts] Interpreting and Understanding Allen Deviation 
>> Results
>>
>> Hi
>>
>> Yes, that’s exactly what I’m saying. You just use the software rather than 
>> dragging around a big hunk of coax. It makes it easy to get one pps into the 
>> “that’s way more than I need” range.
>> With the coax approach, is 50NS enough? Might 100NS be needed? Is there a 
>> 231NS case?.
>> I’ve spent a *lot* of time finding those cases in the middle of long data 
>> runs ….
>>
>> Bob
>>
>>> On Nov 16, 2017, at 10:37 AM, Jerry  wrote:
>>>
>>> Bob,
>>>
>>> Do you mean then you do not need to put a physical long length of cable for 
>>> the delay, just do it in software or do you do both?
>>>
>>> Jerry, NY2KW
>>>
>>> -Original Message-
>>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob
>>> kb8tq
>>> Sent: Thursday, November 16, 2017 9:58 AM
>>> To: Discussion of precise time and frequency measurement
>>> 
>>> Subject: Re: [time-nuts] Interpreting and Understanding Allen
>>> Deviation Results
>>>
>>> Hi
>>>
>>> One “cute” thing to do when looking at GPSDO’s or GPS modules is to use the 
>>> “cable delay” setting. It will allow you to move the pps of one unit 
>>> relative to the pps of the other one. You then can be sure of which pps 
>>> happens first. That makes the A to B measurement much easier to analyze.
>>>
>>> Short intervals also can lessen the impact of the time base accuracy in the 
>>> counter ( you always are measuring a microsecond or so to a nanosecond 
>>> resolution). Indeed there are other issues (like jitter) that still are an 
>>> issue.
>>>
>>> Bob
>>>
>>>> On Nov 16, 2017, at 4:10 AM, Azelio Boriani  
>>>> wrote:
>>>>
>>>> As already stated here, the best measurement mode is the
>>>> time-interval mode. The 5335A is a 2ns single-shot resolution
>>>> counter. Use the PPS output from the GPSDO, route it to the A (start)
>>>> input and to a coaxial cable used as a delay line (10m, 50ns, should
>>>> be enough). The other end of the cable into the B input (stop),
>>>> select the time interval mode TIME A -> B. Let the internal reference
>>>> clock the counter. Set trigger levels and the various parameter to
>>>> get stable readings and collect your data.
>>>>
>>>> On Thu, Nov 16, 2017 at 3:59 AM, Mike Garvey  wrote:
>>>>> Could you post some phase plots

Re: [time-nuts] Interpreting and Understanding Allen Deviation Results

[Azelio Boriani]

As already stated here, the best measurement mode is the time-interval
mode. The 5335A is a 2ns single-shot resolution counter. Use the PPS
output from the GPSDO, route it to the A (start) input and to a
coaxial cable used as a delay line (10m, 50ns, should be enough). The
other end of the cable into the B input (stop), select the time
interval mode TIME A -> B. Let the internal reference clock the
counter. Set trigger levels and the various parameter to get stable
readings and collect your data.

On Thu, Nov 16, 2017 at 3:59 AM, Mike Garvey  wrote:
> Could you post some phase plots?  The data you show is not 1/tau and very 
> likely not white phase noise.
> Mike
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of CubeCentral
> Sent: Wednesday, November 15, 2017 11:12
> To: time-nuts@febo.com
> Subject: [time-nuts] Interpreting and Understanding Allen Deviation Results
>
> Greetings, time-nuts!
>
> After reading [ http://www.leapsecond.com/pages/adev/adev-why.htm ] I felt 
> that I better understood how an Allan Deviation is calculated and endeavored 
> to try an experiment.  It should be noted that I have a hobbyist-level 
> understanding of the concepts described and tools used below.  If my thinking 
> or test methodology is incorrect, please let me know so that I might learn 
> something.
>
> A GPSDO with a 10MHz output was run into the EXT TIME BASE input on the back 
> of an HP5335A.
> Then, the TIME BASE OUT on the back was run to the A input on the front of 
> the HP5335A.
> My intention was to characterize the performance of the HP5335A counter 
> itself so that I might understand better future plots involving other GPSDO 
> and the counter's internal clock (which was bypassed for this test).
>
> The settings of the HP5335A were as follows:
> Gate Mode: Normal
> Cycle: Normal
>
> A Input --
> Trigger Adjust: Full left to 'Preset' detent
> Z select  =  in   =  50ohm
> x10 ATTN  =  in   =  x10 ATTN   (should have been out/off?)
> Slope =  out  =  up
> AC=  in   =  AC coupled
> COMA  =  out  =  Not ComA
> AutoTrig  =  out  =  Not Auto Tiggered (should have been in/on?)
>
> (Tangentially, if someone has a good 'primer' or how-to resource detailing 
> Universal Counter operation, showing when/why/how to set the knobs in certain 
> situations it would be welcome!)
>
> I then set the Time Lab V1.29 software to repeatedly acquire data for 12 
> hours, starting the next test as soon as I could.  This means that, normally, 
> a test was run during the day for 12 hours, and then overnight for
> 12 hours.
>
> The results are shown here:  [ https://i.imgur.com/0sMVMfk.png ]  The 
> associated .TIM files are available upon request.
>
> So, now we get to the heart of the matter and the questions this test and 
> results have raised.
> I am trying to understand what the data is telling me about the test, and 
> therefore the character of the counter.
>
> 1)  Why are the plots a straight line from ~0.25s until ~100s?
> 2)  Why, after falling at the start, do the plots all seem to go back up from 
> ~100s to ~1000s?
> 3)  What do the "peaks" mean, after the plot has fallen and begin to rise 
> again?
> 4)  Why is the period from ~1000s to ~1s so chaotic?
> 5)  The pattern "Fall to a minimum point, then rise to a peak, then fall 
> again" seems to be prevalent.  What does that indicate?
> 6)  Why does that pattern in question (5) seem to repeat sometimes?  What is 
> that showing me?
>
> And finally, some general questions about looking at these plots.
> a)  Would a "perfect" plot be a straight line falling from left to right?
> (Meaning a hypothetical "ideal" source with perfect timing?)
> b)  Is there some example showing plots from two different sources that then 
> describes why one source is better than the other (based upon the ADEV plot)?
> c)  I believe that if I understood the math better, these types of plots 
> would be more telling.  Without having to dive back into my college Calculus 
> or Statistics books, is there a good resource for me to be able to understand 
> this better?
>
> Lastly, thank you for your patience and for keeping this brain-trust alive.
> I am quite grateful for all the time and energy members pour into this list.
> The archives have been a good source of learning material.
>
> -Randal (at CubeCentral Labs...)
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
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Re: [time-nuts] OCXO Vectron 218Y44442

[Azelio Boriani]

The crystal is socketed: the problem might be the socket.

On Tue, Oct 17, 2017 at 1:56 AM, Bob kb8tq  wrote:
> Hi
>
> Welcome to the 1990’s … that’s an *old* design. Since Vectron kept building 
> same / same
> (if you ordered it that way)  who knows when it was built.
>
> Bob
>
>> On Oct 16, 2017, at 4:10 PM, Vlad  wrote:
>>
>>
>> Hello,
>>
>> I am wandering if anybody observe the behavior for OCXO, when its stop to 
>> reproduce the signal, and the only way to return it back to business is 
>> little mechanical stress.
>>
>> I have TWO of such OCXO. One of them is Austron 11.2 Mhz. And another one is 
>> Vectron model 218Y4442 9.8304Mhz
>>
>> In case with Vectron, I even disassemble it (to whom who brave here is a 
>> pictures):
>>
>> http://www.patoka.ca/Vectron-218Y2/
>>
>> Then as I connect it to the PS, I realize it start to reproduce the signal 
>> again ! Before this it was nothing ! I tried different PS before to open 
>> this "can" as a last resort.
>>
>> For the Austron - I didn't disassemble it. Instead I just kick it a little 
>> bit. And immediately after that, it start to produce the signal !
>>
>>
>> --
>> WBW,
>>
>> V.P.
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Re: [time-nuts] NTP linked PC clock is slightly ahead of Lady Heather GPS time

[Azelio Boriani]

For those who are in Europe there is the PTB (Physikalisch-Technische
Bundesanstalt, the German Federal institute of Physics and Technology)
service to check the PC's time:


On Wed, Oct 11, 2017 at 5:25 PM, Mike Cook  wrote:
> I have Win7-64 and my LH and system time are the same (with a very short 
> delta of < 0.2s probably due to their respective window update time).
> I use the Meinberg disturb of NTP. My client’s offset from the paris 
> observatory is less than a millisec.
>
> Maybe you should check your NTP status and see what offset you get from a 
> known good source with ntpdate -b -d .
>
>
>
>
>> Le 11 oct. 2017 à 13:29, Chris Wilson  a écrit :
>>
>>
>>
>>  11/10/2017 12:24
>>
>> Probably   a   simple  answer,  but I am curious as to why my PC clock
>> which  is set by NTP on Windows 7 64 bit OS is ahead of Lady Heather's
>> time,  locked  to  a  Trimble  Thunderbolt  by  about  half  a  second
>> (guesstimate..)  I  caught  a screen shot of the discrepancy just now,
>> it's at http://www.gatesgarth.com/time.jpg
>>
>> I use NTP for low signal WSPR transmissions and a second out isn't the
>> end  of  the  world,  if  indeed  something  IS out. More academic than
>> problematic, thanks
>>
>> --
>>   Best Regards,
>>   Chris Wilson.
>> mailto: ch...@chriswilson.tv
>>
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>
> "The power of accurate observation is commonly called cynicism by those who 
> have not got it. »
> George Bernard Shaw
>
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Re: [time-nuts] Weird GPSDO behavior - update

[Azelio Boriani]

Very interesting: can you flash the firmware? I'm aware (until now)
that there is no firmware around and no firmware flashing tool for
these GPSes. Maybe the flashing tool(s) is(are) suitable for the
Thunderbolt too.

On Wed, Oct 4, 2017 at 10:58 AM, robkimberley
 wrote:
> Is there any way you can run it on batteries? The 8AM glitch still makes me 
> think it is power line problem.Rob
>
>
> Sent from my Samsung Galaxy smartphone.
>  Original message From: Skip Withrow  
> Date: 03/10/2017  19:15  (GMT+00:00) To: time-nuts  
> Subject: [time-nuts] Weird GPSDO behavior - update
> Hello Time-Nuts,
>
> Well, I think I know a little more about my GPSDO problem, but
> probably have more questions now than before.  Thanks for all the
> replies to the first post with thoughts and suggestions.
>
> I first tried restarting Lady Heather and doing a cold boot on the
> NTGS50AA (then entering the same disciplining values). Same behavior.
>
> I let it run over the weekend and the same behavior happened on
> Saturday and Sunday morning.
>
> So, yesterday (Monday morning) I changed the gain to the gain of the
> oscillator (.0072Hz/V), damping to 1.2, and time constant to 900s.  On
> the attached PRS10-2 plot you can see that it quickly settled.  This
> morning, it looks like all is well from the plot (about an hour before
> the furnace kicks in at the right of the plot).  HOWEVER, when the
> plot is expanded there is still funny business going on with the DAC
> control voltage at the same time of day.  I just think the changed
> parameters limit the disturbance.  The expanded plot is the attached
> PRS10-1.
>
> At this point I'm beginning to think that the NTGS50AA is the issue,
> but there are lots of questions left.
>
> 1. There are various version of the NTBW50AA/NTGS50AA GPS/operating
> firmware.  Mine is 10.3 and I notice that it has the LH 'ro'
> designation (as does the 10.4 version).  The 10.5 version does not
> give the LH ro notice.  Maybe it behaves better with the disciplining?
>  I will have to give a 10.5 a try.
>
> 2. Why does the glitch occur at 8am in the morning?  Will have to try
> powering the NTGS50AA up at different times and see it the glitch
> moves around.
>
> 3. Which disciplining parameters are affected by this glitch and which are 
> not?
>
> 4. Have other people seen this same behavior?  Does it happen on
> Thunderbolts too?
>
> I'll update again when I have more data.
>
> Regards,
> Skip Withrow
>
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Re: [time-nuts] Fw: Skytraq / GPS Almanac

[Azelio Boriani]

Maybe this can be useful:



On Wed, Sep 27, 2017 at 5:58 AM, Scott Newell  wrote:
> At 05:20 PM 9/26/2017, Tom Van Baak wrote:
>>
>> An interesting note from Said, below...
>> I've sent a couple of queries out to GPS professionals.
>> Feel free to comment if you have concrete information that would help.
>> Also, if during the past week any of you were logging almanacs or
>> continuously recording the 50 bps raw data from any GPS/SV, please let me
>> know.
>
>
> I have ublox LEA-6T data logged from 18:30 on 8-26 through 05:30 on 9-18. It
> includes the RXM-SFRB subframe buffer messages. Would that be of any help,
> or did I shut it off too early?
>
> --
> newell N5TNL
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Re: [time-nuts] DAC performance [WAS: Papers on timing for lunar laser ranging]

[Azelio Boriani]

This implies that in a Rb or Cs there is not a voltage reference source?

On Mon, Jul 17, 2017 at 3:49 AM, Bob kb8tq  wrote:
> HI
>
> This is a limitation on an OCXO based GPSDO. That’s really the bottom line 
> here.
> It’s a limitation in an OCXO based part, but not in one based on an Rb or a 
> Cs. If
> the added component costs far more than a Cs, it’s not an answer.
>
> Bob
>
>> On Jul 16, 2017, at 7:25 PM, Chris Albertson  
>> wrote:
>>
>> What about josephson standards?   After all, this is "Time Nuts" and we are
>> allowed to propose silly-complex solutions to simple problems if it
>> improves performance even a little.
>>
>> But seriously I thought the issue of making a perfect voltage standard was
>> solved because the Volt is defined to be whatever the Josephson array
>> produces. Yes expensive because to runs at nearly absolute zero.
>>
>> On Sun, Jul 16, 2017 at 4:10 PM, Bob kb8tq  wrote:
>>
>>> Hi
>>>
 On Jul 16, 2017, at 6:33 PM, Richard (Rick) Karlquist <
>>> rich...@karlquist.com> wrote:



 On 7/16/2017 1:51 PM, Bob kb8tq wrote:
> Hi
> One gotcha with any ADC or DAC is going to be the reference. There, you
>>> are in the same
> “get what you pay for” dilemma. Stable and noisy, can do. Quiet and not
>>> very stable, can do.
> Both stable and quiet, not so easy if you want it cheap.
> Noise can also be the sigma delta ADC’s weak point. Even at slow rates,
>>> some of them need
> a lot of averages to quiet down.

 The reference initially used in the E1938A turned out to be too
>>> noisy/unstable.  It was non trivial to find an upgrade.  The
 HP Smart Clocks of 20 years ago were limited in their performance
 by the reference used.

 Has there been much improvement in references in the intervening
 20 years?
>>>
>>> They still don’t seem to have the hysteresis problem licked. Yes, you can
>>> do an oversized reference
>>> and take care of the issue. More or less that’s what you would have done
>>> 20 years ago.
>>>
>>> Bob
>>>
>>>

 Rick N6RK
>>>
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>>>
>>
>>
>>
>> --
>>
>> Chris Albertson
>> Redondo Beach, California
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Re: [time-nuts] WWVB & Eclipse

[Azelio Boriani]

Also DGPS stations logging:


On Thu, Jul 13, 2017 at 10:35 PM, Brooke Clarke  wrote:
> Hi:
>
> There's a massive experiment relating to the strength of WWVB and a
> transmitter in Dixon California.
>
> https://www.washingtonpost.com/news/speaking-of-science/wp/2017/07/12/a-massive-atmospheric-experiment-is-planned-for-august-solar-eclipse/?utm_term=.4d7101b869f6
>
> http://eng.umb.edu/~eclipsemob/index.php
> 
>
> http://www.hamsci.org/sites/default/files/publications/2017_IES_Liles.pdf
> This article says Dixon may transmit at 55.1 and 135.95 kHz.
>
> The EclipseMob receiver works with a smart phone acting as an SDR. as well
> as the source of it's position and the date-time of observation.
>
> There is a parallel study based on ham radio WSPRNet and Reverse Beacon
> Network.
> http://hamsci.org/
>
> Is there a study based on GPS observations?
>
> --
> Have Fun,
>
> Brooke Clarke, N6GCE
> http://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
>
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Re: [time-nuts] Fluke PM6681 'fault' or 'characteristic'?

[Azelio Boriani]

The assumption is that you are using the time interval measurement or
phase measurement. The PM6681 datasheet says that the time interval
range is from 0ns and the phase range from -180 to 360 deg, usually it
is best to avoid the zero degrees zone. Say that your test is another
evidence that managing phase coincidence is not trivial.

On Tue, May 30, 2017 at 4:54 AM, Ed Palmer  wrote:
> I was comparing my Sulzer 2.5 to my Efratom FRT and saw something very odd.
> I don't know if my PM6681 has developed a fault or if I'm just measuring two
> oscillators that are good enought to show oddities in my measurement system.
>
> When the phase of the two signals drifts through zero, the measurement gets
> noisy.  The levels are very low as you can see in the attached graph.
> Without the averaging, you can barely see anything.  But the degradation is
> significant.
>
> I've checked my counter and can't find anything wrong.  Power supplies are
> clean.  I've worked through the voltage tests and adjustments in the service
> manual.  Nothing was out of adjustment and nothing improved.
>
> Does this look like a fault or is it just another reason to avoid phase
> wraps and the dead zone around zero degrees?
>
> Thanks,
> Ed
>
>
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Re: [time-nuts] Network Time Foundation

[Azelio Boriani]

Is the Network Time foundation the only one to have the NTP source
code? Is the Meinberg code (for example) a different one?

On Sat, May 13, 2017 at 1:02 PM, Magnus Danielson
 wrote:
> Fellow time-nuts,
>
> As I came back home from my NYC trip, I found a nice little package in the
> mail. It contained a T-shirt, pens and stickers. This is the added benefit
> from becoming individual member to the Network Time Foundation. I have made
> a donation prior to that.
>
> What does Network Time Foundation do? Well, they maintain some of the more
> important software that keep things running, including the NTPD code.
>
> Why do I contribute this way? They are grossly underfunded, and this is
> important stuff. While there are many ways to support the effort, I decided
> I do have monetary means to do this.
>
> It would be good if there where more companies supporting this activity too.
>
> Read up on it here:
> http://nwtime.org
>
> Cheers & 73,
> Magnus SA0MAD
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Re: [time-nuts] E1938 info regarding LEDs, push button switch and EFC voltage notation

[Azelio Boriani]

You can find schematics and various info here:




On Thu, May 11, 2017 at 3:47 PM, James Robbins  wrote:
> 1.  I have just acquired an E1938 and powered it up.  It seems to work.   I
> see that it has 4 blinking board LEDs (green, red, yellow, yellow) and a
> pushbutton switch at the end of the board opposite to the DB25 connector.
> Can anyone point me to either the schematic for the board or what these LEDs
> and pushbutton show or do?
>
>
>
> 2.  Also, there is an "EFC" voltage ("3.69v") marked in magic marker on top
> of the can.  Can anyone point me to where I can learn what, if anything,
> this voltage notation should be used for?
>
>
>
> Many thanks.
>
>
>
> Jim Robbins
>
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Re: [time-nuts] Frequency counter questions

[Azelio Boriani]

Up to the point that, to get 1milliHz resolution, you have to wait
1000 seconds (without the prescaler)? If you have a prescaler then it
will be N*1000 seconds...

On Sun, Apr 23, 2017 at 9:14 AM, Jerry Hancock  wrote:
> Hello,  I would like to find a person that would be able to answer some 
> frequency counter questions I have.
>
> Basically, I am thinking of building my own using one of the high end STM32F7 
> boards as the counter.  I would like it to count reliably to 12 digits (e.g. 
> 30,000,000.001x hz).  I am not worried about input conditioning as I have a 
> circuit that is suitable for my needs.  Most of my questions have to do with 
> using a prescaler on the front (divide by N where what is N) to get to the 
> desired resolution when using multiples of the PPS coming from my GPSDO.  
> Gate times could be as long as needed to get the resolution.  So what 
> prescaler do I need and what gate time is required are the first two 
> questions.  I suggest if someone is willing to help that they either reply 
> here with an email address or send a note to meters at hanler dot com.  This 
> is for my own non-commercial use.
>
> Thanks!
>
> Jerry
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Re: [time-nuts] phase/frequency data of real atomic clocks

[Azelio Boriani]

These data fles?
ftp://ftp2.bipm.org/pub/tai/data/2017/clocks/
every 5 days...

On Thu, Mar 2, 2017 at 12:18 AM, Magnus Danielson
 wrote:
> Hi,
>
> Have you considered the BIPM logs?
> While not very high sampling rate, it has lots of clocks over long time.
>
> Time to set something up again.
>
> Cheers,
> Magnus
>
>
> On 03/01/2017 11:36 PM, Attila Kinali wrote:
>>
>> Hi,
>>
>> I have been looking into noise and noise processes in the last couple
>> of months. Unfortunately, my seemingly simple question how to simulate
>> power law noise (1/f^a noise) properly led me to a wild goose chase
>> deep into the mathematical lala-land[1].
>>
>> In order to verify that I haven't gone completely off the track,
>> I would like to check some of the assumptions made with real data.
>> Hence I would like to ask, whether people here have continuous
>> phase/frequency data of real atomic clocks, and if I could get
>> a copy of those, together with a description how it was measured.
>>
>> I am looking for any kind of atomic clock and any kind of measurement.
>> The higher the sample rate and the longer the measurement the better,
>> but I will not be picky.
>>
>> If you know someone who has collected such data, any contact
>> information would also be helpful.
>>
>> Computer generated data does not work in this case, as I want to
>> verify that the assumptions made in the mathematical models
>> have a foundation in the real physical implementations.
>>
>>
>> Thanks in advance
>>
>> Attila Kinali
>>
>> [1] For those interested: If you think that calculus or stochastic
>> was difficult, imagine what their offspring "stochastic calculus"
>> looks like. Now add fractional calculus (half-integrals and
>> half-differentials, but nothing about fractals per se) to the
>> whole thing and you get fractals waiting around the corner.
>>
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Re: [time-nuts] advice

[Azelio Boriani]

Does gravity work differently under the surface? Maybe the redshift is
different going below the surface.



On Wed, Feb 22, 2017 at 3:22 AM, Bill Hawkins  wrote:
> In the confusion, I forgot that we are concerned with gravitational time
> dilation, not time of flight.
>
> The University of Minnesota has a lab about 2500 feet down in the Soudan
> mine. The following is their brief description:
>
> "The Soudan Underground Laboratory is a general-purpose science
> facility, which provides the deep underground environment required by a
> variety of sensitive experiments."
>
> Here's a link to the Soudan page:
>  https://www.physics.umn.edu/outreach/soudan/tour/
>
> Why is it named Soudan? The original miners found northern Minnesota to
> be extremely cold at times, so they named the town for someplace warm.
>
> Let me know if you are seriously considering this, and I will find a
> contact for you.
>
> Bill Hawkins
>
> -Original Message-
> From: Bill Hawkins [mailto:bill.i...@pobox.com]
> Sent: Tuesday, February 21, 2017 8:08 PM
>
> Neutrinos? Look up the OPERA experiment that measured neutrinos going
> faster than light. Turned out to be a loose optical fiber connector to a
> timing instrument.
>
> Fermi Lab has/had the MINOS experiment going 500 miles from Chicago to a
> mine in northern Minnesota. The generated neutrinos go through Wisconsin
> but are not noticed there, AFAIK.
>
> Bill Hawkins (Resident of Minnesota, but not a physicist, just a BSME)
>
>
> -Original Message-
> From: Bob Stewart
> Sent: Tuesday, February 21, 2017 1:48 PM
>
> Hi,
> Have you been in touch with Fermi-Lab?  They run a neutrino experiment
> with a receiver somewhere underground in Wisconsin.  At least that's
> what I recall.  I used to live next to a Physics professor who has a
> minor part in the experiment.  I'm not even sure what sort of data they
> collect there; whether it's time or something else.
>
> Bob Stewart (Not a physicist)
>
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Re: [time-nuts] Vintage Frequency Measurement

[Azelio Boriani]

1960's frequency counters


using a counting tube E1T different from the usual dekatron



On Wed, Feb 15, 2017 at 11:54 PM, Bob Camp  wrote:
> Hi
>
> Silly Canadians :)
>
> It seems that the term either has drifted a bit over the last 70 years or 
> there is indeed
> another British / US difference here.
>
> Bob
>
>> On Feb 15, 2017, at 5:00 PM, iovane--- via time-nuts  
>> wrote:
>>
>> This Canadian RCA apparatus was also called wavemeter but is a heterodyne
>> frequency meter and a signal generator.
>>
>> https://www.pa3esy.nl/military/us/meet/TE149/html/te149_set-gb.html
>>
>> iov
>>
>>
>>> Messaggio originale
>>> Da: "Tim Shoppa" 
>>> Data: 15/02/2017 17.29
>>> A: "Discussion of precise time and frequency 
>>> measurement"
>>> Ogg: Re: [time-nuts] Vintage Frequency Measurement
>>>
>>> For those of us who have to translate between the old "cps" and the modern
>>> "Hz", I found this handy conversion table on the web:
>>> http://www.aqua-calc.com/convert/frequency/hertz-to-cycle-per-second
>>>
>>> Tim N3QE
>>>
>>> [image: Inline image 1]
>>>
>>> On Tue, Feb 14, 2017 at 5:29 AM, Peter Vince 
>>> wrote:
>>>
 On 14 February 2017 at 04:23, Raj  wrote:

> I have a Marconi T.F. 643 C, in Megacycles !
>

 Ah, a sensible, descriptive name for the unit.  Some of these modern units
 really do Hert(z) :-)

 Peter
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>>
>>
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Re: [time-nuts] Lost Calibration on CNT-81/PM-6681

[Azelio Boriani]

It seems that "normal mode" is not a mode: from the operator's manual:

SINGLE
When on, the result from each measurement is displayed.
When off, the counter averages all data captured during the set
measurement time.

No normal mode but single mode on or off. The measurments look better
when averages are on...

On Wed, Feb 1, 2017 at 8:46 PM, Ed Palmer  wrote:
> Hi Magnus,
>
> When you did your measurements, did you use 'single' mode or 'normal' mode?
>
> When I got my PM6681, I wanted to check the interpolater to make sure that
> it was healthy.  I couldn't generate pulses over the whole range, but over
> the range of 50ns to 28 ns, my StdDev readings in 'single' mode were in the
> range of 2.6 - 3.6 e-11, i.e. similar to the example in the manual.  In
> normal mode, my readings were significantly better.  So I'm assuming that
> 'single' mode was the correct mode to use.
>
> FYI, my unit was factory calibrated with a 4.05 ns pulse according to the
> PUD command, so I guess that's what gave the best results.  I also see that
> the example in the manual was for a 4.29 ns pulse. Does that suggest that
> shorter, harder to generate, pulses are important for this calibration?
>
> Ed
>
>
>
> On 2017-02-01 11:00 AM, Magnus Danielson  wrote:
>>
>> Fellow time-nuts,
>>
>> With the hints from the former Pendulum service guy, I have started to
>> write my own code in order to restore calibration on a CNT-81/PM-6681.
>> This have been a discussion on and off for a couple of years, so I ended
>> up buying a PM-6681 which had the Loss of Calibration message "CAL LOSS".
>>
>> First things is to replace the CMOS battery, which is a trivial thing to
>> replace the CR2032 battery, had one laying around.
>>
>> Then, I've been digging into the NI VISA files, which have snippets of
>> actual code in it. As I don't have NI VISA and not running with my
>> Prologix, I was a bit out of luck there. So I had to start from the
>> ground up, taking a serial interface hack I already have, write some
>> minimalistic Prologix support for it (TvB hp59309.c provided some needed
>> clues on how to get it working stable).
>>
>> Then more and more bits and pieces have been falling together, like
>> being able to build and write the *PUD string. Also, triggering the
>> calibration itself and using an external source.
>>
>> Now my counter does not display the error anymore and seems to behave
>> more coherently. I'm not completely trusting it, as I am not doing the
>> full sweep over calibration pulse calibration values and measuring their
>> effect, that will be part of the complete solution, but at least I get
>> sufficient part of the way.
>>
>> Far from bullet-proof, it is however worth celebrating these baby steps
>> in the right direction.
>>
>> Cheers,
>> Magnus
>>
>
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Re: [time-nuts] Allan Variance with an HP53132a counter

[Azelio Boriani]

You don't need the OCXO option for the 53132... you need a stable and
accurate source like a GPSDO that will be your reference. Consider
buying the HP53132 but also a GPSDO. Is the 162kHz transmitter the
Allouis one (TDF/Syrte)?

On Sun, Jan 22, 2017 at 3:52 PM, Gilles Clement
 wrote:
> Hi,
>
> I am new to this list and have been following it for a while with great 
> interest. I am afraid I am getting contaminated with the "TN" virus… !
>
> I developed a home-brewed OCXO crystal oscillator disciplined with a long 
> wave radio station signal (162 kHz). Its working quite well with a long term 
> stability that is « probably » better than 10E-8 which I am actually looking 
> forward to better understand. I am considering using an HP53132 counter for 
> this purpose, although I understand that it may not be the most recommended 
> approach….
>
> Please find hereafter the rationale:
> - The HP53132 implements a triangular averaging algorithm (Delta averaging) 
> in its standard frequency or period measurement mode of operation
> - This feature provides a pretty high resolution (up to 0.5*10E-12 if I am 
> correct) which should be appropriate at least to get a first idea of the 
> oscillator performance
> - But it comes with the drawback that an Allan Variance computed directly 
> from such frequency (or period) readings, would be distorted with respect to 
> the "standard" Allan Variance (which assumes a PI averaging instead of a 
> Delta averaging algorithm to compute the fractional frequencies)
> - However, from the Australian paper titled : « Considerations on the 
> Measurement of the Stability of Oscillators with Frequency Counters » I 
> noticed that:
> When I look at OCXO crystals oscillator stability discussions in the 
> literature, White Frequency, Flicker Frequency and Random Walk Frequency seem 
> to be the dominant noise factors considered (ex: in phase noise spectral 
> density graphics)
> The distortion from Allan Variance to Delta Variance is limited for White 
> Frequency, Flicker Frequency and Random Walk Frequency noises (though it can 
> be several orders of magnitudes for White Phase and Flicker Phase noises)
> Moreover formulas are provided in the paper to evaluate the amount of such 
> distortions. The impact appears to be a simple multiplier of 1.33, 1.30 and 
> 1.15 for the three corresponding noises, the slopes of the curves are not 
> impacted (i.e: tauE-1 ; tauE+0 and tauE+1)
> - So the idea is the following: start with a simple bench test, reading the 
> standard mode of Periods measurement, calculate the "naive" Triangular 
> Variance from these data, identifying the noise types (according to the slope 
> of the curve sections), and applying the corresponding offset correction, 
> hopefully leading to an estimate of the "standard" Allan Variance.
> - This approach would have the great advantage to be simple and cost 
> effective, as one can find nowadays second hand 53132’s at reasonable cost 
> even with the (mandatory) OCXO option.
>
> Comments welcomed,
> Best,
> Gilles.
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Re: [time-nuts] Thermal effects on cables --> ADEV

[Azelio Boriani]

May I suggest to turn the 24 hours reset period into a parameter?

On Fri, Jan 13, 2017 at 8:45 PM, Tom Van Baak  wrote:
> Mark, Ole,
>
> Yes, averaging can both enhance precision but also destroy information. In 
> many cases too much data is a bad thing. The solution is to add another 
> dimension to the plot. Stable32 does this with DAVAR (dynamic Allan 
> variance). TimeLab has a multi- "trace" feature. Both of these break large 
> data sets into smaller ones and display each in succession. This way you get 
> the best of both worlds; precision without long-term pollution and also a 
> view of long-term trends. Yes, there's an art to picking the right 
> parameters, but you get the idea. In some cases it is highly informative. The 
> color 3D DAVAR plots in particular can be a thing of beauty.
>
> So, in your case, save each of those 24 hour GIF's and then turn then into a 
> single animated GIF. That way not only do you get a fresh view of current 
> reception conditions, but also a time lapse view of changes over the 
> long-term.
>
> Another idea is to somehow 2D transform your polar plots into a horizontal 
> rectangular strip and then use elapsed time in the vertical. This would allow 
> a waterfall-style representation of GPS reception over time.
>
> /tvb
>
> - Original Message -
> From: "Mark Sims" 
> To: 
> Sent: Friday, January 13, 2017 11:03 AM
> Subject: [time-nuts] Thermal effects on cables --> ADEV
>
>
>>I recently made a change in Lady Heather's satellite signal maps to help with 
>>a very similar issue.  Before, the maps were based upon the accumulated 
>>average value of the sat signals at each point in the sky.  Now, every 24 
>>hours, the signal level averages are reset to their current average and the 
>>sample counts are reset to 1.  That way any change is your antenna 
>>performance won't be masked by days/week/months of previous data.
>>
>> 
>>
>>> Don't use years worth of data.
>> Otherwise it could be days before the xDEV visually changes
>
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Re: [time-nuts] MTI 240 OCXO, anyone?

[Azelio Boriani]

An Oscilloquartz 8660 is its equivalent... OK, slightly worse.

On Mon, Jan 2, 2017 at 12:05 AM, Bruce Lane  wrote:
> Happy New Year, fellow time-tickers!
>
> Would anyone happen to have a spare MTI 240 series OCXO, 10MHz output?
> I'm looking to upgrade my TS2100.
>
> Failing the MTI, what alternates will work? I'd be very surprised if
> Vectron didn't have an equivalent.
>
> Thanks much.
>
> --
> ---
> Bruce Lane, ARS KC7GR
> http://www.bluefeathertech.com
> kyrrin (at) bluefeathertech dot com
> "Quando Omni Flunkus Moritati" (Red Green)
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Re: [time-nuts] A Leap Second is coming

[Azelio Boriani]

The leap second warning is present in the PTB clock too (Europe):


On Fri, Dec 30, 2016 at 8:49 PM, Nick Sayer via time-nuts
 wrote:
> I'm going to definitely observe my GPS clock to check its behavior. It 
> *should* repeat second zero (in my case of 4PM PST). Not the most exactingly 
> accurate depiction, but it's the best I can do with the architecture.
>
> Sent from my iPhone
>
>> On Dec 29, 2016, at 12:22 AM, David J Taylor  
>> wrote:
>>
>> Is everybody setup to watch it and collect lots of data?
>>
>> Anybody have a list of tools/toys for collecting data?
>>
>> An old favorite:
>> www.cl.cam.ac.uk/~mgk25/time/leap/test/timelog.c
>> =
>>
>> Some tools here, to see which NTP servers are announcing the event:
>>
>> http://www.satsignal.eu/software/net.htm#NTPLeapTrace
>>
>> Perhaps they may be of use to someone?
>>
>> Cheers,
>> David
>> --
>> SatSignal Software - Quality software written to your requirements
>> Web: http://www.satsignal.eu
>> Email: david-tay...@blueyonder.co.uk
>> Twitter: @gm8arv
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>
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Re: [time-nuts] SR620 Failure Code.

[Azelio Boriani]

Here you can find all about the SR620:

search for SR620.

On Thu, Dec 22, 2016 at 5:53 PM, W2GPS  wrote:
> Time-nuts,
>
>
>
> My SR620 has started reporting "test error 34" on power-up and will do
> nothing after that. Does anyone know what that message means? I have a
> reasonable lab and I would try to repair the unit myself but I have no
> documentation. Is service documentation available or should I just ship it
> back to Stanford Research to get fixed?
>
>
>
> Rick
>
> W2GPS
>
>
>
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Re: [time-nuts] Lady Heather Version 5 is now available

[Azelio Boriani]

Maybe that the "Start In" field in the Properties Panel must be set if
windows is not in US language mode. When windows is italian, for
example, the Program Files folder becomes Programmi.

On Mon, Dec 12, 2016 at 9:53 AM, David J Taylor
 wrote:
> Hello Mark,
>
> many thanks for your immense and invaluable work!
>
> I am using the trimble thunderbold together with LH version 3 all the
> last years with success, I like your program very much.
> I downloaded and installed today the version 5, but I have some problems
> because it looks like my windows 7 does
> not get access to the heather.cfg file, what do I wrong? Anybody has an
> idea how to do it right?
>
> Many thanks
>
> Arnold, DK2WT
> =
>
> Arnold,
>
> Like much software where the user needs to edit a configuration file, it's
> best installed /outside/ the "Program Files" directory:
>
> - Create a new directory C:\Tools\
> - (optional) Set the permissions to Everyone, Full control
> - Created a new directory C:\Tools\LadyHeather\  (your choice of name)
> - Right-click the LH download, Properties.
>  - If "Unblock" is present & checked, uncheck it.
> - Install LH here.
>
> It's running correctly on my Win10/64 system.  More information:
>
>
> http://planeplotter.pbworks.com/Using%20Plane%20Plotter%20on%20Windows-7%20and%20Vista
>
> 73,
> David GM8ARV
> --
> SatSignal Software - Quality software written to your requirements
> Web: http://www.satsignal.eu
> Email: david-tay...@blueyonder.co.uk
> Twitter: @gm8arv
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Re: [time-nuts] Rohde & Schwarz XSD 2.5 MHz crystal gone bad?

[Azelio Boriani]

A comparison between AT and SC cuts' temperature stability can be found here:



On Mon, Nov 21, 2016 at 4:21 AM, Bob Camp  wrote:
> Hi
>
> If the frequency drops as the oven warms up, you have an AT cut crystal. If
> the frequency goes up as the oven warms up, you have a BT cut crystal. With an
> AT or a BT, the frequency change between room and “hot” will depend a lot on
> the details of the proper oven temperature. A frequency shift of 20 to 40 ppm 
> is not
> at all unusual as the oven warms up. The oscillator will only tune on 
> frequency
> once the oven is hot.
>
> http://www.aextal.com/tutorial-frequency-stability.htm
>
> Regardless of which cut you have (an AT is the best guess). The oven 
> temperature
> would be adjusted to put the crystal at it’s minimum sensitivity point. For 
> an AT that
> is the lowest frequency. If the oven is not heating to the correct 
> temperature, you will
> probably be unable to get the oscillator on frequency.
>
> If there is a circuit problem, the most likely culprit are the inductors. 
> They form tuned
> traps that put the circuit onto the correct overtone. This increases the 
> circuit’s sensitivity
> to changes in inductance. 50 year old inductors may have been made with core 
> materials
> that aged more than just a little bit. I have empirical data on this :)
>
> As others have suggested, check the oven heater along with the oscillator 
> circuit. The
> issues you see might come from either one.
>
> Bob
>
>> On Nov 20, 2016, at 6:49 PM, Michael Ulbrich  wrote:
>>
>> Hi there,
>>
>> I'm new to this list and have some interest in quartz crystal and
>> rubidium oscillators - GPS, NTP, PPS and "clock watching" in general ;-)
>>
>> I snatched an R&S XSD frequency standard accompanied by an XKE frequency
>> controller. Found the manuals on KO4BB's site (Thanks a lot for that!
>> BTW there's a slight mix-up of pages in that some of the XKE pages have
>> found their way into the XSD manual).
>>
>> My initial hope of a quick and easy restoration project faded a bit when
>> I looked at the XSD output frequency after heating up the oven. It was
>> off by about -1 * 10-5 and after cranking the fine tuning for some time
>> and having another look at the specs I realized that the frequency was
>> too far off to be dialed in by the fine tuning which only covers about
>> +/- 2 * 10-7.
>>
>> Next step was to take apart the oven and check series capacitor,
>> oscillator and the crystal itself. I found that even the coarse
>> adjustment range of the cylindrical series capacitor (40 - 110 pF) would
>> not allow to pull the crystal to it's specified frequency. When
>> replacing the series cap by a ceramic and lowering the value to just
>> before the oscillation breaks down (about 10 pF) I managed to set the
>> oscillator frequency offset to  +2.5 * 10-6 at room temperature. But
>> even this will not suffice when taking into account that the frequency
>> will drop by a few parts in 10-5 (cf. XSD manual) when the oven heats up
>> to its operating temperature. I also checked some of the components on
>> the oscillator PCB which might have an influence on frequency but could
>> not find any fault.
>>
>> The crystal itself is a disk of about 30 mm diameter mounted in a sealed
>> glass cylinder of about 38 mm dia. and 43 mm height. There is no socket
>> just 2 bare wires.. It does not show any visual signs of damage.
>> According to a reference given in the R&S XSD manual the crystal's
>> construction follows a publication from A.W. Warner "Design and
>> Performance of Ultraprecise 2.5-mc Quartz Crystal Units" in Vol 39,
>> Issue 5 of Bell Labs Technical Journal (Sept. 1960). According to that
>> it is an AT-cut 5th overtone design.
>>
>> Now my questions:
>>
>> a) Considering that this gear is about 50 years old, a "crystal gone
>> bad" situation shouldn't be that much of a surprise, right?  But could
>> there be any other cause of the "huge" frequency offset besides a bad
>> crystal? I would very much appreciate any idea that I could try to get
>> this baby back on spec.
>>
>> b) if nothing else helps: Could any of you give me a hint about who
>> might be able to supply a spare crystal? I tried my directly reachable
>> contacts but unfortunately to no avail so far. Please consider that
>> similar crystals might also have found their way into other
>> manufacturer's constructions from that era - Sulzer, Racal, HP ... you
>> name it ...
>>
>> Many thanks in advance!
>>
>> Best regards ... Michael U.
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Re: [time-nuts] Thermal impact on OCXO

[Azelio Boriani]

Are Oscilloquartz's Star-4 commands described somewhere? I can't find
them in the wild...

On Sat, Nov 19, 2016 at 4:34 AM, Mark Sims  wrote:
> Several years ago I replaced the OCXOs in some Tektronix DC5010 counters with 
> surplus Oscilloquartz 8663 DOCXOs.   The darn things have freaky good aging 
> characteristics.   They have been on 24/7 (except for a few brief 
> power-outages) for over 3 years.   After a month I set their freq against a 
> cesium oscillator.   They still show 10 MHz out to 8 or 9 decimal places.
>
> I just got in an Oscilloquartz Star-4 ATDC (automatic temperature / drift 
> compensation) that uses the same DOCXO.   They take 24 hours from a cold 
> start before the ATDC learning kicks in (you can fake it out by power cycling 
> during that interval and it thinks it was a brief outage and reports a 1 hour 
> learning delay).   After an unspecified time (at least several days) the 
> device learns the compensation characteristics and the holdover performance 
> status switches from POOR to IN-SPEC.   I have not yet gotten it past the 
> learning stage...
>
> Oh,  and Lady Heather now speaks Star-4 management interface commands which 
> are also used on a NEC GPSDO that shows up on Ebay... I have one of those on 
> order.
>
> ---
>
>> OSA8663: per year, 3.0E-8, in 10 years < 30.0E-8
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Re: [time-nuts] Thermal impact on OCXO

[Azelio Boriani]

One starting point to figure out the 10 years aging can be the
datasheet of an OCXO:
MTI240: per year, 3.0E-7, in 10 years must be less than 30.0E-7
MTI220: per year, 1.0E-6, in 10 years < 10.0E-6
Bliley NV26R: 17 years, 5.0E-6
OSA8663: per year, 3.0E-8, in 10 years < 30.0E-8

On Fri, Nov 18, 2016 at 11:48 PM, Bob Camp  wrote:
> Hi
>
>
>
>> On Nov 18, 2016, at 1:31 PM, Lars Walenius  wrote:
>>
>> Hi Bob (and all others),
>>
>> I agree to all your points but am curious to your comment: ”that OCXO is 
>> aging a lot for one that has been on that long”.
>> As I have only done this test and seen no other test of OCXO´s powered over 
>> at least ten years, I have no idea what is reasonable. I also guess I will 
>> not do another test of an OCXO powered and measured over ten years again.
>>
>> Could you give some examples what is reasonable for aging after ten years? 
>> Maybe others have data? I have searched internet and it isn´t easy to find 
>> long-term data on OCXO’s (at least for me).
>
> The only people I know of that have the gear and the interest to run a number 
> of OCXO’s are oscillator manufacturers. They also track parts
> in the field by various methods. The data takes real effort to collect and 
> thus is “part of our IP”.
>
> Bob
>
>>
>> This oscillator drifted about 60ppm between 1month on to ten years on . Do 
>> others have figures what is reasonable over this time span?
>>
>> For point 1: Is it possible from the aging curve to have some ideas what is 
>> going on??
>>
>> Lars
>>
>> >Från: Bob Camp
>> >Skickat: den 17 november 2016 01:03
>> >Hi
>>
>> >Your data demonstrates a couple of things:
>>
>> >1) There are a number of different things going on with that OCXO and some 
>> >things are a lot less predictable than others.
>> >2) Oscillators do drop rate while on power.
>> >3) Oscillators that age a lot are easier to model (yes, that OCXO is aging 
>> >a lot for one that has been on that long).
>>
>> >Bob
>>
>> >> On Nov 16, 2016, at 2:41 PM, Lars Walenius  
>> >> wrote:
>> >>
>> >> FWIW. Between 2001 and 2011 I run a 5MHz OCXO (in a box). It is a 2x3inch 
>> >> type without EFC marked OFC MC834X4-009W with date code 97. Probably it 
>> >> was from some base station testing and it had been sitting in my shelf 
>> >> since 98. The OCXO were battery backed but at two occasions (2004 and 
>> >> 2007) we had power fails that drained the battery as can be seen in the 
>> >> graph.
>> >>
>> >> Just out of curiosity I yesterday put just the first thirty days (like in 
>> >> the pdf mentioned below) and let Excel calculate the logarithmic 
>> >> function. If I extrapolate that to 10 years it seems that the drift would 
>> >> be 6E-13/day but as can be seen in the aging graph it was more like ten 
>> >> times higher.
>> >>
>> >> Some days ago I started the OCXO again after it had been on the shelf for 
>> >> more than 4 years. Enclosed is a graph for the first 7 days. After six 
>> >> and half days it seems to be a jump of about 1.5E-10 and as I have no 
>> >> indication of anything else I believe it is from the OCXO.
>> >>
>> >> /Lars
>
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Re: [time-nuts] Time nut soon to be in Shenzhen

[Azelio Boriani]

Maybe I have a clue: on the usual auction site there is a new seller
(since April 2015) from ShenZhen (Guangdong provice) that has a lot of
OCXOs on sale. Not so far (~140km) there is another OCXOs seller
(since 2005) in Guangzhou, the capital of Guangdong province.

On Sun, Nov 6, 2016 at 4:43 PM, paul swed  wrote:
> Sorry no clue I suspect you will be the Marco Polo of time-nuttery.
> Have fun and remember pennies per pound. You can have a lot of fun at that
> cost.
> Regards
> Paul
> WB8TSL
>
> On Sun, Nov 6, 2016 at 10:13 AM, Christopher Hoover 
> wrote:
>
>> I'm in Shanghai now but will be leaving for Shenzhen in a few days.  Any
>> one know of any special time nutty stuff to check out in Shenzhen?  I
>> expect if I can find the right place I might see piles of OCXO's.
>>
>> Thanks, Christopher and 73 de AI6KG
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Re: [time-nuts] Thermal impact on OCXO

[Azelio Boriani]

...with a 20bit DAC, a suitable voltage reference for that DAC and an HP3458...

On Sun, Nov 6, 2016 at 12:39 AM, Bob Stewart  wrote:
> Hi Hal,
>
> With a 20 bit DAC, even a small aging rate is going to show up.  I'll let the 
> one GPSDO cook for a month or so and see what it shows then.  I'll also pull 
> the data from the log file and see if I can see any correlation between the 
> temperature and the EFC over time.  IOW, for data points separated by 3.5 
> days, does the temperature difference between the two point seem to play a 
> large part of the change in the recorded DAC value.
>
> The graph was made from the logging data sent to the PC.  But, the firmware 
> doesn't have access to historical data on the PC, so something is needed for 
> aging calculations.  Tom mentioned here recently about the 58503A GPSDO 
> saving 64 hours of data for it's aging calculations.  So, I just added a few 
> hours to that to get to 3.5 days of history in the GPSDO.
> Bob -
> AE6RV.com
>
> GFS GPSDO list:
> groups.yahoo.com/neo/groups/GFS-GPSDOs/info
>
>   From: Hal Murray 
>  To: Bob Stewart 
> Cc: Hal Murray 
>  Sent: Saturday, November 5, 2016 6:23 PM
>  Subject: Re: [time-nuts] Thermal impact on OCXO
>
>> The OCXO has been hot for a number of months.
>
> Then I don't understand why it is still aging that much.
>
>
>> I changed the firmware to save the DAC voltage every 30 minutes for 3.5
>> day
>
> That's not very long.
>
> How did you make the graph?  You had to get the data out to a place where you
> can plot it somehow.  If you can do that, why are you "saving" the data?  I
> assume you have a serial port to a PC or something like that.
>
>
>> The fuzz in the temperature line is, indeed, the HVAC cycling
>
> You could try putting a box over the unit to see if that slows down the
> temperature changes.
>
> Mostly, you are trying to block air flow.
>
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
>
>
>
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Re: [time-nuts] TimeLab

[Azelio Boriani]

In the real world of TICs is not possible to implement a stop pulse
that occurs before its start pulse. When a regular start-stop (stop
pulse after start, positive delay) is followed by a negative delay
(stop pulse before the start) the sample is lost because the start has
not yet occurred. The only way is to intentionally delay the stop so
that it will never occur before the start. The delay must be known and
very stable, of course.

On Sun, Oct 9, 2016 at 1:32 PM, Magnus Danielson
 wrote:
> Fellow time-nuts,
>
> I don't know if it is me who is lazy to not figure TimeLab out better or if
> it is room for improvements. I was considering writing this directly to
> John, but I gather that it might be of general concern for many, so I
> thought it be a good topic for the list.
>
> In one setup I have, I need to measure the offset of the PPS as I upset the
> system under test. The counter I'm using is a HP53131A, and I use the
> time-interval measure. I have a reference GPS (several actually) which can
> output PPS, 10 MHz, IRIG-B004 etc. In itself nothing strange.
>
> In the ideal world of things, I would hook the DUT PPS to the Start (Ch1)
> and the reference PPS to the Stop (Ch2) channels. This would give me the
> propper Time Error (DUT - Ref) so a positive number tells me the DUT is
> ahead of the reference and a negative number tells me that the DUT is behind
> the reference.
>
> Now, as I do that, depending on their relative timing I might skip samples,
> since the counter expects trigger conditions. While TimeLab can correct for
> the period offset, it can't reproduce missed samples.
> I always get suspicious when the time in the program and the time in real
> world does not match up.
>
> I could intentionally shift the PPS output of my DUT to any suitable number,
> which would be one way to solve this, if I would tell TimeLab to withdraw
> say 100 ms. I might want to do that easily afterhand rather than in the
> setup window.
>
> To overcome this, I use the IRIG-B004 output, which is a 100 Hz signal with
> a stable rising edge aligned to the PPS to within about 2 ns. Good enough
> for my purpose. However, for the trigger to only produce meaningful results,
> I will need to swap inputs, so that the PPS from DUT is on Start/Ch1 and the
> IRIG-B is on Stop/Ch2. This way I get my triggers right. However, my
> readings have opposite sign. I might have forgotten about the way to correct
> for it.
>
> However, TimeLab seems unable to unwrap the phase properly, so if I have the
> condition where I would get a negative value of say -100 ns then the counter
> will measure 9,999,900 ns, so I have to force a positive value as I start
> the measurement and then have it trace into the negative. I would very much
> like to see that TimeLab would phase-unwrap into +/- period/2 from first
> sample. That would be much more useful.
>
> I would also like to have the ability to set an offset from which the
> current zoom window use as 0, really a form variant of the 0-base but
> letting me either set the value or it be the first value of the zoom. I have
> use for both of these. I often find myself fighting the offset issues. In a
> similar fashion, I have been unable to change the vertical zoom, if I don't
> care about clipping the signal then it forces me to zoom in further than I
> like to. The autoscale fights me many times in a fashion I don't like.
>
> OK, so there is a brain-dump of the last couple of weeks on and off
> measurement experiences. While a few things might be fixed in the usage, I
> wonder if there is not room for improvements in the tool. I thought it
> better to describe what I do and why, so that the context is given.
>
> Cheers,
> Magnus
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Re: [time-nuts] Normal operating specs of a Morion MV89?

[Azelio Boriani]

Take care that the 'scope is not a 50 ohm load: the TDS2024B has not
the 50ohm/1Mohm input selection. So far I wasn't able to get from the
'scope FFT the same measurements that I get from a spectrum analyzer.

On Wed, Sep 28, 2016 at 7:38 AM, Tim Lister  wrote:
> On Tue, Sep 20, 2016 at 12:56 PM, Bryan _  wrote:
>> May also want to check the output amplitude. If memory serves me correct it 
>> is very common for a capacitor inside this model number to fail. It can be 
>> fixed but requires a torch or a pretty heavy duty soldering iron to get the 
>> can open.
>> http://www.rbarrios.com/projects/MV89A/
>>
>> -=Bryan=-
>>
>
> I managed to borrow a Tek TDS 2024B 200 MHz scope from work and hooked
> it up to the output of my MV89A. I get a peak-to-peak measurement of
> 2.3 V which if I have converted it right is ~11 dBm ? Alternatively if
> I turn on the FFT mode on the scope I get a peak value of -2.17 db if
> I am driving the cursor mode correctly. With the 10 MHz from the
> radioshackus GPSDO used for triggering, it takes ~18 seconds for the
> MV89 waveform to drift 1 cycle (this is without anything connected on
> the Uin or Uref pins).
>
> Tim
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Re: [time-nuts] Lucent RFTFm-II-XO

[Azelio Boriani]

This is your link:

anyway, the J8 connector pinout:

KS-24361 J8 - Diagnostic serial port with SCPI 9600,N,8,1
RXD+  4
RXD-  8
TXD+  5
TXD-  9
GND  3, 7

J6 RS422/PPS
RXD+  4
RXD-  8 no information on this RX line
TXD+  5
TXD-  9one string each second (no SCPI) 9600,N,8,1
pins 1 (+) and 6 (-) are the differential PPS pulse 400us wide

On Thu, Sep 22, 2016 at 8:07 AM, Hal Murray  wrote:
>> Is there a pinout posted somewhere  for the Lucent box RS422 D sub 9 
>> connector?
>
> It's in the mail archives.  Google for something like >time-nuts RS422 pinout<
>
> If you are interested in timing, you want the PPS signal too.  (It won't be
> great over USB, but it might be fun to play with.  You can get your own
> hanging bridges.)
>
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
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Re: [time-nuts] Holdover

[Azelio Boriani]

...the Z3801A requires the device to be in holdover... with the GPS
PPS already acquired: I think that the "jam sync" must be done against
some reference...

On Wed, Aug 17, 2016 at 4:49 AM, Mark Sims  wrote:
> The Trimble GPSDOs and most of the SCPI ones (like the Z3801A) have "jam 
> sync" commands that force the receiver to do an immediate time sync (the 
> Z3801A requires the device to be in holdover before it will accept a jam 
> sync).  Some also have commands where you an also specify thresholds where 
> the receiver alarms and/or does an automatic jam sync and thresholds for 
> loss-of-signal time before the device goes into holdover mode.
>
> ---
>
> I have selected a somewhat more intricate setup in which you can set a
> re-assignment limit, so when the phase error is outside of that limit,
> you turn the output off, jumps the phase difference, and then starts to
> track in from there. The reason being that at some time deviation, the
> time it takes to track in the phase error is too large to be practical
> so turning of and jump has less impact.
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Re: [time-nuts] Q/noise of Earth as an oscillator

[Azelio Boriani]

What about an ADEV/TDEV plot of the pulsar J0437-4715?

On Fri, Jul 29, 2016 at 12:39 AM, Jim Palfreyman  wrote:
> Hi All,
>
> Tom gave me a nudge to look here - I hadn't been following this thread.
>
> For those that don't know, I study pulsars and so the way we measure what
> pulsars do could be relevant to this discussion.
>
> First, I have never heard of a Q measure when referencing a pulsar. I think
> the key here is that it's not resonating as such. Rotating yes, resonating
> no.
>
> Pulsars spin and slow down due to giving off energy (magnetic dipole
> radiation). So in the pulsar world we mainly refer to spin frequency (F0)
> and frequency derivative (F1). With some of the younger and more "erratic"
> pulsars, F2 (and further) can be modelled.
>
> Here's some data on the Vela pulsar (hot off the presses - measured just
> now):
>
> F0  11.1867488542579
> F1  -1.55859177352837e-11
> F2  1.23776878287221e-21
>
> Vela is young and erratic. Millisecond pulsars are outstanding clocks.
> Here's the data for J0437-4715 - one of the most stable pulsars we know
> about:
>
> F0  173.6879458121843
> F1  -1.728361E-15
>
> I'm sure the "Q" of Vela would be pretty decent - but I can tell you now,
> as a time-keeper, she's useless.
>
>
> Jim Palfreyman
>
>
>
> On 28 July 2016 at 20:50, Tony Finch  wrote:
>
>> Neville Michie  wrote:
>>
>> > The conical pendulum has a simple form of a weight on a string, instead
>> > of oscillating in one plane as a conventional pendulum, it swings around
>> > in a circular orbit in the horizontal plane. It has a definite resonant
>> > frequency.
>>
>> I don't think it does have a resonant frequency, any more than the Earth
>> does: the angular velocity of the pendulum is sqrt(g/h) where h is the
>> height of the pendulum; give it more energy, it swings higher, so h is
>> smaller, so the frequency is higher.
>>
>> Tony.
>> --
>> f.anthony.n.finchhttp://dotat.at/  -  I xn--zr8h
>> punycode
>> South Thames, Dover: Southwesterly 5 or 6. Slight or moderate. Rain or
>> showers. Good, occasionally poor.
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Re: [time-nuts] Q/noise of Earth as an oscillator

[Azelio Boriani]

Exciting the Earth with a new frequency (and an adeguate amount of
energy) sets a new rotational speed: you cannot retune a (for example)
quartz crystal in the same way...

On Wed, Jul 27, 2016 at 3:42 PM, Tom Van Baak  wrote:
> Hi Michael,
>
> I sympathize with both your and Attila's comments and would like to dig 
> deeper for the truth on this.
>
> Clearly both the earth and a pendulum (and many other periodic systems) 
> exhibit a decay of energy, when you remove the periodic restoring force. And 
> if you take the classic definition Q = 2 pi * total energy / energy lost per 
> cycle then it would seem earth has a Q factor.
>
> In fact, if you use real energy numbers you get:
>
> - total rotational energy of earth is 2.14e29 J
> - energy lost per cycle (day) is 2.7e17 J
> - so Q = 2pi * 2.14e29 / 2.7e17 = 5e12, the same 5 trillion as my earlier 
> calculation.
>
> But your point about resonance is a good one and it has always intrigued me. 
> Is this one difference between a pendulum and the earth as timekeepers?
>
> On the other hand, if you swept the earth with an external powerful frequency 
> in the range well below to well above 1.16e-5 Hz (1/86164 s) would you not 
> see a resonance peak right at the center? Given the mass of the planet and 
> its pre-existing rotational energy, it seems like there is a "resonance", a 
> preference to remain at its current frequency. Plus it has a slow decay due 
> to internal friction. This sounds like any other timing system with Q to me.
>
> Or imagine a planet the same size as earth made from a Mylar balloon. Much 
> less mass. Give it the same rotational speed. Much easier to increase or 
> decrease its energy by applying external force. Far lower Q than earth, yes?
>
> It might also be useful at this point, to:
>
> read the history Q and its definition:
> http://www.collinsaudio.com/Prosound_Workshop/The_story_of_Q.pdf
>
> and read the patent in which Q first appeared:
> http://leapsecond.com/pages/Q/1927-US1628983.pdf
>
> or view the first paragraph in which Q appeared:
> http://leapsecond.com/pages/Q/1927-Q-patent-600x300.gif
>
> /tvb
>
> - Original Message -
> From: "Michael Wouters" 
> To: "Discussion of precise time and frequency measurement" 
> ; 
> Sent: Wednesday, July 27, 2016 5:43 AM
> Subject: 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 to make a clock. If you think of just a
>> circle, then a point on it viewed in a rectilinear coordinate system
>> executes simple harmonic motion so the motion of that point looks like
>> an oscillator, so that much is OK.
>>
>> But unlike the LCR circuit, the pendulum and quartz crystal, the
>> sphere's rotational motion does not have a
>> resonant frequency. Another way of characterizing the Q of an
>> oscillator, the relative width of the resonance, makes
>> no sense in this context.
>>
>> It seems to me that the model of the earth as an oscillator is
>> misapplied and that the 'Q' is not a meaningful number.
>> I think the confusion arises here because of a conflation of a
>> rotation of the sphere (which marks out a time interval) with an
>> oscillation. Both can be used to define an energy lost per unit time
>> but the former doesn't have anything to do with the properties of an
>> oscillator.
>>
>> Something else that indicates that the model is suspect is that the
>> apparently high 'Q' implies a stability which the earth does not have,
>> as Tom observes. Viewed another way, this suggests that the model is
>> inappropriate because it leads to an incorrect conclusion.
>>
>> Time for bed. I'll probably lie awake thinking about this now :-)
>>
>> Cheers
>> Michael
>>
>> On Wed, Jul 27, 2016 at 8:08 AM, Attila Kinali  wrote:
>>> Hoi Tom,
>>>
>>> On Tue, 26 Jul 2016 12:36:37 -0700
>>> "Tom Van Baak"  wrote:
>>>
 Among other things, the quality-factor, or Q is a measure of how slowly a
 free-running oscillator runs down. There are lots of examples of periodic 
 or
 damped oscillatory motion that have Q -- RC or LC circuit, tuning fork,
 pendulum, vibrating quartz; yes, even a rotating planet in space.
>>>
>>> I am not sure you can apply this definition of Q onto earth. Q is defined
>>> for harmonic oscillators (or oscillators that can be approximated by an
>>> harmonic oscillator) but the earth isn't oscillating, it's rotating.
>>> While, for time keeping purposes, similar in nature, the physical
>>> description of both are different.
>>>
>>> Attila Kinali
>>>
>>> --
>>> Malek's Law:
>>> Any simple idea will be worded in the most complicated way.
>>> ___
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Re: [time-nuts] over-determined clock solution

[Azelio Boriani]

In this receiver mode all the satellites are used to compute the
timing solution. See page 80 of the 2012 Thunderbolt-E manual:



This mode is available when the position of the antenna is known and
is stationary. Timing receivers usually take care of the initial
position survey at power-on and enter this mode automatically after
the survey is over.

On Sat, Jun 25, 2016 at 4:07 PM, Steve  wrote:
> The phrase "over-determined clock solution" is used in the Trimble
> Thunderbolt user manual in describing operation of the Thunderbolt GPS
> receiver. The manual does not discuss the phrase in any detail, appearing to
> assume the reader understands its meaning. An internet search on
> "over-determined clock solution" did not turn up any substantive hits.
>
> What does "over-determined clock solution" mean?
>
> Thanks.
>
> Steve, K8JQ
>
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Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

[Azelio Boriani]

In the July/August 2008 QEX magazine there is an article by VE5FP
"Some Thoughts On Crystal Parameter Measurement" that may be of
interest.

On Sat, Jun 4, 2016 at 11:01 PM, Bob Camp  wrote:
> Hi
>
> There are two things you may be talking about:
>
> 1) The pressure springs on things like FT-243 holders, they are generic 
> springs.
>
> 2) The connection leads on plated blanks, they are indeed strange *and* 
> soldering to the blank is a big problem.
>
> I’m guessing you are in bucket number 2.
>
> Bob
>
>
>> On Jun 4, 2016, at 1:41 PM, Mike Cook  wrote:
>>
>> Thanks all for your advice, hints, tips and links. Lots to read , do and 
>> some hardware to check.  I don’t have a frequency generator so I’ll have to 
>> go another route.
>>
>> Oh. One last Q. Has anyone tried repairing the « spring » wire electric 
>> connections on large quartz plates. In one large unit I have they had 
>> corroded and dropped the plate, luckily no damage.  I have done one, but I 
>> have no Idea what the original wire composition was so have certainly 
>> induced some stray capacitance/resistance. It is possible that it was a 
>> filter rather than a frequency source as it was not in a vacuum.
>>
>> Have a good one.
>>
>>> Le 4 juin 2016 à 18:49, Bernd Neubig  a écrit :
>>>
>>>
>>> Tim Shoppa wrote:
 The Pierce logic-gate-biased-active oscillator is pretty reliable to start 
 and will oscillate somewhere with most crystals from kHz to MHz.
 As you found out, it will often come up on one of many overtones.
 To reduce chance of coming at an overtone, a series resistor from logic 
 gate output to the crystal is often enough. If not, a RC low-pass will cut 
 down even further (although of course adding phase shift.)
>>>
>>> This is certainly the easiest and fastest way for a go/no-go test and to 
>>> find the approximate resonance frequency.
>>> In the attached circuit diagram make CX1 and CX2 about 10 pF and RGK 
>>> several MegOhms.
>>> The inverter gate should be preferably an unbuffered HCMOS or other fast 
>>> inverter.
>>> For crystals in the MHz range you can replace RV by a short, for kHz 
>>> crystals make it a few kOhms. If testing small watch crystals @ 32768 kHz 
>>> or around, RV should be 100 kOhm at least. RV reduces the crystal drive 
>>> level (RF current) to an acceptable level to avoid overloading or even 
>>> damaging of the crystal. For low frequency crystals the RV-CX2 lowpass also 
>>> avoids start-up at the overtone.
>>> It is recommended to add a second inverter gate at the output to isolate 
>>> your oscilloscope or counter input from the oscillator stage. Add some >330 
>>> ohm in series to the output of the 2nd inverter, if you connect a coaxial 
>>> cable. Then terminate the coax at the oscilloscope or frequency counter end 
>>> with 50 Ohms, so the square wave form will be roughly maintained.
>>>
>>> In this circuit the crystal will not operate at its series resonance, but 
>>> at a load resonance with load capacitance of something between 8 pF and 10 
>>> pF (depending on the inverter input and output capacitance plus the stray 
>>> capacitances of your test fixture).
>>> If you want to operate the oscillator at a (low) overtone, such as 3rd (or 
>>> maybe 5th), you must add a series combination of 10 nF plus an inductor in 
>>> parallel to CX2. The 10 nF is to avoid DC short-circuiting of the output. 
>>> The inductor together with CX2 must have a resonance frequency mid between 
>>> fundamental mode and 3rd overtone (not at one of them). So the tuned 
>>> circuit acts like a capacitor at the 3rd OT and is inductive at fundamental 
>>> mode (thus the phase condition for oscillation is not fulfilled at the 
>>> fundamental mode)
>>> Have fun
>>>
>>> Bernd
>>> DK1AG
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>>
>> "The power of accurate observation is commonly called cynicism by those who 
>> have not got it. »
>> George Bernard Shaw
>>
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Re: [time-nuts] FE-5680A tuning step and pre-lock stability?

[Azelio Boriani]

OK, 256*50*17E-15 is a more comfortable 2.176E-10, easier to measure.
Anyway, I have found out just today that there are 17digits/second
counters:


On Sat, May 7, 2016 at 4:18 PM, Nick Sayer via time-nuts
 wrote:
> I'm not measuring the actual step. I'm moving 256 steps at a time and 
> observing that THAT is 50ish times larger than expected. I'm extrapolating 
> that single-stepping would move 50 times more than expected, but I have no 
> way of testing that.
>
> Sent from my iPhone
>
>> On May 7, 2016, at 4:26 AM, Azelio Boriani  wrote:
>>
>> How can anyone of us tell wheater a tuning step is or not at the level
>> of 10 at -15? Maybe only TVB can...
>> Are you sure that the 50 times greater than is not related to your
>> measure instead of the real capability of the 5680A?
>>
>> On Sat, May 7, 2016 at 6:51 AM, Nick Sayer via time-nuts
>>  wrote:
>>> I got a second 5680 in the mail the other day and so far my firmware isn’t 
>>> bricking it, so.. yay.
>>>
>>> A couple of odd things have turned up, though.
>>>
>>> 1. So far as I can experimentally tell, the tuning step on this unit is 50 
>>> times larger than the 17E-15 quoted by FEI. Either the tuning curve is not 
>>> linear or the tuning range is not what they claim (or both). I’d like to 
>>> get a feel for whether the standard deviation of the mid-range (near zero) 
>>> tuning step is. Is it closer to what I’m observing or FEI’s spec? The 
>>> answer will instruct me on how to pick the PLL gain constant for the 
>>> firmware.
>>>
>>> 2. Directly clocking an AVR from the 5680A is unreliable prior to lock. I 
>>> haven’t exhaustively examined the startup behavior of the 5680, but 
>>> power-up reset of my GPS board used to not happen a lot of the time, and 
>>> manual reset was required. The AVR datasheet says that as long as the clock 
>>> frequency is kept within 2% from cycle to cycle that that’s ok, but either 
>>> this 5680A isn’t doing that or the AVR datasheet is wrong. Fortunately, 
>>> there’s a software workaround: fuse the controller for the internal 8 MHz 
>>> oscillator and switch over (I was surprised to learn that changing system 
>>> clock sources on the fly is an option) to the 5680 only once a physics lock 
>>> is indicated by the lock pin. That seems to be acceptably reliable. My 
>>> purpose in mentioning it is to see if anyone has examined the pre-lock 
>>> behavior of the 5680 (I understand it’s not a particularly interesting 
>>> question) to see exactly how jumpy it really is before it locks.
>>>
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Re: [time-nuts] FE-5680A tuning step and pre-lock stability?

[Azelio Boriani]

How can anyone of us tell wheater a tuning step is or not at the level
of 10 at -15? Maybe only TVB can...
Are you sure that the 50 times greater than is not related to your
measure instead of the real capability of the 5680A?

On Sat, May 7, 2016 at 6:51 AM, Nick Sayer via time-nuts
 wrote:
> I got a second 5680 in the mail the other day and so far my firmware isn’t 
> bricking it, so.. yay.
>
> A couple of odd things have turned up, though.
>
> 1. So far as I can experimentally tell, the tuning step on this unit is 50 
> times larger than the 17E-15 quoted by FEI. Either the tuning curve is not 
> linear or the tuning range is not what they claim (or both). I’d like to get 
> a feel for whether the standard deviation of the mid-range (near zero) tuning 
> step is. Is it closer to what I’m observing or FEI’s spec? The answer will 
> instruct me on how to pick the PLL gain constant for the firmware.
>
> 2. Directly clocking an AVR from the 5680A is unreliable prior to lock. I 
> haven’t exhaustively examined the startup behavior of the 5680, but power-up 
> reset of my GPS board used to not happen a lot of the time, and manual reset 
> was required. The AVR datasheet says that as long as the clock frequency is 
> kept within 2% from cycle to cycle that that’s ok, but either this 5680A 
> isn’t doing that or the AVR datasheet is wrong. Fortunately, there’s a 
> software workaround: fuse the controller for the internal 8 MHz oscillator 
> and switch over (I was surprised to learn that changing system clock sources 
> on the fly is an option) to the 5680 only once a physics lock is indicated by 
> the lock pin. That seems to be acceptably reliable. My purpose in mentioning 
> it is to see if anyone has examined the pre-lock behavior of the 5680 (I 
> understand it’s not a particularly interesting question) to see exactly how 
> jumpy it really is before it locks.
>
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Re: [time-nuts] What is "accuracy"? (newbie timenut, hi folks!)

[Azelio Boriani]

For a visual feeling of what are accuracy and stability see page 6 of this PDF:



On Fri, May 6, 2016 at 6:22 AM, wb6bnq  wrote:
> Hello Belinda,
>
> First off there is no such thing as accuracy, in and of itself.  I know many
> people on this list will call me on that, but accuracy requires a point of
> reference.  With regard to frequency that reference point has been defined
> by some World committee as a certain number of oscillations in a Cesium atom
> controlled within a specific set of conditions.
>
> The 100 ppm statement is talking about a change in frequency due to
> temperature,  The typical 100 ppm statement is saying for every change of 1
> degree (usually "C") the oscillator (or other components such as resistors,
> capacitors, etc.) will shift in value by a worst case of 100 ppm (parts per
> million).  This has nothing to do with accuracy except that it would not be
> considered accurate relative to a reference point.  What it does address is
> specifically the stability, but is not the only condition affecting
> stability.
>
> With respect to accuracy and stability, they are not related.  That is to
> say you could have extreme stability (say parts in 10 to the minus 21) and
> it could be way off from the recognized standard reference.  In the other
> direction you could have something that is adjusted to be precisely in
> agreement with the reference standard but will only hold that value for a
> very brief period of time.  The first case is a very good (and quite
> expensive) oscillator and the second example is a poor (and not expensive)
> oscillator.
>
> With regard to precision, the best example would be shooting at a target and
> how tight the grouping is maintained.  The tighter the grouping the better
> the precision.  You could have a tightly well defined small group of holes
> from the bullets but they could be anywhere on the paper target.  The only
> time you have accuracy (with respect to the shooting) is if all the bullets
> were directly in the bulls eye (center of target).  And if you can
> consisterntly repeat hitting just the bulls eye then you have stability.
>
> BillWB6BNQ
>
>
> BJ wrote:
>
>> Hi Time Nuts,
>>
>>
>>
>> I'm fairly new to the fascinating world of time and frequency, so I
>> apologise profusely in advance for my blatant ignorance.
>>
>>
>>
>> When I ask "what is accuracy" (in relation to oscillators), I am not
>> asking
>> for the textbook definition - I have already done extensive reading on
>> accuracy, stability and precision and I think I understand the basics
>> fairly
>> well - although, after you read the rest of this, you may well (rightly)
>> think  I am deluding myself. It doesn't help matters when some textbooks,
>> papers and web articles use the words precision, accuracy and uncertainty
>> interchangeably. (Incidentally, examples of my light reading include the
>> 'Vig tutorial' on oscillators, HP's Science of Timekeeping Application
>> note,
>> various NIST documents including the tutorial introduction on frequency
>> standards and clocks, Michael Lombardi's chapter on Time and Frequency in
>> the Mechatronics Handbook and many other documents including PTTI and
>> other
>> conference proceedings). Anyway, you can safely assume I understand the
>> difference between accuracy and precision in the confused musings that
>> follow below.
>>
>>
>>
>> What I am trying to understand is, what does it REALLY mean when the
>> manufacturer's specs for a frequency standard or 'clock' claim a certain
>> accuracy. For ease and argument's sake let us assume that the accuracy is
>> given as 100 ppm or 1e-4 
>> As per the textbook approach, I know I can therefore expect my 'clock' to
>> have an error of up to 86400x1e-4= 8.64 s per day.
>>
>>
>>
>> But does that mean that, say, after one day I can be certain that my clock
>> will be fast/slow by no more than 8.64 seconds or could it potentially be
>> greater than that? In other words, is the accuracy a hard limit or is it a
>> statistical quantity (so that there is a high probability that my clock
>> will
>> function this way, but that there is still a very small chance (say in the
>> 3sigma range) that the error may be greater so that the clock may be
>> fast/slow by, say, 10 seconds)? Is it something inherent, due to the
>> nature
>> of the type of oscillator (e.g. a characteristic of the crystal or atom,
>> etc.) or does it vary so that it needs to be measured, and if so, how is
>> that measurement made to produce the accuracy figure? Are environmental
>> conditions taken into account when making these measurements (I am
>> assuming
>> so)? In other words, how is the accuracy of a clock determined?
>>
>>
>> Note that I am conscious of the fact that I am being somewhat ambiguous
>> with
>> the definitions myself. It is my understanding that the accuracy (as given
>> in an oscillator's specs) relates to freq

Re: [time-nuts] synchronization for telescopes

[Azelio Boriani]

AM radio in Italy (what is left) is from 525KHz to 1715KHz and the TV
broadcast is now all digital, using QPSK or QAM COFDM modulation: not
so easy to use as a synchronization signal.

On Wed, May 4, 2016 at 7:42 PM, Chris Albertson
 wrote:
> How to increase the SNR.  Remember you are doing this in post processing
> not in real time.  So for each even that needs to be trimmed yo have access
> to literally millions of cycles of RF data both in the past and future
> relative to the event.  The signal cane near the noise floor of your
> receiver but it won't be.  These a stations with tens of kilowatts of power
> and yo get to use any number of them simultaneously if you like.
>
> HDD space might be a problem but you don't need to continuously record the
> data.  you only need X milliseconds per second.  X is what every you need
> for good statistics.  You assume your local oscillator (a $25 crystal) does
> not drift much over 100 milliseconds.
>
> Basically what you'd really like to do is have a two channel recorder one
> for your data and one for a continuously broadcast "timecode"  Then in post
> processing you create the time tag for each event by interpolating the time
> code.  All telescope listen to and record the same broadcast time code.  In
> post you remove the time of flight delay from broadcaster to each telescope.
>
> The question then is what to use as a time code.  You just need a
> transmitter that is common to everyone.  GPS can work.  GPS might be best
> because the receivers are dirt cheap because they are mass produced.
> But if you can sample a "free" rf signal in quadrature you can recover the
> phase very accurately if you have a 100,000 samples of it.  Take those
> 100,000 samples 10 times per second and you only have a 8MB/sec data rate.
> Those are made-up numbers.  I don't thing SNR is a problem as you are using
> an autocorrelation function to time aligned large data blocks not working
> in real time on each sample
>
> On Wed, May 4, 2016 at 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 reference
>> clock: this can be another very cheap solution. There are many AM stations
>> near the places we chosen, and these can be used.
>> A problem found was how to increase SNR: do you have a solution for this?
>> If possible this method would be the best, since longer baselines could be
>> made. The distance from the carrier source is not a problem since we'd use
>> a GPS module at each telescope. Also the software part is not a problem too.
>> Good the relative timestamp also, as it saves HDD space.
>>
>> Regards,
>> Ilia.
>>
>> On 05/04/16 15:28, Chris Albertson wrote:
>>
>>> One more comment.   It seems to me time-raging events is hard because you
>>> need many very good clocks that tracks absolute time.
>>>
>>> If you redefine the problem to be "determine the time difference between
>>> to
>>> events that occurred a couple nights ago it might be much easier.  This
>>> does not need to be done in real  time
>>>
>>> On Wed, May 4, 2016 at 8:25 AM, Chris Albertson <
>>> albertson.ch...@gmail.com>
>>> wrote:
>>>
>>> Maybe there is some simpler way to synchronize the telescopes.   Do they
 even need to know the absolute time?  I think only relative time maters.

 For that all they need is some kind of a signal that all the telescope
 can
 "see".   Could they use an FM or TV broadcast station?  They could sample
 and record the signal at a very high sample rate (maybe 4X the career
 frequency) and record their data at the same time.  each telescope would
 need to know its distance to the broadcast antenna.

 The idea is to make the hardware cheaper and simpler and put all the
 "work" on the post processing software developers.

 For this purpose, measuring the time difference of photons detected at
 different locations, I don't think the broadcast career needs to be
 exceptionally stable.  In post all you do to slide the recorded signal
 until a best match is found.  So we do need a modulated carrier.  We also
 have LOTS of data to use to compute the time alignment because you do it
 later, we'd have billions of samples so it should be immune to noise




>>>
>> --
>> Ilia Platone
>> via Ferrara 54
>> 47841
>> Cattolica (RN), Italy
>> Cell +39 349 1075999
>>
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>> and follow the instructions there.
>>
>
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] Fw: Optical transfer of time and frequency

[Azelio Boriani]

If every station has its own GPSDO, what is the purpose of the optical transfer?

On Mon, May 2, 2016 at 11:14 AM, Michael Wouters
 wrote:
> 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 records the difference. This is
> ambiguous modulo 1 ms but this is trivially resolved using GPS. You
> also probably know the distance between the stations to much better
> than 1 ms = 300 km :-) . You then post-process but this can be done
> with very little latency if you're keen.
>
> Cheers
> Michael
>
> On Mon, May 2, 2016 at 1:44 AM, Tom Van Baak  wrote:
>>> Has anybody experienced with free-space optical gigabit Ethernet
>>> links? I am curious about whether the transceivers have a fixed
>>> latency or at least a latency one can easily quantify online. This is
>>> the trickiest part for adding WR support on top of a given physical
>>> layer.
>>
>> Hi Javier,
>>
>> When searching this topic I ran across a commercial laser solution:
>>
>> http://www.laseroptronics.com/products.cfm/product/27-0-0.htm
>> http://www.laseroptronics.com/index.cfm/id/57-66.htm
>> http://www.laseroptronics.com/index.cfm/id/57-69.htm
>> etc.
>>
>> But, according to /57-67.htm it "starts" at $15k per node. Plus there's the 
>> cost of all the WR pieces, assuming the two are even compatible. So this is 
>> vastly above the ~$2k budget mentioned by OP. I also assume OP is not ready 
>> to embark on a one-off, multi-man-year R&D project.
>>
>> This particular issue -- how to synchronize (or, at least phase compare) 
>> multiple oscillators by a two-way laser link over a few km to within 500 ps 
>> -- is really quite interesting. It would, for example, allow me to do live 
>> monitoring of 5071A Cs time dilation on my next mountain-valley relativity 
>> experiment.
>>
>> /tvb
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Re: [time-nuts] Optical transfer of time and frequency

[Azelio Boriani]

Yes, but I see that the allan deviation figures they cite aren't
achievable with common time-nuts gear now. Considering a VLBI project:
first premium stability then superb time transfer.

On Fri, Apr 29, 2016 at 5:18 AM, Bruce Griffiths
 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 optical link."
> That paper indicates that  one way transfer with noise of a few picosec 
> should be feasible using an IR laser. Especially if only required at night 
> for synchronisation of the timebases of the various telescope/detectors in a 
> stellar intensity interferometer.
> Atmospheric scintillation should be lower as well as background noise from 
> the sky, sun etc. The other factors like rain, hail, snow, fog etc aren't an 
> issue  as these preclude observation of the stars of interest.
> Bruce
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
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Re: [time-nuts] SE880 GPSDO

[Azelio Boriani]

Here in Italy the DVB-T practice is to use GPSDOs to lock the
transmitters' carriers. This is needed to exploit the Single Frequency
Network (SFN) system. The frequency and time stability are stated in
the ETSI TR 101 190, 8.3.1 and 8.3.2 on page 41, in short they say 1us
is enough for the time and about the frequency it is 1/1000th of the
DVB-T carriers' spacing that is, at worst, 1116Hz so 1.1Hz of
stability.



On Fri, Apr 29, 2016 at 12:35 AM, Ilia Platone  wrote:
> Il 28/04/2016 23:22, Attila Kinali ha scritto:
>>
>> On Thu, 28 Apr 2016 21:01:49 +0200
>> Ilia Platone  wrote:
>>
>>> Thanks Attila, I know how to build a transmitter and a receiver, and now
>>> is more clear the system you designed. But as I will propose this system
>>> to an astro club, and in this astro club there's the possibility that
>>> not all would have a radio license, I need something "free-to-play", if
>>> it concern.
>>
>> Ok.. that's quite some constraint. This rules out any kind of
>> transmission.
>>
>>> I was wondering if it would be more convenient to lock to a signal from
>>> an AM broadcasting station, if available to a multiple of the OCXO. What
>>> do you think about?
>>
>> AFAIK most radio and TV transmitters are using some stable reference.
>> I don't know though what they use these days. It used to be an Rb.
>>
>> I would guess that using a radio station should in general work.
>> It should be as close as possible, so that you get as little
>> reflection as possible and that any multi-path from the troposphere
>> and ionosphere is minimized. If you still have any AM stations close
>> by, that would work. But these are more and more switched off and
>> replaced by digital broadcast systems.
>
> I know that some AM station still exists, a place where to setup the
> telescopes will have the local repetitors very close.
> I think that airports use AM modulation, but I sincerely don't know if it's
> legal even to listen at those frequencies. Their signal should be strong,
> however.
>
>> The most common radio and TV transmitters these days are DAB and DVB-T.
>> Both use QPSK or QAM signals. This makes locking to those signals
>> quite a bit more difficult. What you can do is, use a DAB/DVB-T
>> tuner chip like the MAX3580 or MAX3541, down convert the signals,
>> then use the FPGA to track the signals and steer the OCXO's EFC DAC.
>> Yes, this is a lot more complicated and you need to build quite a bit
>> of a DVB-T/DAB receiver in the FPGA. Fortunately, this is something
>> people have already implemented in software using GNURadio. Ie you
>> can have a look at what they have done, copy the over the parts that
>> you need. But still, this will be quite some serious effort and will
>> take you months at best.
>
> Will inform on AM stations.
>>
>> I also have no idea what the signal stability of the DVB-T and DAB
>> stations is. Maybe someone else (Magnus?) can comment on that.
>
> I would appreciate his contibution :)
>>
>> As such... I think using an AM station that is close by would be feasible.
>> Using DVB-T/DAB stations would be a lot of effort and I would advise
>> against it in a first step. GPS alone should give you ~1ns when done
>> right.
>> With more expensive equipment (high qual geodetic or timing antennas with
>> L1/L2 receivers) you should be able to go below that (see Michael Wouters'
>> mail).
>> An alternative approach would be to use an Rb reference instead of an
>> OCXO at the telescopes. This way you have a frequency stable reference
>> that you can use like the reference signal I mentioned in the other mail.
>> You would need one that has low phase noise (that rules out the FE-5680's
>> that are so cheap on ebay, ie you would need to go for LPRO, PRS10, FRS
>> or LPFRS). As now you only have a kind of stable reference, but you don't
>> know how far off it is (and probably not how fast its drifting), some
>> precision will need to be spend on determining its exact frequency.
>> But nonetheless it should give you additional precision when doing
>> the post-processing that you can use to increase the timing solution's
>> precision.
>
> The problem is not the absolute stability, but the relative error between
> the various stations. ie the telescopes clocks must not drift too much by
> each other.
>>
>>
>> Attila Kinali
>>
>
> --
> Ilia Platone
> via Ferrara 54
> 47841
> Cattolica (RN), Italy
> Cell +39 349 1075999
>
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Re: [time-nuts] Oncore battery

[Azelio Boriani]

Panasonic ML621 or equivalent. Alternatively you can use the battery
pin (pin 6): remove the onboard battery and use en external primary
cell (CR2032 or equivalent). See pages 15 to 21 of the M12M user
manual.


On Mon, Apr 25, 2016 at 2:11 AM, Joseph Gray  wrote:
> Can anyone recommend a rechargeable lithium coin cell that is a direct
> replacement for the ones that come on some Oncore receivers? Something
> I can order from Mouser or Digikey, if possible.
>
> Joe Gray
> W5JG
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Re: [time-nuts] Agilent Data logger3 info request

[Azelio Boriani]

Are GNUPlot, Grace and others not suitable? You can plot a CSV data
collection with virtually anything, R included.

On Sat, Apr 23, 2016 at 4:15 PM,   wrote:
>
> I have an Agilent 34970A data logger. It use the "Bencklink Data Logger3" as 
> software.
>
> I would like to capture the graph in a printable format instead the original 
> .csv . A .gif will be good to be inserted in documents.
>
> Can some one help me?
>
> thanks ,
> Luciano
> www.timeok.it
>
> Message sent via Atmail Open - http://atmail.org/
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Re: [time-nuts] Lea-6T Math error?

[Azelio Boriani]

Did you use the CFG-TMODE svinVarLimit to set 350 and the svinMinDur
to set 32400?
The CFG-TMODE svinVarLimit is a variance in squared mm, not a standard
deviation...

On Fri, Apr 15, 2016 at 6:27 AM, Bob Stewart  wrote:
> I hope I haven't posted about this before, but it's something that's bugged 
> me for awhile.  When I run a survey-in on an LEA-6T, the 
> CFG-TMODE2->fixedPosAcc value seems to be wrong.  For instance, I ran a 
> survey today and told it to run for 32,400 seconds and reach at least 350mm 
> accuracy.  When it finished, TIM-SVIM reported it had run 38,126 seconds with 
> a mean 3D std deviation of 350mm.  OK, so far.  So, I go look in the 
> CFG-TMODE2 structure and it reports 122mm.  That seems a bit odd, but OK.  
> And then I squared 350, and came up with 122500.  It appears that instead of 
> just moving the 350mm value over to the TMODE structure, they've squared it 
> and divided it by 1000.  I've noticed this happening on at least 2 versions 
> of the 6T.  I suppose I should do the same test on the M8T.
>
> Bob
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Re: [time-nuts] Lea-6T Math error?

[Azelio Boriani]

Yes, I see: the fixedPosAcc should be 18mm not 122.

On Fri, Apr 15, 2016 at 12:15 PM, Azelio Boriani
 wrote:
> Did you use the CFG-TMODE svinVarLimit to set 350 and the svinMinDur
> to set 32400?
> The CFG-TMODE svinVarLimit is a variance in squared mm, not a standard
> deviation...
>
> On Fri, Apr 15, 2016 at 6:27 AM, Bob Stewart  wrote:
>> I hope I haven't posted about this before, but it's something that's bugged 
>> me for awhile.  When I run a survey-in on an LEA-6T, the 
>> CFG-TMODE2->fixedPosAcc value seems to be wrong.  For instance, I ran a 
>> survey today and told it to run for 32,400 seconds and reach at least 350mm 
>> accuracy.  When it finished, TIM-SVIM reported it had run 38,126 seconds 
>> with a mean 3D std deviation of 350mm.  OK, so far.  So, I go look in the 
>> CFG-TMODE2 structure and it reports 122mm.  That seems a bit odd, but OK.  
>> And then I squared 350, and came up with 122500.  It appears that instead of 
>> just moving the 350mm value over to the TMODE structure, they've squared it 
>> and divided it by 1000.  I've noticed this happening on at least 2 versions 
>> of the 6T.  I suppose I should do the same test on the M8T.
>>
>> Bob
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Re: [time-nuts] Holdover recovery

[Azelio Boriani]

Yes, very interesting, good to have. I see differences: the most
notable is the plot of page 12 on the original italian version that is
missing on the ITU paper, that goes with the figure 4 on page 7 (of
the ITU one).

On Tue, Apr 5, 2016 at 12:57 AM, Magnus Danielson
 wrote:
> Hi,
>
> I had not seen the ITU-R version, nice.
> I have their paper and shared it with Hal on the side.
>
> This ITU-R version seems about the same, but I've got their names on it. I
> got a copy of their paper in english without their names on it, which might
> have been their input contribution to ITU-R. I then demanded a version with
> their names on it, so that I could share it, within a day I had that. When
> someone covered this aspect, why not spread it and they get the credit for
> it?
>
> I've visited them and seen this setup.
>
> Cheers,
> Magnus - who just got back to lodging/dorm-room after discussing things with
> Attila
>
>
> On 04/05/2016 12:01 AM, Logan Cummings wrote:
>>
>> My Italian is not very good, but I think this is the English translation
>> via ITU:
>>
>> https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2253-2012-PDF-E.pdf
>>
>> -Logan
>>
>> On Mon, Apr 4, 2016 at 1:10 PM,  wrote:
>>
>>> Here the italian version:
>>>
>>> http://www.crit.rai.it/eletel/2012-1/121-2.pdf
>>>
>>> Luciano
>>> www.timeok.it
>>>
>>>
>>> On Mon 04/04/16 21:28 , Magnus Danielson 
>>> wrote:
>>>
 Hi Hal,

 On 04/04/2016 05:39 AM, Hal Murray wrote:
>
>
> Has anybody studied what happens when a GPSDO comes out of holdover?
>>>
>>> Has
>
> anybody seen any specs? I don't think I have.
>
> I think you have a choice of quick recovery for time or frequency, but

 you
>
> can't get both.
>
> Suppose your setup has been in holdover for a while. The frequency is
> slightly off. The time offset of the PPS pulse will be the integral of

 the
>
> frequency offset.
>
> What happens when you come out of holdover? If you fix the frequency,

 the
>
> PPS will stay off.
>
> Suppose the PPS has drifted by 1 ns. If you correct that in 1 second,

 the
>
> frequency will need to be off by 1E9 during that second.


 The RAI laboratory in Torino have made such tests and published
 measurements and recommendations. For a long time it was only available
 in italian, but there is now an english version available.

 Cheers,
 Magnus
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 Links:
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>>>
>>> http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma

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Re: [time-nuts] Holdover recovery

[Azelio Boriani]

The only english text I'm able to find is:

Analysis of the GPS frequency reference stability

Laboratory analysis of the dynamic
behaviour of some GPS receivers has
allowed to identify a criticality in their
use as ‘clocks’ to synchronize DVB-T
SFN networks. To fix this criticality, the
Research Centre has defined a new criterion
for the design of GPS equipment
for use in broadcasting applications.
This criterion is proposed as an Italian
contribution to the ITU


On Mon, Apr 4, 2016 at 10:10 PM,   wrote:
> Here the italian version:
>
> http://www.crit.rai.it/eletel/2012-1/121-2.pdf
>
> Luciano
> www.timeok.it
>
>
> On Mon 04/04/16 21:28 , Magnus Danielson  wrote:
>
>> Hi Hal,
>>
>> On 04/04/2016 05:39 AM, Hal Murray wrote:
>> >
>> > Has anybody studied what happens when a GPSDO comes out of holdover? Has
>> > anybody seen any specs? I don't think I have.
>> >
>> > I think you have a choice of quick recovery for time or frequency, but
>> you
>> > can't get both.
>> >
>> > Suppose your setup has been in holdover for a while. The frequency is
>> > slightly off. The time offset of the PPS pulse will be the integral of
>> the
>> > frequency offset.
>> >
>> > What happens when you come out of holdover? If you fix the frequency,
>> the
>> > PPS will stay off.
>> >
>> > Suppose the PPS has drifted by 1 ns. If you correct that in 1 second,
>> the
>> > frequency will need to be off by 1E9 during that second.
>>
>> The RAI laboratory in Torino have made such tests and published
>> measurements and recommendations. For a long time it was only available
>> in italian, but there is now an english version available.
>>
>> Cheers,
>> Magnus
>> ___
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>>
>>
>> Links:
>> --
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Re: [time-nuts] Holdover recovery

[Azelio Boriani]

In italian:

Can't find it in english...

On Mon, Apr 4, 2016 at 9:28 PM, Magnus Danielson
 wrote:
> Hi Hal,
>
> On 04/04/2016 05:39 AM, Hal Murray wrote:
>>
>>
>> Has anybody studied what happens when a GPSDO comes out of holdover?  Has
>> anybody seen any specs?  I don't think I have.
>>
>> I think you have a choice of quick recovery for time or frequency, but you
>> can't get both.
>>
>> Suppose your setup has been in holdover for a while.  The frequency is
>> slightly off.  The time offset of the PPS pulse will be the integral of
>> the
>> frequency offset.
>>
>> What happens when you come out of holdover?  If you fix the frequency, the
>> PPS will stay off.
>>
>> Suppose the PPS has drifted by 1 ns.  If you correct that in 1 second, the
>> frequency will need to be off by 1E9 during that second.
>
>
> The RAI laboratory in Torino have made such tests and published measurements
> and recommendations. For a long time it was only available in italian, but
> there is now an english version available.
>
> Cheers,
> Magnus
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Re: [time-nuts] Not so cheap GPSDO's

[Azelio Boriani]

The Z3815A has the famous hockey puck OCXO designed by Rick Karlquist.
I have one Z3815A from the seller you mention: it works but, inside,
there was heavy rust on the Furuno GPS receiver case. The old Furuno
receiver in the Z3815A has the GPS week rollover bug as all the
surplus Z-series HP GPSDO's. If you buy either one (Z3816 or Z3815 or
both) plan to do some maintenance/cleaning on them.

On Thu, Feb 11, 2016 at 8:30 AM, Joseph Gray  wrote:
> Moving upscale to more well known models that cost quite a bit more, I
> see several Z3805A units. It looks like more than one type of OCXO was
> used in these. Which variant would you recommend?
>
> The less expensive Z3805A's look like they have been beat to crap,
> before or after being pulled from the scrap pile. I'd worry about
> damage to the OCXO in these. For more money, yixunhk has some nicely
> packaged units and AFAIK he has a good reputation.
>
> Another from yixunhk is this Z3816A for $350 w/shipping. This package
> looks similar to my Z3801A:
>
> http://www.ebay.com/itm/271906200825
>
> And finally, for $440 w/shipping, yixunhk has this nicely repackaged Z3815A:
>
> http://www.ebay.com/itm/251226090087
>
> Comments on all of these is welcome. Of these "Z" units, which one
> would you buy, and why?
>
> Thanks again,
>
> Joe Gray
> W5JG
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Re: [time-nuts] Cheap GPSDO's

[Azelio Boriani]

The last you mention is a FEI PicoSync with the even second (PP2S)
output. Usually, for time-nuts purposes (and if it will be your first
GPSDO), it is better to have a pulse-per-second (PPS) output,

On Thu, Feb 11, 2016 at 8:13 AM, Joseph Gray  wrote:
> I searched the list archives and found some discussion mid-to-late
> last year about several inexpensive GPSDO's made by bg7tbl. It seems
> that all of the better models (according to discussion on the EEVBlog
> forum) are gone.
>
> I do find two similar units currently listed:
>
> http://www.ebay.com/itm/252162780444
>
> http://www.ebay.com/itm/181948031179
>
> If these have already been discussed, please point me in the right
> direction. Otherwise, does anyone know anything about these particular
> units?
>
> Then, there is this listing, which looks like factory-made and not homemade:
>
> http://www.ebay.com/itm/181389532308
>
> Comments on this one?
>
> Thanks,
>
> Joe Gray
> W5JG
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Re: [time-nuts] New Member / Z3801

[Azelio Boriani]

Welcome,
you hit the usual GPS week rollover issue, see these:


No impact on the 10MHz/PPS accuracy.
No command can correct the rollover, I seem to remember that if you
set the date before the GPS has a fix (right after a power cycle),
then the date will be correct (until the next power cycle).
There is also this software:


On Sun, Jan 17, 2016 at 3:59 PM, Artek Manuals  wrote:
> Hi guys
>
> Dave at ArtekManuals.com here. Long time electronics enthusiast/tinkerer/
> ham radio op.
> Recently moved and am in the process of setting up my long dreamed of a
> planned electronics lab and radio shack (NR1DX).
>
> At the heart of the lab is a HP Z3801 GPSDO to provide  an external 10MHz
> frequency reference. I bought the unit about 15 years ago but it has been in
> environmentally controlled storage ever since. Serial prefix is 3517Ax
> and I am running this on a +54VDC supply. Upon firing the Z3801 up, the
> first conundrum I am running into is that the unit does not seem to support
> setting the date above 12/31/2007. Sometimes during the survey mode it will
> automatically set the correct 2016 date , other times during the survey the
> date stays stuck on 1996. The unit tracks the satellites and mostly settles
> in around 1 second PPS at +/- 20ns with a holdover of 4 to 8us. More about
> the "mostly" comment in a later post.
>
> On the surface the actual reported date is not a big deal for me. as long as
> the date is not critical to the GPSDO function? The engineer in me would
> like to be able to set the date correctly ..just because. When
> attempting to set the using GPS:INIT:DATE I get an E-222 error (data out of
> range).
>
> So here are my initial questions.
> 1) I assume that the date thing is a firmware issue? Is there updated
> firmware out there that allows dates above 2007, 12, 31?
> 2) If all I care about is 10MHz accuracy, do I need to care about the date?
> 3) Is there a different command string I should be using?
> 4)Software: I am running HP SATSTAT and Z38XX on a WIN-XP/32 laptop ...IS
> there something better (or different) I should be running in the way of FREE
> software? I looked at the GPSCon package and so far questions about support
> for the software and portability eventually to WIN-10 supported have gone
> unanswered (not a good sign)
>
> Finally I am sure that the above have been addressed on older posts, but I
> gave up searching in frustration.  Is there an easy way to search the ENTIRE
> list archive. It seems that the archives must be queried one month at time
> which is REALLY TEDIOUS
>
> Dave
> NR1DX
> ArtekManuals.com
>
> --
> Dave
> manu...@artekmanuals.com
> www.ArtekManuals.com
>
>
> ---
> This email has been checked for viruses by Avast antivirus software.
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Re: [time-nuts] NTBW50AA Problem

[Azelio Boriani]

If there is a problem in the RF front-end, no software can report
this... actually the only way to test the radio section of a GPS
receiver is to just connect it to an antenna (unless there is a GPS
simulator available).

On Sat, Jan 9, 2016 at 2:49 AM, Michael Bauer  wrote:
> My subj Nortel Trimble GPSTM had been working well for about two years.
> Changed QTH by about 20 miles, reconnected with same power supply, coax and
> antenna.  Cannot see any GPS satellites or 10 mHz output (9.8MHz on 8X Chip
> is present and front panel LEDs show the unit responding to software
> commands as before).
>
> Lady Heather and tboltmon both report ROM, RAM, OSC, POWER, EEPROM and
> ANTENNA OK thru RS-232 interface.  Replaced bullet antenna anyway - no
> change.  5VDC present at antenna and it draws about 33 mA.  Other local GPS
> devices (two vehicles and one EarthMate) achieve 3D fixes from ground level
> antennas.  Performed warm, cold and hard resets (erasing former GPS
> position), min elevation set at 15 degrees.  Survey starts, but doesn't
> proceed.  All eight satellite status lines show yellow and zero's across.
> Undisciplined, No GPS time, no Posn.  Start date is reported as 07 April
> 2019 week 2048.
>
> The unit performed flawlessly at previous QTH frequently showing good
> signals from 7-8 GPS satellites.  What happened?  Do I have a broken box
> that cannot be detected by software control/reporting programs?
>
> Thanks in advance for any ideas.
>
> 73,
>
> Mike - W7GW
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Re: [time-nuts] Problems with WinOncore12 2.1X3 and an M12+T

[Azelio Boriani]

Try this 

On Sun, Jan 3, 2016 at 5:19 PM, Philip Pemberton  wrote:
> Hi,
>
> I'm currently testing a Motorola M12+T receiver for possible use in a
> GPS-disciplined 10MHz oscillator. At the moment, I'm using WinOncore12
> version 2.1X3 to communicate with it.
>
> Unfortunately this version of WinOncore seems to be unable to decode the
> 12-channel control messages, which means things like the TRAIM status
> don't display -- Pulse Status is always "Off", the Sawtooth is a flat
> line, and Sigma and Error are zero. If I open up the command monitor, I
> can see a bunch of "unrecognized command" errors for "@@Hn". If I change
> the timing settings I get one for "@@Gf" too, and the
>
> If you use a serial port monitor, you can see that the response to the
> @@Hn and @@Gf messages are actually valid, and the parameters look
> reasonable (e.g. actual sawtooth and pulse status values).
>
> Does anyone have a version of WinOncore12 which works correctly with the
> M12+T, or know of a way to get this one to behave itself?
>
> Thanks,
> --
> Phil.
> li...@philpem.me.uk
> http://www.philpem.me.uk/
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Re: [time-nuts] Problems with WinOncore12 2.1X3 and an M12+T

[Azelio Boriani]

Or this <http://www.stratfordradiosociety.freeserve.co.uk/WinOncore12_1_2.zip>
Interesting to see that there is a 2.1 version...

On Sun, Jan 3, 2016 at 6:34 PM, Azelio Boriani  wrote:
> Try this <http://www.synergy-gps.com/images/stories/Software/WinOncore12.zip>
>
> On Sun, Jan 3, 2016 at 5:19 PM, Philip Pemberton  wrote:
>> Hi,
>>
>> I'm currently testing a Motorola M12+T receiver for possible use in a
>> GPS-disciplined 10MHz oscillator. At the moment, I'm using WinOncore12
>> version 2.1X3 to communicate with it.
>>
>> Unfortunately this version of WinOncore seems to be unable to decode the
>> 12-channel control messages, which means things like the TRAIM status
>> don't display -- Pulse Status is always "Off", the Sawtooth is a flat
>> line, and Sigma and Error are zero. If I open up the command monitor, I
>> can see a bunch of "unrecognized command" errors for "@@Hn". If I change
>> the timing settings I get one for "@@Gf" too, and the
>>
>> If you use a serial port monitor, you can see that the response to the
>> @@Hn and @@Gf messages are actually valid, and the parameters look
>> reasonable (e.g. actual sawtooth and pulse status values).
>>
>> Does anyone have a version of WinOncore12 which works correctly with the
>> M12+T, or know of a way to get this one to behave itself?
>>
>> Thanks,
>> --
>> Phil.
>> li...@philpem.me.uk
>> http://www.philpem.me.uk/
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Re: [time-nuts] Mechanical clock sound pickup circuit

[Azelio Boriani]

Maybe this can be useful to make the pick-up:

http://www.meas-spec.com/downloads/LDT_Series.pdf

they can be found also on the usual auction site.

On Sat, Dec 12, 2015 at 10:28 PM, Alexander Pummer  wrote:
>
> Once upon the time there was a "Vibrograph", see nice pictures here:
> https://www.google.com/search?q=vibrograph&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwigtcmSn9fJAhUW8GMKHVNyAMcQsAQIHA&biw=1760&bih=888
> ,which picked up the sound of watches, clocks, and the watch maker was able
> to set the watch very accurately, these machines did not used any fancy DSP
> despite that they worked very well, I myself used one some 55 years ego in
> Switzerland,.
> to get a reliable digital signal from a noisy analog signal is the most
> reliable way to use an analog PLL with a linear multiplier type phase
> detector  [ at least one input of the phase detector must be linear e.g. a
> transitional gate [cd4016 and it's derivatives ], the noise could be
> filtered out with a low pass filter or integrator, the price of the method
> is that it also eliminates the phase-noise of the the input signal, .
> That was the method which was used by the Vibrograph.
> 73
> LJ6UHN
> Alex
>
>
> On 12/12/2015 7:15 AM, Dave Martindale wrote:
>>
>> Someone is in the process of writing open-source watch timing software.
>> You may want to look into it.
>>
>> It was announced here:
>>
>> http://forums.watchuseek.com/f6/open-source-timing-software-2542874-post21977314.html#poststop
>>
>> It contains these links:
>> First the goodies. Here are Windows binaries
>> http://ciovil.li/tg.zip
>> and here is the full source code
>> https://github.com/vacaboja/tg
>>
>> Apparently this software is better at dealing with noisy signals from
>> microphones than Biburo.  Since it's open source, you can see what it's
>> doing internally.  It expects an analog input, and does its own filtering
>> to find the interesting edges within the sound of each tick.
>>
>> The precision with which you can time events is likely to be limited by
>> the
>> frequency response of your sensor and the amplifier.  If that's limited to
>> 20 kHz, a standard PC sound card is adequate.  For up to 80 kHz or so, you
>> can buy a relatively inexpensive USB "audio interface" that digitizes at
>> 192 kHz (typically 24 bit resolution).  At somewhat higher cost, you can
>> get professional audio interfaces that accept an external clock source.
>>
>> - Dave
>>
>>
>> On Fri, Dec 11, 2015 at 1:44 PM, Andrea Baldoni 
>> wrote:
>>
>>> Hello!
>>>
>>> I decided to do some experiments with mechanical clocks, so I worked a
>>> little
>>> on picking up escapement ticking sound, with the idea of processing it
>>> and
>>> obtaining a "clean" digital pulse to feed a counter.
>>>
>>> So far, I have not yet been able to find the best way to obtain a digital
>>> pulse,
>>> but I have already built the preamp for the piezoelectrick pickup, that
>>> I used to feed the mic input of a PC sound card for spectrum analysis.
>>>
>>> The timing could eventually be done in software because the whole idea of
>>> measuring watches by picking up their noise almost surely doesn't allow
>>> high
>>> resolution anyway, but I will plan to try hardware solutions as well in
>>> the
>>> future. I hope to be able to measure the jitter of the clock, but it will
>>> be
>>> very hard.
>>>
>>> In the meantime, with the free software Biburo you can download here
>>>
>>> http://tokeiyade.michikusa.jp
>>>
>>> you can regulate your wrist watch.
>>>
>>> Best regards,
>>> Andrea Baldoni
>>>
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>>
>> -
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 2016.0.7294 / Virus Database: 4483/11164 - Release Date: 12/12/15
>
>
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Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

[Azelio Boriani]

Something like good_100MHz_OCXO+DDS => same as a BVA?

On Tue, Dec 8, 2015 at 5:32 PM, Attila Kinali  wrote:
> Moin,
>
> I've been digging through some stuff and stumbled (again) over Rick's
> paper on high resolution, low noise DDS generation[1] and got confused.
> The scheme is very simple and looks like to be quite easy and reliably
> to implement. If I understood it correctly, the critical points are the
> DDS, its sideband generation and the LO/RF feedthrough in the mixers.
> Nothing that is not known and nothing that is too difficult to handle
> (the 10.7MHz filter get rid of most of the feedthrough already and
> there has been a lot written on how to design DDS for specific applications).
>
> What puzzled me is, why this has not been used more often to correct
> the frequency of OCXOs instead of using some DAC-to-EFC scheme?
>
> Given that Archita Hati et al. were getting very low noise numbers on
> their RF signal generation scheme using dividers [2], I don't think that
> the noise of the mixers would be the limiting factor here, but rather
> that the phase noise should be still dominated by the 10MHz oscillator.
>
> My guestimate is that something like this would cost approximately 5USD
> per divider stage, plus 20 USD for the DDS plus initial mixer. The only
> problem would be to get a narrow band 10.0MHz filter (I couldn't find
> one within 5 minutes of googling). 5 stages should cost around 50-70USD)
> and will give a resolution better than 5uHz (100MHz DDS with 24bit)
> down to 20pHz range (100MHz DDS with 32bit), which are 1:5e-13
> and 1:2e-15 respectively.
>
> Compared to an EFC system that costs somewhere in the range of 10-50USD
> and gives a resolution of something between 1:5e-12 (0.3ppm tuning range,
> 16bit DAC) and 1:1e-13 (10^-7 tuning range and 20bit DAC). Especially the
> 20bit DAC version gives a lot of electrical problems, starting from the
> stability of the reference, leakage current trough various components and the 
> PCB etc pp, while the DDS scheme, as a "digital" scheme is virtually free
> of those.
>
> So, the DDS scheme is easier to reproduce, more stable over time and
> costs only slightly more (unless you try to use an LTZ1000 as reference,
> then the reference alone costs more then the whole DDS scheme).
>
> So, what did I miss? Why do people use DAC-EFC control instead of
> the DDS scheme?
>
> Attila Kinali
>
> [1] "A narrow band high-resolution synthesizer using a direct digital
> synthesiser followed by repeated dividing and mixing", Richard Karlquist, 1995
> http://www.karlquist.com/FCS95.pdf
>
> [2] "State-of-the-Art RF Signal Generation From Optical Frequency Division".
> by Hati, Nelson, Barnes, Lirette, Fortier, Quinlan, DeSalvo, Ludlow, Diddams,
> Howe, 2013
> http://tf.boulder.nist.gov/general/pdf/2646.pdf
>
> --
> It is upon moral qualities that a society is ultimately founded. All
> the prosperity and technological sophistication in the world is of no
> use without that foundation.
>  -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

[Azelio Boriani]

Given that until now good (maximum stability) OCXO are much less than
100MHz, from the OCXO we exploit its high stability and we impose
accuracy from a coordinated source: the OCXO+EFC method uses the
built-in stability and disciplines the accuracy.
The DDS method virtually can start from any oscillator, apply a
suitable correction function giving the same result, transferring the
hardware characteristic of a BVA (for example) into the driving
function.
Can a DDS be driven with the speed necessary to correct the output so
that it results in the same stability as a BVA, starting from a given
unstable oscillator?
Or, how much unstable can be the 100MHz starting oscillator so that I
can obtain after the DDS+suitable_driving_function  the same final
stability as an ordinary 10MHz OCXO?

On Tue, Dec 8, 2015 at 6:44 PM, Azelio Boriani  wrote:
> Something like good_100MHz_OCXO+DDS => same as a BVA?
>
> On Tue, Dec 8, 2015 at 5:32 PM, Attila Kinali  wrote:
>> Moin,
>>
>> I've been digging through some stuff and stumbled (again) over Rick's
>> paper on high resolution, low noise DDS generation[1] and got confused.
>> The scheme is very simple and looks like to be quite easy and reliably
>> to implement. If I understood it correctly, the critical points are the
>> DDS, its sideband generation and the LO/RF feedthrough in the mixers.
>> Nothing that is not known and nothing that is too difficult to handle
>> (the 10.7MHz filter get rid of most of the feedthrough already and
>> there has been a lot written on how to design DDS for specific applications).
>>
>> What puzzled me is, why this has not been used more often to correct
>> the frequency of OCXOs instead of using some DAC-to-EFC scheme?
>>
>> Given that Archita Hati et al. were getting very low noise numbers on
>> their RF signal generation scheme using dividers [2], I don't think that
>> the noise of the mixers would be the limiting factor here, but rather
>> that the phase noise should be still dominated by the 10MHz oscillator.
>>
>> My guestimate is that something like this would cost approximately 5USD
>> per divider stage, plus 20 USD for the DDS plus initial mixer. The only
>> problem would be to get a narrow band 10.0MHz filter (I couldn't find
>> one within 5 minutes of googling). 5 stages should cost around 50-70USD)
>> and will give a resolution better than 5uHz (100MHz DDS with 24bit)
>> down to 20pHz range (100MHz DDS with 32bit), which are 1:5e-13
>> and 1:2e-15 respectively.
>>
>> Compared to an EFC system that costs somewhere in the range of 10-50USD
>> and gives a resolution of something between 1:5e-12 (0.3ppm tuning range,
>> 16bit DAC) and 1:1e-13 (10^-7 tuning range and 20bit DAC). Especially the
>> 20bit DAC version gives a lot of electrical problems, starting from the
>> stability of the reference, leakage current trough various components and 
>> the PCB etc pp, while the DDS scheme, as a "digital" scheme is virtually free
>> of those.
>>
>> So, the DDS scheme is easier to reproduce, more stable over time and
>> costs only slightly more (unless you try to use an LTZ1000 as reference,
>> then the reference alone costs more then the whole DDS scheme).
>>
>> So, what did I miss? Why do people use DAC-EFC control instead of
>> the DDS scheme?
>>
>> Attila Kinali
>>
>> [1] "A narrow band high-resolution synthesizer using a direct digital
>> synthesiser followed by repeated dividing and mixing", Richard Karlquist, 
>> 1995
>> http://www.karlquist.com/FCS95.pdf
>>
>> [2] "State-of-the-Art RF Signal Generation From Optical Frequency Division".
>> by Hati, Nelson, Barnes, Lirette, Fortier, Quinlan, DeSalvo, Ludlow, Diddams,
>> Howe, 2013
>> http://tf.boulder.nist.gov/general/pdf/2646.pdf
>>
>> --
>> It is upon moral qualities that a society is ultimately founded. All
>> the prosperity and technological sophistication in the world is of no
>> use without that foundation.
>>  -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] Hydrogen maser frequency jumps

[Azelio Boriani]

How are related the three locations' jumps? Do they occur at the same
time? One more than the others?

On Sat, Dec 5, 2015 at 11:45 AM, Poul-Henning Kamp  wrote:
> 
> In message 
> 
> , Jim Palfreyman writes:
>
>>The weird thing is that the jump is ~0.7ns and that 1/0.7E-9 is close-ish
>>to 1420.4MHz which is the hydrogen line. Too much of a coincidence for me.
>
> Is there a direct digital divider chain to the PLL which steers the
> 5Mhz OCXO ?
>
> If so the obvious thing to look at is a weak input signal on the input
> side of that divider.
>
>
> --
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@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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Re: [time-nuts] PM6681 and Timelab (was: PM6680 or 53131A for TimePod)

[Azelio Boriani]

Not necessarily, if you follow the service manual's procedure, you can
replace the backup 3V cell safely, keeping the calibration data: the
problem is checking periodically the backup cell or replacing it
regularly (say, every 5 years).

On Tue, Nov 17, 2015 at 12:33 PM, davidh  wrote:
>
>
> Hi Angus,
>
> I have three 6681s operating concurrently under a single instance of timelab
> beta. It operates perfectly, even live n-cornered measurements. Kudos to
> John!
>
> The only downside (and I understand why it's this way) is that each counter
> needs a unique GPIB interface, but this is a timelab requirement and nothing
> to do with the counters.
>
> My only fear regarding the counters is that I'll lose the cal one day, so
> I'm keen to discover how we can calibrate them ourselves.
>
> Cheers,
>
> david
>
>
> On 17/11/2015 7:32 AM, Angus wrote:
>>
>> Hi,
>>
>> PM6681's turn up at quite a good price too, and you get a lot of
>> extras over the 6680 - does anyone know if Timelab will work with a
>> 6681?
>>
>> Angus.
>>
>>
>>
>> On Sun, 15 Nov 2015 15:10:42 -0800, you wrote:
>>
>
>
>
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Re: [time-nuts] PM6681 and Timelab (was: PM6680 or 53131A for TimePod)

[Azelio Boriani]

Not necessarily, if you follow the service manual's procedure, you can
replace the backup 3V cell safely, keeping the calibration data: the
problem is checking periodically the backup cell or replacing it
regularly (say, every 5 years).

On Tue, Nov 17, 2015 at 12:33 PM, davidh  wrote:
>
>
> Hi Angus,
>
> I have three 6681s operating concurrently under a single instance of timelab
> beta. It operates perfectly, even live n-cornered measurements. Kudos to
> John!
>
> The only downside (and I understand why it's this way) is that each counter
> needs a unique GPIB interface, but this is a timelab requirement and nothing
> to do with the counters.
>
> My only fear regarding the counters is that I'll lose the cal one day, so
> I'm keen to discover how we can calibrate them ourselves.
>
> Cheers,
>
> david
>
>
> On 17/11/2015 7:32 AM, Angus wrote:
>>
>> Hi,
>>
>> PM6681's turn up at quite a good price too, and you get a lot of
>> extras over the 6680 - does anyone know if Timelab will work with a
>> 6681?
>>
>> Angus.
>>
>>
>>
>> On Sun, 15 Nov 2015 15:10:42 -0800, you wrote:
>>
>
>
>
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Re: [time-nuts] The Pendulum Paradigm by Martin Beech, 2014

[Azelio Boriani]

Yes, but first you need a very stable pendulum clock as pointed out by
TVB, a stability better than 0.05ppm for a mechanical clock is a real
challenge.



On Thu, Oct 29, 2015 at 12:56 PM, Jim Lux  wrote:
> On 10/28/15 7:48 PM, Jim Lux wrote:
>>
>> On 10/28/15 7:23 AM, Peter Reilley wrote:
>>>
>>> I have been pondering pendulum clocks.   I was wondering what the ADEV
>>> of a
>>> pendulum would show.   I assume that you could see the errors in the
>>> gear train.
>>> You should see the period of each gear.   You should see the spring wind
>>> down
>>> and being rewound.
>>>
>>> Further, would you be able to see the phase of the moon and the tides?
>>> This
>>> is using the pendulum as a gravimeter.   Would it be sensitive enough
>>> for that?
>>>
>>
>> yes.. it's in the sub-ppm range, as I recall.
>>
>> Period goes as sqrt(L/g)
>>
>>
>> from wikipedia
>> lunar tidal acceleration at the Earth's surface along the Moon-Earth
>> axis is about 1.1 × 10−7 g, while the solar tidal acceleration at the
>> Earth's surface along the Sun-Earth axis is about 0.52 × 10−7 g
>>
>>
>> So sqrt(1/(1+1E-7))... about 0.05 ppm
>>
>
> so you'd need an ADEV <1E-9 at a tau of 12 hours
>
>
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Re: [time-nuts] GPS Crystal Frequencies

[Azelio Boriani]

Usually GPS receivers have CPU clock frequencies that are not an
integer multiple of the chipping rate: that's why there is the
sawtooth correction in the timing units. The LO frequency for the
receiver front-end is not a problem due to the fractional-N PLL. The
Motorola M12 seems to use a 40MHz clock, uBlox receivers use 48MHz
clock...

On Tue, Oct 27, 2015 at 3:06 AM, Brooke Clarke  wrote:
> Hi:
>
> I understand 10.230 MHz since when multiplied it gives 1176.45,1227.60,
> 1381.05 & 1575.42 MHz, all GPS carrier frequencies.
> http://www.prc68.com/I/DAGR.shtml#GPSs
> But I've got a number of GPS receivers that have Rakon unit oscillators with
> a frequency of 10.949297.
> http://www.prc68.com/I/DAGR.shtml#Polaris_Link
> What's the story?
>
> PS I'm looking for documentation on the Polaris Link (civilian) GPS board.
>
> Mail_Attachment --
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
> http://www.prc68.com/I/DietNutrition.html
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Re: [time-nuts] Rohde & Schwarz GPSDO

[Azelio Boriani]

Here are 2 pictures of the 1U unit and the card.

On Thu, Oct 8, 2015 at 1:05 PM, Bob Camp  wrote:
> Hi
>
> One thing you can expect - some sort of issue with the GPS rollover issue.
> Can it be fixed on this or that unit? That’s going to be highly variable 
> model to
> model. Not much of an issue for a frequency standard, but a pain for NTP.
>
> Bob
>
>> On Oct 7, 2015, at 11:21 PM, Tom Knox  wrote:
>>
>> What is interesting is I spent a little time on the Manufactures Web Site 
>> and could find no AD or PN specs.
>> So even if you can find the down converter antenna, you have no idea how 
>> well it will perform.
>> I imagine it has a something like an Oscilloquartz 8663. No doubt as with 
>> almost all RS products it will be very high build quality.
>> Cheers;
>> Thomas Knox
>>
>>
>>
>>> From: rbenw...@verizon.net
>>> To: time-nuts@febo.com
>>> Date: Wed, 7 Oct 2015 22:41:11 -0400
>>> Subject: Re: [time-nuts] Rohde & Schwarz GPSDO
>>>
>>> That's why you can run 300meters of RG-58!  This is the "missing"
>>> antenna/converter unit.
>>>
>>> https://www.meinbergglobal.com/english/products/gps-antenna-converter.htm
>>>
>>> Here is one, this time with the antenna:
>>> http://www.ebay.com/itm/Meinberg-ED170MP-GPS-Satellite-Disciplined-Atomic-Cl
>>> ock-10MHz-Oscillator-Antenna-/281560964740?hash=item418e575e84
>>>
>>> Bob
>>>
>> -Original Message-
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Arthur
>> Dent
>> Sent: Wednesday, October 07, 2015 7:46 AM
>> To: time-nuts@febo.com
>> Subject: [time-nuts] Rohde & Schwarz GPSDO
>>
>> I believe that like a lot of the Meinberg receivers that this uses a
>>> down
>> converter to give an IF frequency of
>> 35.4 MHz. If you don't have the converter that apparently isn't included
>>> with
>> the receiver you have a $300 paperweight.
>> You might want to check with the seller before bidding.
>>
>> -Arthur
>> ___
>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>> -
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 2015.0.6140 / Virus Database: 4435/10749 - Release Date:
>> 10/03/15
>>>
>>> ___
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>>> and follow the instructions there.
>>
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>
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Re: [time-nuts] Rohde & Schwarz GPSDO

[Azelio Boriani]

Forgot to mention: the GPSMON32 is free

<https://www.meinbergglobal.com/english/sw/#gpsmon>

On Thu, Oct 8, 2015 at 3:29 PM, Azelio Boriani  wrote:
> Here are 2 pictures of the 1U unit and the card.
>
> On Thu, Oct 8, 2015 at 1:05 PM, Bob Camp  wrote:
>> Hi
>>
>> One thing you can expect - some sort of issue with the GPS rollover issue.
>> Can it be fixed on this or that unit? That’s going to be highly variable 
>> model to
>> model. Not much of an issue for a frequency standard, but a pain for NTP.
>>
>> Bob
>>
>>> On Oct 7, 2015, at 11:21 PM, Tom Knox  wrote:
>>>
>>> What is interesting is I spent a little time on the Manufactures Web Site 
>>> and could find no AD or PN specs.
>>> So even if you can find the down converter antenna, you have no idea how 
>>> well it will perform.
>>> I imagine it has a something like an Oscilloquartz 8663. No doubt as with 
>>> almost all RS products it will be very high build quality.
>>> Cheers;
>>> Thomas Knox
>>>
>>>
>>>
>>>> From: rbenw...@verizon.net
>>>> To: time-nuts@febo.com
>>>> Date: Wed, 7 Oct 2015 22:41:11 -0400
>>>> Subject: Re: [time-nuts] Rohde & Schwarz GPSDO
>>>>
>>>> That's why you can run 300meters of RG-58!  This is the "missing"
>>>> antenna/converter unit.
>>>>
>>>> https://www.meinbergglobal.com/english/products/gps-antenna-converter.htm
>>>>
>>>> Here is one, this time with the antenna:
>>>> http://www.ebay.com/itm/Meinberg-ED170MP-GPS-Satellite-Disciplined-Atomic-Cl
>>>> ock-10MHz-Oscillator-Antenna-/281560964740?hash=item418e575e84
>>>>
>>>> Bob
>>>>
>>>>>>> -Original Message-
>>>>>>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Arthur
>>>>>>> Dent
>>>>>>> Sent: Wednesday, October 07, 2015 7:46 AM
>>>>>>> To: time-nuts@febo.com
>>>>>>> Subject: [time-nuts] Rohde & Schwarz GPSDO
>>>>>>>
>>>>>>> I believe that like a lot of the Meinberg receivers that this uses a
>>>> down
>>>>>>> converter to give an IF frequency of
>>>>>>> 35.4 MHz. If you don't have the converter that apparently isn't included
>>>> with
>>>>>>> the receiver you have a $300 paperweight.
>>>>>>> You might want to check with the seller before bidding.
>>>>>>>
>>>>>>> -Arthur
>>>>>>> ___
>>>>>>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
>>>>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>>>>> and follow the instructions there.
>>>>>>> -
>>>>>>> No virus found in this message.
>>>>>>> Checked by AVG - www.avg.com
>>>>>>> Version: 2015.0.6140 / Virus Database: 4435/10749 - Release Date:
>>>>>>> 10/03/15
>>>>
>>>> ___
>>>> time-nuts mailing list -- time-nuts@febo.com
>>>> To unsubscribe, go to 
>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>> and follow the instructions there.
>>>
>>> ___
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>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>
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Re: [time-nuts] Rohde & Schwarz GPSDO

[Azelio Boriani]

Unfortunately I have the R&S GPSDO without the antenna: the OCXO is an
MV85. The GPSDO unit is a Meinberg card GPS167:



and the (missing) antenna is:




On Thu, Oct 8, 2015 at 8:26 AM, Björn  wrote:
> You might get some oscillator information by looking at the Meinberg site.
>
> https://www.meinbergglobal.com/english/specs/gpsopt.htm
>
> Is this a badged Meinberg unit or a R&S built on the Meinberg GPScard?
>
> --
>  Björn
>
>  Originalmeddelande Från: Tom Knox 
>  Datum:2015-10-08  05:21  (GMT+01:00) 
> Till: Time-Nuts  Rubrik: Re: 
> [time-nuts] Rohde & Schwarz GPSDO 
> What is interesting is I spent a little time on the Manufactures Web 
> Site and could find no AD or PN specs.
> So even if you can find the down converter antenna, you have no idea how well 
> it will perform.
> I imagine it has a something like an Oscilloquartz 8663. No doubt as with 
> almost all RS products it will be very high build quality.
> Cheers;
> Thomas Knox
>
>
>
>> From: rbenw...@verizon.net
>> To: time-nuts@febo.com
>> Date: Wed, 7 Oct 2015 22:41:11 -0400
>> Subject: Re: [time-nuts] Rohde & Schwarz GPSDO
>>
>> That's why you can run 300meters of RG-58!  This is the "missing"
>> antenna/converter unit.
>>
>> https://www.meinbergglobal.com/english/products/gps-antenna-converter.htm
>>
>> Here is one, this time with the antenna:
>> http://www.ebay.com/itm/Meinberg-ED170MP-GPS-Satellite-Disciplined-Atomic-Cl
>> ock-10MHz-Oscillator-Antenna-/281560964740?hash=item418e575e84
>>
>> Bob
>>
>> >>> -Original Message-
>> >>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Arthur
>> >>> Dent
>> >>> Sent: Wednesday, October 07, 2015 7:46 AM
>> >>> To: time-nuts@febo.com
>> >>> Subject: [time-nuts] Rohde & Schwarz GPSDO
>> >>>
>> >>> I believe that like a lot of the Meinberg receivers that this uses a
>> down
>> >>> converter to give an IF frequency of
>> >>> 35.4 MHz. If you don't have the converter that apparently isn't included
>> with
>> >>> the receiver you have a $300 paperweight.
>> >>> You might want to check with the seller before bidding.
>> >>>
>> >>> -Arthur
>> >>> ___
>> >>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
>> >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> >>> and follow the instructions there.
>> >>> -
>> >>> No virus found in this message.
>> >>> Checked by AVG - www.avg.com
>> >>> Version: 2015.0.6140 / Virus Database: 4435/10749 - Release Date:
>> >>> 10/03/15
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
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>> and follow the instructions there.
>
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Re: [time-nuts] Rohde & Schwarz GPSDO

[Azelio Boriani]

Without the necessary antenna/downconverter.

On Wed, Oct 7, 2015 at 4:06 AM, Bob Benward  wrote:
>
>
> If anyone is interested, a Rohde & Schwarz GPSDO:
>
>
>
>
>
> Rohde & Schwarz GPS RECEIVER ED170MP MEINBERG 2105.5504.00
>
>
>
> http://www.ebay.com/itm/262081245211?_trksid=p2055119.m1438.l2649&ssPageName
> =STRK%3AMEBIDX%3AIT
>
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Re: [time-nuts] Easy-to-use TDC to compare PPS

[Azelio Boriani]

What about the PICTIC?



On Tue, Sep 15, 2015 at 4:30 PM, Xavier Bestel  wrote:
> Hi,
>
> I'd like to do some PPS comparisons on an SBC (like a Beaglebone or RPi)
> using a TDC. So far the ones I've seen which could be suitable are ACAM's
> TDC-GPX and TI's THS788:
> http://www.acam.de/fileadmin/Download/pdf/English/DB_GPX_e.pdf
> http://www.ti.com/lit/ds/symlink/ths788.pdf
>
> However these chips don't look so simple to connect to a standard SBC. Would
> anyone of you already have attempted that journey, or simply have a
> reasonably good idea about how to do that ?
>
> Thanks,
>
> Xav
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Re: [time-nuts] Trimble Resolution [T, SMT, SMT GG] - spontaneous GPS loss of signal events, multiple locations

[Azelio Boriani]

Why there are distribution amps? If there are other non-Resolution
receivers (co-located and driven by the same antenna/distribution
amp), what are they experiencing when there is the outage reported by
the Resolution boards? Less-than-usual satellite count? Poor C/N? Can
you log data?

On Mon, Sep 14, 2015 at 1:28 PM, Wojciech Owczarek
 wrote:
> Hello Time Nuts,
>
> I was wondering if other people have seen this. 20+ receivers and they all
> use different variants of the Resolution boards - majority are the old
> Resolution T.We have observed sudden GPS loss of signal occurring.
> Seemingly nothing unusual, these things happen, that's what holdover is
> for, etc... however:
>
> - All devices are connected via decent distribution amps,
> - All installations use roof-mounted antennas with unobstructed 180 degree
> sky view
> - All devices see about 11 birds most of the time
> - None of these events coincided with known GPS SV outages
>
> And here's the fun part:
>
> - This is happening in multiple locations in the US, AND in the UK
> - The log timestamps (UTC) for the alarms, are *exactly the same* across
> all sites, down to the second. This happens twenty to ten seconds before
> midnight, and usually recovers within two or three minutes.
>
> The last event was on 5th September, at 23:59:37 UTC. We have seen this
> happening anywhere between once every month to once every two months. Time
> may differ by a few seconds, but it's the same across all devices.
>
> I'm trying to establish whether the issue is with Trimble or with the
> vendor who embedded Trimble. Because of what I refer to as "vendor
> anal-digital decoupling delay", I have to investigate in parallel.
>
> Has anyone seen this with Resolution? Unfortunately I have no visibility
> into firmware versions in the Resolution boards.
>
> Any pointers welcome.
>
> Many thanks,
> Wojciech
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Re: [time-nuts] HP 5730 data polling technique?

[Azelio Boriani]

The manual reports that the 5370 is SRQ capable but no example is
given. Anyway, the operation is the serial_poll and read_status_byte
sequence, when the status byte reports the error 0, then a measurement
is complete and the result can be read. How to implement the SRQ
management depends on your GPIB interface and its software suite
(ionsrq to install the SRQ handler for the 82357B and its C library,
for example).

On Thu, Sep 3, 2015 at 12:14 AM, Poul-Henning Kamp  wrote:
> 
> In message 
> 
> , Paul Alfille writes:
>
>>I am stymied by what should be a simple task: I'd like to gather sequential
>>measurements from my HP5370B.
>
> You can do it two ways.
>
> Either use the EXT ARM to pace your measurements, and the computer
> just reads them as they happen.
>
> Or you can use the MD2 mode, where measurements only start when the
> computer sends "MRM" to the counter.
>
> I usually use the former method because I get more precise pacing
> of the measurements (I feed EXT ARM from a HP33120).
>
> --
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@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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Re: [time-nuts] HP 5730 data polling technique?

[Azelio Boriani]

Usually it is possible to trigger an SRQ after a measurement is
completed. I'll have to read the manual for the details on how to
implement this procedure.

On Wed, Sep 2, 2015 at 10:31 PM, Hal Murray  wrote:
>
> paul.alfi...@gmail.com said:
>> While I can see single measurements either with the Beaglebone network
>> interface or using the linux GPIB command line routines, I can't figure out
>> how to get a series of measurements.
>
>> I could just poll the device in a loop, but is that the proper technique?
>> Would I have to worry about missing measurements or reading the same
>> measurement twice if the computers polling frequency is slightly off the
>> measurement frequency?
>
> Try it.  A few experiments should answer your questions.
>
> There is probably a timeout on reading data.  If data is ready before the
> timeout, you will get a data sample.  If not, you get a timeout.  If new data
> is ready before you read the old data, you will miss a sample.
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
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Re: [time-nuts] FLL errors

[Azelio Boriani]

If FLL: something that links frequencies,
  PLL: something that links phases,
  frequency detector: output proportional to frequency error,
  phase detector: output proportional to phase error (XOR),
and the original question (about FLL) was how to implement a simple FLL,
can an FLL be made by a phase detector? Can a PLL be made by a
frequency detector?
Phase_detector_XOR + RC + VCO-> FLL: equal frequencies, phase linked
to VCO odds,
in this case the frequency error is 0.

On Fri, Aug 28, 2015 at 7:14 PM, Charles Steinmetz
 wrote:
> Azelio wrote:
>
>> OK: the XOR gate with an RC is a defective PLL and a defective FLL. It
>> is a simple way to have an idea of what an xLL should be but of no
>> serious use.
>
>
> No, not at all.  I was suggesting that the XOR PLL you were commenting on
> had problems.
>
> First, an XOR with or without an RC is not an FLL at all, of any sort.
> Second, the XOR gate is a time-honored phase detector for PLLs, and if its
> limitations are understood and accounted for, it makes a perfectly
> serviceable PD for a PLL.  There are other phase detectors that are more
> popular these days, for a variety of reasons, but the XOR works just fine in
> a proper design.
>
> See, e.g.:
> Best, Phase-Locked Loops (2007), pp. 16-18
> Gardner, Phaselock Techniques (3rd ed) (2005), pp. 245-46
> Wolaver, Phase-Locked Loop Circuit Design (1991) pp. 55-59
> 
> 
> 
> and many, many, many others.
>
>
> Best regards,
>
> Charles
>
>
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Re: [time-nuts] FLL errors

[Azelio Boriani]

OK: the XOR gate with an RC is a defective PLL and a defective FLL. It
is a simple way to have an idea of what an xLL should be but of no
serious use.

On Fri, Aug 28, 2015 at 5:03 AM, Charles Steinmetz
 wrote:
> Azelio wrote:
>
>> Since I have not found a strong definition for the FLL, I assumed: if
>> PLL= zero phase error (and so zero frequency error) the FLL= same
>> frequency, random phase. The XOR with RC is a perfect fit for this:
>> same frequency all the time but phase determined by the EFC needed to
>> have that frequency. The phase = constant, in the XOR/RC is true as
>> long as the VCO is stable and the EFC has not to be altered to steer
>> the VCO, that constant is not a design parameter but walks with the
>> VCO frequency movement.
>
>
> The "x" in "xLL" refers to the parameter that is measured, which the "LL"
> attempts -- more or less successfully, depending on the particular
> implementation -- to drive to zero.  (More correctly, the "LL" attempts to
> drive the measured quantity to a constant.  Many PLLs do not lock with the
> controlled oscillator at 0 phase relative to the reference oscillator, they
> lock near 90 or 180 degrees.  This includes PLLs with XOR phase detectors,
> which lock with the VCO at ~90 degrees to the reference oscillator.)
>
> An XOR measures the *phase* difference between two oscillators, and an xLL
> with an XOR detector is, therefore, a PLL.  If it is incapable of locking
> stably, that does not make it an FLL -- it is just a defective PLL.
>
> An FLL measures the *frequency* difference between two oscillators and
> attempts to drive it to zero.  (As I mentioned in my previous post, because
> of systematic biases, the FLL actually drives the frequency difference to a
> low value near zero.  Carefully engineered dither can be added to
> redistribute the error stochastically around zero.)
>
> Best regards,
>
> Charles
>
>
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Re: [time-nuts] Chinese GPSDO 10 MHz error

[Azelio Boriani]

Since I have not found a strong definition for the FLL, I assumed: if
PLL= zero phase error (and so zero frequency error) the FLL= same
frequency, random phase. The XOR with RC is a perfect fit for this:
same frequency all the time but phase determined by the EFC needed to
have that frequency. The phase = constant, in the XOR/RC is true as
long as the VCO is stable and the EFC has not to be altered to steer
the VCO, that constant is not a design parameter but walks with the
VCO frequency movement.

On Thu, Aug 27, 2015 at 10:50 PM, Attila Kinali  wrote:
> On Thu, 27 Aug 2015 17:19:34 +0200
> Azelio Boriani  wrote:
>
>> The simplest form of a frequency locked loop is the XOR gate, when the
>> driving signals are 50% square waves. To achieve lock, the phase
>> difference will be proportional to the voltage needed to the VCO to
>> generate the desired frequency. Start with a 5V digital gate, suppose
>> your VCO needs 2.5V to be in frequency: the XOR output will be at 50%
>> duty cycle to generate, out of an RC, 2.5V and the phase difference
>> (between the reference and the VCO) will be 90 (or 270) degrees. The
>> difference will be more or less than 90 if the required voltage is
>> more or less than 2.5V (positive EFC) or will be more or less than 270
>> if the VCO has a negative EFC.
>
> This is the description of a XOR gate based PLL, not an FLL.
>
> The basic difference between PLL and FLL is very very simple:
> A PLL measures phase, a FLL measures frequency.
>
> The control loop then steers the measured value to be as close as
> possible to a predetermined constant. As this steering loop is not
> perfect, there will be a small error. Depending on what is measured,
> it's either a phase or a frequency error.
>
> Attila Kinali
>
> --
> I must not become metastable.
> Metastability is the mind-killer.
> Metastability is the little-death that brings total obliteration.
> I will face my metastability.
> I will permit it to pass over me and through me.
> And when it has gone past I will turn the inner eye to see its path.
> Where the metastability has gone there will be nothing. Only I will remain.
>
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Re: [time-nuts] Chinese GPSDO 10 MHz error

[Azelio Boriani]

The simplest form of a frequency locked loop is the XOR gate, when the
driving signals are 50% square waves. To achieve lock, the phase
difference will be proportional to the voltage needed to the VCO to
generate the desired frequency. Start with a 5V digital gate, suppose
your VCO needs 2.5V to be in frequency: the XOR output will be at 50%
duty cycle to generate, out of an RC, 2.5V and the phase difference
(between the reference and the VCO) will be 90 (or 270) degrees. The
difference will be more or less than 90 if the required voltage is
more or less than 2.5V (positive EFC) or will be more or less than 270
if the VCO has a negative EFC.

On Thu, Aug 27, 2015 at 5:54 AM, Bob Benward  wrote:
> So how does a frequency lock work?  How is it implemented? Can someone sketch 
> a schematic?
>
> And what equipment or technique is used to measure a 2hz error at 100GHz?
>
> Bob
>
 -Original Message-
 From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Tim
 Shoppa
 Sent: Wednesday, August 26, 2015 5:18 PM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] Chinese GPSDO 10 MHz error

 Full KE5FX evaluation of BG7TBL GPSDO here:
 http://www.ke5fx.com/gpscomp.htm

 I'm wondering out loud if it might, like many hobbyist GPSDO's, be
 frequency-locked rather than phase-locked and thus susceptible to 
 last-digit-
 counter bobble in some long-averaging counter.

 Tim N3QE

 On Wed, Aug 26, 2015 at 3:18 PM, Perry Sandeen via time-nuts < time-
 n...@febo.com> wrote:

 > Hi,
 >
 >
 >
 > On the EEVBLOG  (http://www.eevblog.com/forum/index.php)
 >
 >
 >
 > They mention that the "2014-11-06"version GPSDO that was “most
 > extensively tested, so far (by ke5x and others).
 >
 >
 >
 > (Has a) known bug, outputfrequency is not exactly 10mhz
 > (9,999,999.999,800 Hz). This translates to ~2hzerror at 100ghz.”
 >
 >
 >
 > A question is if this bug isjust for this particular model or all
 > other versions suspect?
 >
 >
 >
 > I realize that in and of itsself it is very small error, but errors
 > tend to multiply or cause incorrectconclusions to testing.
 >
 >
 >
 > Another question is will the LHdisplay unit they offer work with other
 > Trimble units such as are offered byRDR?
 >
 >
 >
 > That said, these models seem tobe a very nice turn-key systems.
 >
 >
 >
 > Regards,
 >
 >
 >
 > Perrier
 >
 > ___
 > time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
 > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 > and follow the instructions there.
 >
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