Re: [time-nuts] TCXO drift - related to TVB's posting

[Joseph Gray]

I periodically check that.

On Nov 12, 2016 5:43 PM, "Adrian Godwin"  wrote:

> What if your shop reference were drifting up ?
>
>
> On Sat, Nov 12, 2016 at 11:25 PM, Joseph Gray  wrote:
>
> > TCXO, not OCXO, but related. Sorry, but I have no graphs.
> >
> > I work for a municipal radio shop. We service radios that span 20
> > years (through acquisitions, it was GE, Ericsson, Com-Net, M/A-COM,
> > Tyco, now Harris). There are several different model handhelds and
> > mobiles, with different designs and TCXO's. Some are adjusted manualy,
> > most via software. I have found that every single TCXO in the various
> > model radios drift downward in frequency over time.
> >
> > One interesting case was a set of radios that sat on the shelf, unused
> > for several years. They were issued to some custodians about a year
> > ago. I checked all of them on the service monitor beforehand and they
> > were well within spec. All of these radios came back to the shop
> > recently. They were 1-3 KHz low in transmit frequency. That is an
> > unusual amount of drift in one year. Perhaps it has something to do
> > with how long they sat on the shelf.
> >
> > I don't have enough history on our newest radios, so I don't know if
> > this downward trend will hold true for them.
> >
> > Joe Gray
> > W5JG
> >
> >
> > On Sat, Nov 12, 2016 at 2:54 PM, Tom Van Baak 
> wrote:
> > > There were postings recently about OCXO ageing, or drift rates.
> > >
> > > I've been testing a batch of TBolts for a couple of months and it
> > provides an interesting set of data from which to make visual answers to
> > recent questions. Here are three plots.
> > >
> > >
> > > 1) attached plot: TBolt-10day-fit0-e09.gif (
> > http://leapsecond.com/pages/tbolt/TBolt-10day-fit0-e09.gif )
> > >
> > > A bunch of oscillators are measured with a 20-channel system. Each
> > frequency plot is a free-running TBolt (no GPS, no disciplining). The
> > X-scale is 10 days and the Y-scale is 1 ppb, or 1e-9 per Y-division. What
> > you see at this scale is that all the OCXO are quite stable. Also, some
> of
> > them show drift.
> > >
> > > For example, the OCXO frequency in channel 14 changes by 2e-9 in 10
> days
> > for a drift rate of 2e-10/day. It looks large in this plot but its well
> > under the typical spec, such as 5e-10/day for a 10811A. We see a variety
> of
> > drift rates, including some that appear to be zero: flat line. At this
> > scale, CH13, for example, seems to have no drift.
> > >
> > > But the drift, when present, appears quite linear. So there are two
> > things to do. Zoom in and zoom out.
> > >
> > >
> > > 2) attached plot: TBolt-10day-fit0-e10.gif (
> > http://leapsecond.com/pages/tbolt/TBolt-10day-fit0-e10.gif )
> > >
> > > Here we zoom in by changing the Y-scale to 1e-10 per division. The
> > X-scale is still 10 days. Now we can see the drift much better. Also at
> > this level we can see instability of each OCXO (or the lab environment).
> At
> > this scale, channels CH10 and CH14 are "off the chart". An OCXO like the
> > one in CH01 climbs by 2e-10 over 10 days for a drift rate of 2e-11/day.
> > This is 25x better than the 10811A spec. CH13, mentioned above, is not
> zero
> > drift after all, but its drift rate is even lower, close to 1e-11/day.
> > >
> > > For some oscillators the wiggles in the data (frequency instability)
> are
> > large enough that the drift rate is not clearly measurable.
> > >
> > > The 10-day plots suggests you would not want to try to measure drift
> > rate based on just one day of data.
> > >
> > > The plots also suggest that drift rate is not a hard constant. Look at
> > any of the 20 10-day plots. Your eye will tell you that the daily drift
> > rate can change significantly from day to day to day.
> > >
> > > The plots show that an OCXO doesn't necessarily follow strict rules. In
> > a sense they each have their own personality. So one needs to be very
> > careful about algorithms that assume any sort of constant or consistent
> > behavior.
> > >
> > >
> > > 3) attached plot: TBolt-100day-fit0-e08.gif (
> > http://leapsecond.com/pages/tbolt/TBolt-100day-fit0-e08.gif )
> > >
> > > Here we look at 100 days of data instead of just 10 days. To fit, the
> > Y-scale is now 1e-8 per division. Once a month I created a temporary
> > thermal event in the lab (the little "speed bumps") which we will ignore
> > for now.
> > >
> > > At this long-term scale, OCXO in CH09 has textbook logarithmic drift.
> > Also CH14 and CH16. In fact over 100 days most of them are logarithmic
> but
> > the coefficients vary considerably so it's hard to see this at a common
> > scale. Note also the logarithmic curve is vastly more apparent in the
> first
> > few days or weeks of operation, but I don't have that data.
> > >
> > > In general, any exponential or log or parabolic or circular curve looks
> > linear if you're looking close enough. A straight highway may look linear
> > but 

Re: [time-nuts] TCXO drift - related to TVB's posting

[Adrian Godwin]

What if your shop reference were drifting up ?


On Sat, Nov 12, 2016 at 11:25 PM, Joseph Gray  wrote:

> TCXO, not OCXO, but related. Sorry, but I have no graphs.
>
> I work for a municipal radio shop. We service radios that span 20
> years (through acquisitions, it was GE, Ericsson, Com-Net, M/A-COM,
> Tyco, now Harris). There are several different model handhelds and
> mobiles, with different designs and TCXO's. Some are adjusted manualy,
> most via software. I have found that every single TCXO in the various
> model radios drift downward in frequency over time.
>
> One interesting case was a set of radios that sat on the shelf, unused
> for several years. They were issued to some custodians about a year
> ago. I checked all of them on the service monitor beforehand and they
> were well within spec. All of these radios came back to the shop
> recently. They were 1-3 KHz low in transmit frequency. That is an
> unusual amount of drift in one year. Perhaps it has something to do
> with how long they sat on the shelf.
>
> I don't have enough history on our newest radios, so I don't know if
> this downward trend will hold true for them.
>
> Joe Gray
> W5JG
>
>
> On Sat, Nov 12, 2016 at 2:54 PM, Tom Van Baak  wrote:
> > There were postings recently about OCXO ageing, or drift rates.
> >
> > I've been testing a batch of TBolts for a couple of months and it
> provides an interesting set of data from which to make visual answers to
> recent questions. Here are three plots.
> >
> >
> > 1) attached plot: TBolt-10day-fit0-e09.gif (
> http://leapsecond.com/pages/tbolt/TBolt-10day-fit0-e09.gif )
> >
> > A bunch of oscillators are measured with a 20-channel system. Each
> frequency plot is a free-running TBolt (no GPS, no disciplining). The
> X-scale is 10 days and the Y-scale is 1 ppb, or 1e-9 per Y-division. What
> you see at this scale is that all the OCXO are quite stable. Also, some of
> them show drift.
> >
> > For example, the OCXO frequency in channel 14 changes by 2e-9 in 10 days
> for a drift rate of 2e-10/day. It looks large in this plot but its well
> under the typical spec, such as 5e-10/day for a 10811A. We see a variety of
> drift rates, including some that appear to be zero: flat line. At this
> scale, CH13, for example, seems to have no drift.
> >
> > But the drift, when present, appears quite linear. So there are two
> things to do. Zoom in and zoom out.
> >
> >
> > 2) attached plot: TBolt-10day-fit0-e10.gif (
> http://leapsecond.com/pages/tbolt/TBolt-10day-fit0-e10.gif )
> >
> > Here we zoom in by changing the Y-scale to 1e-10 per division. The
> X-scale is still 10 days. Now we can see the drift much better. Also at
> this level we can see instability of each OCXO (or the lab environment). At
> this scale, channels CH10 and CH14 are "off the chart". An OCXO like the
> one in CH01 climbs by 2e-10 over 10 days for a drift rate of 2e-11/day.
> This is 25x better than the 10811A spec. CH13, mentioned above, is not zero
> drift after all, but its drift rate is even lower, close to 1e-11/day.
> >
> > For some oscillators the wiggles in the data (frequency instability) are
> large enough that the drift rate is not clearly measurable.
> >
> > The 10-day plots suggests you would not want to try to measure drift
> rate based on just one day of data.
> >
> > The plots also suggest that drift rate is not a hard constant. Look at
> any of the 20 10-day plots. Your eye will tell you that the daily drift
> rate can change significantly from day to day to day.
> >
> > The plots show that an OCXO doesn't necessarily follow strict rules. In
> a sense they each have their own personality. So one needs to be very
> careful about algorithms that assume any sort of constant or consistent
> behavior.
> >
> >
> > 3) attached plot: TBolt-100day-fit0-e08.gif (
> http://leapsecond.com/pages/tbolt/TBolt-100day-fit0-e08.gif )
> >
> > Here we look at 100 days of data instead of just 10 days. To fit, the
> Y-scale is now 1e-8 per division. Once a month I created a temporary
> thermal event in the lab (the little "speed bumps") which we will ignore
> for now.
> >
> > At this long-term scale, OCXO in CH09 has textbook logarithmic drift.
> Also CH14 and CH16. In fact over 100 days most of them are logarithmic but
> the coefficients vary considerably so it's hard to see this at a common
> scale. Note also the logarithmic curve is vastly more apparent in the first
> few days or weeks of operation, but I don't have that data.
> >
> > In general, any exponential or log or parabolic or circular curve looks
> linear if you're looking close enough. A straight highway may look linear
> but the equator is circular. So most OCXO drift (age) with a logarithmic
> curve and this is visible over long enough measurements. But for shorter
> time spans it will appear linear. Or, more likely, internal and external
> stability issues will dominate and this spoils any linear vs. log
> discussion.
> >
> > So is 

Re: [time-nuts] TCXO drift - related to TVB's posting

[Bob Camp]

Hi

In *general* the crystal in an OCXO should drift positive. The reason often 
mentioned is fairly simple:

You can only get the blank + base plate + calibration just so clean. You can go
crazy getting the enclosure clean. The result is a long term mass transfer from 
the blank  (it’s “dirty”, looses mass, frequency goes up) to the enclosure.

Are there a whole lot of other things that may be happening? Of course. The 
telling point is still that negative aging is a bit unusual on a well made 
crystal. As Rick pointed out a few decades ago, OCXO performance may or
may not be limited by the crystal ….

Bob

> On Nov 12, 2016, at 6:25 PM, Joseph Gray  wrote:
> 
> TCXO, not OCXO, but related. Sorry, but I have no graphs.
> 
> I work for a municipal radio shop. We service radios that span 20
> years (through acquisitions, it was GE, Ericsson, Com-Net, M/A-COM,
> Tyco, now Harris). There are several different model handhelds and
> mobiles, with different designs and TCXO's. Some are adjusted manualy,
> most via software. I have found that every single TCXO in the various
> model radios drift downward in frequency over time.
> 
> One interesting case was a set of radios that sat on the shelf, unused
> for several years. They were issued to some custodians about a year
> ago. I checked all of them on the service monitor beforehand and they
> were well within spec. All of these radios came back to the shop
> recently. They were 1-3 KHz low in transmit frequency. That is an
> unusual amount of drift in one year. Perhaps it has something to do
> with how long they sat on the shelf.
> 
> I don't have enough history on our newest radios, so I don't know if
> this downward trend will hold true for them.
> 
> Joe Gray
> W5JG
> 
> 
> On Sat, Nov 12, 2016 at 2:54 PM, Tom Van Baak  wrote:
>> There were postings recently about OCXO ageing, or drift rates.
>> 
>> I've been testing a batch of TBolts for a couple of months and it provides 
>> an interesting set of data from which to make visual answers to recent 
>> questions. Here are three plots.
>> 
>> 
>> 1) attached plot: TBolt-10day-fit0-e09.gif ( 
>> http://leapsecond.com/pages/tbolt/TBolt-10day-fit0-e09.gif )
>> 
>> A bunch of oscillators are measured with a 20-channel system. Each frequency 
>> plot is a free-running TBolt (no GPS, no disciplining). The X-scale is 10 
>> days and the Y-scale is 1 ppb, or 1e-9 per Y-division. What you see at this 
>> scale is that all the OCXO are quite stable. Also, some of them show drift.
>> 
>> For example, the OCXO frequency in channel 14 changes by 2e-9 in 10 days for 
>> a drift rate of 2e-10/day. It looks large in this plot but its well under 
>> the typical spec, such as 5e-10/day for a 10811A. We see a variety of drift 
>> rates, including some that appear to be zero: flat line. At this scale, 
>> CH13, for example, seems to have no drift.
>> 
>> But the drift, when present, appears quite linear. So there are two things 
>> to do. Zoom in and zoom out.
>> 
>> 
>> 2) attached plot: TBolt-10day-fit0-e10.gif ( 
>> http://leapsecond.com/pages/tbolt/TBolt-10day-fit0-e10.gif )
>> 
>> Here we zoom in by changing the Y-scale to 1e-10 per division. The X-scale 
>> is still 10 days. Now we can see the drift much better. Also at this level 
>> we can see instability of each OCXO (or the lab environment). At this scale, 
>> channels CH10 and CH14 are "off the chart". An OCXO like the one in CH01 
>> climbs by 2e-10 over 10 days for a drift rate of 2e-11/day. This is 25x 
>> better than the 10811A spec. CH13, mentioned above, is not zero drift after 
>> all, but its drift rate is even lower, close to 1e-11/day.
>> 
>> For some oscillators the wiggles in the data (frequency instability) are 
>> large enough that the drift rate is not clearly measurable.
>> 
>> The 10-day plots suggests you would not want to try to measure drift rate 
>> based on just one day of data.
>> 
>> The plots also suggest that drift rate is not a hard constant. Look at any 
>> of the 20 10-day plots. Your eye will tell you that the daily drift rate can 
>> change significantly from day to day to day.
>> 
>> The plots show that an OCXO doesn't necessarily follow strict rules. In a 
>> sense they each have their own personality. So one needs to be very careful 
>> about algorithms that assume any sort of constant or consistent behavior.
>> 
>> 
>> 3) attached plot: TBolt-100day-fit0-e08.gif ( 
>> http://leapsecond.com/pages/tbolt/TBolt-100day-fit0-e08.gif )
>> 
>> Here we look at 100 days of data instead of just 10 days. To fit, the 
>> Y-scale is now 1e-8 per division. Once a month I created a temporary thermal 
>> event in the lab (the little "speed bumps") which we will ignore for now.
>> 
>> At this long-term scale, OCXO in CH09 has textbook logarithmic drift. Also 
>> CH14 and CH16. In fact over 100 days most of them are logarithmic but the 
>> coefficients vary considerably so it's hard to see this at a common scale. 

[time-nuts] TCXO drift - related to TVB's posting

[Joseph Gray]

TCXO, not OCXO, but related. Sorry, but I have no graphs.

I work for a municipal radio shop. We service radios that span 20
years (through acquisitions, it was GE, Ericsson, Com-Net, M/A-COM,
Tyco, now Harris). There are several different model handhelds and
mobiles, with different designs and TCXO's. Some are adjusted manualy,
most via software. I have found that every single TCXO in the various
model radios drift downward in frequency over time.

One interesting case was a set of radios that sat on the shelf, unused
for several years. They were issued to some custodians about a year
ago. I checked all of them on the service monitor beforehand and they
were well within spec. All of these radios came back to the shop
recently. They were 1-3 KHz low in transmit frequency. That is an
unusual amount of drift in one year. Perhaps it has something to do
with how long they sat on the shelf.

I don't have enough history on our newest radios, so I don't know if
this downward trend will hold true for them.

Joe Gray
W5JG


On Sat, Nov 12, 2016 at 2:54 PM, Tom Van Baak  wrote:
> There were postings recently about OCXO ageing, or drift rates.
>
> I've been testing a batch of TBolts for a couple of months and it provides an 
> interesting set of data from which to make visual answers to recent 
> questions. Here are three plots.
>
>
> 1) attached plot: TBolt-10day-fit0-e09.gif ( 
> http://leapsecond.com/pages/tbolt/TBolt-10day-fit0-e09.gif )
>
> A bunch of oscillators are measured with a 20-channel system. Each frequency 
> plot is a free-running TBolt (no GPS, no disciplining). The X-scale is 10 
> days and the Y-scale is 1 ppb, or 1e-9 per Y-division. What you see at this 
> scale is that all the OCXO are quite stable. Also, some of them show drift.
>
> For example, the OCXO frequency in channel 14 changes by 2e-9 in 10 days for 
> a drift rate of 2e-10/day. It looks large in this plot but its well under the 
> typical spec, such as 5e-10/day for a 10811A. We see a variety of drift 
> rates, including some that appear to be zero: flat line. At this scale, CH13, 
> for example, seems to have no drift.
>
> But the drift, when present, appears quite linear. So there are two things to 
> do. Zoom in and zoom out.
>
>
> 2) attached plot: TBolt-10day-fit0-e10.gif ( 
> http://leapsecond.com/pages/tbolt/TBolt-10day-fit0-e10.gif )
>
> Here we zoom in by changing the Y-scale to 1e-10 per division. The X-scale is 
> still 10 days. Now we can see the drift much better. Also at this level we 
> can see instability of each OCXO (or the lab environment). At this scale, 
> channels CH10 and CH14 are "off the chart". An OCXO like the one in CH01 
> climbs by 2e-10 over 10 days for a drift rate of 2e-11/day. This is 25x 
> better than the 10811A spec. CH13, mentioned above, is not zero drift after 
> all, but its drift rate is even lower, close to 1e-11/day.
>
> For some oscillators the wiggles in the data (frequency instability) are 
> large enough that the drift rate is not clearly measurable.
>
> The 10-day plots suggests you would not want to try to measure drift rate 
> based on just one day of data.
>
> The plots also suggest that drift rate is not a hard constant. Look at any of 
> the 20 10-day plots. Your eye will tell you that the daily drift rate can 
> change significantly from day to day to day.
>
> The plots show that an OCXO doesn't necessarily follow strict rules. In a 
> sense they each have their own personality. So one needs to be very careful 
> about algorithms that assume any sort of constant or consistent behavior.
>
>
> 3) attached plot: TBolt-100day-fit0-e08.gif ( 
> http://leapsecond.com/pages/tbolt/TBolt-100day-fit0-e08.gif )
>
> Here we look at 100 days of data instead of just 10 days. To fit, the Y-scale 
> is now 1e-8 per division. Once a month I created a temporary thermal event in 
> the lab (the little "speed bumps") which we will ignore for now.
>
> At this long-term scale, OCXO in CH09 has textbook logarithmic drift. Also 
> CH14 and CH16. In fact over 100 days most of them are logarithmic but the 
> coefficients vary considerably so it's hard to see this at a common scale. 
> Note also the logarithmic curve is vastly more apparent in the first few days 
> or weeks of operation, but I don't have that data.
>
> In general, any exponential or log or parabolic or circular curve looks 
> linear if you're looking close enough. A straight highway may look linear but 
> the equator is circular. So most OCXO drift (age) with a logarithmic curve 
> and this is visible over long enough measurements. But for shorter time spans 
> it will appear linear. Or, more likely, internal and external stability 
> issues will dominate and this spoils any linear vs. log discussion.
>
> So is it linear or log? The answer is it depends. Now I sound like Bob ;-)
>
> /tvb
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to 

Re: [time-nuts] tcxo

[folkert]

 Some of the Arduinos (not sure about Mini 04 but I am suspicious) use
 ceramic resonators rather than real crystals and thus may have extremely
 poor frequency stability. See here
 http://jorisvr.nl/arduino_frequency.html
 for an example.

ah!
Very intriguing material, those crystals. I wonder what happens in them
that they start to tick(?) at precisely 16MHz for example.

 Is there some reason you are using a 16.9344 MHz oscillator rather than
 16.0? The processor will probably work, but timing of Arduino functions
 like millis() and software serial baud rates will be affected.

Misread I guess :-|
Like that time that I bought 20 max690 instead of max680 ics. sigh.

 On Wed, Dec 10, 2014 at 2:19 PM, folkert folk...@vanheusden.com wrote:
 
   I'm experimenting a bit with time keeping.
   For that I use cheap low power hardware like raspberry pies and
   arduinos.
 
  Hi people,
 
  Thanks for all the replies! Took a bit to respond but I had the flu.
 
  My objective is, to get the best precision/accuracy possible with said
  hardware.
 
  The first step is preparing an arduino. I found one that has an easy to
  desolder crystal:
 
  http://upload.wikimedia.org/wikipedia/commons/thumb/0/04/Arduino_Mini.jpg/170px-Arduino_Mini.jpg
  Bought a couple of those and some of these:
 
  http://www.aliexpress.com/item/Precision-TCXO-square-wave-oscillator-TCXO-16-9344MHz-line-rectangle/1104200137.html
 
  While waiting for these and the parts for the schematics, I'm toying
  around with implementing ntp servers (well, sntp) for arduino. With
  lots of blinkenlights of course and with ethernet. Not trivial I can
  say.
  This is the jitter plot of a test where time is fed from an RTC module.
  I did not plot the drift but it is +/- 120 seconds in the 3.8 days I
  measured it.
  http://vps001.vanheusden.com/~folkert/aRTC.png
 
 
  Folkert van Heusden
 
  --
  --
  Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com
  ___
  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.
 
 
 
 
 -- 
 
 --Jim Harman
 ___
 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.


Folkert van Heusden

-- 
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journalisation et/ou le suivi de l'exécution de commandes. Filtrage,
mise en couleur de mot-clé, fusions, visualisation de différences
(diff-view), etc.  http://www.vanheusden.com/multitail/
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Re: [time-nuts] tcxo

[Jim Harman]

More Arduino clock and timekeeping notes:

If the part connected to the processor's XTAL1 and XTAL2 pins has 2 pins
and external capacitors it is a crystal. If it has 3 pins and no caps it is
a ceramic resonator. If you have a crystal, you can fine-tune its frequency
by replacing one of the capacitors with a variable cap.

You may have trouble using an external oscillator instead of whatever is
there because the chip is supposed to be set up differently when you do
that. See Sec. 9 of the ATMega datasheet for further info.

Another and potentially more flexible approach (again depending on your
requirements) would be to leave the processor clock alone and connect an
accurate external oscillator to a timer input. Then you can use timer
interrupts and/or the timer capture function for precise timekeeping.

On Thu, Dec 11, 2014 at 9:31 AM, folkert folk...@vanheusden.com wrote:

  Some of the Arduinos (not sure about Mini 04 but I am suspicious) use
  ceramic resonators rather than real crystals and thus may have extremely
  poor frequency stability. See here
  http://jorisvr.nl/arduino_frequency.html
  for an example.

 ah!
 Very intriguing material, those crystals. I wonder what happens in them
 that they start to tick(?) at precisely 16MHz for example.

  Is there some reason you are using a 16.9344 MHz oscillator rather than
  16.0? The processor will probably work, but timing of Arduino functions
  like millis() and software serial baud rates will be affected.

 Misread I guess :-|
 Like that time that I bought 20 max690 instead of max680 ics. sigh.

  On Wed, Dec 10, 2014 at 2:19 PM, folkert folk...@vanheusden.com wrote:
 
I'm experimenting a bit with time keeping.
For that I use cheap low power hardware like raspberry pies and
arduinos.
  
   Hi people,
  
   Thanks for all the replies! Took a bit to respond but I had the flu.
  
   My objective is, to get the best precision/accuracy possible with said
   hardware.
  
   The first step is preparing an arduino. I found one that has an easy to
   desolder crystal:
  
  
 http://upload.wikimedia.org/wikipedia/commons/thumb/0/04/Arduino_Mini.jpg/170px-Arduino_Mini.jpg
   Bought a couple of those and some of these:
  
  
 http://www.aliexpress.com/item/Precision-TCXO-square-wave-oscillator-TCXO-16-9344MHz-line-rectangle/1104200137.html
  
   While waiting for these and the parts for the schematics, I'm toying
   around with implementing ntp servers (well, sntp) for arduino. With
   lots of blinkenlights of course and with ethernet. Not trivial I can
   say.
   This is the jitter plot of a test where time is fed from an RTC module.
   I did not plot the drift but it is +/- 120 seconds in the 3.8 days I
   measured it.
   http://vps001.vanheusden.com/~folkert/aRTC.png
  
  
   Folkert van Heusden
  
   --
   --
   Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com
   ___
   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.
  
 
 
 
  --
 
  --Jim Harman
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Re: [time-nuts] tcxo

[folkert]

 I'm experimenting a bit with time keeping.
 For that I use cheap low power hardware like raspberry pies and
 arduinos.

Hi people,

Thanks for all the replies! Took a bit to respond but I had the flu.

My objective is, to get the best precision/accuracy possible with said
hardware.

The first step is preparing an arduino. I found one that has an easy to
desolder crystal:
http://upload.wikimedia.org/wikipedia/commons/thumb/0/04/Arduino_Mini.jpg/170px-Arduino_Mini.jpg
Bought a couple of those and some of these:
http://www.aliexpress.com/item/Precision-TCXO-square-wave-oscillator-TCXO-16-9344MHz-line-rectangle/1104200137.html

While waiting for these and the parts for the schematics, I'm toying
around with implementing ntp servers (well, sntp) for arduino. With
lots of blinkenlights of course and with ethernet. Not trivial I can
say.
This is the jitter plot of a test where time is fed from an RTC module.
I did not plot the drift but it is +/- 120 seconds in the 3.8 days I
measured it.
http://vps001.vanheusden.com/~folkert/aRTC.png


Folkert van Heusden

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Re: [time-nuts] tcxo

[Jim Harman]

Some of the Arduinos (not sure about Mini 04 but I am suspicious) use
ceramic resonators rather than real crystals and thus may have extremely
poor frequency stability. See here
http://jorisvr.nl/arduino_frequency.html
for an example.

Is there some reason you are using a 16.9344 MHz oscillator rather than
16.0? The processor will probably work, but timing of Arduino functions
like millis() and software serial baud rates will be affected.

On Wed, Dec 10, 2014 at 2:19 PM, folkert folk...@vanheusden.com wrote:

  I'm experimenting a bit with time keeping.
  For that I use cheap low power hardware like raspberry pies and
  arduinos.

 Hi people,

 Thanks for all the replies! Took a bit to respond but I had the flu.

 My objective is, to get the best precision/accuracy possible with said
 hardware.

 The first step is preparing an arduino. I found one that has an easy to
 desolder crystal:

 http://upload.wikimedia.org/wikipedia/commons/thumb/0/04/Arduino_Mini.jpg/170px-Arduino_Mini.jpg
 Bought a couple of those and some of these:

 http://www.aliexpress.com/item/Precision-TCXO-square-wave-oscillator-TCXO-16-9344MHz-line-rectangle/1104200137.html

 While waiting for these and the parts for the schematics, I'm toying
 around with implementing ntp servers (well, sntp) for arduino. With
 lots of blinkenlights of course and with ethernet. Not trivial I can
 say.
 This is the jitter plot of a test where time is fed from an RTC module.
 I did not plot the drift but it is +/- 120 seconds in the 3.8 days I
 measured it.
 http://vps001.vanheusden.com/~folkert/aRTC.png


 Folkert van Heusden

 --
 --
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Re: [time-nuts] tcxo

[Bob Camp]

Hi

The piles of this are hidden under the piles of that which are somewhere behind 
the boxes of those…. 

Bob

 On Dec 7, 2014, at 9:09 PM, Tom Miller tmiller11...@verizon.net wrote:
 
 Bob, if you are like me, you probably don't know where they all are, even if 
 you wanted to count them. :)
 
 
 - Original Message - From: Bob Camp kb...@n1k.org
 To: Discussion of precise time and frequency measurement 
 time-nuts@febo.com
 Sent: Sunday, December 07, 2014 8:51 PM
 Subject: Re: [time-nuts] tcxo
 
 
 Hi
 
 
 On Dec 7, 2014, at 8:14 PM, Hal Murray hmur...@megapathdsl.net wrote:
 
 
 albertson.ch...@gmail.com said:
 The very first thing you need to do is figure out what your requirements
 are.
 
 Except that this is time-nuts, so the only requirement for some of us is
 having fun.
 
 
 The original post really gave no information about what the objective is. In 
 the context of that post (Arduino’s etc), it’s a bit hard to guess what is 
 being attempted. With OCXO’s on the surplus market at  $20 sort of prices, 
 fiddling with a TCXO may not make much sense. That goes double if there is 
 also a lack of measurement capability. Buying a $150 GPSDO and a $500 
 counter only to check your “I saved $15” TCXO is probably not a bargain, or 
 a good use of time. Even a cheap OCXO is likely to blow away a “worked over” 
 TCXO for stability.
 
 No don’t ask how many counters and GPSDO’s I have …. it would take *far* to 
 long to count all of them…Then there’s all the TCXO’s and OCXO’s ….
 
 Bob
 
 
 
 But yes, you are correct in that thinking about the big picture is a good
 idea.
 
 
 -- 
 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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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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[time-nuts] tcxo

[folkert]

Hi,

I'm experimenting a bit with time keeping.
For that I use cheap low power hardware like raspberry pies and
arduinos.
I noticed that the accuracy of a crystal makes a big difference. Did a
bit of googling and I learned that a txco may help solve that.
Something that keeps a constant temperature that is that I can then
glue/solder to the crystal of those systems.
My question now is: does anyone know of a simple schema for such a
thing?
I'm not entirely new to soldering but large schemas with lots of
components are a bit daunting as I don't have the background knowledge
to debug them if I soldered something wrong.


Folkert van Heusden

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Re: [time-nuts] tcxo

[Azelio Boriani]

You can go as simple as a PTC glued on the crystal to start with.
Alternatively take a look here:
http://www.w6pql.com/crystal_oven_controller.htm

On Sun, Dec 7, 2014 at 9:53 PM, folkert folk...@vanheusden.com wrote:
 Hi,

 I'm experimenting a bit with time keeping.
 For that I use cheap low power hardware like raspberry pies and
 arduinos.
 I noticed that the accuracy of a crystal makes a big difference. Did a
 bit of googling and I learned that a txco may help solve that.
 Something that keeps a constant temperature that is that I can then
 glue/solder to the crystal of those systems.
 My question now is: does anyone know of a simple schema for such a
 thing?
 I'm not entirely new to soldering but large schemas with lots of
 components are a bit daunting as I don't have the background knowledge
 to debug them if I soldered something wrong.


 Folkert van Heusden

 --
 MultiTail är ett flexibel redskap för att följa en eller flera logfiler, 
 utföra
 kommandon, filtrera, färglägga, sammanfoga, o.s.v...
 --
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Re: [time-nuts] tcxo

[Joseph Gray]

http://www.romanblack.com/xoven.htm

Joe Gray
W5JG


On Sun, Dec 7, 2014 at 1:53 PM, folkert folk...@vanheusden.com wrote:
 Hi,

 I'm experimenting a bit with time keeping.
 For that I use cheap low power hardware like raspberry pies and
 arduinos.
 I noticed that the accuracy of a crystal makes a big difference. Did a
 bit of googling and I learned that a txco may help solve that.
 Something that keeps a constant temperature that is that I can then
 glue/solder to the crystal of those systems.
 My question now is: does anyone know of a simple schema for such a
 thing?
 I'm not entirely new to soldering but large schemas with lots of
 components are a bit daunting as I don't have the background knowledge
 to debug them if I soldered something wrong.


 Folkert van Heusden

 --
 MultiTail är ett flexibel redskap för att följa en eller flera logfiler, 
 utföra
 kommandon, filtrera, färglägga, sammanfoga, o.s.v...
 --
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Re: [time-nuts] tcxo

[Bob Camp]

Hi
 On Dec 7, 2014, at 3:53 PM, folkert folk...@vanheusden.com wrote:
 
 Hi,
 
 I'm experimenting a bit with time keeping.
 For that I use cheap low power hardware like raspberry pies and
 arduinos.
 I noticed that the accuracy of a crystal makes a big difference. Did a
 bit of googling and I learned that a txco may help solve that.
 Something that keeps a constant temperature that is that I can then
 glue/solder to the crystal of those systems.
 My question now is: does anyone know of a simple schema for such a
 thing?

A TCXO “corrects” the (likely) third order temperature curve with some form of 
synthetic adjustment . The resultant cure is likely to be a 5th or higher order 
curve. It may well go peak to peak error over a (say) 10 C range. This makes 
temperature stabilization a gamble. You *might* stabilize it at a step part of 
the result curve. 

Much simpler to just shield the TCXO from drafts and fast changes ….

Bob

 I'm not entirely new to soldering but large schemas with lots of
 components are a bit daunting as I don't have the background knowledge
 to debug them if I soldered something wrong.
 
 
 Folkert van Heusden
 
 -- 
 MultiTail är ett flexibel redskap för att följa en eller flera logfiler, 
 utföra
 kommandon, filtrera, färglägga, sammanfoga, o.s.v...
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Re: [time-nuts] tcxo

[Chris Albertson]

On Sun, Dec 7, 2014 at 12:53 PM, folkert folk...@vanheusden.com wrote:

 Hi,

 I noticed that the accuracy of a crystal makes a big difference. Did a
 bit of googling and I learned that a txco may help solve that.


The very first thing you need to do is figure out what your requirements
are.  How accurate does this need to be.  If you can't do that then just
tell us your big picture problem.  A TXCO might or might not be the
solution.

The net thing is to allocate a budget.  How much can you spend?

As for those huge schematics.  Yes it is wise not to attempt to build
something you can't debug and fix.  It also depends on what test equipment
you have.One why to avid having to build large systems is to connect a
few small systems using very simple interfaces.  So maybe in your case
you'd replace the current cheap crystal with a mini-sized coaxial jack.
Then yo build an oscillator to once to the jack.  Or maybe you ad a switch
so you can use the old crystal or use the jack.Debugging is easier when
you can disconnect a cable and test each part independently.
-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] tcxo

[Angus]

On Sun, 7 Dec 2014 21:53:48 +0100, you wrote:

Something that keeps a constant temperature that is that I can then
glue/solder to the crystal of those systems.


A ready to go version (QH40A):

http://shop.kuhne-electronic.de/kuhne/en/shop/amateur-radio/accessoires/crystal-heater/Precision+crystal+heater+40%C2%B0+QH40A/?card=724

Angus
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Re: [time-nuts] tcxo

[Hal Murray]

albertson.ch...@gmail.com said:
 The very first thing you need to do is figure out what your requirements
 are.

Except that this is time-nuts, so the only requirement for some of us is 
having fun.

But yes, you are correct in that thinking about the big picture is a good 
idea.


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] tcxo

[Bob Camp]

Hi


 On Dec 7, 2014, at 8:14 PM, Hal Murray hmur...@megapathdsl.net wrote:
 
 
 albertson.ch...@gmail.com said:
 The very first thing you need to do is figure out what your requirements
 are.
 
 Except that this is time-nuts, so the only requirement for some of us is 
 having fun.
 

The original post really gave no information about what the objective is. In 
the context of that post (Arduino’s etc), it’s a bit hard to guess what is 
being attempted. With OCXO’s on the surplus market at  $20 sort of prices, 
fiddling with a TCXO may not make much sense. That goes double if there is also 
a lack of measurement capability. Buying a $150 GPSDO and a $500 counter only 
to check your “I saved $15” TCXO is probably not a bargain, or a good use of 
time. Even a cheap OCXO is likely to blow away a “worked over” TCXO for 
stability. 

No don’t ask how many counters and GPSDO’s I have …. it would take *far* to 
long to count all of them…Then there’s all the TCXO’s and OCXO’s ….

Bob



 But yes, you are correct in that thinking about the big picture is a good 
 idea.
 
 
 -- 
 These are my opinions.  I hate spam.
 
 
 
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Re: [time-nuts] tcxo

[Tom Miller]

Bob, if you are like me, you probably don't know where they all are, even if 
you wanted to count them. :)



- Original Message - 
From: Bob Camp kb...@n1k.org
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Sunday, December 07, 2014 8:51 PM
Subject: Re: [time-nuts] tcxo



Hi



On Dec 7, 2014, at 8:14 PM, Hal Murray hmur...@megapathdsl.net wrote:


albertson.ch...@gmail.com said:

The very first thing you need to do is figure out what your requirements
are.


Except that this is time-nuts, so the only requirement for some of us is
having fun.



The original post really gave no information about what the objective is. 
In the context of that post (Arduino’s etc), it’s a bit hard to guess what 
is being attempted. With OCXO’s on the surplus market at  $20 sort of 
prices, fiddling with a TCXO may not make much sense. That goes double if 
there is also a lack of measurement capability. Buying a $150 GPSDO and a 
$500 counter only to check your “I saved $15” TCXO is probably not a 
bargain, or a good use of time. Even a cheap OCXO is likely to blow away a 
“worked over” TCXO for stability.


No don’t ask how many counters and GPSDO’s I have …. it would take *far* 
to long to count all of them…Then there’s all the TCXO’s and OCXO’s ….


Bob




But yes, you are correct in that thinking about the big picture is a good
idea.


--
These are my opinions.  I hate spam.



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Re: [time-nuts] tcxo

[Alex Pummer]

Thermal control circuits could oscillate at very low frequencies there 
is a tricky time constant -- the heat propagation between theater and 
the temperature sensor!

73
Alex

On 12/7/2014 1:01 PM, Azelio Boriani wrote:

You can go as simple as a PTC glued on the crystal to start with.
Alternatively take a look here:
http://www.w6pql.com/crystal_oven_controller.htm




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Re: [time-nuts] tcxo

[Bob Albert via time-nuts]

A TCXO does not keep a constant temperature.  But an OCXO does.  The TCXO 
compensates for the temperature effect, while the OCXO holds the temperature.
Bob
 

 On Sunday, December 7, 2014 1:47 PM, Joseph Gray jg...@zianet.com wrote:
   

 http://www.romanblack.com/xoven.htm

Joe Gray
W5JG


On Sun, Dec 7, 2014 at 1:53 PM, folkert folk...@vanheusden.com wrote:
 Hi,

 I'm experimenting a bit with time keeping.
 For that I use cheap low power hardware like raspberry pies and
 arduinos.
 I noticed that the accuracy of a crystal makes a big difference. Did a
 bit of googling and I learned that a txco may help solve that.
 Something that keeps a constant temperature that is that I can then
 glue/solder to the crystal of those systems.
 My question now is: does anyone know of a simple schema for such a
 thing?
 I'm not entirely new to soldering but large schemas with lots of
 components are a bit daunting as I don't have the background knowledge
 to debug them if I soldered something wrong.


 Folkert van Heusden

 --
 MultiTail är ett flexibel redskap för att följa en eller flera logfiler, 
 utföra
 kommandon, filtrera, färglägga, sammanfoga, o.s.v...
 --
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Re: [time-nuts] tcxo

[Jim Harman]

Folkert,

You don't make your detailed requirements clear, but you might be
interested in this module

http://www.adafruit.com/product/255

It uses a DS3231 chip, which is a 32.768 khz oscillator with built-in
temperature sensing. Based on the temperature, it automatically switches in
internal capacitors to adjust the frequency. You can access and control it
with an Arduino library, including adjusting the nominal frequency with
software.

Accuracy is not up to time-nuts standards, but will be much better than an
Arduino crystal may be adequate for your application.

Disclosure: I have no connection with the manufacturer or distributor, but
I did experiment with one of these before descending further into
time-nuttery.

On Sun, Dec 7, 2014 at 3:53 PM, folkert folk...@vanheusden.com wrote:

 Hi,

 I'm experimenting a bit with time keeping.
 For that I use cheap low power hardware like raspberry pies and
 arduinos.
 I noticed that the accuracy of a crystal makes a big difference. Did a
 bit of googling and I learned that a txco may help solve that.
 Something that keeps a constant temperature that is that I can then
 glue/solder to the crystal of those systems.
 My question now is: does anyone know of a simple schema for such a
 thing?
 I'm not entirely new to soldering but large schemas with lots of
 components are a bit daunting as I don't have the background knowledge
 to debug them if I soldered something wrong.


 Folkert van Heusden

 --
 MultiTail är ett flexibel redskap för att följa en eller flera logfiler,
 utföra
 kommandon, filtrera, färglägga, sammanfoga, o.s.v...
 --
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-- 

--Jim Harman
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Re: [time-nuts] tcxo

[Hal Murray]

folk...@vanheusden.com said:
 I noticed that the accuracy of a crystal makes a big difference. Did a bit
 of googling and I learned that a txco may help solve that. Something that
 keeps a constant temperature that is that I can then glue/solder to the
 crystal of those systems. My question now is: does anyone know of a simple
 schema for such a thing? I'm not entirely new to soldering but large schemas
 with lots of components are a bit daunting as I don't have the background
 knowledge to debug them if I soldered something wrong. 

There are two sorts of parts you can get for making a clock to run a bunch of 
electronics.  You can get the crystal without any electronics (and build the 
electronics yourself), or you can get an oscillator which has the crystal and 
all the electronics in one handy package.

If you feed 10 MHz to Digikey's search box, the Crystals and Oscillators 
section (4th section) has 12775 Crystals and 13769 Oscillators.

For low cost systems like Raspberry PIs and Arduinos, the CPU chip generally 
includes the electronics.  They have 2 pins that connect to the crystal (and 
a few caps).  Most of them can use an external clock (rather than a crystal), 
just connect it to the right pin.

The O in TCXO or OCXO tells you it is an oscillator.  They need power, so 
it's not quite as simple as just replacing the crystal with a TCXO.  Here is 
a very good writeup on providing an external clock to a Soekris net4501:
  http://www.febo.com/time-freq/ntp/soekris/


-- 
These are my opinions.  I hate spam.



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[time-nuts] TCXO pinout / spec wanted

[David Kirkby]

Does anyone know the pinout of the TCXO's on this eBay auction that I won?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=5764129351
I had them delivered to work and left them there yesterday, so can't put 
a better image up at this point in time, although tommorow I'll 
photograph and post a better image.

The company is still in business, but has not answered my request for 
information.
--
Dr. David Kirkby,
G8WRB

Please check out http://www.g8wrb.org/
of if you live in Essex http://www.southminster-branch-line.org.uk/

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