[time-nuts] time-nuts Digest, Vol 148, Issue 28

Skip Withrow skip.withrow at gmail.com
Tue Nov 8 15:42:28 EST 2016


Hello,

1. The comments in Lady Heather are placed there by Mark Sims.  There are
comments for all kinds of events during the year.

2. Yes, the output of the HP 5065A is 5MHz (and also 1MHz and 100kHz).  I
have a board from another HP instrument that multiplies 1MHz to 10MHz
(there is no identification on the board other than an HP logo, at first I
thought it was a 5MHz to 10MHz doubler, but the signal generator and
spectrum analyzer set me straight).

3. I actually saw a 5065A recently that had a modification to decrease the
C-field sensitivity.  It had two 10-turn dial pots, the normal and another
that was about 2x10E-14 per division.  Unfortunately, I did not take note
of the circuit to see how it was implemented.

Regards,
Skip Withrow

On Tue, Nov 8, 2016 at 6:46 AM, <time-nuts-request at febo.com> wrote:

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> Today's Topics:
>
>    1. Re: Thermal impact on OCXO (Scott Stobbe)
>    2. Re: Thermal impact on OCXO (Hal Murray)
>    3. Re: Subject: Re: I love the smell of tantalum in the      morning
>       (Jeremy Nichols)
>    4. Re: Subject: Re: I love the smell of tantalum in the morning
>       (Charles Steinmetz)
>    5. This may be my new favorite old oscillator (Skip Withrow)
>    6. This may be my new favorite old oscillator (Mark Sims)
>    7. Re: This may be my new favorite old oscillator (Ruslan Nabioullin)
>    8. Re: This may be my new favorite old oscillator (paul swed)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 7 Nov 2016 16:47:28 -0500
> From: Scott Stobbe <scott.j.stobbe at gmail.com>
> To: Bob Stewart <bob at evoria.net>
> Cc: Discussion of Precise Time and Frequency Measurement
>         <time-nuts at febo.com>
> Subject: Re: [time-nuts] Thermal impact on OCXO
> Message-ID:
>         <CALg-KtP_UN9qdXH7B-whmG1WHWrXPscLKRS+DhB2kUS9g4A_
> hg at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Deeper into the rabbit hole :)
>
> I'm not sure what specific pic you are you using but most of them have at
> least one timer that will run fully asynchronously and its timer input is
> usually shared with one of the 32k osc pins. Which you can then use to wake
> the prossesor from one of its sleep states. Do you end up hitting a clock
> sync with the pwm block?
>
> Good old 74 series to the rescue.
>
> On Monday, 7 November 2016, Bob Stewart <bob at evoria.net> wrote:
>
> > Hi Scott,
> >
> > I wish I had some long term data, but I don't.  I had initially set out
> to
> > build an accurate GPS frequency reference type of GPSDO.  So, aging
> wasn't
> > an issue.  It's either on and locked or it's not.  So, I didn't worry
> about
> > leaving a unit running for months and collecting aging data.
> >
> > But then I had this crackpot idea of using the latches in a 7474 to
> > stabilize the 1PPS from the receiver to the OCXO.  Tom had a bit of a
> > misunderstanding about what I was doing and we had a bit of a discussion
> > until he caught on to what I was doing and its limitations.
> >
> > But, somewhere along the line, I realized that the idea was sound but my
> > implementation was poor.  The basic problem with using a timer in the
> > dsPIC33 is that they use a PLL to generate the internal clock - even if
> you
> > supply a clock.  That gives you a 1-count jitter in any output pulse you
> > try to create.  So, I realized that I could use the latches in a 7474 to
> > latch the OCXO to the output of a timer on the PIC.  With the PIC running
> > at 40MHz, I have plenty of room for the jitter without the worry of a
> phase
> > slip.  I think I've proved that that works, so now I have the possibility
> > of using my system as a time server.  And that means I now have to deal
> > with such arcane matters as holdover, aging, and generating the time from
> > the OCXO.  The learning curve has been a bit steep.
> >
> > Bob
> >
> > -----------------------------------------------------------------
> > AE6RV.com
> >
> > GFS GPSDO list:
> > groups.yahoo.com/neo/groups/GFS-GPSDOs/info
> >
> >
> > ------------------------------
> > *From:* Scott Stobbe <scott.j.stobbe at gmail.com
> > <javascript:_e(%7B%7D,'cvml','scott.j.stobbe at gmail.com');>>
> > *To:* Bob Camp <kb8tq at n1k.org
> > <javascript:_e(%7B%7D,'cvml','kb8tq at n1k.org');>>
> > *Cc:* Bob Stewart <bob at evoria.net
> > <javascript:_e(%7B%7D,'cvml','bob at evoria.net');>>; Discussion of precise
> > time and frequency measurement <time-nuts at febo.com
> > <javascript:_e(%7B%7D,'cvml','time-nuts at febo.com');>>
> > *Sent:* Monday, November 7, 2016 9:34 AM
> > *Subject:* Re: [time-nuts] Thermal impact on OCXO
> >
> > Here is a sample data point taken from http://tycho.usno.navy.mil/
> > ptti/1987papers/Vol%2019_16.pdf; the first that showed up on a google
> > search.
> >
> >          Year   Aging [PPM]  dF/dt [PPT/Day]
> >             1       180.51       63.884
> >             2       196.65        31.93
> >             5          218       12.769
> >             9       231.69       7.0934
> >            10       234.15        6.384
> >            25        255.5       2.5535
> >
> > If you have a set of coefficients you believe to be representative of
> your
> > OCXO, we can give those a go.
> >
> > On Mon, Nov 7, 2016 at 7:08 AM, Bob Camp <kb8tq at n1k.org
> > <javascript:_e(%7B%7D,'cvml','kb8tq at n1k.org');>> wrote:
> >
> > Hi
> >
> >
> > > On Nov 5, 2016, at 10:43 PM, Bob Stewart <bob at evoria.net
> > <javascript:_e(%7B%7D,'cvml','bob at evoria.net');>> wrote:
> > >
> > > Hi Scott,
> > > D'oh.  Thanks for the correction!  Like I said, I don't do these
> > calculations often.
> > >
> > > If as Bob Camp implies, the aging isn't from the OXCO, then I'm a bit
> > stumped.  I do have an op-amp in the EFC string with  a voltage divider
> for
> > gain.  The resistors are Panasonic ERA-6AEDxxxV resistors.  Mouser says
> > they're temperature stable to 25PPM/C, but of course they don't mention
> an
> > aging rate.  I don't really see anything else, other than the OCXO, that
> is
> > likely to be prone to a linear type of aging.
> >
> > OCXO’s don’t age in a linear fashion. At least 90% of them don’t. If you
> > dig into the FCS papers there are various
> > curves proposed as models. Mil-O-55310 has one of them as the “official”
> > approach. All of them have the basic
> > issue of mistakenly fitting to to short a time constraint.
> >
> > Bob
> >
> > >  The aging rate appears to be stable from unit to unit, so naturally I
> > considered the OCXO first.
> > >
> > > There is one other bit in the EFC string that might be controversial,
> > but I don't see that it would be a candidate for the symptoms of aging.
> > >
> > > Bob
> > >  ------------------------------ ------------------------------ -----
> > > AE6RV.com
> > >
> > > GFS GPSDO list:
> > > groups.yahoo.com/neo/groups/ GFS-GPSDOs/info
> > <http://groups.yahoo.com/neo/groups/GFS-GPSDOs/info?soc_
> src=mail&soc_trk=ma>
> > >
> > >      From: Scott Stobbe <scott.j.stobbe at gmail.com
> > <javascript:_e(%7B%7D,'cvml','scott.j.stobbe at gmail.com');>>
> > > To: Bob Stewart <bob at evoria.net
> > <javascript:_e(%7B%7D,'cvml','bob at evoria.net');>>
> > > Cc: Discussion of Precise Time and Frequency Measurement <
> > time-nuts at febo.com <javascript:_e(%7B%7D,'cvml','time-nuts at febo.com');>>
> > > Sent: Saturday, November 5, 2016 9:19 PM
> > > Subject: Re: [time-nuts] Thermal impact on OCXO
> > >
> > > If your DAC spans the full EFC range than 1LSB is 1/2^20 ~ 1 PPM of the
> > EFC range, and the EFC tuning range is 8/10E6 ~ 1 PPM full scale, so 1
> LSB
> > is ~1PPT. So, if everything else is stable the DAC code reflects changes
> > solely due to the OCXO, which would be an aging of 24 PPT/day.
> > > On Sat, Nov 5, 2016 at 9:57 PM, Bob Stewart <bob at evoria.net
> > <javascript:_e(%7B%7D,'cvml','bob at evoria.net');>> wrote:
> > >
> > > Hi Scott,
> > > The 20 bits span about 6 volts.  The EFC range spans about 8Hz
> > (+/-4Hz).  I don't do these calculations every day, but that's about
> 4.5PPT?
> > > Bob   ------------------------------ ------------------------------
> > -----
> > > AE6RV.com
> > >
> > > GFS GPSDO list:
> > > groups.yahoo.com/neo/groups/
> > <http://groups.yahoo.com/neo/groups/?soc_src=mail&soc_trk=ma>
> > GFS-GPSDOs/info
> > >
> > >
> > >
> > > From: Scott Stobbe <scott.j.stobbe at gmail.com
> > <javascript:_e(%7B%7D,'cvml','scott.j.stobbe at gmail.com');>>
> > > To: Bob Stewart <bob at evoria.net
> > <javascript:_e(%7B%7D,'cvml','bob at evoria.net');>>; Discussion of precise
> > time and frequency measurement <time-nuts at febo.com
> > <javascript:_e(%7B%7D,'cvml','time-nuts at febo.com');>>
> > > Sent: Saturday, November 5, 2016 8:38 PM
> > > Subject: Re: [time-nuts] Thermal impact on OCXO
> > >
> > > I think that's a nice plot, it looks like you have stepped 160 LSB over
> > 7 days or roughly 1 LSB per hour. With a 20bit dac you are trimming
> maybe 1
> > ppt/LSB to 4 ppt/LSB? In allan devation terms, the case of 1ppt/LSB,
> solely
> > due to drift, you're at 1E-12 at 3600*sqrt(2) = 5000 s, in the case of
> > 4ppt/hour your at 1E-12 at 1280 s. Seems reasonable.
> > > On Sat, Nov 5, 2016 at 2:47 PM, Bob Stewart <bob at evoria.net
> > <javascript:_e(%7B%7D,'cvml','bob at evoria.net');>> wrote:
> > >
> > > Oh dear.  I attached the wrong file.  Here's the correct one.
> > >  ----------------------------- ------------------------------ ------
> > > AE6RV.com
> > >
> > > GFS GPSDO list:
> > > groups.yahoo.com/neo/groups/
> > <http://groups.yahoo.com/neo/groups/?soc_src=mail&soc_trk=ma>
> > GFS-GPSDOs/info
> > >
> > >
> > >
> > > ______________________________ _________________
> > > time-nuts mailing list -- time-nuts at febo.com
> > <javascript:_e(%7B%7D,'cvml','time-nuts at febo.com');>
> > > To unsubscribe, go to https://www.febo.com/cgi-bin/
> > mailman/listinfo/time-nuts
> > > and follow the instructions there.
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > ______________________________ _________________
> > > time-nuts mailing list -- time-nuts at febo.com
> > <javascript:_e(%7B%7D,'cvml','time-nuts at febo.com');>
> > > To unsubscribe, go to https://www.febo.com/cgi-bin/
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> > <https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts>
> > > and follow the instructions there.
> >
> >
> >
> >
> >
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 07 Nov 2016 14:26:10 -0800
> From: Hal Murray <hmurray at megapathdsl.net>
> To: Discussion of precise time and frequency measurement
>         <time-nuts at febo.com>
> Cc: hmurray at megapathdsl.net
> Subject: Re: [time-nuts] Thermal impact on OCXO
> Message-ID:
>         <20161107222610.5667F406061 at ip-64-139-1-69.sjc.megapath.net>
> Content-Type: text/plain; charset=us-ascii
>
>
> kb8tq at n1k.org said:
> > Yes, that���s a bit of a long winded reply ��� sorry about that.
>
> It was also valuable.  Thanks.
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 7 Nov 2016 15:31:35 -0800
> From: Jeremy Nichols <jn6wfo at gmail.com>
> To: Discussion of precise time and frequency measurement
>         <time-nuts at febo.com>
> Subject: Re: [time-nuts] Subject: Re: I love the smell of tantalum in
>         the     morning
> Message-ID:
>         <CAPv4gjQ-ZWu3FYcWX0pRFJaR99PeeTP6kheAcj
> usDJ4Y1vThYA at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Amazon indicates the different lenses simply snap in and out. Any idea how
> easy/practical this is? It it better to have two completely different
> visors each holding different magnification lenses?
>
> Jeremy
>
>
> On Monday, November 7, 2016, Scott Hamilton <scottha at me.com> wrote:
>
> > https://www.amazon.com/Donegan-OptiVISOR-Headband-
> > Magnifier-Magnification/dp/B0068OSIIS/ref=sr_1_4?ie=UTF8&
> > qid=1478548961&sr=8-4&keywords=headset+magnifiers
> >
> > Finally, I can offer a contribution to this list. I have found the
> Donegan
> > magnifiers in the above Amazon link with 3.5X lenses to be very
> comfortable
> > and indespensible for SMD work. Different lenses can be obtained for
> other
> > work but the 3.5X is a minimum for me.
> >
> > Scott Hamilton
> > W3SEH
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com <javascript:;>
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> > mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
>
>
> --
> Sent from Gmail Mobile
>
>
> ------------------------------
>
> Message: 4
> Date: Mon, 7 Nov 2016 22:54:47 -0500
> From: Charles Steinmetz <csteinmetz at yandex.com>
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] Subject: Re: I love the smell of tantalum in
>         the morning
> Message-ID: <58214C87.1050704 at yandex.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> Jeremy wrote:
>
> > Amazon indicates the different lenses simply snap in and out. Any idea
> how
> > easy/practical this is? It it better to have two completely different
> > visors each holding different magnification lenses?
>
> Quite easy -- the lens plates are held onto the front of the visor by
> two plastic pins that just snap in and out.  You can see the heads from
> the outside (as opposed to the eye-side) at the far left and right of
> the lens plate.
>
> That said, IMO it is always more convenient to have each lens plate
> mounted in its own visor.
>
> I have to say that contrary to the original post, I find the 3.5x lenses
> WAY too strong for SMD work.  The working distance is only 3-4" -- not
> nearly enough to work safely with hot tools, or comfortably.  Even the
> 2.5x lenses, with 6-8" of working distance, are too strong for me.  For
> anything that requires working on the object you're looking at (as
> opposed to just examining it), I recommend staying at 2x and below (2x,
> 1.75x, 1.5x).
>
> Finally, Donegan makes two series of lenses -- rectangular plastic
> frames with optical glass lenses, and rectangular plastic frames with
> molded-in plastic lenses.  The glass lenses are more expensive, but the
> large difference in optical quality makes them the only real choice, IMO.
>
> At substantially greater cost, you can get "surgical loupes" (a/k/a
> "dental loupes").  These have compound optical systems, so you can get
> longer working distances at a particular magnification than you can with
> a single lens (like the OptiVisor has).
>
> Best regards,
>
> Charles
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Mon, 7 Nov 2016 22:16:48 -0700
> From: Skip Withrow <skip.withrow at gmail.com>
> To: time-nuts <time-nuts at febo.com>
> Subject: [time-nuts] This may be my new favorite old oscillator
> Message-ID:
>         <CA+oSWyUESoTVJ_2rySeaDa8u-OANhVwt00AsooDigXGLsaNU4Q@
> mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hello Time-Nuts,
>
> I recently acquired an HP 5065A rubidium oscillator (with 10811 10MHz
> OCXO). I think I pretty much have it running now and have been letting it
> cook for the last couple of weeks.  I offset the C-field + and - and
> measured the frequency to calculate the C-field sensitivity. My unit came
> out to 1.96x10E-12 per dial unit, which agrees with the manual stated
> 2x10E-12. So, calculated the on frequency C-field value and dialed it in.
>
> Attached is a Lady Heather plot of the frequency over the last 3 days.  The
> purple line is the 1pps plot with the vertical scale being 20ns per
> division.  So, the unit is off about 125ns over the last 72 hours (running
> about 4.92x10E-13 slow).  So my C-field setting is off about 1/4 of a
> division, but I think I'm going to leave well enough alone.
>
> The yellow line is the NTBW50AA temperature sensor, and you can clearly see
> when the furnace cycles.  I was away for the weekend, and you can also
> clearly see when I came home this evening and turned up the heat.  At the
> very end of the plot is the spike when I turned on the lights in the shop.
>
> I love using a Thunderbolt/NTBW50AA for making frequency measurements this
> way.  I remove the OCXO, and insert the 10MHz from the DUT.  Then disable
> disciplining so the DAC voltage doesn't try to chase the open loop
> oscillator.  Of course the short-term performance looks worse than it
> actually is because of measuring against GPS, but the long-term
> measurements are very good.
>
> I want to log this unit at regular intervals to see what the aging looks
> like.  Also need to do some measurements against the cesium to see what the
> short-term performance might be.  But, I think this oscillator will be a
> good reference in many cases in lieu of using the cesium.
>
> Regards,
> Skip Withrow
> -------------- next part --------------
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> ------------------------------
>
> Message: 6
> Date: Tue, 8 Nov 2016 06:49:10 +0000
> From: Mark Sims <holrum at hotmail.com>
> To: "time-nuts at febo.com" <time-nuts at febo.com>
> Subject: [time-nuts] This may be my new favorite old oscillator
> Message-ID:
>         <CY1PR17MB0297B9BAE4DCA664CE1148B1CEA60 at CY1PR17MB0297.
> namprd17.prod.outlook.com>
>
> Content-Type: text/plain; charset="iso-8859-1"
>
> If you connect the Thunderbolt EFC voltage up to the oscillator,  Lady
> Heather's oscillator autotune (&a) command does a good job of
> characterizing the EFC slope/gain (Hz/volt) characteristics of a 10 MHz
> oscillator.  It will step the EFC voltage up and down a few millivolts
> around the 10 MHz point and calculate the oscillator EFC gain.
>
> ---------------------
>
> > I love using a Thunderbolt/NTBW50AA for making frequency measurements
> this
> way.  I remove the OCXO, and insert the 10MHz from the DUT.  Then disable
> disciplining so the DAC voltage doesn't try to chase the open loop
> oscillator
>
> ------------------------------
>
> Message: 7
> Date: Tue, 8 Nov 2016 08:12:38 -0500
> From: Ruslan Nabioullin <rnabioullin at gmail.com>
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] This may be my new favorite old oscillator
> Message-ID: <455f0bf9-da45-efec-5d99-81f182eac1bd at gmail.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> On 11/08/2016 12:16 AM, Skip Withrow wrote:
> > Hello Time-Nuts,
> >
> > I recently acquired an HP 5065A rubidium oscillator (with 10811 10MHz
> > OCXO). I think I pretty much have it running now and have been letting it
> > cook for the last couple of weeks.  I offset the C-field + and - and
> > measured the frequency to calculate the C-field sensitivity. My unit came
> > out to 1.96x10E-12 per dial unit, which agrees with the manual stated
> > 2x10E-12. So, calculated the on frequency C-field value and dialed it in.
> >
> > Attached is a Lady Heather plot of the frequency over the last 3 days.
> The
> > purple line is the 1pps plot with the vertical scale being 20ns per
> > division.  So, the unit is off about 125ns over the last 72 hours
> (running
> > about 4.92x10E-13 slow).  So my C-field setting is off about 1/4 of a
> > division, but I think I'm going to leave well enough alone.
> >
> > The yellow line is the NTBW50AA temperature sensor, and you can clearly
> see
> > when the furnace cycles.  I was away for the weekend, and you can also
> > clearly see when I came home this evening and turned up the heat.  At the
> > very end of the plot is the spike when I turned on the lights in the
> shop.
> >
> > I love using a Thunderbolt/NTBW50AA for making frequency measurements
> this
> > way.  I remove the OCXO, and insert the 10MHz from the DUT.  Then disable
> > disciplining so the DAC voltage doesn't try to chase the open loop
> > oscillator.  Of course the short-term performance looks worse than it
> > actually is because of measuring against GPS, but the long-term
> > measurements are very good.
> >
> > I want to log this unit at regular intervals to see what the aging looks
> > like.  Also need to do some measurements against the cesium to see what
> the
> > short-term performance might be.  But, I think this oscillator will be a
> > good reference in many cases in lieu of using the cesium.
> >
> > Regards,
> > Skip Withrow
> >
> >
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
>
> I hope you will forgive me for reducing the SNR of this forum a bit, but
> is that a pro-Trump message embedded in that Lady Heather plot?
> Furthermore, it might also be promoting electoral fraud, though
> ``...vote often!'' is ambiguous (maybe that's plausible deniability?)
>
> -Ruslan
>
>
> ------------------------------
>
> Message: 8
> Date: Tue, 8 Nov 2016 08:46:15 -0500
> From: paul swed <paulswedb at gmail.com>
> To: Discussion of precise time and frequency measurement
>         <time-nuts at febo.com>
> Subject: Re: [time-nuts] This may be my new favorite old oscillator
> Message-ID:
>         <CAD2JfAhe2rFvS=-ZKzmLEeVHHjCsb3dTi_EV8w0iBCPxnFuppg at mail.
> gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Skip
> Wow a poor mans test setup. Kind of my speed and no HPIB or big counters
> etc. Like the re-use of Lady Heather. Clever.
> OK now to go find the soldering Iron and hack my TBolt... Maybe not today.
> So if you have a 5065 with 5 MHz out it needs to be doubled?
> With respect to the cfield. Yes its pretty sensitive down in the sub minor
> tick area.
> When I had the 5071 for testing I could never get it quite right. But
> nothing was actually wrong or noisy it was at the limit of reality.
> Regards
> Paul.
> WB8TSL
>
>
> On Tue, Nov 8, 2016 at 8:12 AM, Ruslan Nabioullin <rnabioullin at gmail.com>
> wrote:
>
> > On 11/08/2016 12:16 AM, Skip Withrow wrote:
> >
> >> Hello Time-Nuts,
> >>
> >> I recently acquired an HP 5065A rubidium oscillator (with 10811 10MHz
> >> OCXO). I think I pretty much have it running now and have been letting
> it
> >> cook for the last couple of weeks.  I offset the C-field + and - and
> >> measured the frequency to calculate the C-field sensitivity. My unit
> came
> >> out to 1.96x10E-12 per dial unit, which agrees with the manual stated
> >> 2x10E-12. So, calculated the on frequency C-field value and dialed it
> in.
> >>
> >> Attached is a Lady Heather plot of the frequency over the last 3 days.
> >> The
> >> purple line is the 1pps plot with the vertical scale being 20ns per
> >> division.  So, the unit is off about 125ns over the last 72 hours
> (running
> >> about 4.92x10E-13 slow).  So my C-field setting is off about 1/4 of a
> >> division, but I think I'm going to leave well enough alone.
> >>
> >> The yellow line is the NTBW50AA temperature sensor, and you can clearly
> >> see
> >> when the furnace cycles.  I was away for the weekend, and you can also
> >> clearly see when I came home this evening and turned up the heat.  At
> the
> >> very end of the plot is the spike when I turned on the lights in the
> shop.
> >>
> >> I love using a Thunderbolt/NTBW50AA for making frequency measurements
> this
> >> way.  I remove the OCXO, and insert the 10MHz from the DUT.  Then
> disable
> >> disciplining so the DAC voltage doesn't try to chase the open loop
> >> oscillator.  Of course the short-term performance looks worse than it
> >> actually is because of measuring against GPS, but the long-term
> >> measurements are very good.
> >>
> >> I want to log this unit at regular intervals to see what the aging looks
> >> like.  Also need to do some measurements against the cesium to see what
> >> the
> >> short-term performance might be.  But, I think this oscillator will be a
> >> good reference in many cases in lieu of using the cesium.
> >>
> >> Regards,
> >> Skip Withrow
> >>
> >>
> >>
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts at febo.com
> >> To unsubscribe, go to https://www.febo.com/cgi-bin/m
> >> ailman/listinfo/time-nuts
> >> and follow the instructions there.
> >>
> >>
> > I hope you will forgive me for reducing the SNR of this forum a bit, but
> > is that a pro-Trump message embedded in that Lady Heather plot?
> > Furthermore, it might also be promoting electoral fraud, though ``...vote
> > often!'' is ambiguous (maybe that's plausible deniability?)
> >
> > -Ruslan
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/m
> > ailman/listinfo/time-nuts
> > and follow the instructions there.
> >
>
>
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> Subject: Digest Footer
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> End of time-nuts Digest, Vol 148, Issue 28
> ******************************************
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