[time-nuts] time-nuts Digest, Vol 101, Issue 154

Mark Spencer mspencer12345 at yahoo.ca
Fri Dec 21 19:05:58 UTC 2012


Said, not sure where the noise is coming from but I suspect it's from the MV89 OCXO itself which was only powered up for 10 hours when the data was collected.   The  BVA reference and the counter (an HP5370B) have performed  significantly better on other occasions.  When I have some time over the holidays I'll take another look at this and confirm that the BVA and HP5370B are working as they should. I'll likely compare the BVA to another OCXO using another HP5370B at the same time I'm comparing the BVA to the MV89, then swap the two counters and repeat the measurements, but I  didn't have time for that this am (:   

I saw your request for data re OCXO's and fans and this gave me the incentive to spend a few minutes to power up one of my MV89's, then blow some air over it and collect a bit of data the next morning (: 

As a side note I've got two Z3805's in service and yes they are great performers over short time intervals (one of them seems to match the short term performance of my BVA on many occasions.)  I need to save my pennies for better counter / analyzer  as well as the HP5370B is of little use at tau's of less than 100 seconds or so (:

Regards Mark S

--- On Fri, 12/21/12, time-nuts-request at febo.com <time-nuts-request at febo.com> wrote:

> From: time-nuts-request at febo.com <time-nuts-request at febo.com>
> Subject: time-nuts Digest, Vol 101, Issue 154
> To: time-nuts at febo.com
> Received: Friday, December 21, 2012, 10:23 AM
> Send time-nuts mailing list
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> 
> Today's Topics:
> 
>    1. Re: time-nuts Digest, Vol 101, Issue
> 152 (Said Jackson)
>    2. Re: Brooks Shera (Chris Albertson)
>    3. Re: Z3805A cooling requirements?
> (Volker Esper)
>    4. Re: A Day in the Life of Five PPS
> Sources.. (Tom Miller)
>    5. Re: time-nuts Digest, Vol 101, Issue
> 152 (Volker Esper)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Fri, 21 Dec 2012 09:53:51 -0800
> From: Said Jackson <saidjack at aol.com>
> To: Discussion of precise time and frequency measurement
>     <time-nuts at febo.com>
> Cc: "time-nuts at febo.com"
> <time-nuts at febo.com>
> Subject: Re: [time-nuts] time-nuts Digest, Vol 101, Issue
> 152
> Message-ID: <6E6305FD-DF54-44D5-9CEB-5D4AEB5AEB22 at aol.com>
> Content-Type: text/plain;   
> charset=us-ascii
> 
> Mark,
> 
> Your plot still shows excursions of +/-1E-010, about 100x
> higher base noise than the Z3801A/Z3805A are capable of
> achieving. Wonder where that noise is coming from? This
> noise is probably much higher than the thermal effects.
> 
> The original post was the question "does my Z380xA have
> reduced stability if I add a fan" or similar, I think the
> answer is shown to be "yes".
> 
> Volker, I wonder if you also see fan-induced spurs in the
> phase noise from 1Hz to 100Hz. I would not be surprised if
> the fan vibration adds significant spurs to the 10811A
> crystal.
> 
> Bye,
> Said
> 
> Sent from my iPad
> 
> On Dec 21, 2012, at 9:42 AM, Mark Spencer <mspencer12345 at yahoo.ca>
> wrote:
> 
> > This plot should show the frequency change more
> clearly.   (Same data just presented
> differently.)
> > 
> > It seems to me that the noise goes may be going down a
> bit for a minute or so just after the fan is turned on but I
> don't believe these plots provide conclusive evidence of
> this.
> > 
> > 
> > Regards
> > Mark Spencer 
> >> Message: 7
> >> Date: Fri, 21 Dec 2012 09:27:29 -0800
> >> From: Said Jackson <saidjack at aol.com>
> >> To: Discussion of precise time and frequency
> measurement
> >>     <time-nuts at febo.com>
> >> Cc: Discussion of precise time and frequency
> measurement
> >>     <time-nuts at febo.com>
> >> Subject: Re: [time-nuts] Z3805A cooling
> requirements?
> >> Message-ID: <83CE0384-2996-4155-B51B-9D79910B29AA at aol.com>
> >> Content-Type: text/plain;   
> >> charset=us-ascii
> >> 
> >> Great plots guys!
> >> 
> >> Looking at these results I think my original claim
> still
> >> holds: ADEV goes up when a fan is involved versus
> no fan,
> >> even on a double oven 10811..
> >> 
> >> Clearly visible on the 10811, maybe not so much on
> the MV89
> >> but that unit seems to have frequency moves into
> the xE-010
> >> region on Marks plot so maybe the effect is just a
> bit
> >> hidden?
> >> 
> >> Bye,
> >> Said
> >> 
> >> Sent from my iPad
> >> 
> >> On Dec 21, 2012, at 5:44 AM, Volker Esper <ailer2 at t-online.de>
> >> wrote:
> >> 
> >>> ...and the picture of the experiment...
> >>> 
> >>> 
> >>>> The picture enclosed can give you a first
> >> impression. What we see is
> >>>> the difference time between the GPS signal
> and the
> >> OCXO (blue)
> >>>> ("PPS-TI"), which is an HP 10811. In red we
> can see
> >> the EFC. The total
> >>>> span is 24 h.
> >>>> 
> >>>> Before I applied the fan, the noise was at
> a
> >> maximum of about +/- 20 ns.
> >>>> Some hours after starting the fan the noise
> is much
> >> greater. That should
> >>>> have a significant impact on the ADEV.
> >>>> 
> >>>> I don't put the ADEV curves here, I make up
> for it
> >> when the EFC
> >>>> compensation is completely out of the
> scope, that
> >> will be in about 12
> >>>> hours. I don't have the ADEV at 1 s, but
> the ADEV
> >> at 10 s has been
> >>>> almost constant. The ADEV at about 1000 s
> has a
> >> nasty bump now.
> >>>> 
> >>>> IMHO that fits to the physical facts: the
> airflow
> >> will surely not affect
> >>>> the 10 s ADEV since the OCXO tries its best
> to
> >> isolate the oscillator
> >>>> from short time temperature influences.
> However,
> >> the turbulent air flow
> >>>> that I applied will influence the longer
> time
> >> ADEV.
> >>>> 
> >>>> Have a nice solstice
> >>>> 
> >>>> Volker
> >>>> 
> >>>> 
> >>>> 
> >>>> 
> >>>> Am 21.12.2012 12:44, schrieb Volker Esper:
> >>>>> 
> >>>>> Yes, I made such a setup, it's now
> running 22
> >> hours. I'll post the
> >>>>> results in two hours or so (if nothing
> evil
> >> happens to the earth,
> >>>>> meanwhile).
> >>>>> 
> >>>>> Volker
> >>>>> 
> >>>>> 
> >>>>> Am 21.12.2012 03:35, schrieb SAIDJACK at aol.com:
> >>>>>> Wish I had more time to play with
> this
> >> setup.
> >>>>>> 
> >>>>>> How about fellow time nuts spend
> some time
> >> and present similar test
> >>>>>> data on
> >>>>>> their OCXO's to compare?
> >>>>>> 
> >>>>>> I was interested in the 1s to 100s
> ADEV,
> >> and my runs were from 8
> >>>>>> minutes to
> >>>>>> 20 minutes, certainly enough time
> to
> >> capture data for 1s to 100s ADEV
> >>>>>> measurements..
> >>>>>> 
> >>>>>> bye,
> >>>>>> Said
> >>>>>> 
> >>>>>> 
> >>>>>> In a message dated 12/20/2012
> 14:17:59
> >> Pacific Standard Time,
> >>>>>> magnus at rubidium.dyndns.org
> >> writes:
> >>>>>> 
> >>>>>> On 12/20/2012 01:34 PM, Bob Camp
> wrote:
> >>>>>>> Hi
> >>>>>>> 
> >>>>>>> Temperature transients are not
> a good
> >> thing for an OCXO. If you
> >>>>>> deliberately use the fan to create
> a
> >> transient, then yes the OCXO will
> >>>>>> not be
> >>>>>> happy. The question it - what
> happens after
> >> the transient has settled
> >>>>>> out? The
> >>>>>> plot you have still looks a lot
> like a step
> >> function.
> >>>>>> 
> >>>>>> I agree. Temperature steps stresses
> the
> >> OCXO oven loop and easily
> >>>>>> creates a gradient over the
> crystal. As the
> >> oven loop tracks in, the
> >>>>>> frequency returns to around normal.
> The
> >> trouble with forced air over a
> >>>>>> crystal is that the metal shield
> couples
> >> very well and acts like a heat
> >>>>>> sink. A think plastic cover over it
> and
> >> forced convection doesn't have
> >>>>>> the same effect. There is even
> being used
> >> by at least one vendor. Works
> >>>>>> very well for the extra cents of
> >> manufacturing cost.
> >>>>>> 
> >>>>>> The HP10811 is recommended to be
> put in a
> >> airflow-quiet corner of the
> >>>>>> world. Look at it's mounting in
> the
> >> HP5370A/B for instance.
> >>>>>> 
> >>>>>> Cheers,
> >>>>>> Magnus
> >> _______________________________________________
> >>>>>> 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.
> >> _______________________________________________
> >>>>> 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.
> >>> 
> >>> <DSCF1758_bb.jpg>
> >>>
> _______________________________________________
> >>> 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.
> >> 
> >> 
> >> 
> >> ------------------------------
> >> 
> >> _______________________________________________
> >> time-nuts mailing list
> >> time-nuts at febo.com
> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >> 
> >> End of time-nuts Digest, Vol 101, Issue 152
> >> *******************************************
> > <MV89A Fan turned on at 460 seconds v2.png>
> > _______________________________________________
> > 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.
> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Fri, 21 Dec 2012 10:11:46 -0800
> From: Chris Albertson <albertson.chris at gmail.com>
> To: Discussion of precise time and frequency measurement
>     <time-nuts at febo.com>
> Subject: Re: [time-nuts] Brooks Shera
> Message-ID:
>     <CABbxVHt1ZJ260xqpWTZJAS_AMQasgWoqVEyvTBOu2MhpaXp8qA at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
> 
> I just had this same problem, a computer owned by some one
> who had
> passed away.  One dose not even need to know or recover
> the password.
> Simply remove the hard drive and place it on another
> computer and you
> will have access to all the files, copy over what is needed,
> re-format
> the drive, then put it back in the old PC and give the PC to
> the
> Goodwill store.
> 
> If the user encrypted the disk, you are out of luck with out
> the key
> but you only typicaly see encryption with notebook computers
> used for
> business.
> 
> I've seen this kind of dementia where the person needs full
> time care.
>  By the time it goes that far the person does not know where
> they are
> or who anyone is.  Many times they are upset and angry
> all the time
> because they can't figure out what's happening but other
> times they
> simply stair into space.
> 
> I think whatthis says is that if you've worked hard to make
> a design
> available to others and you don't intend to sell it
> commercially,
> PUBLISH the details, the design files and the source
> code.   Yes I
> kknow it is never "good enough" for others to see.  But
> in reality it
> is likely better than what 99.9%  of others can do.
> 
> 
> 
> On Fri, Dec 21, 2012 at 6:15 AM, paul swed <paulswedb at gmail.com>
> wrote:
> > Bert
> > A thought has crossed my mind here.
> > His wife can not access his computer.
> > If its windows XP or earlier the password is
> recoverable. I use a boot cd
> > that exposes all. Its been helpful.
> > Is there a way to reach out and offer help aside from
> snail mail?
> > Would she be open to that help?
> > Regards
> > Paul
> >
> > On Wed, Dec 19, 2012 at 4:03 PM, <EWKehren at aol.com>
> wrote:
> >
> >> Some how time nuts combined two lines  it is
> >> Karen Stoll    46 Crazy Rabbit 
> Rd      Santa Fee, 
> NM   87508
> >>
> >>
> >> In a message dated 12/19/2012 3:55:33 P.M. Eastern
> Standard Time,
> >> EWKehren at aol.com
> writes:
> >>
> >>
> >> Brooks Shera has been a major contributor with his
> GPSDO.   Before Tbolts
> >> where affordable his QST article for the first time
> opened  the  door for
> >> many
> >> amateurs to precision frequency at an
> affordable  price. Over the  years I
> >> build many units. For a year I have tried to 
> buy his latest version  4.02.
> >> I
> >> did not get a response, so last week  I wrote
> a hardcopy  letter.
> >> Yesterday I got an answer from his wife  Karen
> Stoll. She  is not able to
> >> access his emails.
> >> Brooks is in  a Memory Care  Unit in a
> local senior residence, suffering
> >> from  dementia.
> >> I think it is appropriate  that those of us
> that appreciate  his
> >> contribution take the time to write a 
> personal note to his wife,  I am
> >> sure it will
> >> help her in these difficult times  and maybe
> seeing  the letters will help
> >> him
> >> to.
> >> Bert  Kehren
> >> Karen   Stoll46 Crazy Rabbit Rd.
> >> Santa Fe, NM   87508
> >> _______________________________________________
> >> 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.
> >>
> >> _______________________________________________
> >> 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.
> >>
> > _______________________________________________
> > 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.
> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
> 
> 
> 
> ------------------------------
> 
> Message: 3
> Date: Fri, 21 Dec 2012 19:16:54 +0100
> From: Volker Esper <ailer2 at t-online.de>
> To: Discussion of precise time and frequency measurement
>     <time-nuts at febo.com>
> Subject: Re: [time-nuts] Z3805A cooling requirements?
> Message-ID: <50D4A796.3070701 at t-online.de>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> 
> ...and we do not know how much air flow and how turbulent
> each of us 
> applied. We can only give an _idea_ of what happens and in
> which order 
> of magnitude it could be.
> 
> When Stu started the thread (elderly time nuts can surely
> recall) his 
> question was about cooling a Z38xx unit. I recommended
> building a wind 
> shield between the oven and the power supply bricks and cool
> the bricks 
> with a fan. When my current test is completed, I'll try
> that, too.
> 
> The power supply most often seems to be the weak spot, so
> some 
> additional cooling wouldn't be wrong (apart from acoustic
> noise).
> 
> Yes, I bear in mind the warnings about a non ventilated
> seperate oven 
> chamber and the hints about maximum temperature vs oven
> temperature. So 
> I measured the temperature in the closed original aluminium
> case (which 
> however has some ventilation slots). It was about
> 45?C=113?F, at a room 
> temeprature of 21?C=70?F. With an oven temp of about
> 80?C=176?F I don't 
> expect problems, even if the oven chamber temp will increase
> some degrees.
> 
> Till then...
> 
> Volker
> 
> 
> 
> 
> 
> Am 21.12.2012 18:27, schrieb Said Jackson:
> > Great plots guys!
> >
> > Looking at these results I think my original claim
> still holds: ADEV goes up when a fan is involved versus no
> fan, even on a double oven 10811..
> >
> > Clearly visible on the 10811, maybe not so much on the
> MV89 but that unit seems to have frequency moves into the
> xE-010 region on Marks plot so maybe the effect is just a
> bit hidden?
> >
> > Bye,
> > Said
> >
> > Sent from my iPad
> >
> > On Dec 21, 2012, at 5:44 AM, Volker Esper<ailer2 at t-online.de> wrote:
> >
> >> ...and the picture of the experiment...
> >>
> >>
> >>> The picture enclosed can give you a first
> impression. What we see is
> >>> the difference time between the GPS signal and
> the OCXO (blue)
> >>> ("PPS-TI"), which is an HP 10811. In red we can
> see the EFC. The total
> >>> span is 24 h.
> >>>
> >>> Before I applied the fan, the noise was at a
> maximum of about +/- 20 ns.
> >>> Some hours after starting the fan the noise is
> much greater. That should
> >>> have a significant impact on the ADEV.
> >>>
> >>> I don't put the ADEV curves here, I make up for
> it when the EFC
> >>> compensation is completely out of the scope,
> that will be in about 12
> >>> hours. I don't have the ADEV at 1 s, but the
> ADEV at 10 s has been
> >>> almost constant. The ADEV at about 1000 s has a
> nasty bump now.
> >>>
> >>> IMHO that fits to the physical facts: the
> airflow will surely not affect
> >>> the 10 s ADEV since the OCXO tries its best to
> isolate the oscillator
> >>> from short time temperature influences.
> However, the turbulent air flow
> >>> that I applied will influence the longer time
> ADEV.
> >>>
> >>> Have a nice solstice
> >>>
> >>> Volker
> >>>
> >>>
> >>>
> >>>
> >>> Am 21.12.2012 12:44, schrieb Volker Esper:
> >>>>
> >>>> Yes, I made such a setup, it's now running
> 22 hours. I'll post the
> >>>> results in two hours or so (if nothing evil
> happens to the earth,
> >>>> meanwhile).
> >>>>
> >>>> Volker
> >>>>
> >>>>
> >>>> Am 21.12.2012 03:35, schrieb SAIDJACK at aol.com:
> >>>>> Wish I had more time to play with this
> setup.
> >>>>>
> >>>>> How about fellow time nuts spend some
> time and present similar test
> >>>>> data on
> >>>>> their OCXO's to compare?
> >>>>>
> >>>>> I was interested in the 1s to 100s
> ADEV, and my runs were from 8
> >>>>> minutes to
> >>>>> 20 minutes, certainly enough time to
> capture data for 1s to 100s ADEV
> >>>>> measurements..
> >>>>>
> >>>>> bye,
> >>>>> Said
> >>>>>
> >>>>>
> >>>>> In a message dated 12/20/2012 14:17:59
> Pacific Standard Time,
> >>>>> magnus at rubidium.dyndns.org
> writes:
> >>>>>
> >>>>> On 12/20/2012 01:34 PM, Bob Camp
> wrote:
> >>>>>> Hi
> >>>>>>
> >>>>>> Temperature transients are not a
> good thing for an OCXO. If you
> >>>>> deliberately use the fan to create a
> transient, then yes the OCXO will
> >>>>> not be
> >>>>> happy. The question it - what happens
> after the transient has settled
> >>>>> out? The
> >>>>> plot you have still looks a lot like a
> step function.
> >>>>>
> >>>>> I agree. Temperature steps stresses the
> OCXO oven loop and easily
> >>>>> creates a gradient over the crystal. As
> the oven loop tracks in, the
> >>>>> frequency returns to around normal. The
> trouble with forced air over a
> >>>>> crystal is that the metal shield
> couples very well and acts like a heat
> >>>>> sink. A think plastic cover over it and
> forced convection doesn't have
> >>>>> the same effect. There is even being
> used by at least one vendor. Works
> >>>>> very well for the extra cents of
> manufacturing cost.
> >>>>>
> >>>>> The HP10811 is recommended to be put in
> a airflow-quiet corner of the
> >>>>> world. Look at it's mounting in the
> HP5370A/B for instance.
> >>>>>
> >>>>> Cheers,
> >>>>> Magnus
> >>>>>
> >>>>>
> >>>>>
> _______________________________________________
> >>>>> 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.
> >>>>
> >>>>
> >>>>
> >>>>
> _______________________________________________
> >>>> 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.
> >>
> >> <DSCF1758_bb.jpg>
> >> _______________________________________________
> >> 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.
> >
> > _______________________________________________
> > 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.
> >
> >
> 
> 
> 
> 
> 
> ------------------------------
> 
> Message: 4
> Date: Fri, 21 Dec 2012 13:22:36 -0500
> From: "Tom Miller" <tmiller at skylinenet.net>
> To: "Discussion of precise time and frequency measurement"
>     <time-nuts at febo.com>
> Subject: Re: [time-nuts] A Day in the Life of Five PPS
> Sources..
> Message-ID:
> <69051F4C50D9494FBF1ACC7B2FBF4BB1 at FamilyHP>
> Content-Type: text/plain; format=flowed;
> charset=iso-8859-1;
>     reply-type=original
> 
> How did he set up the video? What camera?
> 
> Sorry, I lost the original message.
> 
> Regards,
> Tom
> 
> 
> ----- Original Message ----- 
> From: "paul swed" <paulswedb at gmail.com>
> To: "Discussion of precise time and frequency measurement" 
> <time-nuts at febo.com>
> Sent: Thursday, December 20, 2012 9:55 AM
> Subject: Re: [time-nuts] A Day in the Life of Five PPS
> Sources..
> 
> 
> Chuck he said it was the PRS10 RB the 5th unadjusted
> reference
> 
> On Thu, Dec 20, 2012 at 9:41 AM, Chuck Harris <cfharris at erols.com>
> wrote:
> 
> > Let's see, I understand what the traces are, but what
> is driving
> > the trigger?
> >
> > -Chuck Harris
> >
> > brent evers wrote:
> >
> >> Any idea of what drove the larger drift between the
> Tbolts and the
> >> PRS10 at 1:26 through1:29?
> >>
> >> Be interesting (to me at least) too see the same
> post survey.  Neat idea.
> >>
> >> Brent
> >>
> >> On Thu, Dec 20, 2012 at 1:43 AM, David Martin
> >> <drmartin at ivietechnologies.com**>
> wrote:
> >>
> >>> The video permissions should be fixed so it is
> no longer "private" ...
> >>> Sorry
> >>> --------------------
> >>>
> >>> A Day in the Life of Five PPS Sources..
> >>>
> >>> See http://youtu.be/kOG9ImT2lvY
> >>>
> >>> This is video is a two minute replay of the PPS
> behavior of two PRS-10s,
> >>> two TBolts, and the SSR-6t during it's initial
> 24 hour site survey.
> 
> 
> 
> 
> ------------------------------
> 
> Message: 5
> Date: Fri, 21 Dec 2012 19:22:48 +0100
> From: Volker Esper <ailer2 at t-online.de>
> To: Discussion of precise time and frequency measurement
>     <time-nuts at febo.com>
> Subject: Re: [time-nuts] time-nuts Digest, Vol 101, Issue
> 152
> Message-ID: <50D4A8F8.1070105 at t-online.de>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> 
> Vibration: interesting consideration. In my experiment the
> fan is very 
> softly coupled to the case (since it is lying on some soft
> cables), 
> furthermore the power supply is a different one - not the
> one that 
> powers the Z3805. I've tried to avoid those effects. I send
> some ADEV 
> plots in an hour.
> 
> Volker
> 
> Am 21.12.2012 18:53, schrieb Said Jackson:
> > Mark,
> >
> > Your plot still shows excursions of +/-1E-010, about
> 100x higher base noise than the Z3801A/Z3805A are capable of
> achieving. Wonder where that noise is coming from? This
> noise is probably much higher than the thermal effects.
> >
> > The original post was the question "does my Z380xA have
> reduced stability if I add a fan" or similar, I think the
> answer is shown to be "yes".
> >
> > Volker, I wonder if you also see fan-induced spurs in
> the phase noise from 1Hz to 100Hz. I would not be surprised
> if the fan vibration adds significant spurs to the 10811A
> crystal.
> >
> > Bye,
> > Said
> >
> > Sent from my iPad
> >
> > On Dec 21, 2012, at 9:42 AM, Mark Spencer<mspencer12345 at yahoo.ca> wrote:
> >
> >> This plot should show the frequency change more
> clearly.   (Same data just presented
> differently.)
> >>
> >> It seems to me that the noise goes may be going
> down a bit for a minute or so just after the fan is turned
> on but I don't believe these plots provide conclusive
> evidence of this.
> >>
> >>
> >> Regards
> >> Mark Spencer
> >>> Message: 7
> >>> Date: Fri, 21 Dec 2012 09:27:29 -0800
> >>> From: Said Jackson<saidjack at aol.com>
> >>> To: Discussion of precise time and frequency
> measurement
> >>>      <time-nuts at febo.com>
> >>> Cc: Discussion of precise time and frequency
> measurement
> >>>      <time-nuts at febo.com>
> >>> Subject: Re: [time-nuts] Z3805A cooling
> requirements?
> >>> Message-ID:<83CE0384-2996-4155-B51B-9D79910B29AA at aol.com>
> >>> Content-Type: text/plain;
> >>> charset=us-ascii
> >>>
> >>> Great plots guys!
> >>>
> >>> Looking at these results I think my original
> claim still
> >>> holds: ADEV goes up when a fan is involved
> versus no fan,
> >>> even on a double oven 10811..
> >>>
> >>> Clearly visible on the 10811, maybe not so much
> on the MV89
> >>> but that unit seems to have frequency moves
> into the xE-010
> >>> region on Marks plot so maybe the effect is
> just a bit
> >>> hidden?
> >>>
> >>> Bye,
> >>> Said
> >>>
> >>> Sent from my iPad
> >>>
> >>> On Dec 21, 2012, at 5:44 AM, Volker Esper<ailer2 at t-online.de>
> >>> wrote:
> >>>
> >>>> ...and the picture of the experiment...
> >>>>
> >>>>
> >>>>> The picture enclosed can give you a
> first
> >>> impression. What we see is
> >>>>> the difference time between the GPS
> signal and the
> >>> OCXO (blue)
> >>>>> ("PPS-TI"), which is an HP 10811. In
> red we can see
> >>> the EFC. The total
> >>>>> span is 24 h.
> >>>>>
> >>>>> Before I applied the fan, the noise was
> at a
> >>> maximum of about +/- 20 ns.
> >>>>> Some hours after starting the fan the
> noise is much
> >>> greater. That should
> >>>>> have a significant impact on the ADEV.
> >>>>>
> >>>>> I don't put the ADEV curves here, I
> make up for it
> >>> when the EFC
> >>>>> compensation is completely out of the
> scope, that
> >>> will be in about 12
> >>>>> hours. I don't have the ADEV at 1 s,
> but the ADEV
> >>> at 10 s has been
> >>>>> almost constant. The ADEV at about 1000
> s has a
> >>> nasty bump now.
> >>>>>
> >>>>> IMHO that fits to the physical facts:
> the airflow
> >>> will surely not affect
> >>>>> the 10 s ADEV since the OCXO tries its
> best to
> >>> isolate the oscillator
> >>>>> from short time temperature influences.
> However,
> >>> the turbulent air flow
> >>>>> that I applied will influence the
> longer time
> >>> ADEV.
> >>>>>
> >>>>> Have a nice solstice
> >>>>>
> >>>>> Volker
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> Am 21.12.2012 12:44, schrieb Volker
> Esper:
> >>>>>>
> >>>>>> Yes, I made such a setup, it's now
> running 22
> >>> hours. I'll post the
> >>>>>> results in two hours or so (if
> nothing evil
> >>> happens to the earth,
> >>>>>> meanwhile).
> >>>>>>
> >>>>>> Volker
> >>>>>>
> >>>>>>
> >>>>>> Am 21.12.2012 03:35, schrieb SAIDJACK at aol.com:
> >>>>>>> Wish I had more time to play
> with this
> >>> setup.
> >>>>>>>
> >>>>>>> How about fellow time nuts
> spend some time
> >>> and present similar test
> >>>>>>> data on
> >>>>>>> their OCXO's to compare?
> >>>>>>>
> >>>>>>> I was interested in the 1s to
> 100s ADEV,
> >>> and my runs were from 8
> >>>>>>> minutes to
> >>>>>>> 20 minutes, certainly enough
> time to
> >>> capture data for 1s to 100s ADEV
> >>>>>>> measurements..
> >>>>>>>
> >>>>>>> bye,
> >>>>>>> Said
> >>>>>>>
> >>>>>>>
> >>>>>>> In a message dated 12/20/2012
> 14:17:59
> >>> Pacific Standard Time,
> >>>>>>> magnus at rubidium.dyndns.org
> >>> writes:
> >>>>>>>
> >>>>>>> On 12/20/2012 01:34 PM, Bob
> Camp wrote:
> >>>>>>>> Hi
> >>>>>>>>
> >>>>>>>> Temperature transients are
> not a good
> >>> thing for an OCXO. If you
> >>>>>>> deliberately use the fan to
> create a
> >>> transient, then yes the OCXO will
> >>>>>>> not be
> >>>>>>> happy. The question it - what
> happens after
> >>> the transient has settled
> >>>>>>> out? The
> >>>>>>> plot you have still looks a lot
> like a step
> >>> function.
> >>>>>>>
> >>>>>>> I agree. Temperature steps
> stresses the
> >>> OCXO oven loop and easily
> >>>>>>> creates a gradient over the
> crystal. As the
> >>> oven loop tracks in, the
> >>>>>>> frequency returns to around
> normal. The
> >>> trouble with forced air over a
> >>>>>>> crystal is that the metal
> shield couples
> >>> very well and acts like a heat
> >>>>>>> sink. A think plastic cover
> over it and
> >>> forced convection doesn't have
> >>>>>>> the same effect. There is even
> being used
> >>> by at least one vendor. Works
> >>>>>>> very well for the extra cents
> of
> >>> manufacturing cost.
> >>>>>>>
> >>>>>>> The HP10811 is recommended to
> be put in a
> >>> airflow-quiet corner of the
> >>>>>>> world. Look at it's mounting in
> the
> >>> HP5370A/B for instance.
> >>>>>>>
> >>>>>>> Cheers,
> >>>>>>> Magnus
> >>>
> _______________________________________________
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> there.
> >>>
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> >>>>
> >>>> <DSCF1758_bb.jpg>
> >>>>
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> >>> End of time-nuts Digest, Vol 101, Issue 152
> >>> *******************************************
> >> <MV89A Fan turned on at 460 seconds v2.png>
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