Sarah -
As others will point out the temperature reported by the T-bolt is NOT the oven
temperature. Rather it
is the temperature of a temp sensing chip on the PWB. There were several
versions of this chip installed
and they did not all work the same - on the time nuts archive there is a wealth
of comment on this. There is
also a lot about protecting the T-bolt from sudden temp transients. Keeping out
of drafts will do for most users.
Now if your unit is showing a higher temp than the local ambient and it sort of
follows the ambient up and down the chances are you have a "good" chip. Good
being defined as compatible with LH and reporting sensible numbers. In some
cases the replacement / defective chips report -55 C.
I have several T bolts with this problem and some that do not have it. In all
cases the T-bolts still operated correctly.
Operating correctly is defined as testing them in an environmental chamber and
measuring stability by phase comparison at 10 MHz with other T bolts and with a
Rb standard. I spent about a month at this last summer, and it was not a casual
exercise by any means.
So chances are yours is OK, but you will need to cross check with another unit
to be totally sure. The t-bolt
is supposedly self checking so if there are no alarms it is a good sign.
best regards - john roos k6iql
-----Original Message-----
From: time-nuts-request <time-nuts-requ...@febo.com>
To: time-nuts <time-nuts@febo.com>
Sent: Mon, Dec 10, 2012 5:03 pm
Subject: time-nuts Digest, Vol 101, Issue 86
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Today's Topics:
1. Thunderbolt oven / non-stable operating temperature (Sarah White)
2. Re: Thunderbolt oven / non-stable operating temperature (Bob Camp)
3. Re: Thunderbolt oven / non-stable operating temperature
(Tom Miller)
4. Re: Thunderbolt oven / non-stable operating temperature
(George Dubovsky)
5. Re: 31bit ADC, 1000 samples per second (Didier Juges)
6. Thunderbolt oven / non-stable operating temperature (Arthur Dent)
7. Re: 31bit ADC, 1000 samples per second (Poul-Henning Kamp)
----------------------------------------------------------------------
Message: 1
Date: Mon, 10 Dec 2012 17:15:07 -0500
From: Sarah White <kuze...@gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: [time-nuts] Thunderbolt oven / non-stable operating
temperature
Message-ID: <50c65eeb.9090...@gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Ended up with a gently used trimble thunderbolt a few months ago, and
been trying to figure out the best settings to use (time constant,
damping, etc.) for best performance.
I got distracted though. There is something which I find rather
annoying, and I'm spending more time messing with this factor than
actually observing the performance at different damping / time constant
/ etc...
The temperature seems to be aprox 20C above ambient temperature rather
than a steady 40C. I thought the purpose of the oven was to keep the
temperature stable. When I adjust the thermostat because I'm chilly, the
thunderbolt gets warmer too (but not by as much)
I've tried (seemingly, to me) everything:
light insulation
putting the unit in a spot away from drafts
putting the unit in a place away from drafts in a shoebox with light
insulation with a fan blowing in it (currently in a cupboard in this
state, and the temp seems to fluctuate the least, but still by more than
1-2 degrees centigrade)
I feel like shouldn't need to fuss with ambient conditions this heavily
for an OCXO, and find myself researching construction / design for a DIY
outer-oven to wrap the thunderbolt in.
Anyone have experience with non-stable temperature on a trimble thunderbolt?
I've also noticed (monitoring with Lady Heather's Disciplined Oscillator
Control Program v3.10 by John Miles aka KE5FX) the thunderbolt unit
sometimes flags an alarm briefly (and I rarely ever manage to write it
down before the screen updates or the alarm goes away) and the last one
I was able to "catch" before it went away was related to temperature.
Should I be getting a steady / non-flucturating 40C or something if the
oven is working normally?
Thanks in advance,
Sarah
------------------------------
Message: 2
Date: Mon, 10 Dec 2012 17:22:27 -0500
From: Bob Camp <li...@rtty.us>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: Re: [time-nuts] Thunderbolt oven / non-stable operating
temperature
Message-ID: <f48318e0-3c38-4b2d-a496-a7ca136b9...@rtty.us>
Content-Type: text/plain; charset=us-ascii
Hi
The oven in the OCXO keeps the crystal at a constant temperature. It is normal
for the TBolt it's self to idle 10 to 20C above ambient. The temperature sensor
is located near the 9 pin D connector. It shows a temperature somewhere in
between the ambient and the OCXO case temperature. Some have mounted speed
controlled fans to keep the TBolt case at a constant temperature.
Bob
On Dec 10, 2012, at 5:15 PM, Sarah White <kuze...@gmail.com> wrote:
> Ended up with a gently used trimble thunderbolt a few months ago, and
> been trying to figure out the best settings to use (time constant,
> damping, etc.) for best performance.
>
> I got distracted though. There is something which I find rather
> annoying, and I'm spending more time messing with this factor than
> actually observing the performance at different damping / time constant
> / etc...
>
> The temperature seems to be aprox 20C above ambient temperature rather
> than a steady 40C. I thought the purpose of the oven was to keep the
> temperature stable. When I adjust the thermostat because I'm chilly, the
> thunderbolt gets warmer too (but not by as much)
>
> I've tried (seemingly, to me) everything:
>
> light insulation
>
> putting the unit in a spot away from drafts
>
> putting the unit in a place away from drafts in a shoebox with light
> insulation with a fan blowing in it (currently in a cupboard in this
> state, and the temp seems to fluctuate the least, but still by more than
> 1-2 degrees centigrade)
>
> I feel like shouldn't need to fuss with ambient conditions this heavily
> for an OCXO, and find myself researching construction / design for a DIY
> outer-oven to wrap the thunderbolt in.
>
> Anyone have experience with non-stable temperature on a trimble thunderbolt?
>
> I've also noticed (monitoring with Lady Heather's Disciplined Oscillator
> Control Program v3.10 by John Miles aka KE5FX) the thunderbolt unit
> sometimes flags an alarm briefly (and I rarely ever manage to write it
> down before the screen updates or the alarm goes away) and the last one
> I was able to "catch" before it went away was related to temperature.
>
> Should I be getting a steady / non-flucturating 40C or something if the
> oven is working normally?
>
> Thanks in advance,
> Sarah
>
>
> _______________________________________________
> 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.
------------------------------
Message: 3
Date: Mon, 10 Dec 2012 17:29:32 -0500
From: "Tom Miller" <tmil...@skylinenet.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Subject: Re: [time-nuts] Thunderbolt oven / non-stable operating
temperature
Message-ID: <E4C6FCA958714C35B2A558AF05B6B221@FamilyHP>
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
reply-type=original
Hi Sarah,
The temperature you are seeing is that of a Dallas IC mounted on the main PC
board. You are seeing the ambient temp of the board, not inside the OCXO
oven.
Regards,
Tom
----- Original Message -----
From: "Sarah White" <kuze...@gmail.com>
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Sent: Monday, December 10, 2012 5:15 PM
Subject: [time-nuts] Thunderbolt oven / non-stable operating temperature
Ended up with a gently used trimble thunderbolt a few months ago, and
been trying to figure out the best settings to use (time constant,
damping, etc.) for best performance.
I got distracted though. There is something which I find rather
annoying, and I'm spending more time messing with this factor than
actually observing the performance at different damping / time constant
/ etc...
The temperature seems to be aprox 20C above ambient temperature rather
than a steady 40C. I thought the purpose of the oven was to keep the
temperature stable. When I adjust the thermostat because I'm chilly, the
thunderbolt gets warmer too (but not by as much)
I've tried (seemingly, to me) everything:
light insulation
putting the unit in a spot away from drafts
putting the unit in a place away from drafts in a shoebox with light
insulation with a fan blowing in it (currently in a cupboard in this
state, and the temp seems to fluctuate the least, but still by more than
1-2 degrees centigrade)
I feel like shouldn't need to fuss with ambient conditions this heavily
for an OCXO, and find myself researching construction / design for a DIY
outer-oven to wrap the thunderbolt in.
Anyone have experience with non-stable temperature on a trimble thunderbolt?
I've also noticed (monitoring with Lady Heather's Disciplined Oscillator
Control Program v3.10 by John Miles aka KE5FX) the thunderbolt unit
sometimes flags an alarm briefly (and I rarely ever manage to write it
down before the screen updates or the alarm goes away) and the last one
I was able to "catch" before it went away was related to temperature.
Should I be getting a steady / non-flucturating 40C or something if the
oven is working normally?
Thanks in advance,
Sarah
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
------------------------------
Message: 4
Date: Mon, 10 Dec 2012 17:26:15 -0500
From: George Dubovsky <n4ua...@gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: Re: [time-nuts] Thunderbolt oven / non-stable operating
temperature
Message-ID:
<CAALHBrZFq=sb_waJMugqJe7h10qWhpev4hikB9r87=7pxr2...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Sarah,
The reported temperature is not the oven temp, but rather the temp of the
circuit board just behind the DB-9 serial connector. As far as I know, the
actual oven temp is not available outside the OCXO.
Regards,
geo
On Mon, Dec 10, 2012 at 5:15 PM, Sarah White <kuze...@gmail.com> wrote:
> Ended up with a gently used trimble thunderbolt a few months ago, and
> been trying to figure out the best settings to use (time constant,
> damping, etc.) for best performance.
>
> I got distracted though. There is something which I find rather
> annoying, and I'm spending more time messing with this factor than
> actually observing the performance at different damping / time constant
> / etc...
>
> The temperature seems to be aprox 20C above ambient temperature rather
> than a steady 40C. I thought the purpose of the oven was to keep the
> temperature stable. When I adjust the thermostat because I'm chilly, the
> thunderbolt gets warmer too (but not by as much)
>
> I've tried (seemingly, to me) everything:
>
> light insulation
>
> putting the unit in a spot away from drafts
>
> putting the unit in a place away from drafts in a shoebox with light
> insulation with a fan blowing in it (currently in a cupboard in this
> state, and the temp seems to fluctuate the least, but still by more than
> 1-2 degrees centigrade)
>
> I feel like shouldn't need to fuss with ambient conditions this heavily
> for an OCXO, and find myself researching construction / design for a DIY
> outer-oven to wrap the thunderbolt in.
>
> Anyone have experience with non-stable temperature on a trimble
> thunderbolt?
>
> I've also noticed (monitoring with Lady Heather's Disciplined Oscillator
> Control Program v3.10 by John Miles aka KE5FX) the thunderbolt unit
> sometimes flags an alarm briefly (and I rarely ever manage to write it
> down before the screen updates or the alarm goes away) and the last one
> I was able to "catch" before it went away was related to temperature.
>
> Should I be getting a steady / non-flucturating 40C or something if the
> oven is working normally?
>
> Thanks in advance,
> Sarah
>
>
> _______________________________________________
> 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.
>
------------------------------
Message: 5
Date: Mon, 10 Dec 2012 16:28:52 -0600
From: Didier Juges <shali...@gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: Re: [time-nuts] 31bit ADC, 1000 samples per second
Message-ID:
<CAMQqFunNbAjFCpfBkt2-z3-vE=hvc1bwiki2rjzcm_df7fm...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
I agree, but there is a difference between something that you should be
able to achieve by design and being able to prove it, or even if it's
useful in practice.
In a case like this, the wide span between resolution and effective bits
makes me wonder what's the point of advertising the former other than
bragging rights?
On Mon, Dec 10, 2012 at 3:38 PM, David <davidwh...@gmail.com> wrote:
> Integrating converters including delta-sigma converters can be no
> missing codes by design without being able to take advantage of the
> full resolution that implies. Integral nonlinearity, drift, and noise
> will limit the usable resolution.
>
> On Mon, 10 Dec 2012 15:08:38 -0600, Didier Juges <shali...@gmail.com>
> wrote:
>
> >How long does it take to prove it?
> >And what's the point?
> >
> >
> >On Mon, Dec 10, 2012 at 3:04 PM, Gerhard Hoffmann <dk...@arcor.de> wrote:
> >
> >> Am 10.12.2012 21:53, schrieb Didier Juges:
> >>
> >> I do not understand how anyone can guaranty no missing codes when the
> >>> lower
> >>> 11 bits are essentially noise? (31 bits resolution versus 20 effective
> >>> bits)
> >>>
> >>
> >> With that much noise it is really guaranteed that no code will be
> missing.
> >>
> >> :-) Gerhard
>
> _______________________________________________
> 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.
>
------------------------------
Message: 6
Date: Mon, 10 Dec 2012 14:41:37 -0800 (PST)
From: Arthur Dent <golgarfrinc...@yahoo.com>
To: "time-nuts@febo.com" <time-nuts@febo.com>
Subject: [time-nuts] Thunderbolt oven / non-stable operating
temperature
Message-ID:
<1355179297.85446.yahoomail...@web125004.mail.ne1.yahoo.com>
Content-Type: text/plain; charset=us-ascii
>I feel like shouldn't need to fuss with ambient conditions this heavily
>for an OCXO, and find myself researching construction / design for a DIY
>outer-oven to wrap the thunderbolt in.
>
>Anyone have experience with non-stable temperature on a trimble thunderbolt?"
The temperature you see is not from the OCXO but from the thermometer chip
near the RS-232 connector. The DS1620 is probably at fault and the rest of the
Thunderbolt is operating as it should. I've see a lot of Thunderbolts and the
most
common failure mode of the non E revision DS1620 thermometer is for them to
display -55 degrees C although it could just have erratic output like yours.
The
erratic temperature that it is reporting could cause the processor to try to
compensate for the erratic jumps and cause the Thunderbolt output to be less
stable. The DS1620 should be replaced.
-Arthur
------------------------------
Message: 7
Date: Mon, 10 Dec 2012 23:01:49 +0000
From: "Poul-Henning Kamp" <p...@phk.freebsd.dk>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>, David <davidwh...@gmail.com>
Subject: Re: [time-nuts] 31bit ADC, 1000 samples per second
Message-ID: <98332.1355180...@critter.freebsd.dk>
--------
In message <tilcc892a6ntfk64t2nljm92idr92df...@4ax.com>, David writes:
>The gain drift is specified at 2ppm per degree C. There are
>provisions for a calibration cycle but that requires external
>multiplexing.
That's the really smart thing about this particular chip: You can
drive the geophone calibration signal in through the second input
and out onto the first, which eliminates the external calibration
mux and the errors that usually cause.
And yes, in seismology you do care about frequencies from 0.1Hz and up
(0.01Hz if you're involved with the CTBT) and most voltage references
will be stable enough for that.
For longer term you calibrate your entire system, starting with the
geophone, so the voltage reference is caught that way.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
------------------------------
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