Well bob's comments & caution are accurate, everything drifts. In your
case, if the OCXO is rock solid then you would see a 160 PPM change on the
EFC line over 7 days which is a 1mV change on your 6 V full scale, which is
fairly easy to measure if you have a 6 1/2 digit DMM.
On Sat, Nov 5, 2016 at
Ian,
You have a very nice setup. I also bought an AM-Scope about three
years ago. Mine has the associated 8-bazillion ton white stand on
the edge of the bench with double arms that lets me swing it over to
where I'm working. As I recall, it has a zoom range of about 3.5 to
45x which is mor
Hi Bob,
Sadly, all I have is what I have. The GSPDOs are in an unvented Hammond
aluminum case. I've got a thermistor on the bottom side of the board.
Actually, it's right below the PIC, so the temperature from the PIC would seem
to be the driver of what I see. Except that I've also done some
Anton,
To answer both questions:
You can use a Laser in place of the Rubidium lamp, however assuming the
problem is the lamp it would be cheaper to buy several LPRO units to
scavenge for a replacement lamp.
How did you determine it's the lamp that is dead?
Using a Laser is more complicated t
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 resi
Hi
If you go back to my previous list, all the things that have a tempco also age.
Holding temperature
over weeks or months is not at all easy …. You have gradients between parts so
it is impossible to
look at temperature (or aging) as a single effect. In the case of a fairly
normal room, tempe
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,
Hi Bob,
Could you expound on "so far below a number of issues"?
In any case, your post implies that something else is aging. I'm using an
ADR4533A as my voltage reference. That feeds an AD8638 op-amp driving an
MMBTA pass transistor. That pretty much leaves the divider resistors on an
AD8
Yes. Unless you're grinding it away with a dremel (which I wouldn't recommend
as far as chemical dust is concerned), nibbling away with sidecutters would be
trying to force the 2 ends of the component apart. That may be stressing the
pads they're soldered to, leading to a possible pad lifting a
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/GFS-GPSDOs/info
For through hole parts sure, but I would not recommend that on SMD parts,
the copper foil of a little pad is pretty easy to tear off and it's a royal
pain if you have to mount a device missing some of its landing pads.
On Sat, Nov 5, 2016 at 4:37 PM, Tom Miller wrote:
> I usually nibble away at
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
It should wind up in the standard Lady Heather directory... depends upon the
operating system and how the program was started. From the keyboard in Lady
Heather, type ? That will bring up the command line option help. Scroll/page
down to the end of the info and there will be a line that say
Hi Bob,
But will any of the things you mentioned show up as a more or less linear march
downhill at about 1 step per hour over the course of 7 days? In fact, I think
Dan's units show about the same -1 per hour, and he's had them running
continuously for many months. I believe you use these sam
Hi all,a few day ago I read "super HP5065A" from Mr Corby and I wondering if
any one has done same thing with "telecom" Rubidium pack ? I found an optical
bandpass filter cost is cheap enough to a third country people like me but if
any one has tried before and know a lot more than what I know I
Hi
2^20 is roughly 1 ppm. It is about 5 uV on a 5V line or 2.5 uV on a 2.5 V EFC
center.
A DAC that does 100 ppm / C is a pretty typical part. 10 ppm / C is
unusually good
A “good” voltage reference might do 2 ppm / C
A very typical room will swing around +/- 2C without much goi
This seems to be turning into a rabbit hole from which there can be no possible
return. With no evidence, you question my competence and cast aspersions on my
testing methodology. I give up.
Have a nice day.
Bob -
AE6RV.com
GF
Where will the file go?
-Original Message-
From: Mark Sims
To: time-nuts
Sent: Fri, Nov 4, 2016 2:37 pm
Subject: [time-nuts] Lady Heather and LeapSecond
Yes, and it will also automatically do a screen dump to the file
"leap_sec.gif" That all assume that the GPS device reports a lea
...with a 20bit DAC, a suitable voltage reference for that DAC and an HP3458...
On Sun, Nov 6, 2016 at 12:39 AM, Bob Stewart wrote:
> Hi Hal,
>
> With a 20 bit DAC, even a small aging rate is going to show up. I'll let the
> one GPSDO cook for a month or so and see what it shows then. I'll als
On 11/05/2016 03:12 PM, Tom Van Baak wrote:
> Having not done SMT before, how should I do it with minimal risk to the very
> precious PCB. Or, what equipment should I use this as a good excuse to buy?
Tom, I used the obvious but never read about using two soldering irons,
invented it myself,
Am 05.11.2016 um 12:51 schrieb Bill Riches:
Hi Mark,
Thank you for working with the KS24361. Looking forward to when the program
will be available.
Any ideas on being able to use the 1 PPS signal out of the KS24361 to drive SL
sound card calibration? It is a weird pulse and someone mentione
Hi Hal,
With a 20 bit DAC, even a small aging rate is going to show up. I'll let the
one GPSDO cook for a month or so and see what it shows then. I'll also pull
the data from the log file and see if I can see any correlation between the
temperature and the EFC over time. IOW, for data points
metcal has a "hot twizer " to remove SMD components it heats the
component on both end
73
Alex
On 11/5/2016 12:55 PM, Hal Murray wrote:
t...@leapsecond.com said:
Having not done SMT before, how should I do it with minimal risk to the
very precious PCB. Or, what equipment should I use this a
On Sat, 5 Nov 2016 20:57:11 +0100, you wrote:
>> Having not done SMT before, how should I do it with minimal risk to the very
>> precious PCB. Or, what equipment should I use this as a good excuse to buy?
>
>Now, for these caps, you can use a normal soldering-iron without too
>much trouble, but
So much information from so many that have obviously run into the smell of
a burnt part.
I do the cut the part to pieces and unsolder each leg. Also the 2 iron
approach.
The absolute goal, do not damage the board.
I have a hot air station also and much like the comments made not impressed.
I did gr
Tom's method is what I use when replacing commodity parts that I don't care
about salvaging. Much less chance of damaging anything. Hack the part apart,
cut the leads on gull wing packages, etc. Don't waste your time with
tweezers, lifting one end, etc. I have a very nice set of hot twee
I usually nibble away at the center of the part until it is two separate
pieces. Then unsolder each piece. Clean the pads off with wick then install
the new part.
Use a good sharp pair of flush cut side cutters.
Tom
- Original Message -
From: "Bob Camp"
To: "Tom Van Baak" ; "Discus
On Sat, Nov 05, 2016 at 12:12:18PM -0700, Tom Van Baak wrote:
> Having not done SMT before, how should I do it with minimal risk to
> the very precious PCB. Or, what equipment should I use this as a good
> excuse to buy?
Hello Tom.
I do this kind of repairs quite often and as you have already rea
Hi
A *lot* depends on how many planes there are in that board. The weight of he
copper
also maters a bit. If there is enough thermal mass, you will need a pre-heat
process.
There are lots of ways to do it ranging from the kitchen oven to various “frame
and
lightbulb” setups and on into ever m
Ok, thanks, Chris! Some day I'll learn SMT but I don't think it's wise for me
to use a 5071 main board as my first mistake. So I'll follow-up with your
generous offer off-list.
/tvb
- Original Message -
From: Chris Waldrup
To: Tom Van Baak ; Discussion of precise time and freque
Hi Tom,
I'm a SMT rework technician for a large satcom and defense company.
I have a shop at home too and all the equipment to repair this if I can be
provided with the replacement cap.
Please let me know if I can be of help.
Chris
KD4PBJ
> On Nov 5, 2016, at 14:12, Tom Van Baak wrote:
>
>
Dear Tom,
On 11/05/2016 08:12 PM, Tom Van Baak wrote:
See C13 in the attached photo. I need to replace some blown caps on a few
boards [1]. In one instance the cap got so hot it melted itself off the board.
Quiet convenient, actually -- it acts like its own fuse -- but I don't think
the 5071
t...@leapsecond.com said:
> Having not done SMT before, how should I do it with minimal risk to the
> very precious PCB. Or, what equipment should I use this as a good excuse
> to buy?
If you can get at it, 2 soldering irons, one on each end, works reasonably
well. When both ends are melted, j
Hi John,
I've never used the hot tweezers. I'm going to have to look into them.
Normally, for desoldering, I use a narrower nozzle with an elevated temperature
- usually between 280C and 350C. That blows the part completely off the pads
just as soon as the solder flows, with little impact on
Surprisingly the 852D+ which is a very cheap rework station is quite good.
Quite a few reviews on the EEVblog.
-=Bryan=-
From: time-nuts on behalf of Bob Stewart
Sent: November 5, 2016 12:18 PM
To: Tom Van Baak; Discussion of precise time and frequency measu
Either hot tweezers or a hot air rework station are the best/easiest
ways to remove dead parts. But two fine-tip soldering irons will also
work and are a lot cheaper. The idea is to heat both ends of the part
at once, and when the solder flows, lift or flip the part off. Then,
use some liqui
On Saturday, November 05, 2016 12:12:18 PM Tom Van Baak wrote:
> See C13 in the attached photo. I need to replace some blown caps on a
few
> boards [1]. In one instance the cap got so hot it melted itself off the
> board. Quiet convenient, actually -- it acts like its own fuse -- but I
> don't thi
Metcal /OKI might be that other brand. I'd certainly recommend them, but
the tweezers are not as fast to heat as the single tip devices.
I've had little success personally with the hot air devices. I seem to
toast the board before I melt the solder, and when it does melt it's not
limited to one co
Hi Tom,
Personally, I wouldn't touch this without a hot air gun. I don't know what
your budget is. What I consider reasonable may be an order of magnitude
smaller than for you. So, I use a generically labeled 852D+ rework combo. It
has both solder pencil and hot air gun. There are better ho
On 11/5/16 12:12 PM, Tom Van Baak wrote:
See C13 in the attached photo. I need to replace some blown caps on a few
boards [1]. In one instance the cap got so hot it melted itself off the board.
Quiet convenient, actually -- it acts like its own fuse -- but I don't think
the 5071 designers had
Oh dear. I attached the wrong file. Here's the correct one.
-
AE6RV.com
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
___
time-nuts mailing list -- time-nuts@febo.com
T
In message , "Tom Van Baak" writes:
>Attila, PHK, et al --
>
>Rb maser proposal, including some photos. 3 PDF's, 175 pages of weekend
>reading:
>
>https://archive.org/details/NASA_NTRS_Archive_19720025867
>
>https://archive.org/details/NASA_NTRS_Archive_19730017775
>
>https://archive.org/
Hi Hal,
I don't think I understand your question. So, I've attached a plot and you can
tell me if that gives you anything to work with. This uses my standard
plotting script, so there are things you aren't interested in. But, this is a
plot of one unit from startup on the night of 10/29 throu
On 11/03/2016 06:10 PM, Attila Kinali wrote:
On Thu, 3 Nov 2016 16:37:06 -0400
Ruslan Nabioullin wrote:
What about instead establishing an open-source hardware project for a
frequency standard fusor? I was researching COTS solutions for this for
my rubidium ensemble and could only find this o
> At 12 hours of holdover...
> I think I'll need a lot more understanding of the impact of aging vs
> temperature
At that timescale, I'd expect aging to be lost in the noise.
How are you calibrating things?
--
These are my opinions. I hate spam.
__
On 11/05/2016 03:16 PM, Attila Kinali wrote:
On Sat, 05 Nov 2016 12:25:35 +
"Poul-Henning Kamp" wrote:
Active maser like the hydrogen would be possible naturally, but would
require the resonator.
I don't think they are.
They are. It took a while, but they have been a thing since '64
Hi Bob,
Ugh! 40C to 70C is not something I plan to deal with. If I were selling to a
commercial market, that would be a different story. But at my price point, not
gonna happen. But it does bring up the point that I need to have some sort of
idea of what I'm willing to manage.
Bob -
Attila, PHK, et al --
Rb maser proposal, including some photos. 3 PDF's, 175 pages of weekend reading:
https://archive.org/details/NASA_NTRS_Archive_19720025867
https://archive.org/details/NASA_NTRS_Archive_19730017775
https://archive.org/details/NASA_NTRS_Archive_19750006044
/tvb
___
Hi
Remember - most holdover specs also include a delta temperature (like 40 to
70C) during the
holdover period ….
Bob
> On Nov 5, 2016, at 12:15 PM, Bob Stewart wrote:
>
> Hi Scott and Bob and others,
> I keep telling myself that I won't get involved with the temperature problem,
> and yet
Hi Scott and Bob and others,
I keep telling myself that I won't get involved with the temperature problem,
and yet for some reason I keep going down that rabbit hole. It seems to me
that it's one thing to correct well enough to stay on frequency within some
degree of accuracy, and yet another t
Sounds like you already realized this. Phase is the integral of frequency
and the derivative of phase (phase rate) is frequency. So if you go from
nominal frequency - slow - nominal or equivalently nominal frequency - fast
- nominal the phase integrates up/down.
It would be a little more complicat
One of the main limiting factors in the 5061 was
microwave leakage. An excellent Italian engineer
named DiMarchi mastered the so called "top cover
effect", where removing the top cover changed the
frequency. He had a small business going refurbishing
5061's by cleaning up the waveguide gasketing
On 11/5/2016 12:18 AM, Poul-Henning Kamp wrote:
In message <768ee5a7-1c53-06cf-cf36-ec75e2901...@karlquist.com>, "Richard (Rick)
Karlquist" w
rites:
Reminds me of an interesting Jack Kusters story.
There was some customer who was having problems with
his atomic clocks being noisy (I
Hoi Rick,
On Sat, 5 Nov 2016 07:17:21 -0700
"Richard (Rick) Karlquist" wrote:
> I think this is all described in the 1992 FCS papers,
> but the executive summary is that a direct synthesizer
> on 9192.63177 is to be avoided at all costs because
> of the danger of it leaking into the CBT cavity.
On Sat, 5 Nov 2016 06:53:45 -0700
jimlux wrote:
> On 11/5/16 2:59 AM, Attila Kinali wrote:
> But we still need to ensure that the field is properly
> > oriented and homogenous over the whole vapor cell. For this you need
> > a cavity that is properly designed and most likely will be resonant at
I own a 5680b and while it only outputs a PPS signal there is a very stable
30MHz signal available inside the unit IIRC.
I can dig mine out and find the signal if that's of use?
I believe they can be modded for 10MHz output on the 15p D type but I've
just not managed to find time to get around t
I think this is all described in the 1992 FCS papers,
but the executive summary is that a direct synthesizer
on 9192.63177 is to be avoided at all costs because
of the danger of it leaking into the CBT cavity.
This is also the reason why you don't multiply up
a subharmonic of this frequency.
It wo
On Sat, 05 Nov 2016 12:25:35 +
"Poul-Henning Kamp" wrote:
> >Active maser like the hydrogen would be possible naturally, but would
> >require the resonator.
>
> I don't think they are.
They are. It took a while, but they have been a thing since '64.
Though all of them have been using vapo
On 11/5/16 2:59 AM, Attila Kinali wrote:
But we still need to ensure that the field is properly
oriented and homogenous over the whole vapor cell. For this you need
a cavity that is properly designed and most likely will be resonant at 6.9GHz.
(I don't know whether it is possible to design a non
I agree that FE-5680 is a whole family of products with very different
features and these can not deducted from the labels.
In my case I own a FE-5680A which outputs 1 PPS and a fixed (but
slightly tunable) 10 MHz and needs 2 power supply voltages, +5 V and + 15 V.
I am sending directly to yo
In message <0e976194-3cc1-2bc7-1289-0d9433132...@rubidium.dyndns.org>, Magnus D
anielson writes:
>> They won't be coherent photons, like in a Hydrogen maser, but we
>> don't need them to be, in fact that just causes the same exact
>> problems as the tuned cavity anyway, as long as we can
Hi
You have a first order, second order and third order coefficient to the
temperature rate dependance
on a crystal. Since the second order term is a square, it does not care about
the sign of the
rate.
Bob
> On Nov 4, 2016, at 9:56 PM, Bob Stewart wrote:
>
> In the general case, is the im
HI
If you use a good wire wound pot and run it off of and oscillator EFC source
(not
all have them), the temperature effect is pretty much zero. You are using the
pot
as a ratio device.
A mechanical cap that is part of the heated region of the OCXO (the normal case)
has already been taken into
Hi
A ten or twenty turn pot on a normal EFC will get you past the point that
you can reasonably set the oscillator. The typical (not GPS version) EFC is down
around 1 to 2 x 10^-7. A 20 turn pot will be running 1x10^-8 per turn. 100 to
200
points per turn is a pretty typical “set” number for a p
Hi Mark,
Thank you for working with the KS24361. Looking forward to when the program
will be available.
Any ideas on being able to use the 1 PPS signal out of the KS24361 to drive SL
sound card calibration? It is a weird pulse and someone mentioned the timing
is wrong. I use the pulse out
Am 05.11.2016 um 00:45 schrieb David:
On Fri, 04 Nov 2016 14:39:54 -0700, you wrote:
87-Rb has a half life of something like 4.9e10 years you'll be waiting
a while for that strontium. /gp
Various online sources say that natural rubidium is radioactive enough
to fog photographic film in 1 to 2
On Fri, 04 Nov 2016 23:04:22 +
"Poul-Henning Kamp" wrote:
> First: Yes, but if you pick a sensible vibration mode for your
> microwave resonance, that can be done with an screw-in endcap.
>
> Second: No, I would actually not need to tune it.
>
> Historically resonance cavities were used s
Satellite TV (Dish, Direct, etc) has been having trouble for 10 hours or so,
sometimes losing some channels and occasionally all of them.
Fox News is consistently down, so it could have a human cause, but Space
Weather says we have unusual solar activity.
I no longer have GPS time receivers,
On Sat, 5 Nov 2016 04:19:08 + (UTC)
Perry Sandeen via time-nuts wrote:
> Time may be relative, but physicists are a stickler for accuracy.
Ok.. the story without out the whole media mambojambo and mixup
of things can be found at [1]. A description of the setup they used
can be found at [2] a
Hi,
Wrote:I am the proverbial man with too many clocks and I don'tknow what time
it is.
To correct this situation I have decided to calibrateeverything.
I have a HP 5370B, a HP6370A, and a HP 5328A all with the TCXO
option.
Hi Peter,
You can't really calibrate the 5370B oscillator. I tri
In message <768ee5a7-1c53-06cf-cf36-ec75e2901...@karlquist.com>, "Richard
(Rick) Karlquist" w
rites:
>Reminds me of an interesting Jack Kusters story.
>There was some customer who was having problems with
>his atomic clocks being noisy (I don't remember exactly
>the story) but the bottom
Attached to this mail there are three files: the APD.asc LTSpice4
simulation schematics, a model for the AD8561 comparator, a model for
the VN2210 mosfet transistor, and a model for the BF959 bipolar transistor.
Please note that the APD model included into the schematics may have
errors: I too
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