Recent postings on 'sawtooth' hardware correction; several years ago SigNav
Australia (no longer is business) had a timing product called TM3-02 that
claimed to "Eliminate sawtooth correction" via some technology they had
developed.
My bad its in front and easily accessible.
On Wed, Jul 10, 2019 at 7:36 PM paul swed wrote:
> Walter looking at the manual. There is a coarse adjust in back of the unit
> and the cap was c102. But its a test and install cap and I do not see it
> listed in the parts.
> Regards
> Paul
> WB8TSL
>
I took all of the advice and made what I thought was the most sensible thing.
Not using switches of any kind at all. Out of TICC in a case, N connector
comes out as input (1 pps). I made an external box that houses 5/10MHz to 1
pps. They are completely independent. No possibility for cross
I recently got some prices on Russian masers. The passive masers are about
$us90K and the active masers are about $US250K. There’s apparently quite a
bit of paperwork to do with the export licensing but it just needs a bit of
patience :-)
Cheers
Michael
On Thu, 11 Jul 2019 at 3:01 am, Bob kb8tq
about 20 years ago, JPL was operating a Hg ion clock at the Tidbinbilla
tracking station just outside Canberra, Australia. I think they installed a
few at various nodes in the Deep Space Network at the time. It operated for
a few years but never reliably enough to be a useful UTC clock ( we were
Hi
> On Jul 10, 2019, at 4:26 PM, Hal Murray wrote:
>
>
>> Would someone please expand on what the practical frequency calibration limit
>> might be?
>
> That's not quite a well formed question yet. You need to say something about
> the time scale. What are you trying to calibrate?
>
>
jim...@earthlink.net said:
> I wonder what it would cost to build a trapped Hg ion clock - I don't think
> it's $10M, but it might be in the range of $500k-1M if you pay people to do
> the work. Things like the quadrupole trap and ion sources are catalog
> items.
If you are lucky, you might
I have several pages of schematics at:
https://www.febo.com/pages/hardware/AN_URQ_10/
but unfortunately not the full manual.
John
On 7/10/19 12:43 PM, Walter Shawlee 2 wrote:
> Does anybody have the manual for this old standard? mine works, but is
> a bit high, and needs internal
> Would someone please expand on what the practical frequency calibration limit
> might be?
That's not quite a well formed question yet. You need to say something about
the time scale. What are you trying to calibrate?
Poke around for some ADEV curves. Find one for your device (or
Walter Shawlee 2 wrote:
Does anybody have the manual for this old standard? mine works, but is
a bit high, and needs internal adjustment, and a new battery pack.
pretty good condition for this old unit, and the 5MHz output is only
4.8Hz off after heaven only knows how many years in a dark
On 7/10/19 10:55 AM, Richard (Rick) Karlquist wrote:
FWIW, about 20 years ago, Len Cutler and Robin Giffard of 5071A fame
built several Hg ion clocks to be shipped to some govt customer I
don't remember. One of the clocks was dropped by the shipping company
UPS or FedEX) and destroyed. Only
Glen English VK1XX writes:
> Has anyone tried to use a Neural net to control oven tmep, rather than
> the ye olde PID ?
If you believe the marketing, that is why the Nest thermostat is
connected to the cloud.
> IE the algorithm learns from previous beheviour and successfully
> predicts behaviour
FWIW, about 20 years ago, Len Cutler and Robin Giffard of 5071A fame
built several Hg ion clocks to be shipped to some govt customer I
don't remember. One of the clocks was dropped by the shipping company
UPS or FedEX) and destroyed. Only then did Len learn that HP was
self insured, probably as
>
https://www.microsemi.com/product-directory/active-hydrogen-maser/4123-mhm-2010-active-hydrogen-maser
Corby,
Did you notice a week or two ago there's an updated version:
https://www.microsemi.com/product-directory/active-hydrogen-maser/5548-mhm-2020-active-hydrogen-maser
There are links to
Does anybody have the manual for this old standard? mine works, but is
a bit high, and needs internal adjustment, and a new battery pack.
pretty good condition for this old unit, and the 5MHz output is only
4.8Hz off after heaven only knows how many years in a dark corner. it's
only been
On 7/10/19 6:10 AM, Azelio Boriani wrote:
Tom Van Baak said on Aug 29, 2013:
The pursuit of precision tends to be exponential rather than linear.
...
As a rough example in the ADEV world:
- for 1e-11, you can buy almost any XO, TCXO, or risky OCXO for $10.
- for 1e-12, you can find a
Hi
One of the gotcha’s if you are in the US is that the most often seen “alternate
brand” of Maser comes out of Russia. Depending on the phase of the moon and
just what the rule book says this week, you may well not be able to bring one
into the country.
Back when things were a bit more
Hi
The whole clock error / orbit error thing can be corrected after the fact with
data from
various agencies. It impacts survey work at least as much as timing. Looking at
it that
way, it does not really present a hard limit.
The “what’s the frequency limit?” question depends on just what
Hi
It depends a lot on the offset you are looking at. For close in phase noise,
you probably don’t
want high drive. If you are only after phase noise past 10KHz, you may not want
/ need
an OCXO in the first place. Selecting crystals (like one in a hundred) for very
high drive /
low phase
Perrier,
Hi!
Depends on the type and model, Active or Passive Maser etc.
I believe new active Masers run in the 1/4 million dollar range.
T4 science offers some nice Passive Masers but I don't know the cost.
pH Maser 1008 https://www.t4science.com/products/phmaser-1008/
On the basis of just
Yo Bubba Dudes!
In a number of fascinating and highly educational for me were the explanation
of accuracy by TVB and others. I learned quite a lot, thank you.
Bob mentioned about slight orbital variations in the GPS satellites.
IIRC those slight variations meant that you could only reliably get
> > Folkert van Heusden has a driver for NTP which includes PPS output:
> > https://vanheusden.com/time/rpi_gpio_ntp/
> > Perhaps this might help?
>
> Indeed I did! :-)
>
> But please note that the jitter is high, iirc around 18ms.
> Personally I would use
Asked and answered before I think, but as far as I know a new maser is in
the 2-300K euro range, a used one you can perhaps expect to pay about a
tenth of that - if you can find one. Not that many around, but some of the
older ones on VLBI sites are getting a bit long in the tooth. If you are
Tom Van Baak said on Aug 29, 2013:
>The pursuit of precision tends to be exponential rather than linear.
...
>As a rough example in the ADEV world:
>- for 1e-11, you can buy almost any XO, TCXO, or risky OCXO for $10.
>- for 1e-12, you can find a reputable OCXO on eBay for under $100.
>- for
Perry,
The only H-maser with which I've had direct experience (the MHM-2010) costs
around $250,000 new. But there are some other brands, mostly foreign.
The immediate operating cost is that of AC power. IIRC, the '2010 uses
about
100W or maybe 125W, *all the time*. The H-maser is *not* the
> Folkert van Heusden has a driver for NTP which includes PPS output:
> https://vanheusden.com/time/rpi_gpio_ntp/
> Perhaps this might help?
Indeed I did! :-)
But please note that the jitter is high, iirc around 18ms.
Personally I would use https://github.com/mlichvar/pps-gpio-poll.git and
then
Those measurements don't go low enough in frequency to capture the very low
frequency noise of the LT3042 which uses a noisy current source to produce a
voltage drop in a resistor as the reference. At low enough frequencies the
LT3042 is very noisy. Low pass reference filters with milliHz or
Yo Bubba Dudes!,
OK, I'll finally ask the question that probably a lot of list members wanted to
know but were reticent to ask.
First, what is the price of one of a new Hydrogen Maser? (This is important if
I win the lottery.)
Second, what would be prices for used Hydrogen Maser in *reasonable*
Hi Chase
thanks for the email. thanks for the tip on use of logistical classifiers.
Agreed the PID (and variations ) is a seemingly perfect fit , at least
at the top level.. My guess is that the type of disturbance the 'the
system' (affecting, ultimately, the set temperature) (the device)
Am 10.07.19 um 11:27 schrieb Bruce Griffiths:
Like virtually all low dropout regulator ICs the LT3042 is quite noisy at
frequencies below its reference low pass filter high frequency cutoff. Some
zener based references are considerably quieter in this region.
We had that already last year.
From: Frank O'Donnell
Forrest,
Thanks very much for the extensive comments, they're greatly helpful.
[]
I have very poor view of the sky immediately outside the room my gear is
located in, so for the Trimble I've been using a run of about 50 feet of
coax to an active GPS antenna. If I run
FWIW for the 10MHz distribution amplifier I have been using LT1963 (40
uVrms in 10Hz to 100kHz) which is about 40x worse than the LT3042 spec of
0.8 uVrms in 10Hz to 100kHz.
With decent op-amps I think the distribution-amp performance is limited by
the op-amp noise and thermal noise in the
Like virtually all low dropout regulator ICs the LT3042 is quite noisy at
frequencies below its reference low pass filter high frequency cutoff. Some
zener based references are considerably quieter in this region.
Bruce
> On 10 July 2019 at 18:18 Perry Sandeen via time-nuts
> wrote:
>
>
https://www.electronicdesign.com/analog/whats-all-p-i-d-stuff-anyhow
For all Bob Pease fans: there's a fabulous 9 volume ~1200 page scan of
his columns here:
https://archive.org/details/Bob_Pease_Lab_Notes
The P-I-D article Ben mentions appears in volume 2, starting on page 167.
/tvb
Yo Bubba Dudes!,
The LT3042 seems to be a wonderful part. But having learned a long time ago
the it wasn't wise to gold plate a Yugo, so when are there diminishing returns?
For example I have several HP 10811 oscillators. one is in a HP5335a counter
that I'd like to make as stable as reasonably
I did, sorry, - it was a finger slip.
Now, what I find kind of funny is that one of the meanings of "monotonous" is
"repetitious or periodic" which is almost exactly the opposite of monotonic.
Leo
> From: "David G. McGaw"
> Leo -
> I do believe you mean non-monotonic, rather than
> From: Bob kb8tq
> Drive power on an OCXO will pretty much always be below a milli-watt. A
> typical design will be in
> the range of 1/10 to 1/100 of that power level.
It depends whether OCXO is designed for long term stability and low ageing or
low phase noise.
Low ageing requires low
The article link in my post doesn't have valid links to the figures
(Pease hand-drawn schematics), but these links work:
https://web.archive.org/web/20121113202641/https://www.electronicdesign.com/files/29/6131/figure_01.gif
I recall Bob Pease in one of his many "What's all this ...stuff"
columns made a small oven and PID temperature controller that he
claimed kept the temperature within 0.001 degrees or something like
that. This would make machine learning severe overkill. Temp control
is slow enough (and
39 matches
Mail list logo
