Time machines makes a similar box.
However, one would expect that with that many devices at a site one could
find a couple of devices which could run a ntp server along with their
normal workload.
On Thu, Apr 21, 2022, 2:23 AM Paul Watts wrote:
> Long time lurker, first time poster.
>
> In the
I know your request was a bit off topic, but it has me intrigued.
Is the need for a higher end lathe related to improving accuracy on your
"pendulum project"?
I've always been intrigued by the timekeeping accuracy of a pendulum. It
seems like there are so many things that could affect its accu
I have used GPS-SDR-SIM with good results.
It's an open source tool that will generate the right files to be able to
generate simulated GPS signals using many of the open source SDR platforms
including HackRF. It uses the publically available ephermis files along
whith desired receiver position d
Some of these sites already have a internet-connected temperature sensor on
a PCB inside a unvented plastic (electronics) enclosure inside the outdoor
weatherpoof metal enclosure. With just a quick look, I found one which
slewed from 21C to 65C over 2 hours within the last couple weeks. I don't
the
"environmental chamber" (aka converted old freezer) for testing.
On Wed, Sep 23, 2020 at 6:20 PM Forrest Christian (List Account) <
li...@packetflux.com> wrote:
> I'm hoping some of the list are familiar with the newer
> currently-available oscillators available
I'm hoping some of the list are familiar with the newer currently-available
oscillators available from the distributors.
Some background:
I'm starting to play with a short-term 1PPS holdover application, mainly to
cover up brief GPS signal loss events (a few minutes at most).
Since I may at some
lso curious
about the GPS L5 signal once it becomes operational since that is far
enough away frequency wise that one would hope that it wouldn't be affected
by the same interference source.
On Thu, Aug 6, 2020 at 6:19 PM jimlux wrote:
> On 8/6/20 4:28 PM, Forrest Christian (List A
If you look at generally-available GNSS PNT solutions, you'll find a few
failure modes:
1) Loss of a satellite (or two). This is why the constellations have more
satellites than is strictly necessary, so not a big deal.
2) Loss of control/failure in the control system/constellation wide
softwar
We seem to be going through another stage in our technological evolution
right now as far as redundancy goes.
To explain what I mean:
A long time ago things were so unreliable that everyone knew that you
needed two systems, even if one was the watch in your pocket and a compass
and sextant for PN
I'll second this thought.
I've got one of the symmetricom-branded distribution amplifiers in use here
and it's worked like a charm. Unfortunately it only works with GPS L1.
GALILEO seems to be at least mostly in it's passband, GLONASS is not.
As the bands I've needed have started to increase,
So a couple of notes from here:
I solder 0.5mm pitch TQFP's on a fairly regular basis with just a
reasonably-sized chisel tip and plenty of flux. I often will end up with
just a bit at the end of surplus which wick will pull off.I actually
have done this on the bench with a $100 hakko FX601
I noted Skip Winthrow's message about the listing of a Cesium standard on
eBay.
I've had some questions generally about these used standards for some time
now, figured this was a good time to ask them.
So let's assume I buy a used unit in working condition. I get it here, it
works fine, and eve
For a few grand you can get an off the shelf fs740 or something similar,
probably with a rubidium timebase. But I get the impression this is more
of a learning experience.
One thing which it took me a while to wrap my head around is that for
frequency, sawtooth error generally dissappears for a l
Like many things, price does not necessarily reflect a better antenna,
however there are differences between antennas.
One difference is in the quality of the filters in the antenna itself.
This matters more when one is mounting an antenna at a communications site
than say at a home timing lab.
I think I've mentioned this before but I attended the NIST T&F metrology
seminar in June. Although a good chunk of of it was at least somewhat over
my head, I definitely learned a lot and feel like I have a lot better
handle on some of the questions I had. I may even consider going back for
a se
Just to let everyone know what I ended up doing and seems to be working for
me...
I grabbed a raspberry pi. Hooked up the TICC via USB to it.
I also hardwired my TTL-level NMEA serial output to the serial input on the
raspberry pi's header.
I wrote a tiny script which sets up both serial ports,
Let me see if I can give this a go. Some of this will likely be
oversimplified and not exactly accurate. Consider this a simplified 101
level class taught by an assistant and not the professor.
Most GPS receivers with 1PPS outputs are only able to align the 1PPS to the
nearest edge of some inte
ent on things matching up.
>
> Bob
>
> > On Sep 13, 2019, at 7:01 PM, Forrest Christian (List Account) <
> li...@packetflux.com> wrote:
> >
> > I suspect someone figured out some of the side effects what you're
> > describing and adjusted the divisors
One of the GPS modules I'm currently playing with outputs quantization
error data in the NMEA data.
I can capture the NMEA data and the TICC data - this is not a problem.
But I'd really like to be able to capture both datasets in some sort of
time-correlated way, so I can easily post-process the
bly a good idea to make sure your board has the “normal” components on
> it that correspond to the numbers in the manual. There may have been a
> running
> change at some point that is not reflected in the doc’s.
>
> Bob
>
> > On Sep 13, 2019, at 12:12 AM, Forrest Christian (L
Mainly wanting to post this to the list so it will end up in the archives.
So I decided to give calibration/adjustment of my bench PRS-10 a go.
What I discovered is that on my particular unit, the frequency was enough
off that in order to bring it close to spec, I had to adjust the Mag Offset
to
The TICC uses an Arduino mega clone, not a Raspberry Pi.
My understanding is that most of the magic happens on the shield board not
in the processor - the processor is just there to capture the data from the
shield and format and report it via the serial port.
On Wed, Aug 14, 2019 at 12:10 PM Per
Long winded answer to your question:
I'm sort of an "Advanced beginner" time-nut or maybe a bit beyond that.
In relation to your question: It really depends on your goals. The
following is a high level overview of your options, and is intentionally
lacking and/or simplifying some details. Th
I have a couple of GPS receivers I'm experimenting with that I've been
using a TICC to gather timestamps of the 1PPS output to ascertain
their relative quality.
In the process of doing this, I've discovered that some of the 1PPS
outputs are not as stable as I'd like them to be. For instance, the
I apologize if the following isn't helpful. I'm still getting my
head around all of the details of statistical analysis of clocks so
I'm not 100% sure this matches what you're asking for, but I figured
it might be helpful so...
A portion of the document at https://tf.nist.gov/general/pdf/1288.pd
I realize that this doesn't help old receivers, but I'm sort of
surprised that this wasn't addressed as the GPS system has had various
additions made to it such as WAAS. Even 3-4 bits allocated to this
purpose in one of the datastreams would move us out beyond any
reasonable expectation of the lif
ds a lot
> on just how stable
> your particular unit is and how drafty your lab is.
>
> Running any sort of electronics gear 24 hours a day is a risk. It may wear
> out, it may cause
> a fire, it may be fine … who knows. It also pulls power and you pay the
> electric compan
Hopefully you'll all grace me with a few answers to a beginner
time-nut question or two.
I have a PRS-10 I've never used other than to power it on with a
recently-acquired heatsink and verify that it seems to operate
correctly and that the operational parameters don't seem out of
tolerance. I wo
I'm actually debating on whether to attend this or not. I really
need to understand a lot of the things related to time and Frequency
better, and it looks like this covers pretty much all of the bases.
The price, although high, isn't out of the range of expectations for
this type of workshop.
Fo
If you don't find a schematic, typically you'll find that most devices have
a RS-232 driver IC, and that is pretty much what fails when the com port
goes dead. I have a silver thunderbolt which I just opened and on this
one there's a chip right next to the serial port labeled "232IBE" with an
int
I am wanting some general advice on the following:
I currently have among my timing-related devices a couple of Trimble
Thunderbolts (a silver one w/ the inbuilt power supply and a gold flat
one), a PRS10, and a TAPR/TICC.
My current end goal is to use these to get an idea of the quality of the
1
I use a national instruments PCI-GPIB card in a Windows 10 PC, works just
fine. Usually can find them <$100 on eBay.
I've also used a HP/Agilent 82357A (or B) which does USB-GPIB for those
cases when you need it for a laptop or something else without a pci or pcie
slot.
I understand the USB one
Would a mems oscillator such as a dsc6183 possibly work for you? I'm
uncertain if the characteristics of a mems oscillator is compatible with
your application.
For odd frequencies I often head toward a mems oscillator since many can be
programmed to any reasonable frequency. For example one can
Thanks to everyone who has responded so far.
My underlying interest is learning about 1PPS holdover methodologies in the
presence of environmental changes (think outdoor day/night temperature
cycles). My thoughts are that there are two ways that seem obvious to me
to implement a temperature-stabl
I'm trying to fill in some gaps in my knowledge about PLL's, GPSDO's, etc.,
with the goal to eventually implement some of these either in a
microcontroller or fpga or some combination thereof.
My problem is that the resources I've found either are very basic -
oriented toward just the high level u
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