I may have mis-spoken on one aspect of these devices... it is now seems to be
doing 4-hour power-on surveys... Or perhaps it has some measurement threshold
that allows it to end a survey before the full 14,400 samples have been taken.
I did a power cycle, went to dinner, and three hours la
Hi John,
That is a thought. The 1s ADEV had been very stable across units until just
now. But, I don't know how to look at the beam current. There is a "Monitor3"
program that I can use (see link below) that can plot the Clock Servo values,
as well as Zeeman Servo, Gain Servo, CBT Supplies, a
Recently some Datum Startloc II GPSDO's appeared on Ebay (originally around
$50, now $100). The main seller appears to be in Canada. These are a telco
type GPSDO that appears to be an attempt at a replacement for Trimble
Thunderbolts. I recently got one in and did some playing with it (Lady
dan...@verizon.net said:
> Maybe, but simply by adjusting mine by measuring the 32 kHz output with an
> accurate counter I can get them to keep to within about one second a month.
What did you adjust? I assume it's software.
How well do typical VCO adjustments work with tuning forks?
My samp
Hi
For most OCXO’s most certainly not. The typical OCXO improves on ADEV as it
runs. That said, a good OCXO should have a 1 second ADEV
of at least parts in 10^-12 rather than 10^-11. A 5370 should have a floor at 1
second of around 2x10^-11. You may be measuring your counter
doing something st
Thanks Bob. That makes sense.
---
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
From: Bob Camp
To: Bob Stewart ; Discussion of precise time and frequency
measurement
Sent: Monday, June 27, 2
> I've had a specific GPSDO running for some time now, and I notice that the
> noise at tau 1s has gotten worse as the retrace flattens out. In this case,
> the ADEV was about 3.6E-11 a month or so ago, and has now gone up to about
> 8.5E-11. (Measurements performed by a 5370A against a PRS-45A
Hi
This whole thing *is* a multi solution problem. There is no one right answer
for everybody and everything. It
is refreshing to get past the whole “the world ends when we run out of DIP
packages” hysteria that often grips
us when talking about *building* a Time Nut gizmo. A *lot* of the things
On 6/27/2016 1:51 PM, Hal Murray wrote:
I assume you are doing this for fun. That means you get to do whatever you
think will be fun.
The DS3231 is pretty crappy by time nuts standards.
Maybe, but simply by adjusting mine by measuring the 32 kHz output with
an accurate counter I can get them t
I've had a specific GPSDO running for some time now, and I notice that the
noise at tau 1s has gotten worse as the retrace flattens out. In this case,
the ADEV was about 3.6E-11 a month or so ago, and has now gone up to about
8.5E-11. (Measurements performed by a 5370A against a PRS-45A Cs st
t...@patoka.org said:
> For very long time, may be Main Frequency (60 Hz) could be utilised. Say,
> MCU could count and compare Zero-Crossings and impulses from DS32xx chips.
> After several days, you'll see where it goes.
Power in Silicon Valley isn't stable enough to make that approach inter
> So to travel 22 meters is about .000,000,073 Seconds. Or 73 nanoSecond.
Hi Gary,
I want to echo what Bob just wrote. People get carried away with "a nanosecond
is a foot" and think it applies 100% to GPS timing and position, or in this
case, elevation errors.
Equating 22 m with 73 ns, or eq
> But TimeLab doesn´t list any GPIB interfaces.
>
> Did anyone have success with this combination? Any insights
> highly appreciated...
Agilent's NI488.2 compatibility layer seems to work only with 32-bit apps, not
64-bit ones, so you may be able to get it running by modifying your Windows
shor
Appreciate all the input. I now realize that I know nothing about this subject!
For fun ran my gpsdo with the antenna height calculated from an available Topo
chart it really made the timing intervals and EFC show much larger swings. So
answering one of my own questions, YES there does seem to
Hi
If your time is off because your antenna location is off and you are running a
GPSDO …
The error does matter for frequency.
1) Start with a group of sats in the sky all in the direction of the error
vector. Your
GPSDO will get a time solution that is 72 ns early.
2) Move the group of sats
Hello Time-Nuts,
I got an Agilent 82357b USB <-> IEC-Bus adaptor at a ham
fest. Now I´m trying to get it to work with TimeLab.
I Installed some hundred MB of Keysight software and
followed the recipes I found in the web to get the 82357b
working with 488.2 applications - basically checking "
I assume you are doing this for fun. That means you get to do whatever you
think will be fun.
The DS3231 is pretty crappy by time nuts standards. If you can also measure
the temperature, you should be able to make neat graphs. If you watch it as
the temperature ramps up slowly, you should s
> On Jun 27, 2016, at 1:34 PM, Nick Sayer wrote:
>
>
> In the firmware, the timer that has the input capture ability is set to
> free-run at the system clock frequency. The ICP interrupt reports back the
> timer delta from the last interrupt. Nominally, you’d expect 16,384 counts. I
> calcul
For very long time, may be Main Frequency (60 Hz) could be utilised.
Say, MCU could count and compare Zero-Crossings and impulses from DS32xx
chips. After several days, you'll see where it goes.
On 2016-06-27 11:22, Pete Stephenson wrote:
Hi all,
I have a few Maxim DS3231 temperature-compen
I went through this exercise some time ago with my Crazy Clock.
The Crazy Clock is itself an ATTiny45 clocked with a 32 kHz crystal. I desired
to determine the accuracy of the oscillator. I wound up making a purpose-built
frequency counter.
First, the device under test gets special firmware tha
Pete,
Instead of doing this in an ISR, feed the 32KHz into one of the timer/counter
inputs, and clock the timer off of that (probably TIMER2), then just have an
ISR for the overflow vector. So, when your X bit timer overflows, you can just
add that to your total, when you reach your 1000s (or w
All timing receivers (including Trimble) calculate an overdetermined clock
solution if more than 4 sats are being tracked (and the signal meets their
TRAIM quality level). But, again, in Trimble-speak, "overdetermined clock
mode" is what most manufacturers call "position hold" mode. Position
Thanks all for the info about the GPS over-determined clock solution,
helps me much. Bill's suggestion to internet search the term absent the
hyphen turns up numerous hits as well.
Steve, K8JQ
On 6/25/2016 2:10 PM, Bill Hawkins wrote:
Try overdetermined as one word. Also include GPS in the s
Hi all,
I have a few Maxim DS3231 temperature-compensated real-time clock
chips I use for various embedded hobby projects. They're specced to
have an accuracy +/-2ppm between 0 Celsius and 40 Celsius. One is from
a standard, reputable vendor, while a few are from somewhat more
dubious internet sel
How about putting the pictures of the TB on a site with overlays
saying what it is, so we know to stay away from the seller with many
names
On Sun, Jun 26, 2016 at 5:38 PM, skipp Isaham via time-nuts
wrote:
>
>> From: Mark Sims
>> Subject: [time-nuts] Trimble / Symmetricom UCCM mini-GPSDO boards
Yo Mark!
On Sun, 26 Jun 2016 09:02:55 -0400
Mark Barettella via time-nuts wrote:
> I
> estimate my antenna’s actual height at about +5 m high and the gps
> indicates -17 m.
Others have covered some obvious details. Different ellipsoids,
long term surveying, etc.
> My question is will this adv
Poor coordinates for the antenna couple into the apparent distance to
a satellite in such a way that the error in the distance tracks a
parabola-shape as the satellite rises and descends, with a
corresponding error in the apparent satellite time. At any instant,
the combination of N satellites then
On Sat, Jun 25, 2016 at 9:26 AM, Steve Wiseman wrote:
>
> There are mailing lists for this stuff, chaps - openpnp, firepick,
> versatronics, plenty of others. All full of people finding out that,
> like everything, it's trickier than you first think. See you over
> there, let time nuts be time nu
I read through the thread so far and thought I’d throw out there some of how I
do it. I’ve done a lot of manual pick-n-place in a very short career. :)
I used to always use stencils for paste, but now most of the time I use a
dispenser and place the paste by hand. The exceptions are some of my s
> From: Mark Sims
> Subject: [time-nuts] Trimble / Symmetricom UCCM mini-GPSDO boards
> For those of you that have one of these... good-ish news. I have Lady
> Heather working with
> them (well, at least the Trimble works, the Symmetricoms have not arrived
> yet and there are
> a couple o
> Indeed there is an physical limitation for the Q of piezoelectric
> resonators, which is given by phonon interactions etc. For quartz this
> limit is given approximately by Q*f = 15E12. See attached graph (sorry, in
> German).
NIce figure! Here's a similar one for MEMS resonators (mostly Si I t
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