Some tests of timing receivers' PPS:
ftp://tycho.usno.navy.mil/pub/gps/Furuno/
http://www.cnssys.com/files/PTTI/PTTI_2002_CNS_Testbed.pdf (Motorola M12M)
http://www.cnssys.com/files/PTTI/Low_cost_GPS-based_time_and_frequency_products.pdf
(u-blox LEA-6T)
Non-timing receivers could be unsuitable
Hi Magnus,
2) Timing versions might get an upgraded oscillator. Maybe a TCXO
instead
of a standard XO.
Don't think so. The noise and systematic stability is as important for
positional as for timing versions, the timing version can benefit of the
fixed position.
Look at the uBlox6 lineup.
Tom Knox wrote:
Dual oscillators in Cross Correlated
measurements will also produce a 3dB theoretical reduction in a Phase
Noise measurement system.
Since when?
Its way better than that.
I routinely achieve a PN floor below -170dBc/Hz (I don't have an OCXO
with a phase noise floor below ~
Robert Atkinson wrote:
Hi,
While it may be a waste of time and money for time nuts, it may be a good
introduction for others. It may even spawn a few time nuts. Better someone
build this and learn something than just buy a cheap Chinese counter on ebay.
I've seen much worse projects
On Fri, 28 Dec 2012 19:18:06 -0800
Hal Murray hmur...@megapathdsl.net wrote:
att...@kinali.ch said:
From the data ntp gives me in the networks i manage. I hardly get any
jitter number below 1ms, even with unloaded network and unloaded hosts. The
200us comes from the usual rtt time
Moin,.
On Sat, 29 Dec 2012 19:20:16 -0800
Said Jackson saidj...@aol.com wrote:
We recently did a test by putting an antenna in a side window in
the office that had maybe 10% view of the sky, then let the unit
run in mobile mode while doing the auto survey. After two days,
we switched it
On 30 December 2012 03:04, ewkehren ewkeh...@aol.com wrote:
I do feed a Rb in to all my istruments including my 7 spectrum analser. I
had two choices 301 or create 100 Mhz.
I'm not sure what a 301 is, so it means little to me.
There blank modulrs available but make sure you get one with
On 30/12/12 10:06, b...@lysator.liu.se wrote:
Hi Magnus,
2) Timing versions might get an upgraded oscillator. Maybe a TCXO
instead
of a standard XO.
Don't think so. The noise and systematic stability is as important for
positional as for timing versions, the timing version can benefit of the
and maybe that reflashing a 1uS nav receiver to have a 100nS timing
receiver is related only to firmware improvements. Accurate timing is
mandatory for accurate position/navigation. The CW12 timing receiver has a
position hold mode that can't be turned off but always gives the computed
position.
On 30/12/12 13:56, Azelio Boriani wrote:
and maybe that reflashing a 1uS nav receiver to have a 100nS timing
receiver is related only to firmware improvements.
Most probably. A possibility would be to have a bad running state, but
this should not be the case and then a firmware upgrade should
and not having a -175dBc/Hz reference, how you can tell that your dual
-150dBc/Hz performs like a -170dBc/Hz?
Moreover: what is the physical principle that can explain this? Injection
locking? Average in the power summer? Taking hundreds or thousands
oscillators it seems possible to reach
Hi
When asked about the difference, that's not what the people who wrote the code
had to say about it….
Bob
On Dec 30, 2012, at 7:56 AM, Azelio Boriani azelio.bori...@screen.it wrote:
and maybe that reflashing a 1uS nav receiver to have a 100nS timing
receiver is related only to firmware
On 12/29/2012 8:28 PM, Adrian wrote:
Chris,
patience is the key to successfully trimming your Cs unit.
You will really want to compare it to your GPS for a week or so.
You might be surprised about your findings.
Actually, you're in need of a third high performance source...
how else can
On Sun, Dec 30, 2012 at 2:58 AM, David Kirkby david.kir...@onetel.net wrote:
On 30 December 2012 03:04, ewkehren ewkeh...@aol.com wrote:
I do feed a Rb in to all my istruments including my 7 spectrum analser.
I had two choices 301 or create 100 Mhz.
I'm not sure what a 301 is, so it
On 30 December 2012 15:43, Pete Lancashire
If you know your always going to have an external 10 MHz, what you
need is a 70310A Option 002. Option 002 deletes the oscillator (and
the battery pack).
But I've only once seen an option 002. My take is if you had the $'s
to buy a MMS setup, you
Azelio Boriani wrote:
and not having a -175dBc/Hz reference, how you can tell that your dual
-150dBc/Hz performs like a -170dBc/Hz?
You can't.
Moreover: what is the physical principle that can explain this? Injection
locking?
Not injection locking just the magic of cross corrrelation.
Am 30.12.2012 06:18, schrieb Hal Murray:
,The Tuxedo Park book reported that Loomis had 3 Shortt clocks setup
in a basement lab carved out of bedrock. They would get locked unless
they were swinging 60 degrees to each other.
Rohde Co have the math for the phase noise of arbitrary many
Hello Time-nuts, Happy New Year,
I am having a problem with my SR620. I am using the RS232 interface to
configure and read the results. I am using my own code, and I am
continually make revisions, updates, (Spelled: E-R-R-O-R) to my code. Every
couple days I manage to scramble the brains of
Bruce,
The Tsc5125A and miles Timepod show a phase noise floor 3dB above the noise
floor of the two oscillators (if two are used with identical noise floors).
Your oscillators are better than you think, or your equipment is not calibrated.
Btw: that result IS what you want, why would you want
Hi
It sounds like a bit like buffer overflow in the SR620 that's nuking something
else. You may be asking it to do slightly more than it's capable of….
Bob
On Dec 30, 2012, at 1:42 PM, Ed Mersich wa6...@comcast.net wrote:
Hello Time-nuts, Happy New Year,
I am having a problem with my
maybe if it ever gets gebraucht enough . . . :-)
happy new year to all
Don
Gerhard Hoffmann
Am 30.12.2012 06:18, schrieb Hal Murray:
,The Tuxedo Park book reported that Loomis had 3 Shortt clocks setup
in a basement lab carved out of bedrock. They would get locked unless
they were swinging 60
On Fri, 21 Dec 2012 09:53:51 -0800
Said Jackson saidj...@aol.com wrote:
Volker, I wonder if you also see fan-induced spurs in the phase
noise from 1Hz to 100Hz. I would not be surprised if the fan
vibration adds significant spurs to the 10811A crystal.
How susceptible are OCXOs on magnetic
An update regarding the GPS module,
simply shielding it from air currents
improved the things:
http://www.flickr.com/photos/14336723@N08/8327229820/
At 48000s I swapped references, hence
the change in slope.
I think the poor receiver module
(Azelio, 20€, I think it can be
considered cheap :) is
Salut!
On Fri, 21 Dec 2012 08:17:40 -0800 (PST)
Robert LaJeunesse rlajeune...@sbcglobal.net wrote:
FWIW I've combined all 3 parts into one PDF and put them on KO4BB's great
website. Look in Manuals 10) Recent Uploads for Reference na na Other-EDN
article SuccessfulPCBgrounding. Since my PDF
On Sun, 30 Dec 2012 21:14:12 +0100
Attila Kinali att...@kinali.ch wrote:
Salut!
Meh.. stupid me... sorry, this was intended as private mail.
Attila Kinali
--
There is no secret ingredient
-- Po, Kung Fu Panda
___
Hi
A quartz crystal in insensitive to magnetic field. This being Time Nut's that's
not the whole story. Ferrite core inductors can indeed exhibit a bit of static
mag field sensitivity. Your OCXO may or may not have some in it.
In the case of AC fields you can always have induction. There will
Hi
If you go back far enough in the NIST papers done for the Frequency Control
Symposium, you can find a number of them on GPS receivers. One that got a
pretty full go through was the (now golden) Motorola timing receiver. They
found a number of issues with it. The receiver did get better as
Bob,
On 30/12/12 23:27, Bob Camp wrote:
Hi
A quartz crystal in insensitive to magnetic field. This being
Time Nut's that's not the whole story.
As I recall it, the steel clips sometimes used to hold the resonators is
claimed to be one of the sources for static magnetic field sensitivity.
Hi Attila,
Makes a big difference if there are AC magnetic fields in the system, they can
create spurs through mutual inductance.
Our Fury GPSDO is designed completely without any switching regulators for that
reason. One customer used it on helicopters for measuring magnetic field
variations
and not having a -175dBc/Hz reference, how you can tell that your dual
-150dBc/Hz performs like a -170dBc/Hz?
Moreover: what is the physical principle that can explain this? Injection
locking? Average in the power summer? Taking hundreds or thousands
oscillators it seems possible to reach
Bruce,
The Tsc5125A and miles Timepod show a phase noise floor 3dB above the
noise floor of the two oscillators (if two are used with identical noise
floors).
Bruce is actually talking about a semi-undocumented trick with the TimePod
that allows it to act like an E5052 or TSC 5120A-01 with
Hi
Precision crystals have clips made from nickel. The posts are likely Kovar.
That's been true for a *long* time. Neither one is very magnetic. Both likely
are hard enough to be even less magnetic than they might be.
Bob
On Dec 30, 2012, at 6:27 PM, Magnus Danielson
Bob,
But all those inductors surrounding the crystal will be sensitive to magnetic
flux variations and could cause spurs and jitter..
Bye
Said
Sent From iPhone
On Dec 30, 2012, at 18:04, Bob Camp li...@rtty.us wrote:
Hi
Precision crystals have clips made from nickel. The posts are likely
John,
If the math works out, then I guess it must work.. If one has the time to wait..
Bye,
Said
Sent From iPhone
On Dec 30, 2012, at 16:23, John Miles jmi...@pop.net wrote:
Bruce,
The Tsc5125A and miles Timepod show a phase noise floor 3dB above the
noise floor of the two oscillators
Said,
On 31/12/12 03:36, Said Jackson wrote:
John,
If the math works out, then I guess it must work.. If one has the time to wait..
It does work. Tried it with a handfull of BVAs and the graphs make sense.
Want quieter oscillators now.. :)
Cheers,
Magnus
On Dec 30, 2012, at 9:25 PM, Said Jackson saidj...@aol.com wrote:
Bob,
But all those inductors surrounding the crystal will be sensitive to magnetic
flux variations and could cause spurs and jitter..
Bye
Said
Sent From iPhone
On Dec 30, 2012, at 18:04, Bob Camp li...@rtty.us
Hi
…. sorry for the previous blank message….
A lot depends on what kind of inductors they are. If it's a static field, then
you have to saturate the core. That's pretty hard unless the core is ferrite.
Most powdered iron and (of course) air are fairly immune to static field.
If it's an AC
Bob Camp-
A quartz crystal in insensitive to magnetic field. This being Time Nut's
that's
not the whole story. Ferrite core inductors can indeed exhibit a bit of static
mag field sensitivity. Your OCXO may or may not have some in it.
Precision crystals have clips made from nickel. The posts
Greetings, I'm new here!
I'm tinkering with a discarded Symmetricom Timesource 2700 which won't lock.
After letting it cook for a few days, the Rb alarms never went away, so I
opened it up and connected directly to the serial pins of the PRS10 inside.
This allowed me to run Stanford RbMon,
Hi
They are using some pretty major fields in that paper. As they point out, high
level tests likely do not extrapolate well to low level performance. Their data
shows the impact diminishing quickly as the field drops.
If you accept their 1x10^-11 per gauss number as correct, your OCXO might
On 12/30/12 11:35 AM, Attila Kinali wrote:
On Fri, 21 Dec 2012 09:53:51 -0800
Said Jackson saidj...@aol.com wrote:
Volker, I wonder if you also see fan-induced spurs in the phase
noise from 1Hz to 100Hz. I would not be surprised if the fan
vibration adds significant spurs to the 10811A
On 12/30/12 8:03 PM, Bob Camp wrote:
Hi
They are using some pretty major fields in that paper. As they point out, high
level tests likely do not extrapolate well to low level performance. Their data
shows the impact diminishing quickly as the field drops.
If you accept their 1x10^-11 per
Hi
Indeed, there will always be some EMF into the EFC from some field. You can
never really get rid of a loop with some cross section in the EFC circuit. Most
of us don't get to worry about 1x10^-16 at 1,000 seconds on our OCXO's….
Bob
On Dec 30, 2012, at 11:16 PM, Jim Lux
Nate wrote:
The PRS10 manual has a full parts list and makes numerous references
to the schematic, but the schematic itself isn't part of the
document. Anyone able to confirm the identity of the part I'm looking at here?
For schematics, see http://www.ko4bb.com/manuals/. Search for prs10.
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