On 05/01/2013 10:02 PM, Poul-Henning Kamp wrote:
In message51815556.4050...@partiallystapled.com, Michael Tharp writes:
On 5/1/2013 11:40, Sarah White wrote:
Symmetricom doesn't go out of their way to say how the damn thing
actually works, [...]
NIST has documented that in a LOT of detail,
On 05/01/2013 10:09 PM, Ed Palmer wrote:
I recently made some measurements between 3 oscillators. It wasn't a
true 'Three-Cornered Hat' measurement because the measurements were made
sequentially. When I do the three-cornered hat calculation for the
hopefully 'better' oscillator, I end up trying
On 05/05/2013 01:31 AM, Mark Spencer wrote:
The article available for download via this URL contains some history about
development issues with Rb and Cs Clocks for GPS. It seems at one point after
the GPS system was placed into service a development program for new Cs GPS
clocks failed and
Hi,
Buffert gas slows down the rubidium atoms, which increases the Q value.
Already that is an important factor in the performance of rubidiums.
Then, the inevitable wall-shift can be first degree compensated by the
buffer gas mixture, and in there can the details of the RF synthesis be
On 05/05/2013 10:05 AM, Attila Kinali wrote:
On Sat, 4 May 2013 12:36:20 -0700
Tom Van Baak (lab)t...@leapsecond.com wrote:
Rule of thumb: quartz is best short term, Rb or H-maser mid-term,
and Cs by far the best long-term.
Ah.. so it's a fundamental limitation. And i was looking for
Hi Jim,
On 05/05/2013 03:59 PM, Jim Lux wrote:
On 5/5/13 1:48 AM, Magnus Danielson wrote:
The above is a summary of things collected from a variety of sources,
but I think this coarse walk-through of issues gives some insight as to
what issues pops up where and the milage vary a lot within
On 05/05/2013 06:50 PM, Jim Lux wrote:
On 5/5/13 8:42 AM, Richard (Rick) Karlquist wrote:
At HP in the 1990's, Len Cutler's group built some experimental
mercury ion standards for USNO (IIRC). They were of the
trapped ion type. BTW, it is important to understand that
the architecture is the key
On 05/05/2013 04:15 PM, James Robbins wrote:
What is the relationship between the T'Bolt survey fixes number (e.g. 2000) and number
of hours duration of the survey? Is it one fix per second or something? What number
of fixes should be input to accomplish a 24 hour or a 48 hour survey?
If
Hi Jim,
On 05/05/2013 07:33 PM, Jim Lux wrote:
On 5/5/13 10:05 AM, Magnus Danielson wrote:
They have been targeting this goal for a very long time. Several
interesting papers is to be found at PTTI, NIST etc.
Yeah.. some years (6 or 7?) ago, John Prestage had a prototype of the
physics
Hi Poul-Henning,
On 05/05/2013 08:29 PM, Poul-Henning Kamp wrote:
In message51867df4.4010...@karlquist.com, Richard (Rick) Karlquist writes:
BTW, it is important to understand that
the architecture is the key factor, not the flavor of atom.
Well, somewhat.
Some flavours of atoms don't work
On 05/05/2013 09:28 PM, Poul-Henning Kamp wrote:
In message20130505205257.8497f166abb1e49186953...@kinali.ch, Attila Kinali w
rites:
I also have never seen a H gas cell standard, probably for the same reason
of needing UV light.
Hydrogen is very hard to contain.
The way you *filter*
On 05/05/2013 11:14 PM, Jim Lux wrote:
On 5/5/13 11:45 AM, Magnus Danielson wrote:
Hi Jim,
On 05/05/2013 07:33 PM, Jim Lux wrote:
On 5/5/13 10:05 AM, Magnus Danielson wrote:
They have been targeting this goal for a very long time. Several
interesting papers is to be found at PTTI, NIST etc
Hi Tom,
On 05/05/2013 11:33 PM, Tom Knox wrote:
The idea of a Mercury Ion clocks started about 2000 and from about 2005 until
recently has held the title of worlds most accurate clock.
Approx 1 sec per 1.6 billion years the last I heard. At the heart is a single
trapped mercury atom. Jim
On 05/06/2013 02:29 AM, Mike S wrote:
On 5/4/2013 2:40 PM, Attila Kinali wrote:
Can anyone shed some light on why the GPS Cs beams have a worse stability
than the Rb vapor clocks?
I don't know, but it makes me wonder about things like
1) How sensitive is each to C-field tuning - i.e. for the
Oh... 24 bit mantissa should give 1.25 m resolution if my headcounting is about
right. Thats about 4 ns.
Royal kludge indeed.
Cheers
Magnus
Originalmeddelande
Från: Mark Sims hol...@hotmail.com
Datum:
Till: time-nuts@febo.com
Rubrik: [time-nuts] GPS position survey
The
I was using 90 deg = 1000 m as approximation. I forgot about the sign but
as I recall the leading 1 is surpressed. 360 deg on 25 bits. Reducing approx
gave me 10 and 3 bits.
Cheers
Magnus
Originalmeddelande
Från: Mark Sims hol...@hotmail.com
Datum:
Till:
, Rb vs Cs
Hi
Fountain's don't work very well in zero G….:)
Bob
On May 6, 2013, at 12:23 AM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
On 05/06/2013 02:29 AM, Mike S wrote:
On 5/4/2013 2:40 PM, Attila Kinali wrote:
Can anyone shed some light on why the GPS Cs beams have a worse
On 05/08/2013 10:50 PM, Bob Camp wrote:
Hi
If it's moving up and down from +1 to +17 Hz from 10 MHz relative to 10 MHz,
it's broke. Either the OCXO it's self is in trouble or the supply going into
it has an issue.
... or as a remotely an issue a weak connection creating too much serial
On 13/05/13 00:13, Bob Camp wrote:
Hi
Is the M12 going away or they just going through (another) parts change?
You are correct. I read it sloppy, but I did recall that there was
something going on (easy to check by just reading the link I did provide
- so brown paper bag on my head this
Hi,
One should be careful with transformers, since they can bite you in
interesting ways. While they give galvanic isolation, they also act like
a capacitive divider. Just a primary and secondary coil will connect to
each other, and it is not uncommon for the connection to be asymmetric.
A
On 05/26/2013 06:04 PM, Attila Kinali wrote:
Hi,
I'm looking for the datasheet of the Oscilloquartz 8602 oscillator.
I cannot find it at the usual places or anywhere with google.
Any help would be appreciated
The OSA 8602 is a variant of the OSA 8600 and 8601. These variants is
mainly on
Raj wrote:
While comparing a Rb FE5680 frequency reference with another RB or GPSDO I find
that tapping a Rb unit causes a sudden shift in the scope display meaning the
frequency has slightly shifted momentarily and locks back steadily with a phase
shift. This does not happen in another Rb
Raj,
Raj wrote:
Hi Stan,
I will explore this issue tomorrow, 20:00 here now. I was just going
through a boyish thrill of fiddling with a Sony ICF-S10Mk2 and the amazing
numbers of AM stations it picks up.. maybe it can be used at 60Khz.. for 10$ it
worth it !!
How about
Dear Mark,
Mark Sims wrote:
A while back there was a discussion on just how Trimble's AMU (amplitude
measurement units) signal levels related to the dBc values. Here is a
conversion table.
It was generated by doing a 24 hour antenna signal level survey in dBc and another one in AMUs and
Mark Sims wrote:
The data was collected in 0.1 dB / AMU steps. There was a lot of noise in the raw data (maybe +/- 1 dB or AMU), but the general trend of the curve was quite distinct. I smoothed it out by hand and filled in a few (maybe 15) of the missing steps that had no signal.
The 0.1
Arnold,
Arnold Tibus wrote:
Magnus Mark,
for my Thunderbolt system I found a very good correlation
between AMU and dBc/ Hz ( observed on my system using
the ThunderboltMonitor watching over long time stable satellite signals )
when I use the Formula: C/N0(dBHz) = 20 log(AMU) + 23.5.
It
Stan, W1LE wrote:
Hello The Net:
About a year ago I asked CTS Knights that very question.
They said it was a custom unit and they would NOT divulge the specs.
They referred me to SRS, their customer.
So I talked with SRS and they would only sell me a complete FS700
rebuild service
for more
Henry Hallam wrote:
Timing newbie here, so please educate me - why does aging matter?
Isn't the whole purpose of a GPSDO to completely eliminate long-term
drift?
First degree effect yes, but depending on how you do it, more or less of
the drift remains uncompensated. If you just try to do
Bruce Griffiths wrote:
Lux, Jim (337C) wrote:
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]
On Behalf Of Bruce Griffiths
Sent: Wednesday, February 17, 2010 2:10 PM
To: Discussion of precise time and frequency measurement
Subject: Re:
Bruce Griffiths wrote:
Magnus Danielson wrote:
Bruce Griffiths wrote:
Lux, Jim (337C) wrote:
-Original Message-
From: time-nuts-boun...@febo.com
[mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths
Sent: Wednesday, February 17, 2010 2:10 PM
To: Discussion of precise time
Lux, Jim (337C) wrote:
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf
Of Bob Camp
Sent: Wednesday, February 17, 2010 4:24 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] DMTD to MMTD
Hi
No Windows
Hal Murray wrote:
The trick of including a PLL in an oscillator package has been around for a
while.
The initial ones were programmed at the factory or distributor. The idea was
to avoid the long wait while they polished the crystal to your specific
frequency. They stocked them in a
Richard (Rick) Karlquist wrote:
David C. Partridge wrote:
Cough - the rubidium clock or oscillator does have an intrinsic
frequency,
which is the rubidium hyperfine transition of 6 834 682 610.904 324
Hz, it's
just that the frequency generated by the transition in question isn't
used
to
Rick Karlquist wrote:
ewkeh...@aol.com wrote:
The HP 5062C is not a Primary Standard, and that is why it is called a
Reference because it uses a different transition of Cesium 133 with the
frequency of 9192.631,774,3 MHz which does not meet the definition of a
second
and resulted in a relative
Rick Karlquist wrote:
If you want to get technical, the frequency of a cesium standard
also depends on the gravitational acceleration, but for relativistic
reasons, not newtonian physics. Any decent cesium is accurate
enough that it will noticably speed up at NIST in Boulder. NIST's
best
Poul-Henning Kamp wrote:
In message 20100223214204.eae71117...@hamburg.alientech.net, Mike S writes:
renamed, since the discussion has shifted.
In the time and frequency field, the term primary standard is
sometimes used to refer to any cesium oscillator, [...]
That rhymes with and Karls
Bruce Griffiths wrote:
Garry Thorp wrote:
With the 723, you can make the reference noise as low as you want, by
heavy RC filtering. This applies whether you use its own reference or a
better external reference.
The 723 also seems to work quite happily with a feedback capacitor from
the output
Gerard,
Gerard PG5G wrote:
Hello all,
First post here, so I'll start with a quick introduction. I trained as
an electronic engineer but don't work in that field any more, which has
given me the appetite back to do some electronic engineering as a
hobby. I have been a licensed ham
Bob Camp wrote:
Hi
The winds in Sweden change directions in a *very* predictable fashion?
Ghaa! Our secret is out! :)
No, by rock I mean crystal, gas is Rb and Cs but could also be H but I
don't have one of those babies, and by air I mean GPS or other radio-signal.
Cheers,
Magnus
of what others have asked
me as well.
Regards
Gerard
Magnus Danielson wrote:
Would you consider to disclose your architecture somewhat more?
In broad terms:
Input conditioning with ADCMP600 comparators followed by FF divide by 2
to get a 50% duty cycle signal on both the ref and input
Jim Palfreyman wrote:
Anyone here have any experience with these masers?
In particular the VCH-1005A?
I have been tasked to look after a number of these units and am currently
going through the manuals (which are in English but written by a Russian, so
they can be challenging :-)
Any
Bob Camp wrote:
Hi
I hear that the US ones look better than the Russian ones when you have them
spinning around on a frozen pond. Nether one does a very good triple axle
jump though. At least that's what I read on the internet
---
There's always been a *lot* of debate about
Gerard,
Gerard PG5G wrote:
I have had a few replies, both on list and off list, including some
offers for help and some suggestions regarding the capabilities of my
counter. Thanks to everyone who took the time to write.
I understand from various replies I had that I cannot measure ADEV the
Bob Camp wrote:
Hi
So a parts donor 5370B is a donor for 5370B's and not so much for a 5370A.
It should be decided on a board-for-board level. Several boards are just
the same, so it would be no problem.
Cheers,
Magnus
___
time-nuts mailing
Bob Camp wrote:
Hi
I'm about 90% sure I'm going to hang on to the counter. It may wind up with
a bunch of fixed level inputs on it, but for the price - I'll live with
that. Other than the blow to the front panel it seems to be in ok shape.
If I do keep it, tearing it open and checking all the
Yuri Ostry wrote:
Hello,
J Anyone here have any experience with these masers?
J In particular the VCH-1005A?
J I have been tasked to look after a number of these units and am currently
J going through the manuals (which are in English but written by a Russian, so
J they can be challenging :-)
Mark Sims wrote:
99.95 ns is a typical number for the period reading at minimum gate time. Set
the gate time to 1 sec. My 5370A shows 99.999 999 9650 +/- 50 at 1 sec gate
time.
Measuring it's own time-base is expected to give value not exactly
on-beat. Internal cross-talk with the
Mike S wrote:
At 12:44 AM 3/10/2010, Ed Palmer wrote...
It would seem to make more sense to have the fan blowing hot air out
the back and drawing the hot inside air over the temperature sensor.
The reason to have a fan blow in is so you can put a filter on it. It
also creates more
Ed Palmer wrote:
Good point about the filter, but it doesn't appear that the 5371a or
5372a ever had a filter. Unless it was just done out of habit because
other HP units did have a filter.
If you want to toss a filter on it because your environment isn't
exactly clean, it is trivial. Maybe
Bob Camp wrote:
Hi
Yes indeed, the period was measured with the two channels in the com mode and
the reference
into one of them. I hadn't considered the trigger offset issues and was
expecting something
sub-100 ps rather than 500 ps. Obviously I need to spend some quality time
with this
Ed Palmer wrote:
One trick I always use to quiet down a rowdy fan is to replace the
mounting screws with rubber mounts. This isolates the fan's mechanical
vibrations from the chassis. The difference is audible - even with a
good fan. I salvaged some mounts from IBM machines that work
Bob Camp wrote:
Hi
Fanless Atom motherboard / solid state disk / wall wart power supply ... DVD
is still the main source of noise.
This was far from that. It is a AMD PHENOM II X4 90SE 2,5GHz CPU with 8
SAMSUNG ECOGREEN F2 1,5TB SATA disks is certainly not tailored in such a
fashion. The
Hal Murray wrote:
Concerning my query about what's good enough to count as a contact...
We've done Moonbounce with 3mW (Hobart - Dwingeloo) in JT65 - but a
26m and a 25m dish is stretching 'amateur' a bit again.
Googling for JT65 finds a nice paper:
Hal Murray wrote:
mag...@rubidium.dyndns.org said:
Their modulation scheme is 1 of 65 tones. 6 bits per baud.
The extra tone is the synchronizing signal.
6 bits per symbol. 1 baud is 1 symbol per second.
Happy to see someone using baud, just unhappy about seeing it being
used
John Ackermann N8UR wrote:
There is a way to slide the board in that clears the standoffs; almost
impossible to describe so I should make a video of it one of these days!
In general, you slide the board in with a very shallow angle of
attack and do an overshoot-and-reverse. I'm sure that's
Peter Vince wrote:
As I understand it, the GPS signals are circularly polarised, and so
surely reflections will reverse the sense of that polarisation such
that the antenna will be insensitive to them?
Yes, as a first degree analysis. However, cancellation will not be 100%
since neither the
jimlux wrote:
David C. Partridge wrote:
definition of pie
3.1415926535 etc ?
Ooops
D.
And, as my daughter reminds me, today is pi day (in the U.S. where we
write the date month/year.. those of you in the rest of the world will
have to wait a long time, as there is no April 31st)
Nope.
Bob Camp wrote:
Hi
Wedding cake pans normally come in 1 increments and are either 2 or 3 deep. Sets
are 2 increments on the diameter:
http://cooksdream.com/store/wedding-round.html
Joe Gwinn wrote:
Date: Sun, 14 Mar 2010 21:09:00 +0100
From: Magnus Danielson mag...@rubidium.dyndns.org
Subject: Re: [time-nuts] Choke Ring Pictures
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 4b9d425c.2050...@rubidium.dyndns.org
Content-Type
WarrenS wrote:
Bruce wrote:
Which antenna performance metric do you have in mind?
Could do GPSDO hold over performance, but that would not be much of a
test of the antenna.
How about the antenna's effect on the ADEV Osc noise and Phase noise.
What else does the Time Nut care about?
WarrenS wrote:
Magnus wrote:
Multipath rejection, antenna selectivity, antenna amplifier gain,
antenna noise factor... all weigh in.
And Your point is?
Their effects would all be included in as much as they effect ADEV Osc
noise and Phase noise.
They would show up on the ADEV and
Bert, VE2ZAZ wrote:
OK, I am doing a 24-hour ADEV analysis of the HP 5328A Timebase Output when set to divide-by-10,000,000. I use the 10MHz output from an HP 8644A sig.gen. OCXO. I split that 10MHz signal into two; one end goes to the the input of the HP 5328A counter. The other 10MHz end goes
Hi Bert,
Reverting back to the list for more people to see.
Bert, VE2ZAZ wrote:
Hi Magnus,
No, I don't see why there would be any cycle slips since the readings are
around 65 ns and both Start and Stop come from the same reference OCXO. Quickly
browsing through the data does not show any.
John Miles wrote:
I would tend to say that the divider is pretty lousy for short
term, but it is all fine for longer runs, right?
Is this what I should expect from a TTL/ECL divider chain
designed in the '70s-'80s? How would this compare to a modern
divider chain, like the PIC divider or David
Demian Martin wrote:
At some point I'll re-run tempco and jitter measurements of the dividers
and 1PPS distribution amps I have here.
Last time I used a 5370B and a SR620. This time I'd like to try a
Wavecrest. If someone on the list has done this already can you let me
know?
Thanks,
/tvb
Tom Van Baak wrote:
Hi David,
Thanks for the detailed comments. I understand better
how the two boards differ now. You did a fine job. And
thanks for making it available to the group, with good
documentation and all.
One comment in the use of microcontrollers -- a reason
I (and many others)
Bob Camp wrote:
Hi
Can we all come live at your house and play with your toys?
That would cause some troubles with logistics, like places to sleep. ;)
Tom has far more toys than me. I might have a few things he doesn't
have, but other than that he outperforms me in most fields.
So far,
Dear Corby,
Corby Dawson wrote:
Bill,
The receiver unit is not sealed.
To remove the lamp assy. you remove the two nuts (one inside) and the 3
shields from the central threaded rod that protrudes from the lamp end.
Then remove the tiny phillips head screws (3) around the circumference of
the
Bob Camp wrote:
Hi
I've had pretty good luck with Quartus setting up delay relationships and optimizing for them. You are correct that you do get speed variations from the slow model to the fast model. Getting it all to work out is usually a two step process. Find the delay clusters and then
Bob Camp wrote:
Hi
Good point, pretty much everything I worry about is timing to or from an external pin.
Once it's inside it's all clocked to the global clock(s).
If you look at the modern families, you no longer have only clocking
on both edges... but even higher rates.
The I/O-block
Mark Sims wrote:
Basically it means the unit has lost the battery backup to the calibration memory.
The cure is a rather simple calibration step. On the 5372A you input a 60 mV
10KHz sinewave and perform Test 25.
The adjustment is also called Maximum Hysteresis
It also tells you that
John Miles wrote:
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
Behalf Of Bob Voelker
Sent: Sunday, March 21, 2010 1:59 PM
To: time-nuts@febo.com
Subject: [time-nuts] HP 5065A performance vs. others
As several postings have indicated, the
Tom Van Baak wrote:
Group,
If Dave P's current divider design has design jitter specs approaching
SOTA vvs cost levels whilst the TAPR board is (perhaps) slightly
inferior in performance, where does that leave Tom's venerable 1pps PIC
divider in the pecking order ?
Will all designs be
Bruce Griffiths wrote:
The performance of the sine to square wave conversion clock shaper
circuit may dominate the divider performance.
Thus an evaluation of the jitter performance of sine to square wave
conversion circuits would also be informative/useful.
We should standardise some test for
Mark Sims wrote:
If the battery has not been replaced, you also get the warning message about
the config being lost... Just the 160 error usually means the battery was
replaced, but the system was not recalibrated (or a glitch wiped the memory).
Anyway, I always replace the battery.
Bruce,
Bruce Griffiths wrote:
Magnus Danielson wrote:
Bruce Griffiths wrote:
The performance of the sine to square wave conversion clock shaper
circuit may dominate the divider performance.
Thus an evaluation of the jitter performance of sine to square wave
conversion circuits would also
Tom Van Baak wrote:
The TSC5120A allows phase noise measurements on signals with
frequencies down to 1MHz.
Classical diode mixer based systems can go somewhat lower in frequency.
You should realize that I have reasons to believe that the limit is
one of software parameters rather than anything
Mark Sims wrote:
Nope, Magnus was right... this is Time Nuts... it does indeed make Julian fries.
You can use the hot wire stripper to peel the spud, the Microchine dremel tool
(with instant stop probe brake) to cut the fries, the vacuum pick to move 'em
around, slather them with
Bruce Griffiths wrote:
Magnus Danielson wrote:
Mark Sims wrote:
Nope, Magnus was right... this is Time Nuts... it does indeed
make Julian fries.
You can use the hot wire stripper to peel the spud, the Microchine
dremel tool (with instant stop probe brake) to cut the fries, the
vacuum
Dave Baxter wrote:
Relatively easy to do in principle, and good no doubt that this would be
results wise, it's suddenly not a DIY project any more for 99% of
people.
There is now plenty of people doing things like it in DIY projects. The
software is available for free download, the chips is
Fellow time-nuts,
I am a curious mind, which should come as no big supprise, and I know
that lots of people have looked deeply into these devices before me.
So, first of all I wonder, what other commands than SCr and F=32-bit
hex numberCr is there? Anything fun? Anything useful? Anything
Dear Raj,
Raj wrote:
Ahem!, time-nuts. Please release all GPS satellites you are holding up on the
other side of the world. I don't seem to have any over my head over Asia.
I wonder what happens to those guided missiles that depend of GPS or those in
vehicles looking for directions ?
Oh,
J. Forster wrote:
From an unnamed, but VERY credible source:
It might be that the DoD is turning the civilian signals off in combat
areas to deny GPS to the Taliban and others.
Quite possible. This countermeasure was discussed more than ten years
ago.
It is possible to turn of the
. I did not have that pointer on collected info, even if I
have seen the parts floating around.
Cheers,
Magnus
Regards,
Murray Greenman ZL1BPU
---
Message: 8
Date: Wed, 24 Mar 2010 23:18:12 +0100
From: Magnus
Bob Camp wrote:
Hi
If it's the same magic gift as I got - some of them have a very unusual
smell. It sort of makes you wonder where this stuff may have been stored.
The magic gift smells of soap.
If you have one of the hand converted ones that puts out 10 MHz you might
consider an
Ulrich Bangert wrote:
It's not real clear that building a part with monolithic
diode pairs or quads buys much over a part from MiniCircuits.
Rumours are that the famous HP10514 is made from 4 discrete hand selected
diodes. If you have thousands of diodes to select from building your own
Peter Vince wrote:
Warren,
If you turn over an oscillator, is the frequency change
completely reversible (to your under 1e-12 resolution) when it is
restored? Thinking aloud, if an hour-glass is turned over twice, the
final level will be the same, but the grains will be mixed. A quartz
Bob Camp wrote:
Hi
When there's a leap second, what do you want to do?
Ignore it = GPS time
put in an extra pulse = UTC time
No, this is about which set of corrections to use. The GPS time is what
the navigation solution cranks out, and UTC time is what you then
correct that into for user
Tom Van Baak wrote:
It also has an option to sync the PPS with GPS or UTC. I thought
they were off by an integral number of seconds so I don't expect any
change. Does anybody know what's going on here?
The GPS broadcast message includes leap second and
a0 and a1 terms which are used to
Bruce Griffiths wrote:
Magnus Danielson wrote:
Bob Camp wrote:
Hi
When there's a leap second, what do you want to do?
Ignore it = GPS time
put in an extra pulse = UTC time
No, this is about which set of corrections to use. The GPS time is
what the navigation solution cranks out, and UTC
Steve Rooke wrote:
So there are 250 clocks, presumably, spread around the World and owned
by the member countries of the BIPM.
There is a fair spread geographically, yes. See map:
http://www.bipm.org/en/scientific/tai/tai.html
Their time is somehow compared centrally and an absolute time is
Bob Camp wrote:
Hi
There are a couple of problems you will run into.
The first is that if you do a very good job with the dewar flask, the dead
heat (power of the oscillator, regulator etc) can indeed raise the
temperature of the OCXO beyond the oven control temperature.
I.e. there needs to
b...@lysator.liu.se wrote:
Hi Sanjeev,
On Wed, Mar 31, 2010 at 13:51, b...@lysator.liu.se wrote:
Zealand is an island between Denmark and Sweden.
Was not aware of that. Lat/Lon?
55.5N 11.75E
Ahaa... Zealand is the English name for Sjaelland. Well, Sjaelland
Bob Camp wrote:
Hi
The bring it back to the shop for a quick repair option seems to be missing
from their list of proposed fixes
That goes for most of the birds, part of the field. Dockable stuff like
ISS and Hubble and a few others share this property. But the price for
that kind of
Bob Camp wrote:
Hi
True, the 3048 is not much of a frequency counter. It's also pretty limited
as an Adev box.
Box???
Cheers,
Magnus
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To unsubscribe, go to
b...@lysator.liu.se wrote:
About the only way for a civilian to make use of L2 is with a carrier
phase surveying receiver. They can be had in the $1000 range. Perhaps
the most common/useful unit you are likely to find is the Ashtech Z12 or
one of its many cousins.
A modern (aka 1.6W
Fellow time-nuts,
Another article about GPS PPS tracking. Their twist to it has been to
lower the PPS jitter, not to create a locked 10 MHz clock. I though it
may be useful for someone at least:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.129.8625rep=rep1type=pdf
Cheers,
Magnus
Matt Ettus wrote:
Interesting work. They measured the before and after signals with
2 very different oscilloscopes one with 100 MHz BW and one with 500
MHz, which they shouldn't trust.. I guess they only had 2 2-channel
scopes in their lab.
Their methods did leave something to desire, but I
saidj...@aol.com wrote:
I see other problems in the paper as well, for example why did they just
plot a time-domain plot of before and after which doesn't really say much. It
looks less noisy, but that doesn't mean anything. The peak to peak is
very similar.
Instead they should have put
Craig S McCartney wrote:
A bit off topic, but likely interesting to time-nuts:
In the early days of HDTV (late 80s - early 90s) we were at a European
trade show and had to borrow, at the last minute, a large (~40)
CRT-based HD monitor from a Dutch company that was also exhibiting
there. We
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