Le 30/08/2011 11:21, Rob Kimberley a écrit :
The original question asked whether the speed of light was taken into
account in the definition of UTC. From where I'm standing (and please excuse
the pun), it isn't.
Rob Kimberley
There were 2 questions. I was agreeing to your response to the first a
Le 30/08/2011 09:40, Chris Albertson a écrit :
How is the speed of light accounted for in the definition of UTC?
In other words, how did they solve the conflict where on one hand we'd all
expect two "perfect" clocks to "tick" at the same time but wether they do
depends on the location of the obs
Le 08/09/2011 23:03, Ken , VK7KRJ a écrit :
Is anyone else having trouble with this url?
I've been trying it since the email came through, it just times out
waiting for a reply.
I did try to get to it from the parent site, with the same effect. No
problem with the nist site direct, but no go wi
Le 09/09/2011 00:05, Tristan Steele a écrit :
Yep, I can't get it either - and I am also in Australia, so I think there
might be something in that.
Is there any chance someone could mirror it on a server accessible from Down
Under. :-)
Thanks!
Tristan
try me - might work
http://gluon.s
Le 22/09/2011 12:35, Martyn Smith a écrit :
Hello,
I'm trying to measure the Allan Deviation of an amplifier and need
help with
the maths.
My measurement process uses the SR620 in time interval mode and I make
one
measurement per second for about a day.
I then use Ulrichs excellent plotter
Le 22/09/2011 13:45, Bruce Griffiths a écrit :
I have always thought of a noise floor as the lower limit to which
you can trust your measurement. Measurements below the floor can be
statistically derived IIRC, but calculating the Allan deviation of it
makes no sense to me. As your measuremen
Le 04/10/2011 11:42, jeffh...@comcast.net a écrit :
Have ever been to the best on-line shop?
looks like some new anti-spam control is required.
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.. and for the convenience of a board which includes USB and serial
connectors:
http://www.sureelectronics.net/goods.php?id=99
http://www.satsignal.eu/ntp/Sure-GPS.htm
Some assembly required. US $34.90 + P&P
Nice box David. I confirm that results with FreeBSD are better and are,
for short
Le 16/10/2011 18:34, David J Taylor a écrit :
I've just got a Rapco 1804M and while it works, within the limits of
my antenna placement, the RS-232 serial out doesn't read very well,
and seems to have incorrect characters. The voltage levels look OK,
and the terminal emulation program is set t
Le 17/10/2011 16:55, Bill Dailey a écrit :
I need an NTP guru for a couple NTP questions. I have my Fury GPSDO hooked
up to a linux (ubuntu) computer have offset in the "time-nuts" category
(less than a microsecond) with pps. I am wondering where to go from here so
I can actually quantify the p
Le 19/10/2011 07:03, Yuri Ostry a écrit :
Hello,
Wednesday, October 19, 2011, 1:21:31, Tom Van Baak wrote:
T> So the antenna and receiver architecture is more complicated. Have you seen
any
T> portable car navigation or cell phones with GLONASS?
Smartphone with both nav systems (sorry, Russ
Le 24/10/2011 19:03, Bob Camp a écrit :
Hi
The "quick and dirty" way to improve the timing is pretty old school.
Toss a modern Cesium clock in the back of a car along with a bunch of
batteries. Drive it back and forth between Batavia and Soudan. If you drive
fast, that should be about an 8 hour
Think big. The experiment has been done over 168,000 light years.
http://en.wikipedia.org/wiki/Supernova_1987A
The neutrinos got here 3 hours before the light. (Empty space isn't really
empty. The dielectric constant slows the light down a tiny tiny bit.)
I am not sure that this is a val
Le 25/10/2011 03:51, Rick Thomas a écrit :
When I first heard of this, I had a thought for a 4th explanation:
It seems likely, given everything we know, that neutrinos have a
very-small, but non-zero mass. Part of the point of this experiment
was to try to get a better idea of what what mass
Le 30/10/2011 20:21, Javier Serrano a écrit :
This can be done without
much regard to high precision. Some 100 ns are OK. If neutrino
time-of-flight had been the original goal of these experiments, quite
a number of things would have been done differently from the start.
I read that the OPERA e
Le 13/11/2011 18:21, Chuck Forsberg WA7KGX N2469R a écrit :
Seems like a lot of folks selling these lately.
Curious minds would like to know why.
I expect they are lots from telecom providers who are are replacing kit
that is being upgraded.
I don't see any date codes on the boxes. Has anyone w
Le 16/11/2011 18:33, Chris Albertson a écrit :
On Wed, Nov 16, 2011 at 7:03 AM, David J Taylor
wrote:
A pity that there isn't a port of the reference NTP for the Mac, such as we
have on Windows.
As I remember you simply compile NTP on the Mac and it just worked.
No need for a "port". Has so
Le 16/11/2011 18:42, mike cook a écrit :
Le 16/11/2011 18:33, Chris Albertson a écrit :
On Wed, Nov 16, 2011 at 7:03 AM, David J Taylor
wrote:
A pity that there isn't a port of the reference NTP for the Mac,
such as we
have on Windows.
As I remember you simply compile NTP on the Ma
Le 20/11/2011 23:57, Hal Murray a écrit :
Perhaps if enough funding can be obtained repeating the measurments between
three or more stations (with diferent distances between them but similar
equipment at each site) might eleminate some of the ambiguity. Being able
to compare the measurements ove
Le 21/11/2011 09:49, Hal Murray a écrit :
michael.c...@sfr.fr said:
I heard on the BBC the other day that a repeat experiment is planned,
firing neurinos from the US into Canada. The labs were not cited, but I
expect it would be Fermilab to Sudbury Ontario. If this is the case, then
there will
Le 22/11/2011 01:28, Joe Leikhim a écrit :
Fear Uncertainty and Doubt from "Wireless For America dot Org" (AKA
Lightsquared) . "Approved by Republican and Democratic Regulators."
http://www.youtube.com/watch?v=HyyDIk8W6Kw
Local wireless networks are already in use here in France to cover areas
Le 29/11/2011 10:08, Mark C. Stephens a écrit :
Hi All, Risking opening a potential can of worms, has anyone have a specs
roundup of GPSDO?
Ideally, Maximums of Phase noise, Jitter, accuracy...
lots of great stuff at leapsecond.com
___
time-nuts ma
Le 02/12/2011 01:53, Bob Camp a écrit :
Hi
Ok, 62.5 ppb at 1 second would be 62.5 ns. that sounds right for a 16 MHz clock.
Your accuracy will be related to the offset between the two 1 ops events
(divided TCXO and GPS PPS) and the accuracy of your crystal.
With some luck you can get the crys
Le 15 déc. 2011 à 23:24, Azelio Boriani a écrit :
> There are GPS simulators for lab use (never seen live or in a picture), I
> suppose they have one connector to feed the GPS receiver antenna.
> Generating in one equipment all the signals you don't need many but only
> one precise timing source.
Le 15 déc. 2011 à 23:57, Peter Gottlieb a écrit :
> Just watch how GPS stuff will get all restricted now.
>
Too late, Simulators are on paybay now. Just need deep pockets.
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I wonder how long it will be before we see Brinks vans, Ferrari's and other
more mundane GPS dependent things being hijacked. Possibilities seem limitless.
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Le 18/12/2011 20:40, Poul-Henning Kamp a écrit :
In message<4eee405b.3050...@pacific.net>, Brooke Clarke writes:
DO NOT REPLY TO THIS MESSAGE HERE.
s/REPLY TO/POST/ ?
Talk about being totally of-topic for time-nuts...
maybe "Time's running short" was his trigger.
__
Le 19/12/2011 06:47, Perry Sandeen a écrit :
Is a 10 MHz or so crystal on the horizon?
Dunno, but some 10-50MHz TCXO/VCTCXO are now available in 2mm
packages, so why not. There might be battery longevity issues with
driving the higher frequency. I guess it comes down to whether the
ma
Le 21/12/2011 10:53, Attila Kinali a écrit :
On Tue, 20 Dec 2011 13:12:13 +1100
Jim Palfreyman wrote:
Why don't they build a watch that measures the temperature and every time
you accurately set it, it adds to a small database of time change v
temperature and then adjusts itself internally.
O
Le 26/12/2011 21:31, Hal Murray a écrit :
I turned on a Z3801 that had been idle for a while. The status screen said:
UTC 20:03:44 [?] 11 May 1992
That looks like 1024 weeks (19.7 years) ago.
When I first turned it on, before finding any satellites, it said:
UTC 12:05:00 [?] 01
Hi,
Just got my cheapo 5680A. It was accompanied by a little teddy bear
clutching a L7805CV !
Got a couple of questions.
1) What is the expected 10MHz peak to peak voltage. FEI doc seems to
indicate 0,5V but I am getting only 200mv.
2) What is the sensitivity to 15V input level. I am only m
Le 29/12/2011 09:28, Chris Albertson a écrit :
1) What is the expected 10MHz peak to peak voltage. FEI doc seems to
indicate 0,5V but I am getting only 200mv.
I'm getting a lot more, about 2V peak to peak. What are you loading it
with, I'm using a 10X scope probe. How are you measuring the
Mine was slow, but I expected it. 25/11-28/12.
Le 30/12/2011 11:30, Rob Kimberley a écrit :
I bought a couple of these on EBay recently. Would like to know from the
group what the typical shipping times have been so far from China.
Cheers
Rob Kimberley
Le 02/01/2012 13:44, Robert Atkinson a écrit :
Hi Jim,
Well done, on the parking. Earlier this year I noticed that a new "pay and
display" meter in the city center (Cambridge UK) has what appears o be a GPS patch
antenna on top. Presumably a GPS receiver is cheaper than manually setting time or
Le 04/01/2012 02:58, Brian, WA1ZMS a écrit :
My E-bay FE-5680A finally arrived. (4weeks later)
Of the pins on the DB-9 connector, which one is the RF output?
The manual only talks about an SMA output.
It may depend on the version as there are lots.
If you have the cheapo 30352-1 part like
Le 04/01/2012 09:58, Hal Murray a écrit :
Neat. Thanks for sharing.
With a XOR, you can't tell which input is higher frequency. I think you can
fix that with a second XOR and a delay line.
I think 90 degrees of delay will provide the most information. At 10 MHz,
that's 25 ns. I think that's
Le 06/01/2012 17:02, Chuck Forsberg WA7KGX N2469R a écrit :
The Tech Manual does not call for heat sinking (unless I missed
something).
The top has labels over much of the surface.
The bottom has a plastic sheet between the circuitry and bottom plate.
Yes, I am inclined to agree as I suspect the
Le 06/01/2012 18:05, David a écrit :
Yes, I am inclined to agree as I suspect these devices were designed to
run in uncontrolled temperature environments.
Maybe the test would be to measure the current draw over temperature,
when the box thinks it is warm enough it will stop heating the cell and
Le 11/01/2012 19:24, Chuck Forsberg WA7KGX N2469R a écrit :
The FE-5680A 1pps is not sync'd to UTC.
According to my calculations, it would take several hours
to walk the 1pps to UTC given the 3.8e-5 adjustment
range via the RS232 input. A thunderbolt, an arduino,
and patience.
You don't need to
Le 11/01/2012 19:36, mike cook a écrit :
Le 11/01/2012 19:24, Chuck Forsberg WA7KGX N2469R a écrit :
The FE-5680A 1pps is not sync'd to UTC.
According to my calculations, it would take several hours
to walk the 1pps to UTC given the 3.8e-5 adjustment
range via the RS232 input. A thunde
Le 18/01/2012 23:41, Mike S a écrit :
So, I'd still like to know who says "don't use TAI," and for what reason.
I'm not sure anyone says "don't" use TAI. What they say is that you
"can't" use TAI because it is not disseminated , unlike UTC(k).
UTC has the same rate as TAI , so we have a sourc
Le 19/01/2012 01:04, Mike S a écrit :
On 1/18/2012 6:15 PM, mike cook wrote:
I'm not sure anyone says "don't" use TAI. What they say is that you
"can't" use TAI because it is not disseminated , unlike UTC(k).
UTC has the same rate as TAI , so we have a source
Le 19/01/2012 21:55, k4...@aol.com a écrit :
Last time I checked (first of this week) subframe 4 of page 18 in the
data stream from the GPS satellites, they are not indicating there is
a pending leap second. Last time there was a leapsecond (couple years
ago), I think the GPS SV's were anoun
Le 20/01/2012 09:37, Attila Kinali a écrit :
On Thu, 19 Jan 2012 10:02:56 +0100
mike cook wrote:
H (from a time serf). Some labs provide UTC(k) but do not generate
a TA(k) , maybe as there not enough clocks available. Some UTC(k)
providers have only one clock,.
This somehow doesn&#
Le 20/02/2012 07:18, Bill Woodcock a écrit :
Murphy says we won't. Bell curve, again. A very few will have good symmetric
paths to Stratum-1 servers, most will have mediocre asymmetric paths, and some
will have nothing usable at all.
Are you targeting homes, offices, or machine rooms?
The
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