Hi
My guess, is it's a mechanical failure, as unless you've had a series of long
power cuts, the battery/quartz backup won't kick in. AFIK, the Quartz clock
only is in effect, if the 50Hz supply fails. The utility 50Hz is maintaind to
a close tolerance and "tweaked" to maintain a very g
AFIK a lot of the clocks were radio controlled from MSF Rugby (now Anthorn,
Cumbria). You would need to have some sort of automated system to
accommodate daylight savings switchovers in Spring and Autumn. That said, I
would have thought once synchronised, they would "tick" off the 50 Hz
supply.
Ro
Over here they use a tone system that is modulated onto the mains to
operate a relay to switch over to night rate and turn on the immersion
heater in the hot water cylinder.
Steve Rooke
2009/12/29 Rob Kimberley :
> AFIK a lot of the clocks were radio controlled from MSF Rugby (now Anthorn,
> Cumb
Rob Kimberley wrote:
AFIK a lot of the clocks were radio controlled from MSF Rugby (now Anthorn,
Cumbria). You would need to have some sort of automated system to
accommodate daylight savings switchovers in Spring and Autumn. That said, I
would have thought once synchronised, they would "tick" of
Do you have a photo of your meter?
Rob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Dr. David Kirkby
Sent: 29 December 2009 13:59
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Can a quartz crystal
Hello time-nuts,
I'm looking for the group expertise to tell me what would be the best test
setup for looking at ADEV of several oscillators.
I have severa crystal, rubidium, and GPSDO oscillators that I would like to
characterize. I have a 5370B and cesium that has 1, 5, and 10 MHz output
Semiconductorstore.com also have the CW25-TIM at a cheaper price ($64
vs $89) and it is more sensitive, so can possibly work indoors. They
both, apparently, use the same NavSync chips, so does the '25 have
disadvantages I haven't spotted?
Peter
2009/12/28 Hal Murray :
>
>> Does the factory
I wonder how the power company changes the meter rate, based on the local
timer. Are there two different meters, with a separate circuit for cheap
loads?
Perhaps not, because you continue to run your computers without
interruption. OTOH, you said in the first posting, "Sometimes we hear the
contac
Hi Rob,
Actually they are controlled from a low bit-rate signal
phase-modulated onto Radio-4 long-wave (198KHz). If you have an SSB
or CW receiver that tunes down to that frequency, switch on the BFO
and look at the output on something like Spectrum Lab, and the phase
modulation is readily s
They just switch the meter over to count "night" units. Strictly of course
both day and night units are counted as kWh, and the supply company apply
different charge rates to the "night units". Effectively there are two
meters in the same case that are switched over by the time clock output
signa
The CW-12 consists of the CW-25 mounted on a circuit board with some glue
logic, connectors, etc. The CW-25 itself is the surface-mount module in the
middle of the CW-12. Compare the pictures - you'll see what I mean. Both units
are listed as having a tracking sensitivity of -155 dbm. I don't k
2009/12/26 Robert Lutwak :
>...
> CSAC is intended for portable battery-powered operation. Surely your
> basement has the space and wallplug power to support an LPRO. (p.s. don't
> cool the damn thing, heat it).
>...
Hi Robert,
Do I understand you are suggesting heating an LPRO, not cooling
Thanks Ed, yes, I hadn't looked closely enough at the pictures.
The "higher sensitivity" I mentioned came from the second line of the
"Features" section near the bottom of:
http://www.semiconductorstore.com/cart/pc/viewPrd.asp?idproduct=41599
"Enables indoor use -173 dBW acquisition and -185 dBW
I've had several discussions with Chris Bartram about this and similar
VHF oscillators.
My understanding is that Chris' variant of this particular Driscoll osc.
has been designed specifically for low close-in phase noise, and that is
why the phase-shift network has a low-pass response (to try
-185dBW = -155dBm
so both sensitivity measures are equivalent.
Bruce
Peter Vince wrote:
Thanks Ed, yes, I hadn't looked closely enough at the pictures.
The "higher sensitivity" I mentioned came from the second line of the
"Features" section near the bottom of:
http://www.semiconductorstore.com
Oh Good Lord - not paying attention to the units! Sorry guys!
Peter.
2009/12/29 Bruce Griffiths :
> -185dBW = -155dBm
> so both sensitivity measures are equivalent.
>
> Bruce
>
> Peter Vince wrote:
>>
>> Thanks Ed, yes, I hadn't looked closely enough at the pictures.
>>
>> The "higher sensi
Grant Hodgson wrote:
I've had several discussions with Chris Bartram about this and similar
VHF oscillators.
My understanding is that Chris' variant of this particular Driscoll
osc. has been designed specifically for low close-in phase noise, and
that is why the phase-shift network has a low-
> I have severa crystal, rubidium, and GPSDO oscillators that I
> would like to
> characterize. I have a 5370B and cesium that has 1, 5, and 10
> MHz output.
> The question is what is the best configuration of internal/external
> oscillator, start input, and stop input of the 5370B (and do I use
Skip Withrow wrote:
Hello time-nuts,
I'm looking for the group expertise to tell me what would be the best
test setup for looking at ADEV of several oscillators.
I have severa crystal, rubidium, and GPSDO oscillators that I would
like to characterize. I have a 5370B and cesium that has 1, 5,
Bruce Griffiths wrote:
Skip Withrow wrote:
Hello time-nuts,
I'm looking for the group expertise to tell me what would be the best
test setup for looking at ADEV of several oscillators.
I have severa crystal, rubidium, and GPSDO oscillators that I would
like to characterize. I have a 5370B an
Mike
Assuming you have learned to tame some of LH behavior issues, and that is
not what is causing the problems then:
MB) the temperature graph exhibits a sharp, which recovers over a period
of a few minutes.
ws)Likley a basic 'bug' in the LH Hardware. Best to ignore it.
MB) blue PPS
> My understanding is that Chris' variant of this particular Driscoll osc.
> has been designed specifically for low close-in phase noise, and that is
> why the phase-shift network has a low-pass response (to try and reduce
> flicker noise) rather than the more common high-pass network.
>
> Th
dk...@arcor.de said:
> What we already have seen is that crystals from the same production
> run may yield up to 15 or 20 dB worse phase noise at 100 Hz than the
> best. (in the same oscillator)
If I have several crystals and I want to find the ones with good phase noise,
do I have to let them
If both sources drift less than 100ns max (pk to pk) at 10MHz, then their
10MHz outputs can be used directly to start/stop the 5370B.
Choose a cable length, and a rise/fall trigger so as to measure as close to
50ns as possible, so the signals can drift up or down from that 50ns
average.
T
If I have several crystals and I want to find the ones with good phase noise,
do I have to let them run in their ovens for a week/month, or can I just turn
them on and measure the phase noise?
I'll make a distinction between time domain and frequency
domain measurements.
A long warm-up is help
Tom Van Baak said the following on 12/29/2009 04:24 PM:
But, depending on the equipment you use, a phase noise
measurement (e.g., script L of f) doesn't require the source
to be long-term stable; you get pretty much the same phase
noise results in the first minute as you would a day or week
late
Lady Heather version 3.0 flags holdover events in the plot with a red line at
the top of the plot. You can toggle the display from the G)raph menu.
If the holdover display is enabled, you can go to the start of the plot (HOME
key), place the mouse cursor in the plot area, and press %. The
That relies on the internal arming of the 5370B which isnt all that
stable in that the time interval between successive measurements doesnt
have great stability and one actually has to measure this by other means.
Using an external arm signal with known repetition rate that is
synchronised to
Tom Van Baak wrote:
If I have several crystals and I want to find the ones with good phase
noise, do I have to let them run in their ovens for a week/month, or
can I just turn them on and measure the phase noise?
I'll make a distinction between time domain and frequency
domain measurements.
A
> If both sources drift less than 100ns max (pk to pk) at 10MHz,
> then their
> 10MHz outputs can be used directly to start/stop the 5370B.
>
> Choose a cable length, and a rise/fall trigger so as to measure
> as close to
> 50ns as possible, so the signals can drift up or down from that 50ns
> av
Hi
It depends a lot on who made the crystals, how long they have been on the
shelf, and how accurate your sort needs to be.
If the crystals are from an unknown source or have been sitting for years, some
burn in (days) may be helpful.
I would suggest sorting out the dogs pretty quickly and th
Rob Kimberley wrote:
AFIK a lot of the clocks were radio controlled from MSF Rugby (now Anthorn,
Cumbria). You would need to have some sort of automated system to
accommodate daylight savings switchovers in Spring and Autumn. That said, I
would have thought once synchronised, they would "tick" of
Peter Vince wrote:
2009/12/26 Robert Lutwak :
...
CSAC is intended for portable battery-powered operation. Surely your
basement has the space and wallplug power to support an LPRO. (p.s. don't
cool the damn thing, heat it).
...
Hi Robert,
Do I understand you are suggesting heating an LPR
Bruce Griffiths wrote:
-185dBW = -155dBm
so both sensitivity measures are equivalent.
But -185 dB(something) looks more impressive than -155 dB(something).
Specsmanship... indeed. I also spoted this detail.
Cheers,
Magnus
___
time-nuts mailing lis
Peter Vince wrote:
Oh Good Lord - not paying attention to the units! Sorry guys!
This is exactly what they wanted to achieve, but the good thing is that
more people got to become aware of it, so something good came out of
that misstake. At least something good came out of it.
When somethin
If you have a spectrum analyzer, depending on its resolution, you can
also measure the phase noise directly.
When I worked in the Satellite Communications industry, we needed up and
down converters faster than our vendor could make them. They use to go
thru a long QA process and they were ver
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