Re: [time-nuts] Line Frequeny Stablity

[Bryan _]

There is a pretty nice "How it Works" video on steam turbines. As Pete mentions 
they use valving to control the speed of the turbines, interesting how they 
reheat the steam for the high/medium/low stages.


https://youtu.be/SPg7hOxFItI


-=Bryan=-



From: time-nuts  on behalf of Peter Reilley 

Sent: April 5, 2017 9:34 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Line Frequeny Stablity

The response time in a large plant is very slow.   Large steam plants
running at steady
state are running with their steam valves wide open.   A partially
closed valve is an energy
loss and is only used when changes occur.

The power control for a plant running at a steady load is the amount of
fuel thrown into
the boiler.   When you want more power you shoot more gas, oil, or coal
into the boiler.
For a nuke you pull the control rods.   Behind all of this is a lot of
thermal mass.   Things
don't change quickly.

Pete.

On 4/5/2017 9:01 AM, jimlux wrote:
> On 4/4/17 2:28 PM, Thomas D. Erb wrote:
>> Thanks for the info.
>>
>>
>> So that tells me how data is recorded - but not how the frequency is
>> kept stable ?
>>
>> Is the line frequency now directly tied to GPS clock - with no drift ?
>
> The line frequency is adjusted, for the most part, by adjusting the
> prime power (steam valves, dam penstocks, etc.) on the generators at
> power stations. That changes the speed, slightly, although as
> generator 1 of N starts to get ahead, the electrical load increases,
> and it slows down.
>
> It's actually a pretty complex system, since there are a whole raft of
> "spring constants" in between the multiple generators in a system,
> there's phase shifts due to transmission line inductance and capacitance.
>
> "Stabilizing" a system in the face of changing demand is a non-trivial
> task.
>
>
>
>
>
>>
>> Thomas D. Erb
>> t...@electrictime.com /
>> Electric Time Company, Inc.
>> Office: 508-359-4396 x 117 / Fax: 508-359-4482
>> 97 West Street Medfield, MA 02052 USA
>> www.electrictime.com>
>> [Facebook][Twitter][pinterest]
>>
>> [htmlsig.com]
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Re: [time-nuts] Line Frequeny Stablity

[Bob kb8tq]

Hi

Well ok, the rest of the story ….

The process of watching the line voltage slip lead me to buy my first 
“frequency counter”. 
It was a 1950’s vintage tube based Beckman “EPUT Meter”. I doubt it cost me 
over $40 at 
the time. It was well used but still functional   It clocked away on a  massive 
 MHz time base 
(that’s singular not plural) and turned out to be plenty good enough to show 
jitter
on a 60 Hz sine wave. That got me into questions about why and stability and …. 
here I am
decades later.

Bob

> On Apr 5, 2017, at 7:57 PM, Jeremy Nichols  wrote:
> 
> A fun way to monitor the state of the grid is to watch the web site of
> the Power
> Information Technology Laboratory  at the University
> of Tennessee , Their site lists in both tabular and
> graphical (map) form the frequency of the grid. Most of it is USA-based but
> there are a few other countries also monitored.
> 
> I have one of the monitors (in the table display page <
> http://fnetpublic.utk.edu/tabledisplay.html> my monitor is #853 in the
> Western Interconnection—I'm in California).
> 
> The monitors, about the size of a thick hardback book, plug into a
> convenient AC line outlet, connect to your Internet router, and have a
> small puck-style GPS antenna so that it knows the time and where it is. The
> unit has an LCD display of date, time, line voltage, and line frequency.
> The voltage is shown to 3 decimal digits of resolution and the frequency to
> four digits.
> 
> I got my monitor from the U of T after I sent them a report on my home-made
> monitor's results. It's interesting to watch the frequency wander up and
> down but always average very close to 60.000 Hz. They saw I had an interest
> and offered me one of their toys. The only thing it doesn't do is connect
> to my PC so I can monitor it long-term. I suppose if I were clever with
> network stuff there'd be a way to tap into its data stream.
> 
> Jeremy, N6WFO
> 
> 
> On Wed, Apr 5, 2017 at 2:12 PM, Bob kb8tq  wrote:
> 
>> Hi
>> 
>> Back in high school, one of the radio club members figured out that the
>> “clock adjustment” took place
>> locally between 4:30 and 5:00 PM. Needless to say, pretty much everybody
>> spent the next week listening
>> to WWV and watching the clock’s second hand go out of sync with the beeps.
>> This was back in the  late 1960’s
>> and the idea of a grid was a bit looser than it is today. Indeed it was
>> post 1964 so there *were* grids big
>> enough to take out the whole north east section of the US. Since we were
>> very much in that area the
>> topic of grid sync came up. Nobody ever really had a good answer to that
>> question. That included the
>> guys who ran the local power company.
>> 
>> Bob
>> 
>>> On Apr 5, 2017, at 3:05 PM, Hal Murray  wrote:
>>> 
>>> 
>>> preilley_...@comcast.net said:
 When I installed power plants in the 1970's they has a special "clock"
>> that
 showed the cumulative error in terms of clock time.
>>> 
>>> How big were the grids back then?
>>> 
>>> What was the typical range of error over a day or month?
>>> 
>>> 
 If the generator ran a little too fast the clock would move forward.
>> As
 the operator observed the clock moving away from zero he would reduce
>> the
 plant's  power and the clock would move backward toward zero.  ...
>>> 
>>> Does that operator control a single generator or a whole grid?
>>> 
>>> Does having a human in the loop help the control loop stability?
>>> 
>>> 
>>> 
>>> --
>>> These are my opinions.  I hate spam.
>>> 
>>> 
>>> 
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
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>> mailman/listinfo/time-nuts
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Re: [time-nuts] USB protocol for digital logic events, measurement

[Hugh Blemings]

Hi George,

On 6/4/17 09:47, George McCollister wrote:

Can anyone recommend a self describing, device/vendor independent USB
protocol standard for transferring digital logic events timestamped
relative to 1pps as well as voltage and current measurements and
digital output controls (latched or pulse)? So far SCPI over USBTMC
seems to be the closest thing I can find though it certainly isn't a
perfect fit. I'm trying not to invent something new (though it's
tempting). I'd like to hook it into the Linux IIO subsystem though
digital logic events aren't supported.


Apologies if you're already familiar with it - but perhaps something in 
the sigrok project ?  https://sigrok.org/


Cheers,
Hugh

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Re: [time-nuts] Line Frequeny Stablity

[Jeremy Nichols]

A fun way to monitor the state of the grid is to watch the web site of
the Power
Information Technology Laboratory  at the University
of Tennessee , Their site lists in both tabular and
graphical (map) form the frequency of the grid. Most of it is USA-based but
there are a few other countries also monitored.

I have one of the monitors (in the table display page <
http://fnetpublic.utk.edu/tabledisplay.html> my monitor is #853 in the
Western Interconnection—I'm in California).

The monitors, about the size of a thick hardback book, plug into a
convenient AC line outlet, connect to your Internet router, and have a
small puck-style GPS antenna so that it knows the time and where it is. The
unit has an LCD display of date, time, line voltage, and line frequency.
The voltage is shown to 3 decimal digits of resolution and the frequency to
four digits.

I got my monitor from the U of T after I sent them a report on my home-made
monitor's results. It's interesting to watch the frequency wander up and
down but always average very close to 60.000 Hz. They saw I had an interest
and offered me one of their toys. The only thing it doesn't do is connect
to my PC so I can monitor it long-term. I suppose if I were clever with
network stuff there'd be a way to tap into its data stream.

Jeremy, N6WFO


On Wed, Apr 5, 2017 at 2:12 PM, Bob kb8tq  wrote:

> Hi
>
> Back in high school, one of the radio club members figured out that the
> “clock adjustment” took place
> locally between 4:30 and 5:00 PM. Needless to say, pretty much everybody
> spent the next week listening
> to WWV and watching the clock’s second hand go out of sync with the beeps.
> This was back in the  late 1960’s
> and the idea of a grid was a bit looser than it is today. Indeed it was
> post 1964 so there *were* grids big
> enough to take out the whole north east section of the US. Since we were
> very much in that area the
> topic of grid sync came up. Nobody ever really had a good answer to that
> question. That included the
> guys who ran the local power company.
>
> Bob
>
> > On Apr 5, 2017, at 3:05 PM, Hal Murray  wrote:
> >
> >
> > preilley_...@comcast.net said:
> >> When I installed power plants in the 1970's they has a special "clock"
> that
> >> showed the cumulative error in terms of clock time.
> >
> > How big were the grids back then?
> >
> > What was the typical range of error over a day or month?
> >
> >
> >> If the generator ran a little too fast the clock would move forward.
> As
> >> the operator observed the clock moving away from zero he would reduce
> the
> >> plant's  power and the clock would move backward toward zero.  ...
> >
> > Does that operator control a single generator or a whole grid?
> >
> > Does having a human in the loop help the control loop stability?
> >
> >
> >
> > --
> > These are my opinions.  I hate spam.
> >
> >
> >
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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[time-nuts] USB protocol for digital logic events, measurement

[George McCollister]

Can anyone recommend a self describing, device/vendor independent USB
protocol standard for transferring digital logic events timestamped
relative to 1pps as well as voltage and current measurements and
digital output controls (latched or pulse)? So far SCPI over USBTMC
seems to be the closest thing I can find though it certainly isn't a
perfect fit. I'm trying not to invent something new (though it's
tempting). I'd like to hook it into the Linux IIO subsystem though
digital logic events aren't supported.

Thanks,
George
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[time-nuts] Hot Wire Ionizers

[Donald E. Pauly]

https://www.febo.com/pipermail/time-nuts/2017-April/104600.html

I posted this patent assigned to Frequency Control Corporation on hot
wire ionizers at http://gonascent.com/papers/hp/hp5061/US3433944.pdf .
They must have been an HP competitor in the 1960s.  It discusses the
physics of cesium ionization and should be of interest

πθ°μΩω±√·Γλ
WB0KVV
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Re: [time-nuts] Line Frequeny Stablity

[Bob Bownes]

In college we had a Vax 11/730 that would freak out and reboot the same time 
every day. Turns out the culprit was the sync pulses put on the AC for 
synchronizing the classroom clocks...But it took DEC a few weeks to find the 
culprit. 

> On Apr 5, 2017, at 17:12, Bob kb8tq  wrote:
> 
> Hi
> 
> Back in high school, one of the radio club members figured out that the 
> “clock adjustment” took place 
> locally between 4:30 and 5:00 PM. Needless to say, pretty much everybody 
> spent the next week listening 
> to WWV and watching the clock’s second hand go out of sync with the beeps. 
> This was back in the  late 1960’s 
> and the idea of a grid was a bit looser than it is today. Indeed it was post 
> 1964 so there *were* grids big 
> enough to take out the whole north east section of the US. Since we were very 
> much in that area the 
> topic of grid sync came up. Nobody ever really had a good answer to that 
> question. That included the 
> guys who ran the local power company. 
> 
> Bob
> 
>> On Apr 5, 2017, at 3:05 PM, Hal Murray  wrote:
>> 
>> 
>> preilley_...@comcast.net said:
>>> When I installed power plants in the 1970's they has a special "clock"  that
>>> showed the cumulative error in terms of clock time.
>> 
>> How big were the grids back then?
>> 
>> What was the typical range of error over a day or month?
>> 
>> 
>>> If the generator ran a little too fast the clock would move forward.As
>>> the operator observed the clock moving away from zero he would reduce the
>>> plant's  power and the clock would move backward toward zero.  ...
>> 
>> Does that operator control a single generator or a whole grid?
>> 
>> Does having a human in the loop help the control loop stability?
>> 
>> 
>> 
>> -- 
>> These are my opinions.  I hate spam.
>> 
>> 
>> 
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
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>> and follow the instructions there.
> 
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Re: [time-nuts] The ultraAtomic clock for home

[paul swed]

Yes its quite common. The clocks are always off by sometime and generally
never account for winter and summer time. Lastly ooops the ole batteries
dead or corroded.
In Broadcast facilities all of the clocks are actually driven by
synchronized time codes. Either LTC or IRIG. The clocks can be either
analog or digital.
Being a time nut numbers of my clocks run on LTC and I have used IRIG.
Silly. I know.

But what I can say is as mentioned the new ultraclocks should be very very
good over the troublesome AM units.
I used the CME8000 chip for quite some time supporting some testing.
Essentially logging when it did or didn't obtain complete sentances. Boy
did it work.
Regards
Paul
WB8TSL

On Wed, Apr 5, 2017 at 3:01 PM, Hal Murray  wrote:

>
> kb...@n1k.org said:
> > UTC I understand. I’ve used that feature on “atomic” clocks in the past.
> > I’m still a bit unclear on how many people will set up a wall of clocks
> > running on a dozen or so time zones. Obviously the people making clocks
> are
> > very much in favor of doing that :)
>
> I think it's common for companies/groups with offices in several countries
> to
> have a cluster of clocks showing the time in each office.
>
> 24 hour clocks would work better.  I think you have to correct for DST
> changes manually.
>
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
>
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Re: [time-nuts] Line Frequeny Stablity

[Bob kb8tq]

Hi

Back in high school, one of the radio club members figured out that the “clock 
adjustment” took place 
locally between 4:30 and 5:00 PM. Needless to say, pretty much everybody spent 
the next week listening 
to WWV and watching the clock’s second hand go out of sync with the beeps. This 
was back in the  late 1960’s 
and the idea of a grid was a bit looser than it is today. Indeed it was post 
1964 so there *were* grids big 
enough to take out the whole north east section of the US. Since we were very 
much in that area the 
topic of grid sync came up. Nobody ever really had a good answer to that 
question. That included the 
guys who ran the local power company. 

Bob

> On Apr 5, 2017, at 3:05 PM, Hal Murray  wrote:
> 
> 
> preilley_...@comcast.net said:
>> When I installed power plants in the 1970's they has a special "clock"  that
>> showed the cumulative error in terms of clock time.
> 
> How big were the grids back then?
> 
> What was the typical range of error over a day or month?
> 
> 
>> If the generator ran a little too fast the clock would move forward.As
>> the operator observed the clock moving away from zero he would reduce the
>> plant's  power and the clock would move backward toward zero.  ...
> 
> Does that operator control a single generator or a whole grid?
> 
> Does having a human in the loop help the control loop stability?
> 
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> ___
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Re: [time-nuts] The ultraAtomic clock for home

[Richard (Rick) Karlquist]

In the office where I work, they have 5 clocks on the wall
showing local time here at HQ and at 4 other company sites.  It
is embarrassing that the clocks are always a few minutes
off from each other.  I can see where these would make sense.

Rick N6RK



On 4/5/2017 4:30 AM, Bob kb8tq wrote:

HI

UTC I understand. I’ve used that feature on “atomic” clocks in the past.
I’m still a bit unclear on how many people will set up a wall of clocks running
on a dozen or so time zones. Obviously the people making clocks are
very much in favor of doing that :)

Bob


On Apr 4, 2017, at 7:56 PM, Richard (Rick) Karlquist  
wrote:



On 4/4/2017 3:19 PM, Bob kb8tq wrote:

Hi

Based on their web site, the model you saw is the one and only version that
does the new modulation. One very useful feature is the ability to set it to
any time zone world wide. I guess I missed the note on the WWVB coverage
area expanding to cover the entire planet …..:)

Bob



This feature is mainly so you can set the time zone for GMT/UTC.
Hopefully, there is a way to turn off daylight savings time as well.
Many previous atomic clocks covered only the time zones near Boulder
and could not display UTC.

Rick N6RK
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Re: [time-nuts] The ultraAtomic clock for home

[Hal Murray]

kb...@n1k.org said:
> UTC I understand. I’ve used that feature on “atomic” clocks in the past.
> I’m still a bit unclear on how many people will set up a wall of clocks
> running on a dozen or so time zones. Obviously the people making clocks are
> very much in favor of doing that :) 

I think it's common for companies/groups with offices in several countries to 
have a cluster of clocks showing the time in each office.

24 hour clocks would work better.  I think you have to correct for DST 
changes manually.



-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] The ultraAtomic clock for home

[Bob kb8tq]

Hi

> On Apr 5, 2017, at 9:00 AM, Jim Harman  wrote:
> 
> On Wed, Apr 5, 2017 at 7:30 AM, Bob kb8tq  wrote:
> 
>> I’m still a bit unclear on how many people will set up a wall of clocks
>> running
>> on a dozen or so time zones. Obviously the people making clocks are
>> very much in favor of doing that
>> 
> 
> It's probably for flashy newsrooms, where they like to have clocks with the
> time in London, Moscow, Tokyo, etc. It's nice to have all the second hands
> jumping simultaneously!
> 
> The challenge there is to keep the clocks correct for summer time, which
> changes on different dates in Europe and of course in the other direction
> in the Southern Hemisphere.

I’m *sure* :) that the embedded information in the chip takes care of all that 
stuff
correctly …. 

On a side note, my Citizen WWVB watch missed the change to DST this year. 
I still had it set to European time and it was not able to figure out which 
system
to update to. I suppose it also may have been looking for DCF77 rather than 
WWVB.

Multiple time zone stuff is *not* simple.

Bob


> 
> 
> -- 
> 
> --Jim Harman
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Re: [time-nuts] The ultraAtomic clock for home

[Bob kb8tq]

Hi

The Lacrosse wall clocks I’m using now are hybrid analog / digital displays. 
You get the time analog and the date off the digital display. For whatever 
reason, that model is now history. 

Bob

> On Apr 5, 2017, at 11:30 AM, Richard (Rick) Karlquist  
> wrote:
> 
> Why? oh why? is this only available as an analog clock??
> I am wondering if Lacrosse only has the rights to an analog
> version and that a higher priced digital version will
> show up in some "professional" line from another vendor.
> This is at least a plausible theory because this is
> a well known business model:  "incremental" revenue
> that doesn't "cannibalize" the cash cow.  At least
> this is/was popular with HP/Agilent/Keysight management
> where I work(ed).
> 
> Rick N6RK
> 
> 
> On 4/4/2017 8:00 PM, paul swed wrote:
>> Really can't say that its c-max or not. Since if you try to download
>> anything from the sight the links are dead. But I do believe its the true
>> wwvb bpsk decoder. If it is the cme 8000 that chip works impressively well
>> even in New England.
>> But this is the first time I have stumbled across anything that used it if
>> I am guessing correctly. Heck I seem to remember it was supposed to be out
>> some 2-3 years ago around Christmas.
>> Regards
>> Paul
>> WB8TSL
>> 
>> On Tue, Apr 4, 2017 at 9:04 PM, Tim Shoppa  wrote:
>> 
>>> I have been happy with the Casio Waveceptor watches. They can display UTC.
>>> 
>>> They seem to reliably set themselves between midnight and 3AM each morning
>>> when I'm wearing them here in Maryland, more reliably than the (non-PSK)
>>> WWVB wall clocks.
>>> 
>>> The Casio WV58A-1AVCR is a plastic LCD watch for $28 that lasts a couple
>>> years. The face scuffs easily and the band only lasts a little more than a
>>> year before needing replacement.
>>> 
>>> I upgraded to the Metal-body-metal-band Casio WVA-M640D-1ACR almost a year
>>> ago and am very happy. Analog display for local time, and the LCD display
>>> can show UTC. About $90.
>>> 
>>> Tim N3QE
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Re: [time-nuts] Line Frequeny Stablity

[jimlux]

On 4/5/17 11:13 AM, Bill Hawkins wrote:

The rotary generators in a system of connected generators are
synchronous
machines. There is no frequency difference between them, only phase
angle,
and not much of that - if the system is stable.




Yes.. basically a bunch of coupled oscillators, and unlike the cool 
demos with a bunch of metronomes on a table that self sync, the coupling 
factors among oscillators are not all the same, and the damping of each 
oscillator is different.


Managed historically by people turning a knob and relying on the large 
mass (both literally and figuratively) keeping it from going awry.
If you mess up too much, you get a trip and your generator is offline, 
suddenly, with no load.


Long transmission lines (1000s of km) cause real problems because they 
have time delay that is a significant fraction of a cycle.
So now you have coupled oscillators connected by a transmission line 
(with the characteristics of that transmission line time varying, to a 
certain extent).


Computerized Dispatch (which is what the process of coordinating the 
generation and load is) has been around since the 1960s, but it's not 
perfect.



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Re: [time-nuts] Line Frequeny Stablity

[Hal Murray]

preilley_...@comcast.net said:
> When I installed power plants in the 1970's they has a special "clock"  that
> showed the cumulative error in terms of clock time.

How big were the grids back then?

What was the typical range of error over a day or month?


> If the generator ran a little too fast the clock would move forward.As
> the operator observed the clock moving away from zero he would reduce the
> plant's  power and the clock would move backward toward zero.  ...

Does that operator control a single generator or a whole grid?

Does having a human in the loop help the control loop stability?



-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] Spirent STR4500 GPS simulator

[Bob kb8tq]

Hi




> On Apr 5, 2017, at 1:36 PM, Magnus Danielson  
> wrote:
> 
> Hi Phil,
> 
> I just wanted to chime in an make a note that the STR4500 seems to have USB 
> connection rather than serial. The manual mentions installing a driver. I 
> wonder if the USB port is nothing but a glorified serial port.
> When you hook it up, what does your computer report? You should be able to 
> get some info that way. If so, finding the 4100 manual that Bob mentioined 
> was not too hard, and banging away on those commands where not too complex by 
> the looks of it.
> 
> Tempted.
> 
> Cheers,
> Magnus

That would be yet another layer of problem. The Spirent guys used custom USB 
drivers for their devices. At least that is true for the boxes I have seen. 
They stopped issuing drivers for the 6100 with XP. I have no idea when they 
dropped drivers for the 4500. It’s a pretty good bet that you will need one ….

Bob


> 
> On 04/05/2017 03:46 PM, paul swed wrote:
>> Phil
>> Welcome to the group.
>> Funny you mention the Spirent. I see many available for semi reasonable
>> pricing though for Ham/Time-nuts a bit pricey still at $295 for a tinkerer.
>> And they do not come with the disk.
>> But as was pointed out to me by a fellow time-nut you don't need it. You
>> can directly control the unit by rs232 through quite simple commands. Use a
>> USB to RS232 converter if you do not have a real port.
>> You can create batch files of the comands on and on. I had downloaded the
>> manual to look at.
>> However I will not be buying a unit for quite a long time. Would need to be
>> sub $100 for me at least.
>> Good luck and have fun.
>> Regards
>> Paul
>> WB8TSL
>> 
>> On Wed, Apr 5, 2017 at 6:24 AM, Phil Parsons 
>> wrote:
>> 
>>> This is my first post after lurking for quite a while reading & trying to
>>> get to grips with the technology. I just purchased a Spirent STR4500 GPS
>>> simulator  along with a pile of other kit. Unfortunately the CD was missing
>>> (no great surprise) & Spirent are not interested in selling me a
>>> replacement disk. So, can anyone help me with software for this or should I
>>> accept it is  a door stop & get rid? My plan was to use this to get
>>> consistent signals to test a few GPSDOs I have acquired. Any advice
>>> gratefully received.
>>> 
>>> Phil
>>> ___
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>>> mailman/listinfo/time-nuts
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Re: [time-nuts] Sinlge ADC multi-band receiver

[Magnus Danielson]

Hi,

There are many things to be done before attempting the full E5 approach 
anyway, so I would not have make it a make or break for a first design.


Cheers,
Magnus

On 04/05/2017 02:27 PM, Bob kb8tq wrote:

Hi

Galileo E5 is a bit of a strange case. It’s really E5a and E5b. You can either 
grab it all as one
giant signal or as two separate signals. You may (or may not) care about the 
data on E5a or
b depending on what you are trying to do. Getting the entire very wide signal 
likely has some
interesting benefits when it comes to working out very small differences in 
location or … errr…
time.

One way to do the E5 signal would be a dual (duplicate) IF ISB downconverter. 
How practical that turns out
to be is an open question. The more conventional approach is to take a 
monstrous chunk of
L band down to a high speed sampler.

Bob


On Apr 5, 2017, at 4:37 AM, Magnus Danielson  wrote:



On 04/05/2017 01:21 AM, Attila Kinali wrote:

On Tue, 4 Apr 2017 06:55:24 -0700
jimlux  wrote:



So those folks were trying to use 1 ADC for all three bands, so they had
to choose a sampling rate that lets them separate the signals later in
software.

But that ADC is a MAX104 - a 1GSPS, 8 bit converter - that draws 5 Watts!!!

I'm not sure that's a good trade against a 1 or 2 bit converter for each
band, in terms of the downstream data rate and processing.


Honestly, I don't think the direct sampling approach is a good idea.
It folds a lot of noise into the signal band. I'd rather use a single
heterodyne with an LO frequncy of around 1000MHz, or something between
L2 and E5, such that the bands stay still seperated. Here I would add
a filterbank to get rid of as much noise as possible. And after that
use an ADC sampling frequency to fold the signals down again.
(Effectively forming a super-heterodyne receiver)


Regardless you already have SAW filters on the LNA to provide selectivity.

Also, you don't really need to keep the bands fully separate in their 
mixed-down form, since they do not correlate except for the P(Y), but keeping 
enough frequency difference, such that doppler shift does not remove 
correlation margin, they remain uncorrelated. Some of the literature pay much 
attention to the band not wrapping around the band-edge, but I'm not convinced 
it is such a big issue.

A direct sampler of 100 MHz would work well for GPS for instance, but not for 
GLONASS, but 90 MHz would work there. The S/H would need to have the BW of the 
top frequency, but then the S/H action will act as the first mixer.


The advantage of such a system would be that there is only a single
path through the system for all signals, especially through the filters.
Thus the variability of the differential phase shift between the
frequency bands would be significantly reduced, which would result
in better stability. Of course, that's the theory. Whether things work
out this way in reality is a different question. What can be said for
sure is, because of the high IF frequency of >200MHz, the standard tuner
chips cannot be used anymore and the RX chain has to be build from
"discrete" components, which increases the BOM cost quite considerably.


Since you don't really need to keep signals very separated, you can pack them 
relatively tight. It's the E5 of GALILEO which is wide.

Using a 1,4 GHz range LO1 to pick L1 and L2 has been known to be used before. 
There is even existing chips which uses 1.4 GHz on LO1, which with a different 
set of filters could almost support L2, will have to check the details. While 
that front-end would be neat, I would not use that chip since it is no longer 
in production.

The fun thing about these types of receivers, is that there is so many ways to do it, 
that it allows for many different approaches to be tried as technology develops. There is 
no single one "right" way of doing it.

Cheers,
Magnus
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Re: [time-nuts] Line Frequeny Stablity

[Bill Hawkins]

The rotary generators in a system of connected generators are
synchronous
machines. There is no frequency difference between them, only phase
angle,
and not much of that - if the system is stable.

The ocean liner analogy is correct, as there is only one captain
directing
the ship's course. If each plant set its own power levels it would be
very
difficult to maintain stability, due to the springiness of long
transmission
lines.

A set of connected generators is controlled by regional dispatchers, who
tell their plants how much power to generate in order for the day to
average
out to 60.000 cycles per second. They count cycles instead of measuring
the
frequency. You can count cycles with a synchronous clock.

This becomes less tidy when DC tie lines are used, because inverters
have
to be adjusted to get the correct power flow.

Hope I got most of that right.

Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter
Reilley
Sent: Wednesday, April 05, 2017 7:42 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Line Frequeny Stablity

Think of it as an ocean liner trying to keep a dead straight course to
it's destination.
It weighs many tons and wind and waves may drive it off it's path but
the captain
can correct for this.   It eventually arrives at it's destination and is

only a few feet
from the dock.

The total rotating mass of all the generators in a network is many times
the mass of an
ocean liner.   The operators do their best to keep them running at the 
correct frequency.
Unexpected load changes can cause some divergence, but over time the
average is dead on.

When I installed power plants in the 1970's they has a special "clock" 
that showed the
cumulative error in terms of clock time.   The clock had two inputs, one

from the utility
power and the other from some reference, possibly WWV.   Normally the 
"clock" was
pointing up at zero and not moving.

If the generator ran a little too fast the clock would move forward.   
As the operator
observed the clock moving away from zero he would reduce the plant's
power and the
clock would move backward toward zero.   His goal was to keep the clock 
at zero and
not moving.   Thus, your bedside clock was always on time even if there 
were temporary
excursions fast or slow.

Pete.


On 4/4/2017 5:28 PM, Thomas D. Erb wrote:
> Thanks for the info.
>
>
> So that tells me how data is recorded - but not how the frequency is
kept stable ?
>
> Is the line frequency now directly tied to GPS clock - with no drift ?
>
> Thomas D. Erb
> t...@electrictime.com / Electric Time 
> Company, Inc.
> Office: 508-359-4396 x 117 / Fax: 508-359-4482
> 97 West Street Medfield, MA 02052 USA

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Re: [time-nuts] Spirent STR4500 GPS simulator

[Magnus Danielson]

Hi Phil,

I just wanted to chime in an make a note that the STR4500 seems to have 
USB connection rather than serial. The manual mentions installing a 
driver. I wonder if the USB port is nothing but a glorified serial port.
When you hook it up, what does your computer report? You should be able 
to get some info that way. If so, finding the 4100 manual that Bob 
mentioined was not too hard, and banging away on those commands where 
not too complex by the looks of it.


Tempted.

Cheers,
Magnus

On 04/05/2017 03:46 PM, paul swed wrote:

Phil
Welcome to the group.
Funny you mention the Spirent. I see many available for semi reasonable
pricing though for Ham/Time-nuts a bit pricey still at $295 for a tinkerer.
And they do not come with the disk.
But as was pointed out to me by a fellow time-nut you don't need it. You
can directly control the unit by rs232 through quite simple commands. Use a
USB to RS232 converter if you do not have a real port.
You can create batch files of the comands on and on. I had downloaded the
manual to look at.
However I will not be buying a unit for quite a long time. Would need to be
sub $100 for me at least.
Good luck and have fun.
Regards
Paul
WB8TSL

On Wed, Apr 5, 2017 at 6:24 AM, Phil Parsons 
wrote:


This is my first post after lurking for quite a while reading & trying to
get to grips with the technology. I just purchased a Spirent STR4500 GPS
simulator  along with a pile of other kit. Unfortunately the CD was missing
(no great surprise) & Spirent are not interested in selling me a
replacement disk. So, can anyone help me with software for this or should I
accept it is  a door stop & get rid? My plan was to use this to get
consistent signals to test a few GPSDOs I have acquired. Any advice
gratefully received.

Phil
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Re: [time-nuts] TAPR TICC boxed (input protection)

[David]

On Wed, 5 Apr 2017 02:40:13 -0400, you wrote:

>David wrote:
>
>> So collector-base junctions make good low leakage high voltage diodes
>> although they are slow
>
>I guess it depends on what one means by "slow" and "fast."

I was referring to within the same transistor; emitter-base junctions
are much faster than collector-base junctions.

>The B-C junction of an MPSH10/MMBTH10 or 2N/PN/MMBT5179 switches on in 
><1nS and off in <2nS, which is comparable with Schottky microwave mixer 
>diodes such as the Agilent HSMS282x series and better than "ultra-fast" 
>silicon switching diodes such as the FD700 and 1S1585.  (I did my 
>switching tests at 20mA.)  (Note that the silicon and Schottky switching 
>diodes have reverse leakage currents from several hundred to tens of 
>thousands of times higher than the B-C junction of an MPSH10/MMBTH10.)

I have never actually tried this with RF transistors.  I know one
thing to watch out for if you are looking for low leakage is gold
doping and some less that reputable manufacturers "cheat" in this
respect so transistors used as low leakage diodes should be at least
qualified by manufacturer which is a problem with counterfeits and
unscrupulous purchasing managers.

Out of curiosity, and I tried to look this up years ago, what doping
is used for PNP RF transistors and saturated switches if it is not
gold?  Does it also increase leakage?

And I have another question if you know.  How is rb'Cc measured?
Tektronix at some point was grading 2N3906s for rb'Cc < 50ps.

>The gate junction of a 2N/PN/MMBF4117A JFET switches on in <2nS and off 
>in <4nS.
>
>> The cheapest guaranteed low leakage diode is probably some variety of
>> 4117/4118/4119 n-channel JFET.
>
>If the 5pA reverse leakage current of the MPSH10/MMBTH10 is too much and 
>one must, must, must get leakage down to 1pA, the 2N/PN/MMBF4117A is the 
>best inexpensive choice that I'm aware of.

The advantage of the 4117/4118/4119 is that the leakage is already
tested to a given specification so no qualification or testing is
necessary.
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[time-nuts] Line Frequeny Stablity

[Thomas D. Erb]

I actually have a 1930's unit in my clock collection - and in the 1980's we 
used to make an AC power clock in a panel next to a quartz clock for small 
island frequency control.

This is a link to my master clock
http://electricclock.omeka.net/items/show/6

I'm just wondering how is it set now ?





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Re: [time-nuts] Line Frequeny Stablity

[Scott Stobbe]

I would guess the tightest control loop is on the generator stator field
windings, with mechanical control being secondary. Definitely a lot of
poles and zeros to worry about.

On Wed, Apr 5, 2017 at 9:01 AM, jimlux  wrote:

> On 4/4/17 2:28 PM, Thomas D. Erb wrote:
>
>> Thanks for the info.
>>
>>
>> So that tells me how data is recorded - but not how the frequency is kept
>> stable ?
>>
>> Is the line frequency now directly tied to GPS clock - with no drift ?
>>
>
> The line frequency is adjusted, for the most part, by adjusting the prime
> power (steam valves, dam penstocks, etc.) on the generators at power
> stations. That changes the speed, slightly, although as generator 1 of N
> starts to get ahead, the electrical load increases, and it slows down.
>
> It's actually a pretty complex system, since there are a whole raft of
> "spring constants" in between the multiple generators in a system, there's
> phase shifts due to transmission line inductance and capacitance.
>
> "Stabilizing" a system in the face of changing demand is a non-trivial
> task.
>
>
>
>
>
>
>
>> Thomas D. Erb
>> t...@electrictime.com /
>> Electric Time Company, Inc.
>> Office: 508-359-4396 x 117 / Fax: 508-359-4482
>> 97 West Street Medfield, MA 02052 USA
>> www.electrictime.com
>> [Facebook]> Company-Inc/127918073950854?ref=hl>[Twitter]> twitter.com/tower_clocks>[pinterest]> pinterest.com/electrictime/>
>> [htmlsig.com]
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Re: [time-nuts] Line Frequeny Stablity

[David]

I have seen some proposals to require VAR capability in photoelectric
installations but how feasible is that?  I cannot imagine utility
customers being pleased with having to pay extra for such a nebulous
to them capability.

I could see the utility companies pushing it as a requirement in lieu
of installing banks of synchronous condensers.  Maybe this could be
integrated with net metering so that users get paid for providing VAR
correction and pay for VARs but I bet it would be politically
infeasible.

Thinking about the stability problems associated with distributed
generation gives me a headache.  I am inclined to believe that any
solution which relies on central management or timing is an invitation
to major failure.

On Wed, 5 Apr 2017 09:52:32 +0200, you wrote:

>...
>
>Until recently, photoelectric would not provide any of the rotating iron 
>properties, but the increase popularity of it now requires it to start 
>to have such properties for the stability of the system.
>
>Cheers,
>Magnus
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Re: [time-nuts] Line Frequeny Stablity

[Peter Reilley]

The response time in a large plant is very slow.   Large steam plants 
running at steady
state are running with their steam valves wide open.   A partially 
closed valve is an energy

loss and is only used when changes occur.

The power control for a plant running at a steady load is the amount of 
fuel thrown into
the boiler.   When you want more power you shoot more gas, oil, or coal 
into the boiler.
For a nuke you pull the control rods.   Behind all of this is a lot of 
thermal mass.   Things

don't change quickly.

Pete.

On 4/5/2017 9:01 AM, jimlux wrote:

On 4/4/17 2:28 PM, Thomas D. Erb wrote:

Thanks for the info.


So that tells me how data is recorded - but not how the frequency is 
kept stable ?


Is the line frequency now directly tied to GPS clock - with no drift ?


The line frequency is adjusted, for the most part, by adjusting the 
prime power (steam valves, dam penstocks, etc.) on the generators at 
power stations. That changes the speed, slightly, although as 
generator 1 of N starts to get ahead, the electrical load increases, 
and it slows down.


It's actually a pretty complex system, since there are a whole raft of 
"spring constants" in between the multiple generators in a system, 
there's phase shifts due to transmission line inductance and capacitance.


"Stabilizing" a system in the face of changing demand is a non-trivial 
task.








Thomas D. Erb
t...@electrictime.com /
Electric Time Company, Inc.
Office: 508-359-4396 x 117 / Fax: 508-359-4482
97 West Street Medfield, MA 02052 USA
www.electrictime.com
[Facebook][Twitter][pinterest] 


[htmlsig.com]
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Re: [time-nuts] Spirent STR4500 GPS simulator

[Bob kb8tq]

Hi

Just to clarify a bit:

These gizmos fall into two broad categories:

1) The single sat simulators like the GSS6100 that show up cheap.

2) The full constellation simulators that show up for a bit more money.

The single sat stuff is simple to run from a serial port and limited in 
function. They are
quite useful for checking things like GPS week rollover or sensitivity. They 
will often 
run in a fully autonomous mode ( = boots to full function) if desired. The 
target audience 
is / was production testing. 

The full constellation gear is a bit more complex. At least the boxes I have 
seen require
a computer with the proper “dongle key” to do much of anything. They will let 
you set up
all sorts of cool navigation processes. How long they will run those setups and 
with how
many satellites involved is a “that depends” sort of thing. 

Within both categories you have the inevitable “how many systems?” question. 
Early stuff
is generally GPS / SBAS only. Later stuff has various options to let you 
customize the 
systems it will simulate. In some cases it’s a pick them one at a time, pay for 
each sort of thing.
On other boxes it’s a “here they all are” license. Working out from the cryptic 
numbers 
on the typical box which options it is / was licensed for can be nearly 
impossible. 

Even with a support contract, getting info from the various outfits that make 
some of these
devices is a major hassle. Getting information without a support contract is 
even worse. 
It is not specific to one vendor. They all seem to be focused on selling you 
the latest and 
greatest rather than upgrading the box they sold you a couple of years ago. 
None of them
seem to be at all excited about supporting the surplus market. 

Before we all go off on a bender about lack of support, consider how small this 
market 
is and how fast stuff changes. The GSS6100 was brand new 10 years ago. Now it 
is 
past end of life. It was replaced roughly 5 years ago. Other vendors have 
similar 
cycles. There are industries out there that would consider 10 years to be a 
*really* long
support period ….

The big advantage to us of this process is that the value (to a real customer) 
of these boxes
goes to zero very quickly. When that happens, we get to buy them dirt cheap on 
the 
secondary market Rather than paying $4,000, they go for $200. The odds of 
getting 
a fully functional device are quite high even at the $200 level. 

Lots of fun.

Bob  

> On Apr 5, 2017, at 9:46 AM, paul swed  wrote:
> 
> Phil
> Welcome to the group.
> Funny you mention the Spirent. I see many available for semi reasonable
> pricing though for Ham/Time-nuts a bit pricey still at $295 for a tinkerer.
> And they do not come with the disk.
> But as was pointed out to me by a fellow time-nut you don't need it. You
> can directly control the unit by rs232 through quite simple commands. Use a
> USB to RS232 converter if you do not have a real port.
> You can create batch files of the comands on and on. I had downloaded the
> manual to look at.
> However I will not be buying a unit for quite a long time. Would need to be
> sub $100 for me at least.
> Good luck and have fun.
> Regards
> Paul
> WB8TSL
> 
> On Wed, Apr 5, 2017 at 6:24 AM, Phil Parsons 
> wrote:
> 
>> This is my first post after lurking for quite a while reading & trying to
>> get to grips with the technology. I just purchased a Spirent STR4500 GPS
>> simulator  along with a pile of other kit. Unfortunately the CD was missing
>> (no great surprise) & Spirent are not interested in selling me a
>> replacement disk. So, can anyone help me with software for this or should I
>> accept it is  a door stop & get rid? My plan was to use this to get
>> consistent signals to test a few GPSDOs I have acquired. Any advice
>> gratefully received.
>> 
>> Phil
>> ___
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>> mailman/listinfo/time-nuts
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Re: [time-nuts] The ultraAtomic clock for home

[Jim Harman]

On Wed, Apr 5, 2017 at 7:30 AM, Bob kb8tq  wrote:

> I’m still a bit unclear on how many people will set up a wall of clocks
> running
> on a dozen or so time zones. Obviously the people making clocks are
> very much in favor of doing that
>

It's probably for flashy newsrooms, where they like to have clocks with the
time in London, Moscow, Tokyo, etc. It's nice to have all the second hands
jumping simultaneously!

The challenge there is to keep the clocks correct for summer time, which
changes on different dates in Europe and of course in the other direction
in the Southern Hemisphere.


-- 

--Jim Harman
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Re: [time-nuts] The ultraAtomic clock for home

[Richard (Rick) Karlquist]

Why? oh why? is this only available as an analog clock??
I am wondering if Lacrosse only has the rights to an analog
version and that a higher priced digital version will
show up in some "professional" line from another vendor.
This is at least a plausible theory because this is
a well known business model:  "incremental" revenue
that doesn't "cannibalize" the cash cow.  At least
this is/was popular with HP/Agilent/Keysight management
where I work(ed).

Rick N6RK


On 4/4/2017 8:00 PM, paul swed wrote:

Really can't say that its c-max or not. Since if you try to download
anything from the sight the links are dead. But I do believe its the true
wwvb bpsk decoder. If it is the cme 8000 that chip works impressively well
even in New England.
But this is the first time I have stumbled across anything that used it if
I am guessing correctly. Heck I seem to remember it was supposed to be out
some 2-3 years ago around Christmas.
Regards
Paul
WB8TSL

On Tue, Apr 4, 2017 at 9:04 PM, Tim Shoppa  wrote:


I have been happy with the Casio Waveceptor watches. They can display UTC.

They seem to reliably set themselves between midnight and 3AM each morning
when I'm wearing them here in Maryland, more reliably than the (non-PSK)
WWVB wall clocks.

The Casio WV58A-1AVCR is a plastic LCD watch for $28 that lasts a couple
years. The face scuffs easily and the band only lasts a little more than a
year before needing replacement.

I upgraded to the Metal-body-metal-band Casio WVA-M640D-1ACR almost a year
ago and am very happy. Analog display for local time, and the LCD display
can show UTC. About $90.

Tim N3QE
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Re: [time-nuts] The ultraAtomic clock for home

[paul swed]

Will say that is pretty interesting that it takes either 2 or 4 c cells. It
appears they parallel the C cells for more time. In eco mode 2 batteries 3
years or 4 batteries 6 years. Run time will vary depending on the batteries
leaking in 3.5 years. At least it seems that way today. (Not to trigger a
left turn in the discussion)
All in all looks like a nice arrangement.
Regards
Paul
WB8TSL

On Wed, Apr 5, 2017 at 7:30 AM, Bob kb8tq  wrote:

> HI
>
> UTC I understand. I’ve used that feature on “atomic” clocks in the past.
> I’m still a bit unclear on how many people will set up a wall of clocks
> running
> on a dozen or so time zones. Obviously the people making clocks are
> very much in favor of doing that :)
>
> Bob
>
> > On Apr 4, 2017, at 7:56 PM, Richard (Rick) Karlquist <
> rich...@karlquist.com> wrote:
> >
> >
> >
> > On 4/4/2017 3:19 PM, Bob kb8tq wrote:
> >> Hi
> >>
> >> Based on their web site, the model you saw is the one and only version
> that
> >> does the new modulation. One very useful feature is the ability to set
> it to
> >> any time zone world wide. I guess I missed the note on the WWVB coverage
> >> area expanding to cover the entire planet …..:)
> >>
> >> Bob
> >>
> >
> > This feature is mainly so you can set the time zone for GMT/UTC.
> > Hopefully, there is a way to turn off daylight savings time as well.
> > Many previous atomic clocks covered only the time zones near Boulder
> > and could not display UTC.
> >
> > Rick N6RK
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Re: [time-nuts] Line Frequeny Stablity

[jimlux]

On 4/4/17 2:28 PM, Thomas D. Erb wrote:

Thanks for the info.


So that tells me how data is recorded - but not how the frequency is kept 
stable ?

Is the line frequency now directly tied to GPS clock - with no drift ?


The line frequency is adjusted, for the most part, by adjusting the 
prime power (steam valves, dam penstocks, etc.) on the generators at 
power stations. That changes the speed, slightly, although as generator 
1 of N starts to get ahead, the electrical load increases, and it slows 
down.


It's actually a pretty complex system, since there are a whole raft of 
"spring constants" in between the multiple generators in a system, 
there's phase shifts due to transmission line inductance and capacitance.


"Stabilizing" a system in the face of changing demand is a non-trivial task.







Thomas D. Erb
t...@electrictime.com /
Electric Time Company, Inc.
Office: 508-359-4396 x 117 / Fax: 508-359-4482
97 West Street Medfield, MA 02052 USA
www.electrictime.com
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Re: [time-nuts] Spirent STR4500 GPS simulator

[paul swed]

Phil
Welcome to the group.
Funny you mention the Spirent. I see many available for semi reasonable
pricing though for Ham/Time-nuts a bit pricey still at $295 for a tinkerer.
And they do not come with the disk.
But as was pointed out to me by a fellow time-nut you don't need it. You
can directly control the unit by rs232 through quite simple commands. Use a
USB to RS232 converter if you do not have a real port.
You can create batch files of the comands on and on. I had downloaded the
manual to look at.
However I will not be buying a unit for quite a long time. Would need to be
sub $100 for me at least.
Good luck and have fun.
Regards
Paul
WB8TSL

On Wed, Apr 5, 2017 at 6:24 AM, Phil Parsons 
wrote:

> This is my first post after lurking for quite a while reading & trying to
> get to grips with the technology. I just purchased a Spirent STR4500 GPS
> simulator  along with a pile of other kit. Unfortunately the CD was missing
> (no great surprise) & Spirent are not interested in selling me a
> replacement disk. So, can anyone help me with software for this or should I
> accept it is  a door stop & get rid? My plan was to use this to get
> consistent signals to test a few GPSDOs I have acquired. Any advice
> gratefully received.
>
> Phil
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Re: [time-nuts] Spirent STR4500 GPS simulator

[Bob kb8tq]

Hi

To the extent that the device runs like a 4100 or a 6100, it does not need any 
software to support it. The same may be true of the 6300. They all run from a 
drop dead simple serial command set. On the 6100 you fire up a terminal program 
at 38.4 K baud 8N1 and type away. All of the features of the 4100 and 6100 can 
be utilized this way.  The super duper XP only software is a joke with these 
boxes. 

On the boxes that *do* need software to run them, the stuff is node locked. You 
don’t just need the software, you also need a license key dongle(?). For boxes 
that are inside the support window (6300 or later) that’s roughly a $1K sort of 
expense. Exact cost is something I never dug into. I simply passed on the idea 
of one of the fancy modern boxes. 

Spirent has indeed dropped all support of anything earlier than the 6300. The 
only exception appears to be for people who have agreements in place on 
specific boxes that pre-date the 6300. It is unclear how much of an extension 
that gives people. It’s a topic right now on the 6100 since normal support 
stopped at the end of 2016. Since the 4500 is still being sold, I suspect you 
can get a support agreement on it. I would *guess* the software would be 
available under support …. maybe not ….

Bob




> On Apr 5, 2017, at 6:24 AM, Phil Parsons  wrote:
> 
> This is my first post after lurking for quite a while reading & trying to get 
> to grips with the technology. I just purchased a Spirent STR4500 GPS 
> simulator  along with a pile of other kit. Unfortunately the CD was missing 
> (no great surprise) & Spirent are not interested in selling me a replacement 
> disk. So, can anyone help me with software for this or should I accept it is  
> a door stop & get rid? My plan was to use this to get consistent signals to 
> test a few GPSDOs I have acquired. Any advice gratefully received.
> 
> Phil
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Re: [time-nuts] Line Frequeny Stablity

[Peter Reilley]

Think of it as an ocean liner trying to keep a dead straight course to 
it's destination.
It weighs many tons and wind and waves may drive it off it's path but 
the captain
can correct for this.   It eventually arrives at it's destination and is 
only a few feet

from the dock.

The total rotating mass of all the generators in a network is many times 
the mass of an
ocean liner.   The operators do their best to keep them running at the 
correct frequency.
Unexpected load changes can cause some divergence, but over time the 
average is

dead on.

When I installed power plants in the 1970's they has a special "clock" 
that showed the
cumulative error in terms of clock time.   The clock had two inputs, one 
from the utility
power and the other from some reference, possibly WWV.   Normally the 
"clock" was

pointing up at zero and not moving.

If the generator ran a little too fast the clock would move forward.   
As the operator
observed the clock moving away from zero he would reduce the plant's 
power and the
clock would move backward toward zero.   His goal was to keep the clock 
at zero and
not moving.   Thus, your bedside clock was always on time even if there 
were temporary

excursions fast or slow.

Pete.


On 4/4/2017 5:28 PM, Thomas D. Erb wrote:

Thanks for the info.


So that tells me how data is recorded - but not how the frequency is kept 
stable ?

Is the line frequency now directly tied to GPS clock - with no drift ?

Thomas D. Erb
t...@electrictime.com /
Electric Time Company, Inc.
Office: 508-359-4396 x 117 / Fax: 508-359-4482
97 West Street Medfield, MA 02052 USA
www.electrictime.com
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Re: [time-nuts] Sinlge ADC multi-band receiver

[Bob kb8tq]

Hi

Galileo E5 is a bit of a strange case. It’s really E5a and E5b. You can either 
grab it all as one
giant signal or as two separate signals. You may (or may not) care about the 
data on E5a or 
b depending on what you are trying to do. Getting the entire very wide signal 
likely has some 
interesting benefits when it comes to working out very small differences in 
location or … errr…
time. 

One way to do the E5 signal would be a dual (duplicate) IF ISB downconverter. 
How practical that turns out
to be is an open question. The more conventional approach is to take a 
monstrous chunk of
L band down to a high speed sampler. 

Bob

> On Apr 5, 2017, at 4:37 AM, Magnus Danielson  
> wrote:
> 
> 
> 
> On 04/05/2017 01:21 AM, Attila Kinali wrote:
>> On Tue, 4 Apr 2017 06:55:24 -0700
>> jimlux  wrote:
>> 
>> 
>>> So those folks were trying to use 1 ADC for all three bands, so they had
>>> to choose a sampling rate that lets them separate the signals later in
>>> software.
>>> 
>>> But that ADC is a MAX104 - a 1GSPS, 8 bit converter - that draws 5 Watts!!!
>>> 
>>> I'm not sure that's a good trade against a 1 or 2 bit converter for each
>>> band, in terms of the downstream data rate and processing.
>> 
>> Honestly, I don't think the direct sampling approach is a good idea.
>> It folds a lot of noise into the signal band. I'd rather use a single
>> heterodyne with an LO frequncy of around 1000MHz, or something between
>> L2 and E5, such that the bands stay still seperated. Here I would add
>> a filterbank to get rid of as much noise as possible. And after that
>> use an ADC sampling frequency to fold the signals down again.
>> (Effectively forming a super-heterodyne receiver)
> 
> Regardless you already have SAW filters on the LNA to provide selectivity.
> 
> Also, you don't really need to keep the bands fully separate in their 
> mixed-down form, since they do not correlate except for the P(Y), but keeping 
> enough frequency difference, such that doppler shift does not remove 
> correlation margin, they remain uncorrelated. Some of the literature pay much 
> attention to the band not wrapping around the band-edge, but I'm not 
> convinced it is such a big issue.
> 
> A direct sampler of 100 MHz would work well for GPS for instance, but not for 
> GLONASS, but 90 MHz would work there. The S/H would need to have the BW of 
> the top frequency, but then the S/H action will act as the first mixer.
> 
>> The advantage of such a system would be that there is only a single
>> path through the system for all signals, especially through the filters.
>> Thus the variability of the differential phase shift between the
>> frequency bands would be significantly reduced, which would result
>> in better stability. Of course, that's the theory. Whether things work
>> out this way in reality is a different question. What can be said for
>> sure is, because of the high IF frequency of >200MHz, the standard tuner
>> chips cannot be used anymore and the RX chain has to be build from
>> "discrete" components, which increases the BOM cost quite considerably.
> 
> Since you don't really need to keep signals very separated, you can pack them 
> relatively tight. It's the E5 of GALILEO which is wide.
> 
> Using a 1,4 GHz range LO1 to pick L1 and L2 has been known to be used before. 
> There is even existing chips which uses 1.4 GHz on LO1, which with a 
> different set of filters could almost support L2, will have to check the 
> details. While that front-end would be neat, I would not use that chip since 
> it is no longer in production.
> 
> The fun thing about these types of receivers, is that there is so many ways 
> to do it, that it allows for many different approaches to be tried as 
> technology develops. There is no single one "right" way of doing it.
> 
> Cheers,
> Magnus
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Re: [time-nuts] The ultraAtomic clock for home

[Bob kb8tq]

HI

UTC I understand. I’ve used that feature on “atomic” clocks in the past. 
I’m still a bit unclear on how many people will set up a wall of clocks running
on a dozen or so time zones. Obviously the people making clocks are
very much in favor of doing that :)

Bob

> On Apr 4, 2017, at 7:56 PM, Richard (Rick) Karlquist  
> wrote:
> 
> 
> 
> On 4/4/2017 3:19 PM, Bob kb8tq wrote:
>> Hi
>> 
>> Based on their web site, the model you saw is the one and only version that
>> does the new modulation. One very useful feature is the ability to set it to
>> any time zone world wide. I guess I missed the note on the WWVB coverage
>> area expanding to cover the entire planet …..:)
>> 
>> Bob
>> 
> 
> This feature is mainly so you can set the time zone for GMT/UTC.
> Hopefully, there is a way to turn off daylight savings time as well.
> Many previous atomic clocks covered only the time zones near Boulder
> and could not display UTC.
> 
> Rick N6RK
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[time-nuts] Spirent STR4500 GPS simulator

[Phil Parsons]

This is my first post after lurking for quite a while reading & trying to get 
to grips with the technology. I just purchased a Spirent STR4500 GPS simulator  
along with a pile of other kit. Unfortunately the CD was missing (no great 
surprise) & Spirent are not interested in selling me a replacement disk. So, 
can anyone help me with software for this or should I accept it is  a door stop 
& get rid? My plan was to use this to get consistent signals to test a few 
GPSDOs I have acquired. Any advice gratefully received.

Phil
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Re: [time-nuts] Sinlge ADC multi-band receiver

[Magnus Danielson]

On 04/05/2017 01:21 AM, Attila Kinali wrote:

On Tue, 4 Apr 2017 06:55:24 -0700
jimlux  wrote:



So those folks were trying to use 1 ADC for all three bands, so they had
to choose a sampling rate that lets them separate the signals later in
software.

But that ADC is a MAX104 - a 1GSPS, 8 bit converter - that draws 5 Watts!!!

I'm not sure that's a good trade against a 1 or 2 bit converter for each
band, in terms of the downstream data rate and processing.


Honestly, I don't think the direct sampling approach is a good idea.
It folds a lot of noise into the signal band. I'd rather use a single
heterodyne with an LO frequncy of around 1000MHz, or something between
L2 and E5, such that the bands stay still seperated. Here I would add
a filterbank to get rid of as much noise as possible. And after that
use an ADC sampling frequency to fold the signals down again.
(Effectively forming a super-heterodyne receiver)


Regardless you already have SAW filters on the LNA to provide selectivity.

Also, you don't really need to keep the bands fully separate in their 
mixed-down form, since they do not correlate except for the P(Y), but 
keeping enough frequency difference, such that doppler shift does not 
remove correlation margin, they remain uncorrelated. Some of the 
literature pay much attention to the band not wrapping around the 
band-edge, but I'm not convinced it is such a big issue.


A direct sampler of 100 MHz would work well for GPS for instance, but 
not for GLONASS, but 90 MHz would work there. The S/H would need to have 
the BW of the top frequency, but then the S/H action will act as the 
first mixer.



The advantage of such a system would be that there is only a single
path through the system for all signals, especially through the filters.
Thus the variability of the differential phase shift between the
frequency bands would be significantly reduced, which would result
in better stability. Of course, that's the theory. Whether things work
out this way in reality is a different question. What can be said for
sure is, because of the high IF frequency of >200MHz, the standard tuner
chips cannot be used anymore and the RX chain has to be build from
"discrete" components, which increases the BOM cost quite considerably.


Since you don't really need to keep signals very separated, you can pack 
them relatively tight. It's the E5 of GALILEO which is wide.


Using a 1,4 GHz range LO1 to pick L1 and L2 has been known to be used 
before. There is even existing chips which uses 1.4 GHz on LO1, which 
with a different set of filters could almost support L2, will have to 
check the details. While that front-end would be neat, I would not use 
that chip since it is no longer in production.


The fun thing about these types of receivers, is that there is so many 
ways to do it, that it allows for many different approaches to be tried 
as technology develops. There is no single one "right" way of doing it.


Cheers,
Magnus
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Re: [time-nuts] TAPR TICC boxed (input protection)

[Charles Steinmetz]

David wrote:


So collector-base junctions make good low leakage high voltage diodes
although they are slow


I guess it depends on what one means by "slow" and "fast."

The B-C junction of an MPSH10/MMBTH10 or 2N/PN/MMBT5179 switches on in 
<1nS and off in <2nS, which is comparable with Schottky microwave mixer 
diodes such as the Agilent HSMS282x series and better than "ultra-fast" 
silicon switching diodes such as the FD700 and 1S1585.  (I did my 
switching tests at 20mA.)  (Note that the silicon and Schottky switching 
diodes have reverse leakage currents from several hundred to tens of 
thousands of times higher than the B-C junction of an MPSH10/MMBTH10.)


The gate junction of a 2N/PN/MMBF4117A JFET switches on in <2nS and off 
in <4nS.



The cheapest guaranteed low leakage diode is probably some variety of
4117/4118/4119 n-channel JFET.


If the 5pA reverse leakage current of the MPSH10/MMBTH10 is too much and 
one must, must, must get leakage down to 1pA, the 2N/PN/MMBF4117A is the 
best inexpensive choice that I'm aware of.


Best regards,

Charles


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Re: [time-nuts] Line Frequeny Stablity

[Magnus Danielson]

Hi,

Ok, quick intro to the frequency steering.

There still remains rules that say that network frequency should be on 
average 60 Hz on the US grid. (Yes, there is proposals to remove it, but 
it is still effective.)


Since the generation (let's talk traditional here not to make things 
more complex than they need to be for the first overview) is from 
generators, essentially big rotating lumps of iron, the balance between 
load and generation causes the frequency change. If you have more load 
than generation, the frequency will lower while if you have more 
generation than load the frequency will go up. Essentially, if you 
undergenerate, you would need the rotating energy of the lumps of load 
to deliver, but that reduces their speed and if you underconsume the 
energy goes into the rotation of the lumps.


Now, by monitoring the frequency you can steer the balance, askning 
hydropower to increase or decrease production to balance the shift of 
load. The operators have a fair clue on how the day will proceed as 
people wake up, industry starts, workday, industry closes down, people 
get home etc, so there is a basic pattern there to give a clue, but they 
monitor it and balance it.


By also balance the phase, you can know how much you lag behind and 
needs to run up by running the frequency high. This require spending 
energy by increasing production compared to the load. Now, by being 
smart you do that when you have low load, so that you don't have to 
spend as much energy to achieve it, but never the less.


Then you have to manage your reactive energy, the VAr, which is a 
different matter.


Breakers have several form of catastrophic protections in them, among 
those if the frequency goes bad. Turns out that the frequency monitoring 
of breakers gives so diverse readings such that for post mortem 
analysis, they provide bogus values. They learned this the hard way 
after the North-Eastern Blackout. When they threw out all the 
traditional frequency readings, the PMU data that remained painted a 
consistent picture.


The detailed monitoring of PMU gives much more data, also illustrates 
forced oscillation, inter-area-oscillations etc. which makes the phase 
wobble in interesting ways, and when analyzed gives good clues about 
problems in the network.


An even more "fun" scenario is when the network runs into islanding, 
since the link between areas is to weak to keep the frequency at the 
same rate, i.e. the link is to weak to support the load, so one part has 
overload and goes down in frequency while the other have overproduction 
and gos high in frequency, which you can see by the way that phase 
starts to deviate between the networks, and that before you have the de 
facto islanding.


The islanding illustrates the need of the links to be strong enough so 
that generators synchronize, or should we say syntonize to be correct 
with terms, that is, they have the same rate.


The four islands that you identified do their own independent frequency 
steering, but they exchange power. The generation-load thing still 
happens, but phase/frequency decoupled. HVDC cables achieve the same thing.


Anyway, phase monitoring has become a very good tool for so many of 
these measurements, and that requires a common "reference" phase and 
that is GPS. That helps to monitor the phase and frequency of the grid 
so that it can be controlled.


A peculiarity of the field is the ROCOF - Rate Of Change OF Frequency. 
This is what we call linear frequency drift. Looking on those numbers 
give you a good hint where you are going.


Until recently, photoelectric would not provide any of the rotating iron 
properties, but the increase popularity of it now requires it to start 
to have such properties for the stability of the system.


Cheers,
Magnus

On 04/04/2017 11:28 PM, Thomas D. Erb wrote:

Thanks for the info.


So that tells me how data is recorded - but not how the frequency is kept 
stable ?

Is the line frequency now directly tied to GPS clock - with no drift ?

Thomas D. Erb
t...@electrictime.com /
Electric Time Company, Inc.
Office: 508-359-4396 x 117 / Fax: 508-359-4482
97 West Street Medfield, MA 02052 USA
www.electrictime.com
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Re: [time-nuts] TAPR TICC boxed

[Bruce Griffiths]

The gold standard is a random pulse source.
Using something like a SPAD as the source of random pulses is popular as the 
average rate can be easily adjusted by changing the light level. It also avoids 
using radioactive sources.

Bruce
> On 03 April 2017 at 15:05 Bruce Griffiths  wrote:
> 
> 
> For even more fun you could try to detect the PTFE phase change  at around 
> 20C using a cable with PTFE dielectric.
> 
> A pulse source with somewhat more pulse to pulse jitter may be more useful in 
> that averaging will occur over a wider range of fine interpolator codes.
> 
> Bruce
> 
> > 
> > On 03 April 2017 at 05:34 Mark Sims  wrote:
> > 
> > I implemented the channel offset compensation feature specifically to 
> > make measuring cable delays more accurate. I wanted to measure my TDR 
> > calibration cable and another very precision delay line. I used Heather to 
> > null out the channel/connector delays and then replaced one of the "T" 
> > cables with the TDR cable.
> > 
> > My test setup / TICC was coming up with a -306 ps channel offset error. 
> > The test signal was the 1PPS output of a FTS4060 cesium. Connecting / 
> > reconnecting one of the test setup cables and re-doing the offset test (I 
> > was averaging for 1800 seconds) could produce compensation values that 
> > varied from -300 ps to -325 ps. Just de-doing the offset test without 
> > messing with the cables produced values around -300 to -310 ps.
> > 
> > BNC connectors aren't the best for precision timing. I need to re-run 
> > the test with SMA cables / T adapter and the precision HP connector torque 
> > wrench and see what that looks like. It would also be fun to lay a coax 
> > outdoors and see how the delay changes over a day as it heats/cools.
> > 
> > 
> > 
> > > > 
> > > Some “cables” have very long delay numbers.
> > > 
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[time-nuts] Timelab file needed

[Bob Stewart]

Does anyone have a timelab file for a KS-24361?  My KS has a much worse 1s ADEV 
(and on down the line) than I would have expected, and I'd like to see what 
others are getting.
Bob

AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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