Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Didier Juges]

Not a time-nut issue but most banks that batch process will process the
debits before the credit so that they get to charge you no matter what.
They probably don't all do it but some definitely do. I had one bank even
charge me multiple overdraft fees because they processed the largest checks
first, before the smaller ones in order to get my balance negative before
processing the smaller checks in order to maximize the fees. If the
transactions had been processed in the actual order, there would have been
no overdraft fee.
When I asked, they said the debits were processed electronically
(immediately) but the deposits (which I made by cash at the front desk)
were sent to a central office across the state BY MAIL for reconciliation,
and therefore processed (and credited to my account) several days later. I
did not remain a customer very long after that.
They closed in the 90s when it was revealed they were laundering money for
major drug traffickers.

But I see your point :)


On Sep 8, 2018 9:26 AM, "jimlux"  wrote:

On 9/7/18 10:05 PM, John Reid wrote:
> Hi all,
>
>
> discussion of how to keep accurate time without access to GPS seems very
> on topic to me.
>
>
> These people involved in major catastrophe ('end of the world' as you
> put it) scenarios have a wealth of experience in other ways of keeping
> accurate time.
>


Actually, they don't necessarily have a wealth of experience, because
they may have marched themselves down a path where they have a
*requirement* for much better timing than they realize, because it is so
easy and cheap to get good time today.

Imagine this scenario - you're a bank, and you batch process checks and
deposits in one physical location, so you don't much care about when the
check was written or the deposit made.  Then you move to a distributed
system across the US, where the reconciliation is done on the basis of
the date of the transaction - still probably ok, because there are no
transactions during non-business hours, so as long as you reconcile at
1AM, if transaction time stamps are off by 5 minutes, it doesn't matter.


Now say "we're going to charge you, the customer a fee, if your balance
goes negative" and go to 24/7 operations, where transactions are
journaled immediately, rather than batch processed at night  If a
deposit that was made at 12:00 (but timestamped 12:05)  is followed by a
withdrawal made at 12:03 (but timestamped 12:00), you get unfairly
charged the overdraft fee.

For small problems, banks have ways to "unwind" errors.  But if it
becomes a systemic thing that's a problem.

So the bank sets up GPSDOs at each transaction point - problem solved.

Until GPS fails.




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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Scott McGrath]

My company paid for my shield room the real trick was getting the door in which 
weighed 600-800 pounds.

As to the old generator I restore old machinery as another hobby for the times 
I want to disengage brain.   But photoetched brass id plates show so much more 
thought than thermal printed labels

Content by Scott
Typos by Siri

On Sep 8, 2018, at 9:48 PM, William H. Fite  wrote:

We sound like we could be cousins, Scott. When we bought our current house,
I discovered that the previous owner had built a Faraday cage in a small
room off the basement. I put all my stuff in there. I also have a generator
with magneto ignition so I should be good to go when the end-of-the-world
arrives.



> On Saturday, September 8, 2018, Scott McGrath  wrote:
> 
> Actually
> 
> I do have much of my equipment inside a shield room,  not for tinfoil hat
> reasons but to keep experimental systems from causing interference and to
> eliminate existing RF sources in the 800 Mhz to 8 Ghz range as error
> sources in measurements.
> 
> If one is concerned there are lots of old screen rooms coming up for sale
> on e-bay as WiFi manufacturers prepare to dip their toes into bands above
> 10 Ghz and many of the old ones were only good to 6-8 Ghz.
> 
> As to backup generators I have a modern one and an ‘old school’
> mechanically governed one with magneto ignition.I keep that one mainly
> because i like its Art Deco design.Sometimes bring it to local Ag Fair
> to display among the gear from that era.
> 
> Content by Scott
> Typos by Siri
> 
> On Sep 8, 2018, at 8:11 PM, William H. Fite  wrote:
> 
> 
> 
> Gentlemen, I've found this discussion interesting and informative. This
> household works on quantum information theory rather than engineering so
> there is much for us to learn.
> 
> I must observe that if an event takes out the entire GPS system (which a
> Carrington event would not do) we will have issues a great deal more
> immediate and pressing than getting hyper-precise timing systems restored.
> 
> And speaking of Carrington events, how many of us have our equipment
> surrounded by Faraday cages and supplied with off-grid power? Because
> without those, we won't have instruments to measure T at home or even in
> a great many labs and businesses.
> 
> Just a thought.
> 
> 
> 
> 
>> On Saturday, September 8, 2018, Dana Whitlow 
> wrote:
>> 
>> I argue that when the "big one" happens, getting back to where we are
>> technologically
>> will be in large part a bootstrapping kind of affair.  And I believe that
>> starting off with
>> WWV* will be a far better starting point than starting with sun clocks
> and
>> dripping
>> water.
>> 
>> Dana
>> 
>> 
>> On Sat, Sep 8, 2018 at 5:54 PM, Ruslan Nabioullin > 
>> wrote:
>> 
 On Fri, Sep 7, 2018 at 8:32 PM Bob kb8tq  wrote:
 
 This is Time Nuts, not end of the world nuts …..
 ...
 I think we’ve all heard plenty of “the world is ending” stuff.
 
>>> 
>>> But the availability of a T service under adverse conditions and the
>>> ability of a system which consumes a T reference to gracefully degrade
>>> its functionality upon degradation or absence of reference input(s) are
>>> features/figures of merit---I do not see how discussion of that aspect
>> can
>>> be considered to be offtopic.
>>> 
>>> -Ruslan
>>> 
>>> --
>>> Ruslan Nabioullin
>>> Wittgenstein Laboratories
>>> rnabioul...@gmail.com
>>> (508) 523-8535
>>> 50 Louise Dr.
>>> Hollis, NH 03049
>>> ___
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to http://lists.febo.com/mailman/
>>> listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>> 
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to http://lists.febo.com/mailman/
>> listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>> 
> 
> 
> --
> Patriotism is supporting your country all the time, and your government
> when it deserves it.
> --Mark Twain
> 
> We may be surprised at the people we find in heaven. God has a soft spot
> for sinners. His standards are quite low.
> --Desmond Tutu
> ___
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> listinfo/time-nuts_lists.febo.com
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> 


-- 
Patriotism is supporting your country all the time, and your government
when it deserves it.
--Mark Twain

We may be surprised at the people we find in heaven. God has a soft spot
for sinners. His standards are quite low.
--Desmond Tutu
___
time-nuts mailing list -- 

Re: [time-nuts] Lost GPS lock or 1PPS recently?

[William H. Fite]

We sound like we could be cousins, Scott. When we bought our current house,
I discovered that the previous owner had built a Faraday cage in a small
room off the basement. I put all my stuff in there. I also have a generator
with magneto ignition so I should be good to go when the end-of-the-world
arrives.



On Saturday, September 8, 2018, Scott McGrath  wrote:

> Actually
>
> I do have much of my equipment inside a shield room,  not for tinfoil hat
> reasons but to keep experimental systems from causing interference and to
> eliminate existing RF sources in the 800 Mhz to 8 Ghz range as error
> sources in measurements.
>
> If one is concerned there are lots of old screen rooms coming up for sale
> on e-bay as WiFi manufacturers prepare to dip their toes into bands above
> 10 Ghz and many of the old ones were only good to 6-8 Ghz.
>
> As to backup generators I have a modern one and an ‘old school’
> mechanically governed one with magneto ignition.I keep that one mainly
> because i like its Art Deco design.Sometimes bring it to local Ag Fair
> to display among the gear from that era.
>
> Content by Scott
> Typos by Siri
>
> On Sep 8, 2018, at 8:11 PM, William H. Fite  wrote:
>
> 
>
> Gentlemen, I've found this discussion interesting and informative. This
> household works on quantum information theory rather than engineering so
> there is much for us to learn.
>
> I must observe that if an event takes out the entire GPS system (which a
> Carrington event would not do) we will have issues a great deal more
> immediate and pressing than getting hyper-precise timing systems restored.
>
> And speaking of Carrington events, how many of us have our equipment
> surrounded by Faraday cages and supplied with off-grid power? Because
> without those, we won't have instruments to measure T at home or even in
> a great many labs and businesses.
>
> Just a thought.
>
>
>
>
> > On Saturday, September 8, 2018, Dana Whitlow 
> wrote:
> >
> > I argue that when the "big one" happens, getting back to where we are
> > technologically
> > will be in large part a bootstrapping kind of affair.  And I believe that
> > starting off with
> > WWV* will be a far better starting point than starting with sun clocks
> and
> > dripping
> > water.
> >
> > Dana
> >
> >
> > On Sat, Sep 8, 2018 at 5:54 PM, Ruslan Nabioullin  >
> > wrote:
> >
> >>> On Fri, Sep 7, 2018 at 8:32 PM Bob kb8tq  wrote:
> >>>
> >>> This is Time Nuts, not end of the world nuts …..
> >>> ...
> >>> I think we’ve all heard plenty of “the world is ending” stuff.
> >>>
> >>
> >> But the availability of a T service under adverse conditions and the
> >> ability of a system which consumes a T reference to gracefully degrade
> >> its functionality upon degradation or absence of reference input(s) are
> >> features/figures of merit---I do not see how discussion of that aspect
> > can
> >> be considered to be offtopic.
> >>
> >> -Ruslan
> >>
> >> --
> >> Ruslan Nabioullin
> >> Wittgenstein Laboratories
> >> rnabioul...@gmail.com
> >> (508) 523-8535
> >> 50 Louise Dr.
> >> Hollis, NH 03049
> >> ___
> >> time-nuts mailing list -- time-nuts@lists.febo.com
> >> To unsubscribe, go to http://lists.febo.com/mailman/
> >> listinfo/time-nuts_lists.febo.com
> >> and follow the instructions there.
> >>
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to http://lists.febo.com/mailman/
> > listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
> >
>
>
> --
> Patriotism is supporting your country all the time, and your government
> when it deserves it.
> --Mark Twain
>
> We may be surprised at the people we find in heaven. God has a soft spot
> for sinners. His standards are quite low.
> --Desmond Tutu
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/
> listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
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> To unsubscribe, go to http://lists.febo.com/mailman/
> listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>


-- 
Patriotism is supporting your country all the time, and your government
when it deserves it.
--Mark Twain

We may be surprised at the people we find in heaven. God has a soft spot
for sinners. His standards are quite low.
--Desmond Tutu
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Scott McGrath]

Actually 

I do have much of my equipment inside a shield room,  not for tinfoil hat 
reasons but to keep experimental systems from causing interference and to 
eliminate existing RF sources in the 800 Mhz to 8 Ghz range as error sources in 
measurements.

If one is concerned there are lots of old screen rooms coming up for sale on 
e-bay as WiFi manufacturers prepare to dip their toes into bands above 10 Ghz 
and many of the old ones were only good to 6-8 Ghz.  

As to backup generators I have a modern one and an ‘old school’ mechanically 
governed one with magneto ignition.I keep that one mainly because i like 
its Art Deco design.Sometimes bring it to local Ag Fair to display among 
the gear from that era.

Content by Scott
Typos by Siri

On Sep 8, 2018, at 8:11 PM, William H. Fite  wrote:



Gentlemen, I've found this discussion interesting and informative. This
household works on quantum information theory rather than engineering so
there is much for us to learn.

I must observe that if an event takes out the entire GPS system (which a
Carrington event would not do) we will have issues a great deal more
immediate and pressing than getting hyper-precise timing systems restored.

And speaking of Carrington events, how many of us have our equipment
surrounded by Faraday cages and supplied with off-grid power? Because
without those, we won't have instruments to measure T at home or even in
a great many labs and businesses.

Just a thought.




> On Saturday, September 8, 2018, Dana Whitlow  wrote:
> 
> I argue that when the "big one" happens, getting back to where we are
> technologically
> will be in large part a bootstrapping kind of affair.  And I believe that
> starting off with
> WWV* will be a far better starting point than starting with sun clocks and
> dripping
> water.
> 
> Dana
> 
> 
> On Sat, Sep 8, 2018 at 5:54 PM, Ruslan Nabioullin 
> wrote:
> 
>>> On Fri, Sep 7, 2018 at 8:32 PM Bob kb8tq  wrote:
>>> 
>>> This is Time Nuts, not end of the world nuts …..
>>> ...
>>> I think we’ve all heard plenty of “the world is ending” stuff.
>>> 
>> 
>> But the availability of a T service under adverse conditions and the
>> ability of a system which consumes a T reference to gracefully degrade
>> its functionality upon degradation or absence of reference input(s) are
>> features/figures of merit---I do not see how discussion of that aspect
> can
>> be considered to be offtopic.
>> 
>> -Ruslan
>> 
>> --
>> Ruslan Nabioullin
>> Wittgenstein Laboratories
>> rnabioul...@gmail.com
>> (508) 523-8535
>> 50 Louise Dr.
>> Hollis, NH 03049
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to http://lists.febo.com/mailman/
>> listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/
> listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
> 


-- 
Patriotism is supporting your country all the time, and your government
when it deserves it.
--Mark Twain

We may be surprised at the people we find in heaven. God has a soft spot
for sinners. His standards are quite low.
--Desmond Tutu
___
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[William H. Fite]

Gentlemen, I've found this discussion interesting and informative. This
household works on quantum information theory rather than engineering so
there is much for us to learn.

I must observe that if an event takes out the entire GPS system (which a
Carrington event would not do) we will have issues a great deal more
immediate and pressing than getting hyper-precise timing systems restored.

And speaking of Carrington events, how many of us have our equipment
surrounded by Faraday cages and supplied with off-grid power? Because
without those, we won't have instruments to measure T at home or even in
a great many labs and businesses.

Just a thought.




On Saturday, September 8, 2018, Dana Whitlow  wrote:

> I argue that when the "big one" happens, getting back to where we are
> technologically
> will be in large part a bootstrapping kind of affair.  And I believe that
> starting off with
> WWV* will be a far better starting point than starting with sun clocks and
> dripping
> water.
>
> Dana
>
>
> On Sat, Sep 8, 2018 at 5:54 PM, Ruslan Nabioullin 
> wrote:
>
> > On Fri, Sep 7, 2018 at 8:32 PM Bob kb8tq  wrote:
> >
> > > This is Time Nuts, not end of the world nuts …..
> > > ...
> > > I think we’ve all heard plenty of “the world is ending” stuff.
> > >
> >
> > But the availability of a T service under adverse conditions and the
> > ability of a system which consumes a T reference to gracefully degrade
> > its functionality upon degradation or absence of reference input(s) are
> > features/figures of merit---I do not see how discussion of that aspect
> can
> > be considered to be offtopic.
> >
> > -Ruslan
> >
> > --
> > Ruslan Nabioullin
> > Wittgenstein Laboratories
> > rnabioul...@gmail.com
> > (508) 523-8535
> > 50 Louise Dr.
> > Hollis, NH 03049
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to http://lists.febo.com/mailman/
> > listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
> >
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/
> listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>


-- 
Patriotism is supporting your country all the time, and your government
when it deserves it.
--Mark Twain

We may be surprised at the people we find in heaven. God has a soft spot
for sinners. His standards are quite low.
--Desmond Tutu
___
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Ruslan Nabioullin]

On Fri, Sep 7, 2018 at 8:32 PM Bob kb8tq  wrote:

> This is Time Nuts, not end of the world nuts …..
> ...
> I think we’ve all heard plenty of “the world is ending” stuff.
>

But the availability of a T service under adverse conditions and the
ability of a system which consumes a T reference to gracefully degrade
its functionality upon degradation or absence of reference input(s) are
features/figures of merit---I do not see how discussion of that aspect can
be considered to be offtopic.

-Ruslan

-- 
Ruslan Nabioullin
Wittgenstein Laboratories
rnabioul...@gmail.com
(508) 523-8535
50 Louise Dr.
Hollis, NH 03049
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Bob kb8tq]

Hi

> On Sep 8, 2018, at 1:53 PM, Scott McGrath  wrote:
> 
> This is precisely the scenario even a short GPS blackout of 1-2 weeks would 
> cause.   Its not that GPS is not the finest time transfer system ever 
> devised.   Its that with the loss of legacy systems we’ve lost the ability to 
> degrade gracefully.

How will the presence of a “backup” system that in no way at all interconnects 
with a cell tower have any 
effect at all on it’s performance with loss of GPS ??? The legacy system (which 
does not even exist) 
has *zero* impact in this case. 

> 
> With a eLORAN system cell networks during a prolonged outage would probably 
> degrade to 3G,

Except that they have no way at all to do that. They simply are not designed 
that way and can not function 
that way. The systems that *could* function at lower timing tolerance all got 
scrapped out long ago. That 
of course *assumes* that eLoran can deliver < 100 ns timing. Is there any data 
to support that ? 

Do any members have data on the 1 second timing out of eLoran? We’re about as 
deep into it as any
group not working for the eLoran people. If we haven’t seen any performance 
data …. I kinda doubt 
anybody else has. 


>  but they would still be up.   No you cant stream HD video or play GTA Online 
> X,  but talk,text email and Facebook would still work Time transfer for most 
> applications would still work.  The HFT boyos on Wall St would be SOL.  Not 
> sure how to evaluate that eventuality.
> 
> 
> People like US need to educate political and business leadership on the need 
> for BACKUPS to GPS

The reason the systems are designed just with GPS is *not* because “nobody 
mentioned the need
for a backup”. There are indeed people out there who spent a lot of time 
talking about this with the
guys who designed and spec’d these systems. The very simple answer *always* 
came back:

1) There is no alternative out there

2) There is not FCC requirement to do so = cost is not justified

3) There is absolutely zero demonstrated need

That’s very much three strikes you’re out.

Bob


> mainly because things like the Carrington Event have happened before and WILL 
> happen again. 
> 
>   And having terrestrial systems mean that you can get techs onsite to repair 
> by horse if necessary unlike a space based system where some idiot retired 
> the fleet of repair trucks. So the only remaining option is to launch new 
> ones.
> 
> 
> On Sep 8, 2018, at 10:25 AM, jimlux  wrote:
> 
>> On 9/7/18 10:05 PM, John Reid wrote:
>> Hi all,
>> discussion of how to keep accurate time without access to GPS seems very
>> on topic to me.
>> These people involved in major catastrophe ('end of the world' as you
>> put it) scenarios have a wealth of experience in other ways of keeping
>> accurate time.
> 
> 
> Actually, they don't necessarily have a wealth of experience, because they 
> may have marched themselves down a path where they have a *requirement* for 
> much better timing than they realize, because it is so easy and cheap to get 
> good time today.
> 
> Imagine this scenario - you're a bank, and you batch process checks and 
> deposits in one physical location, so you don't much care about when the 
> check was written or the deposit made.  Then you move to a distributed system 
> across the US, where the reconciliation is done on the basis of the date of 
> the transaction - still probably ok, because there are no transactions during 
> non-business hours, so as long as you reconcile at 1AM, if transaction time 
> stamps are off by 5 minutes, it doesn't matter.
> 
> 
> Now say "we're going to charge you, the customer a fee, if your balance goes 
> negative" and go to 24/7 operations, where transactions are journaled 
> immediately, rather than batch processed at night  If a deposit that was made 
> at 12:00 (but timestamped 12:05)  is followed by a withdrawal made at 12:03 
> (but timestamped 12:00), you get unfairly charged the overdraft fee.
> 
> For small problems, banks have ways to "unwind" errors.  But if it becomes a 
> systemic thing that's a problem.
> 
> So the bank sets up GPSDOs at each transaction point - problem solved.
> 
> Until GPS fails.
> 
> 
> 
> ___
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Scott McGrath]

This is precisely the scenario even a short GPS blackout of 1-2 weeks would 
cause.   Its not that GPS is not the finest time transfer system ever devised.  
 Its that with the loss of legacy systems we’ve lost the ability to degrade 
gracefully.

With a eLORAN system cell networks during a prolonged outage would probably 
degrade to 3G,  but they would still be up.   No you cant stream HD video or 
play GTA Online X,  but talk,text email and Facebook would still work Time 
transfer for most applications would still work.  The HFT boyos on Wall St 
would be SOL.  Not sure how to evaluate that eventuality.


People like US need to educate political and business leadership on the need 
for BACKUPS to GPS mainly because things like the Carrington Event have 
happened before and WILL happen again. 

   And having terrestrial systems mean that you can get techs onsite to repair 
by horse if necessary unlike a space based system where some idiot retired the 
fleet of repair trucks. So the only remaining option is to launch new ones.


On Sep 8, 2018, at 10:25 AM, jimlux  wrote:

> On 9/7/18 10:05 PM, John Reid wrote:
> Hi all,
> discussion of how to keep accurate time without access to GPS seems very
> on topic to me.
> These people involved in major catastrophe ('end of the world' as you
> put it) scenarios have a wealth of experience in other ways of keeping
> accurate time.


Actually, they don't necessarily have a wealth of experience, because they may 
have marched themselves down a path where they have a *requirement* for much 
better timing than they realize, because it is so easy and cheap to get good 
time today.

Imagine this scenario - you're a bank, and you batch process checks and 
deposits in one physical location, so you don't much care about when the check 
was written or the deposit made.  Then you move to a distributed system across 
the US, where the reconciliation is done on the basis of the date of the 
transaction - still probably ok, because there are no transactions during 
non-business hours, so as long as you reconcile at 1AM, if transaction time 
stamps are off by 5 minutes, it doesn't matter.


Now say "we're going to charge you, the customer a fee, if your balance goes 
negative" and go to 24/7 operations, where transactions are journaled 
immediately, rather than batch processed at night  If a deposit that was made 
at 12:00 (but timestamped 12:05)  is followed by a withdrawal made at 12:03 
(but timestamped 12:00), you get unfairly charged the overdraft fee.

For small problems, banks have ways to "unwind" errors.  But if it becomes a 
systemic thing that's a problem.

So the bank sets up GPSDOs at each transaction point - problem solved.

Until GPS fails.



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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Peter Laws]

On Tue, Sep 4, 2018 at 3:23 PM Graham / KE9H  wrote:
>
> The following are active GPS NOTAMs.

Didn't know NOTAMs went out for GPS interruptions but of course they
do.  Surprised, actually, that there are so many.  And yet, life goes
on.  Must be all those WWV backups.

https://pilotweb.nas.faa.gov/PilotWeb/noticesAction.do?queryType=ALLGPS=ICAO




-- 
Peter Laws | N5UWY | plaws plaws net | Travel by Train!

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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Bob kb8tq]

Hi

I believe the 50 ns is the “as transmitted” signal from the tower. The “as 
received” signal after going 
through all the various gyrations is not that good on a  ~1 second basis. 



One of the gotchas here is that we lump “systems” into one giant bag. That’s 
not a good way
to analyze things. One system may be quite happy with 10 ms timing another may 
be happy
with 10 us and yet another may die completely at 1 us and only run right at 100 
ns. All of that
is on a 2 second basis for CDMA (they time every other second). 

By far the biggest / baddest / most venerable system out the that uses GPS 
timing is the 
cell tower system. They started out back in the 80’s with a 10us max timing / 1 
us running  
spec on CDMA. AFIK they were the first major system to adopt GPS time as their 
reference 
(rather than UTC). 

This worked out fine for a few decades while companies got a lot of towers 
built. People started
using those systems and they became congested. Others started streaming video 
over them
and they ran out of bandwidth. Upgrades followed. There have been a lot of 
them. Much of what
we TimeNuts buy on the surplus market comes to us as a result of older systems 
being scrapped
out. 

The latest set of upgrades does / will / is getting them into the sub 1 us 
range at the end of holdover. 
In normal operation they are spec’d at 100 ns worst case. To do that, you need 
a timing source in 
the roughly 10 ns range. No you don’t see those GPSDO’s on the surplus market. 
You will see
them someday ….

Again, they went this way a decade ago. Rolling that all back …. not at all 
easy. 

Are there other systems that have issues with sync? Of course there are. There 
also are a lot
of instances where miss-configuration ( or junk implementation) is a much 
bigger issue. Sorting 
that all out requires a deep dive into the timing of each individual system / 
implementation.  No
two systems do things quite the same way. Unless you want to deal with the 
numbers and the
implementation details, simply moaning and groaning isn’t going anywhere. 

Bob

> On Sep 8, 2018, at 3:23 AM, Hal Murray  wrote:
> 
> 
> kb...@n1k.org said:
>> You are not trying to run a cell system when checking your local oscillator
>> against LORAN. 
> 
> The eLoran committee said 50 ns.  Is that good enough for cell towers?
> 
> Too bad it isn't up so we could collect some data.
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[jimlux]

On 9/7/18 10:05 PM, John Reid wrote:

Hi all,


discussion of how to keep accurate time without access to GPS seems very
on topic to me.


These people involved in major catastrophe ('end of the world' as you
put it) scenarios have a wealth of experience in other ways of keeping
accurate time.




Actually, they don't necessarily have a wealth of experience, because 
they may have marched themselves down a path where they have a 
*requirement* for much better timing than they realize, because it is so 
easy and cheap to get good time today.


Imagine this scenario - you're a bank, and you batch process checks and 
deposits in one physical location, so you don't much care about when the 
check was written or the deposit made.  Then you move to a distributed 
system across the US, where the reconciliation is done on the basis of 
the date of the transaction - still probably ok, because there are no 
transactions during non-business hours, so as long as you reconcile at 
1AM, if transaction time stamps are off by 5 minutes, it doesn't matter.



Now say "we're going to charge you, the customer a fee, if your balance 
goes negative" and go to 24/7 operations, where transactions are 
journaled immediately, rather than batch processed at night  If a 
deposit that was made at 12:00 (but timestamped 12:05)  is followed by a 
withdrawal made at 12:03 (but timestamped 12:00), you get unfairly 
charged the overdraft fee.


For small problems, banks have ways to "unwind" errors.  But if it 
becomes a systemic thing that's a problem.


So the bank sets up GPSDOs at each transaction point - problem solved.

Until GPS fails.



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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Hal Murray]

kb...@n1k.org said:
> You are not trying to run a cell system when checking your local oscillator
> against LORAN. 

The eLoran committee said 50 ns.  Is that good enough for cell towers?

Too bad it isn't up so we could collect some data.


-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Bob Martin]

Here is an interesting and fairly recent link regarding eloran and 
telecom.


https://rntfnd.org/2017/09/17/telecom-organization-recommends-eloran-system/

The report is here:
https://access.atis.org/apps/group_public/download.php/36304/ATIS-095.pdf

Page 11 has an nice table called "Time and phase end application 
synchronization requirements.  It then really gets interesting 
starting on page 14.


Again, I have no skin in this discussion other than it would be neat 
if that old gear I designed were to be resurrected! It does appear 
that poor old Loran has it's share of lovers and haters. I wonder if 
the numbers and assertions in this document truly reflect reality?


As I said before, all this Time Nut debating over GPS dependency 
appears to be raging at many levels of government and industry.


Best,

Bob Martin

On 9/7/2018 3:18 PM, Bob kb8tq wrote:

Hi

You are not trying to run a cell system when checking your local oscillator 
against LORAN.
It’s two completely different things. The timing requirements of the modern 
systems are indeed
way past what LORAN can deliver. We’re not talking about 1970’s state of the 
art anymore. You
need a time source that is in the 10 ns range to keep this stuff running. 
Multiple microseconds of
error in your timing source aren’t good enough for what they have up and are 
rolling out.  Full
end of holdover spec on many of them is below 2 microseconds. Normal operation 
is under 100 ns.
Give the cell outfits another couple years and that’s all they will have on the 
air.


Bob


On Sep 6, 2018, at 9:08 PM, Scott McGrath  wrote:


As to eLORAN,  you can deny positioning but maintain timing service simply by 
modifying the GRI and since eLORAN is software based thats not a difficult 
change.

Navigation receivers go into fail but timing receivers only need ONE station.   
As the users of SRS700’s and Austrons do when Wildwood is active.

With GNSS its a hell of a lot harder and without SA your only option is to turn 
off all the C/A signals hence denying civillian use of GNSS

I’m pretty sure if a non-state actor was doing weaponized drone attacks with 
GPS for guidance,  GPS for civilian use would be shut down in a NY minute .

Remember govt users would not be affected as they have access to the PPS and 
the ‘word of the day’ to make it active.

You dont need conspiracies to think of conditions where GPS would be shut down 
for long periods of time and where reasonable people would agree with the 
shutdown.

On Sep 6, 2018, at 8:44 PM, Scott McGrath  wrote:

Gee,  thats strange especially for those of us who ran the Austron comparitors 
to check our local standards against the LORSTA’s



On Sep 6, 2018, at 8:04 PM, Bob kb8tq  wrote:

Hi

No, eLoran *never* on it’s best day could ever deliver the kind of timing that 
the vast majority
of these systems require. It simply is not and can not do the job. The world 
has moved *way*
past the sort of timing it can actually deliver.

Bob


On Sep 6, 2018, at 6:35 PM, Scott McGrath  wrote:

Actually we DID have a radio based system that provided sufficient accuracy it 
was called eLORAN but it was killed by US politicians because they did not want 
a much more inexpensive to operate system ‘competing’ with GPS.Shutting 
down LORAN saved 32m dollars annually the NAVSTAR GPS program costs billions 
annually.

Ironically while LORAN’s absolute accuracy is less than GPS,  repeatability was 
much better so fishermen liked LORAN better.

Once again the empty suits won and the navigation and timing community lost.

Wrt cellsites staying operational i imagine the oscillators in holdover would 
probably remain sufficiently synchronized for a month or so.



On Sep 6, 2018, at 4:56 PM, Bob kb8tq  wrote:

Hi

Well, we *do* have experience with that. It was called selective availability. 
Indeed it might get turned back on again. It’s impact on a properly designed 
GPSDO - not much. It takes a bit longer to get to best stability. System time 
wise, it still works “good enough”.

A four hour long test format also does basically nothing to a GPSDO based 
system. You didn’t read anything in the papers about all cell service in three 
states going away. The devices did what they are supposed to do and everything 
did it’s boringly normal thing ….. it worked fine.

I still don’t quite understand just what people think could replace satellite 
based timing in these systems. None of the “radio based” systems are within a 
factor many thousands to a few million of being adequate.

=

Now, if this is headed off into a “the government is coming to break down the 
doors and take away all my toys sort of thing. That’s very much *not* a Time 
Nuts topic.

Bob


On Sep 6, 2018, at 11:34 AM, Scott McGrath  wrote:

And there is the other significant vulnerability since GPS is a MILITARY system 
the DoD can take it offline for any reason at any time.

Leaving civilian users with nothing,

If its a national security threat its likely the 

Re: [time-nuts] Lost GPS lock or 1PPS recently?

[John Reid]

Hi all,


discussion of how to keep accurate time without access to GPS seems very 
on topic to me.


These people involved in major catastrophe ('end of the world' as you 
put it) scenarios have a wealth of experience in other ways of keeping 
accurate time.


My 2c worth.


John


On 08/09/18 10:35, time-nuts-requ...@lists.febo.com wrote:
>
> Message: 10
> Date: Fri, 7 Sep 2018 20:31:32 -0400
> From: Bob kb8tq 
> To: Discussion of precise time and frequency measurement
>       
> Subject: Re: [time-nuts] Lost GPS lock or 1PPS recently?
> Message-ID: <75fbe25c-fae6-4f1e-8ae5-a52d3aebe...@n1k.org>
> Content-Type: text/plain; charset=utf-8
>
> Hi
>
> This is Time Nuts, not end of the world nuts ?..
>
> 

> Bob
>
>> On Sep 7, 2018, at 7:01 PM, Scott McGrath  wrote:
>>
>> You are SO convinced that GPS will ALWAYS be there,   I?m NOT (Think 
>> Carrington Event) and i?ve been part of a few disaster exercises where both 
>> Internet and GPS were considered ?down? for the exercise and these exercises 
>> are done in conjunction with the military so PPS was also ?off the table?.
>>
>>


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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Bob kb8tq]

Hi

This is Time Nuts, not end of the world nuts …..

I most certainly did *not* design these systems. The *do* have timing 
requirements. If those requirements 
are not met, they stop working. That’s just the way it goes. Designing these 
systems at the timing level was
done a decade ago. You can object to what they did, it’s about ten years to 
late to change anything. Tight timing
gives then more capacity … tough to argue with even if you weren’t to late. 

If *you* believe there is an alternative system now in existence that will 
supply the timing these systems require … 
that *is* a Time Nuts topic. So, let’s hear about the numbers on the system you 
believe will supply what’s needed.
I think we’ve all heard plenty of “the world is ending” stuff. 

Bob

> On Sep 7, 2018, at 7:01 PM, Scott McGrath  wrote:
> 
> You are SO convinced that GPS will ALWAYS be there,   I’m NOT (Think 
> Carrington Event) and i’ve been part of a few disaster exercises where both 
> Internet and GPS were considered ‘down’ for the exercise and these exercises 
> are done in conjunction with the military so PPS was also ‘off the table’.
> 
> It was quite an eye opener to see how many networks could not keep time 
> synchronized within 5 minutes much less 5 seconds because of the cheap XO’s 
> used in servers and workstations(NTP will ALWAYS BE AVAILABLE).  Just like 
> the old Sun workstations.
> 
> It was also fun watching the multimillion dollar Harris radios drift once 
> they no longer had a 10 Mhz input from a GPSDO.   One would think the local 
> timebase would be a bit better than it was.  
> 
> The older ‘Pacer Bounce’ and Falcon series radios did much better because 
> they had good local timebases and made no assumptions of the availability of 
> a external timebase.  Whereas the new radios depend upon it.
> 
> These exercises are intended to practice restoring government communications 
> after a large scale natural disaster.And without readily available 
> precision time it aint easy.
> 
> Its also fun watching executives realizing that their phone during the 
> exercise is a paperweight useful only in weighting down stacks of Form 213’s
> 
> Its not for nothing that Symmetricom is building more 5071’s than HP/Agilent 
> ever did.
> 
> On Sep 7, 2018, at 5:18 PM, Bob kb8tq  wrote:
> 
> Hi
> 
> You are not trying to run a cell system when checking your local oscillator 
> against LORAN.
> It’s two completely different things. The timing requirements of the modern 
> systems are indeed
> way past what LORAN can deliver. We’re not talking about 1970’s state of the 
> art anymore. You
> need a time source that is in the 10 ns range to keep this stuff running. 
> Multiple microseconds of 
> error in your timing source aren’t good enough for what they have up and are 
> rolling out.  Full 
> end of holdover spec on many of them is below 2 microseconds. Normal 
> operation is under 100 ns.
> Give the cell outfits another couple years and that’s all they will have on 
> the air.
> 
> 
> Bob
> 
>> On Sep 6, 2018, at 9:08 PM, Scott McGrath  wrote:
>> 
>> 
>> As to eLORAN,  you can deny positioning but maintain timing service simply 
>> by modifying the GRI and since eLORAN is software based thats not a 
>> difficult change.
>> 
>> Navigation receivers go into fail but timing receivers only need ONE 
>> station.   As the users of SRS700’s and Austrons do when Wildwood is active.
>> 
>> With GNSS its a hell of a lot harder and without SA your only option is to 
>> turn off all the C/A signals hence denying civillian use of GNSS
>> 
>> I’m pretty sure if a non-state actor was doing weaponized drone attacks with 
>> GPS for guidance,  GPS for civilian use would be shut down in a NY minute .
>> 
>> Remember govt users would not be affected as they have access to the PPS and 
>> the ‘word of the day’ to make it active.
>> 
>> You dont need conspiracies to think of conditions where GPS would be shut 
>> down for long periods of time and where reasonable people would agree with 
>> the shutdown.
>> 
>> On Sep 6, 2018, at 8:44 PM, Scott McGrath  wrote:
>> 
>> Gee,  thats strange especially for those of us who ran the Austron 
>> comparitors to check our local standards against the LORSTA’s
>> 
>> 
>> 
>> On Sep 6, 2018, at 8:04 PM, Bob kb8tq  wrote:
>> 
>> Hi
>> 
>> No, eLoran *never* on it’s best day could ever deliver the kind of timing 
>> that the vast majority
>> of these systems require. It simply is not and can not do the job. The world 
>> has moved *way*
>> past the sort of timing it can actually deliver. 
>> 
>> Bob
>> 
>>> On Sep 6, 2018, at 6:35 PM, Scott McGrath  wrote:
>>> 
>>> Actually we DID have a radio based system that provided sufficient accuracy 
>>> it was called eLORAN but it was killed by US politicians because they did 
>>> not want a much more inexpensive to operate system ‘competing’ with GPS.
>>> Shutting down LORAN saved 32m dollars annually the NAVSTAR GPS program 
>>> costs billions annually.

Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Scott McGrath]

You are SO convinced that GPS will ALWAYS be there,   I’m NOT (Think Carrington 
Event) and i’ve been part of a few disaster exercises where both Internet and 
GPS were considered ‘down’ for the exercise and these exercises are done in 
conjunction with the military so PPS was also ‘off the table’.

It was quite an eye opener to see how many networks could not keep time 
synchronized within 5 minutes much less 5 seconds because of the cheap XO’s 
used in servers and workstations(NTP will ALWAYS BE AVAILABLE).  Just like the 
old Sun workstations.

It was also fun watching the multimillion dollar Harris radios drift once they 
no longer had a 10 Mhz input from a GPSDO.   One would think the local timebase 
would be a bit better than it was.  

The older ‘Pacer Bounce’ and Falcon series radios did much better because they 
had good local timebases and made no assumptions of the availability of a 
external timebase.  Whereas the new radios depend upon it.

These exercises are intended to practice restoring government communications 
after a large scale natural disaster.And without readily available 
precision time it aint easy.

Its also fun watching executives realizing that their phone during the exercise 
is a paperweight useful only in weighting down stacks of Form 213’s

Its not for nothing that Symmetricom is building more 5071’s than HP/Agilent 
ever did.

On Sep 7, 2018, at 5:18 PM, Bob kb8tq  wrote:

Hi

You are not trying to run a cell system when checking your local oscillator 
against LORAN.
It’s two completely different things. The timing requirements of the modern 
systems are indeed
way past what LORAN can deliver. We’re not talking about 1970’s state of the 
art anymore. You
need a time source that is in the 10 ns range to keep this stuff running. 
Multiple microseconds of 
error in your timing source aren’t good enough for what they have up and are 
rolling out.  Full 
end of holdover spec on many of them is below 2 microseconds. Normal operation 
is under 100 ns.
Give the cell outfits another couple years and that’s all they will have on the 
air.


Bob

> On Sep 6, 2018, at 9:08 PM, Scott McGrath  wrote:
> 
> 
> As to eLORAN,  you can deny positioning but maintain timing service simply by 
> modifying the GRI and since eLORAN is software based thats not a difficult 
> change.
> 
> Navigation receivers go into fail but timing receivers only need ONE station. 
>   As the users of SRS700’s and Austrons do when Wildwood is active.
> 
> With GNSS its a hell of a lot harder and without SA your only option is to 
> turn off all the C/A signals hence denying civillian use of GNSS
> 
> I’m pretty sure if a non-state actor was doing weaponized drone attacks with 
> GPS for guidance,  GPS for civilian use would be shut down in a NY minute .
> 
> Remember govt users would not be affected as they have access to the PPS and 
> the ‘word of the day’ to make it active.
> 
> You dont need conspiracies to think of conditions where GPS would be shut 
> down for long periods of time and where reasonable people would agree with 
> the shutdown.
> 
> On Sep 6, 2018, at 8:44 PM, Scott McGrath  wrote:
> 
> Gee,  thats strange especially for those of us who ran the Austron 
> comparitors to check our local standards against the LORSTA’s
> 
> 
> 
> On Sep 6, 2018, at 8:04 PM, Bob kb8tq  wrote:
> 
> Hi
> 
> No, eLoran *never* on it’s best day could ever deliver the kind of timing 
> that the vast majority
> of these systems require. It simply is not and can not do the job. The world 
> has moved *way*
> past the sort of timing it can actually deliver. 
> 
> Bob
> 
>> On Sep 6, 2018, at 6:35 PM, Scott McGrath  wrote:
>> 
>> Actually we DID have a radio based system that provided sufficient accuracy 
>> it was called eLORAN but it was killed by US politicians because they did 
>> not want a much more inexpensive to operate system ‘competing’ with GPS.
>> Shutting down LORAN saved 32m dollars annually the NAVSTAR GPS program costs 
>> billions annually.
>> 
>> Ironically while LORAN’s absolute accuracy is less than GPS,  repeatability 
>> was much better so fishermen liked LORAN better.
>> 
>> Once again the empty suits won and the navigation and timing community lost.
>> 
>> Wrt cellsites staying operational i imagine the oscillators in holdover 
>> would probably remain sufficiently synchronized for a month or so.
>> 
>> 
>> 
>> On Sep 6, 2018, at 4:56 PM, Bob kb8tq  wrote:
>> 
>> Hi
>> 
>> Well, we *do* have experience with that. It was called selective 
>> availability. Indeed it might get turned back on again. It’s impact on a 
>> properly designed GPSDO - not much. It takes a bit longer to get to best 
>> stability. System time wise, it still works “good enough”. 
>> 
>> A four hour long test format also does basically nothing to a GPSDO based 
>> system. You didn’t read anything in the papers about all cell service in 
>> three states going away. The devices did what they are supposed to do and 
>> 

Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Hal Murray]

aph...@comcast.net said:
> Here is a powerpoint presentation arguing for e-loran:
> https://www.gps.gov/governance/advisory/meetings/2009-05/doherty.pdf 

Thanks.

eLoran meets needs of all identified critical applications -- and others
 -- 10-20 meter navigation accuracy for harbor entrance
 -- 0.3 mile required navigation performance (RNP 0.3) & aviation integrity
 -- Stratum 1 for precise frequency users & 50 ns time accuracy

Lots more info there.  It wasn't expensive.


-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Bob Martin]

Hi,

  This is so not my area of interest but I did come across the 
following quote from the link listed below.


"A backup system is also a possible element. The British have 
demonstrated that eLoran can deliver time with 50 nanoseconds 
accuracy or better “pretty much anywhere you want to,” said Dana 
Goward, president of the Resilient Navigation and Timing Foundation."


http://insidegnss.com/broad-effort-underway-on-assured-accurate-time-for-critical-infrastructure/

I'm sure someone will identify some hidden "but" in the above claim.

 I designed the timing hardware for the Loran upgrade well over 10 
years ago and haven't thought about it until now. It is fascinating 
to me that it is still alive and twitching even after it was killed off.


  It is also interesting to see that the Time-Nut concern about GPS
vulnerability is shared by many organizations and governments.

Best,


Bob Martin



On 9/6/2018 6:04 PM, Bob kb8tq wrote:

Hi

No, eLoran *never* on it’s best day could ever deliver the kind of timing that 
the vast majority
of these systems require. It simply is not and can not do the job. The world 
has moved *way*
past the sort of timing it can actually deliver.

Bob


On Sep 6, 2018, at 6:35 PM, Scott McGrath  wrote:

Actually we DID have a radio based system that provided sufficient accuracy it 
was called eLORAN but it was killed by US politicians because they did not want 
a much more inexpensive to operate system ‘competing’ with GPS.Shutting 
down LORAN saved 32m dollars annually the NAVSTAR GPS program costs billions 
annually.

Ironically while LORAN’s absolute accuracy is less than GPS,  repeatability was 
much better so fishermen liked LORAN better.

Once again the empty suits won and the navigation and timing community lost.

Wrt cellsites staying operational i imagine the oscillators in holdover would 
probably remain sufficiently synchronized for a month or so.



On Sep 6, 2018, at 4:56 PM, Bob kb8tq  wrote:

Hi

Well, we *do* have experience with that. It was called selective availability. 
Indeed it might get turned back on again. It’s impact on a properly designed 
GPSDO - not much. It takes a bit longer to get to best stability. System time 
wise, it still works “good enough”.

A four hour long test format also does basically nothing to a GPSDO based 
system. You didn’t read anything in the papers about all cell service in three 
states going away. The devices did what they are supposed to do and everything 
did it’s boringly normal thing ….. it worked fine.

I still don’t quite understand just what people think could replace satellite 
based timing in these systems. None of the “radio based” systems are within a 
factor many thousands to a few million of being adequate.

=

Now, if this is headed off into a “the government is coming to break down the 
doors and take away all my toys sort of thing. That’s very much *not* a Time 
Nuts topic.

Bob


On Sep 6, 2018, at 11:34 AM, Scott McGrath  wrote:

And there is the other significant vulnerability since GPS is a MILITARY system 
the DoD can take it offline for any reason at any time.

Leaving civilian users with nothing,

If its a national security threat its likely the other GNSS systems will be 
unavailable as well.





On Sep 6, 2018, at 9:53 AM, John Sloan  wrote:


Folks:

Well blow me down. It took some Google Maps fu on the web on my part, but
my time and place does indeed coincide with this “GPS Interference Testing” at
White Sands Missile Range. I just happened to be in my home office watching
several of my GPS-disciplined NTP servers when this occurred. Thanks, Graham!

:John


ZDV   DENVER (ARTCC),CO. [Back to Top] !GPS 08/260 (KZDV A0287/18) ZDV NAV
GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL WI A
359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230


--
J. L. SloanDigital Aggregates Corp.
+1 303 940 9064 (O)3440 Youngfield St. #209
+1 303 489 5178 (M)Wheat Ridge CO 80033 USA
jsl...@diag.comhttp://www.diag.com 


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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Scott McGrath]

As to eLORAN,  you can deny positioning but maintain timing service simply by 
modifying the GRI and since eLORAN is software based thats not a difficult 
change.

Navigation receivers go into fail but timing receivers only need ONE station.   
As the users of SRS700’s and Austrons do when Wildwood is active.

With GNSS its a hell of a lot harder and without SA your only option is to turn 
off all the C/A signals hence denying civillian use of GNSS

I’m pretty sure if a non-state actor was doing weaponized drone attacks with 
GPS for guidance,  GPS for civilian use would be shut down in a NY minute .

Remember govt users would not be affected as they have access to the PPS and 
the ‘word of the day’ to make it active.

You dont need conspiracies to think of conditions where GPS would be shut down 
for long periods of time and where reasonable people would agree with the 
shutdown.

On Sep 6, 2018, at 8:44 PM, Scott McGrath  wrote:

Gee,  thats strange especially for those of us who ran the Austron comparitors 
to check our local standards against the LORSTA’s



On Sep 6, 2018, at 8:04 PM, Bob kb8tq  wrote:

Hi

No, eLoran *never* on it’s best day could ever deliver the kind of timing that 
the vast majority
of these systems require. It simply is not and can not do the job. The world 
has moved *way*
past the sort of timing it can actually deliver. 

Bob

> On Sep 6, 2018, at 6:35 PM, Scott McGrath  wrote:
> 
> Actually we DID have a radio based system that provided sufficient accuracy 
> it was called eLORAN but it was killed by US politicians because they did not 
> want a much more inexpensive to operate system ‘competing’ with GPS.
> Shutting down LORAN saved 32m dollars annually the NAVSTAR GPS program costs 
> billions annually.
> 
> Ironically while LORAN’s absolute accuracy is less than GPS,  repeatability 
> was much better so fishermen liked LORAN better.
> 
> Once again the empty suits won and the navigation and timing community lost.
> 
> Wrt cellsites staying operational i imagine the oscillators in holdover would 
> probably remain sufficiently synchronized for a month or so.
> 
> 
> 
> On Sep 6, 2018, at 4:56 PM, Bob kb8tq  wrote:
> 
> Hi
> 
> Well, we *do* have experience with that. It was called selective 
> availability. Indeed it might get turned back on again. It’s impact on a 
> properly designed GPSDO - not much. It takes a bit longer to get to best 
> stability. System time wise, it still works “good enough”. 
> 
> A four hour long test format also does basically nothing to a GPSDO based 
> system. You didn’t read anything in the papers about all cell service in 
> three states going away. The devices did what they are supposed to do and 
> everything did it’s boringly normal thing ….. it worked fine. 
> 
> I still don’t quite understand just what people think could replace satellite 
> based timing in these systems. None of the “radio based” systems are within a 
> factor many thousands to a few million of being adequate. 
> 
> =
> 
> Now, if this is headed off into a “the government is coming to break down the 
> doors and take away all my toys sort of thing. That’s very much *not* a Time 
> Nuts topic.
> 
> Bob
> 
>> On Sep 6, 2018, at 11:34 AM, Scott McGrath  wrote:
>> 
>> And there is the other significant vulnerability since GPS is a MILITARY 
>> system the DoD can take it offline for any reason at any time.  
>> 
>> Leaving civilian users with nothing, 
>> 
>> If its a national security threat its likely the other GNSS systems will be 
>> unavailable as well.
>> 
>> 
>> 
>> 
>> 
>> On Sep 6, 2018, at 9:53 AM, John Sloan  wrote:
>> 
>> 
>> Folks:
>> 
>> Well blow me down. It took some Google Maps fu on the web on my part, but
>> my time and place does indeed coincide with this “GPS Interference Testing” 
>> at
>> White Sands Missile Range. I just happened to be in my home office watching
>> several of my GPS-disciplined NTP servers when this occurred. Thanks, Graham!
>> 
>> :John
>> 
>>> ZDV   DENVER (ARTCC),CO. [Back to Top] !GPS 08/260 (KZDV A0287/18) ZDV NAV
>>> GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL WI A
>>> 359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
>>> RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
>>> RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230
>> 
>> --
>> J. L. SloanDigital Aggregates Corp.
>> +1 303 940 9064 (O)3440 Youngfield St. #209
>> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
>> jsl...@diag.comhttp://www.diag.com 
>> 
>> 
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>> 

Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Scott McGrath]

Gee,  thats strange especially for those of us who ran the Austron comparitors 
to check our local standards against the LORSTA’s



On Sep 6, 2018, at 8:04 PM, Bob kb8tq  wrote:

Hi

No, eLoran *never* on it’s best day could ever deliver the kind of timing that 
the vast majority
of these systems require. It simply is not and can not do the job. The world 
has moved *way*
past the sort of timing it can actually deliver. 

Bob

> On Sep 6, 2018, at 6:35 PM, Scott McGrath  wrote:
> 
> Actually we DID have a radio based system that provided sufficient accuracy 
> it was called eLORAN but it was killed by US politicians because they did not 
> want a much more inexpensive to operate system ‘competing’ with GPS.
> Shutting down LORAN saved 32m dollars annually the NAVSTAR GPS program costs 
> billions annually.
> 
> Ironically while LORAN’s absolute accuracy is less than GPS,  repeatability 
> was much better so fishermen liked LORAN better.
> 
> Once again the empty suits won and the navigation and timing community lost.
> 
> Wrt cellsites staying operational i imagine the oscillators in holdover would 
> probably remain sufficiently synchronized for a month or so.
> 
> 
> 
> On Sep 6, 2018, at 4:56 PM, Bob kb8tq  wrote:
> 
> Hi
> 
> Well, we *do* have experience with that. It was called selective 
> availability. Indeed it might get turned back on again. It’s impact on a 
> properly designed GPSDO - not much. It takes a bit longer to get to best 
> stability. System time wise, it still works “good enough”. 
> 
> A four hour long test format also does basically nothing to a GPSDO based 
> system. You didn’t read anything in the papers about all cell service in 
> three states going away. The devices did what they are supposed to do and 
> everything did it’s boringly normal thing ….. it worked fine. 
> 
> I still don’t quite understand just what people think could replace satellite 
> based timing in these systems. None of the “radio based” systems are within a 
> factor many thousands to a few million of being adequate. 
> 
> =
> 
> Now, if this is headed off into a “the government is coming to break down the 
> doors and take away all my toys sort of thing. That’s very much *not* a Time 
> Nuts topic.
> 
> Bob
> 
>> On Sep 6, 2018, at 11:34 AM, Scott McGrath  wrote:
>> 
>> And there is the other significant vulnerability since GPS is a MILITARY 
>> system the DoD can take it offline for any reason at any time.  
>> 
>> Leaving civilian users with nothing, 
>> 
>> If its a national security threat its likely the other GNSS systems will be 
>> unavailable as well.
>> 
>> 
>> 
>> 
>> 
>> On Sep 6, 2018, at 9:53 AM, John Sloan  wrote:
>> 
>> 
>> Folks:
>> 
>> Well blow me down. It took some Google Maps fu on the web on my part, but
>> my time and place does indeed coincide with this “GPS Interference Testing” 
>> at
>> White Sands Missile Range. I just happened to be in my home office watching
>> several of my GPS-disciplined NTP servers when this occurred. Thanks, Graham!
>> 
>> :John
>> 
>>> ZDV   DENVER (ARTCC),CO. [Back to Top] !GPS 08/260 (KZDV A0287/18) ZDV NAV
>>> GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL WI A
>>> 359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
>>> RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
>>> RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230
>> 
>> --
>> J. L. SloanDigital Aggregates Corp.
>> +1 303 940 9064 (O)3440 Youngfield St. #209
>> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
>> jsl...@diag.comhttp://www.diag.com 
>> 
>> 
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>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>> 
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>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> 
> 
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Bob kb8tq]

Hi

No, eLoran *never* on it’s best day could ever deliver the kind of timing that 
the vast majority
of these systems require. It simply is not and can not do the job. The world 
has moved *way*
past the sort of timing it can actually deliver. 

Bob

> On Sep 6, 2018, at 6:35 PM, Scott McGrath  wrote:
> 
> Actually we DID have a radio based system that provided sufficient accuracy 
> it was called eLORAN but it was killed by US politicians because they did not 
> want a much more inexpensive to operate system ‘competing’ with GPS.
> Shutting down LORAN saved 32m dollars annually the NAVSTAR GPS program costs 
> billions annually.
> 
> Ironically while LORAN’s absolute accuracy is less than GPS,  repeatability 
> was much better so fishermen liked LORAN better.
> 
> Once again the empty suits won and the navigation and timing community lost.
> 
> Wrt cellsites staying operational i imagine the oscillators in holdover would 
> probably remain sufficiently synchronized for a month or so.
> 
> 
> 
> On Sep 6, 2018, at 4:56 PM, Bob kb8tq  wrote:
> 
> Hi
> 
> Well, we *do* have experience with that. It was called selective 
> availability. Indeed it might get turned back on again. It’s impact on a 
> properly designed GPSDO - not much. It takes a bit longer to get to best 
> stability. System time wise, it still works “good enough”. 
> 
> A four hour long test format also does basically nothing to a GPSDO based 
> system. You didn’t read anything in the papers about all cell service in 
> three states going away. The devices did what they are supposed to do and 
> everything did it’s boringly normal thing ….. it worked fine. 
> 
> I still don’t quite understand just what people think could replace satellite 
> based timing in these systems. None of the “radio based” systems are within a 
> factor many thousands to a few million of being adequate. 
> 
> =
> 
> Now, if this is headed off into a “the government is coming to break down the 
> doors and take away all my toys sort of thing. That’s very much *not* a Time 
> Nuts topic.
> 
> Bob
> 
>> On Sep 6, 2018, at 11:34 AM, Scott McGrath  wrote:
>> 
>> And there is the other significant vulnerability since GPS is a MILITARY 
>> system the DoD can take it offline for any reason at any time.  
>> 
>> Leaving civilian users with nothing, 
>> 
>> If its a national security threat its likely the other GNSS systems will be 
>> unavailable as well.
>> 
>> 
>> 
>> 
>> 
>> On Sep 6, 2018, at 9:53 AM, John Sloan  wrote:
>> 
>> 
>> Folks:
>> 
>> Well blow me down. It took some Google Maps fu on the web on my part, but
>> my time and place does indeed coincide with this “GPS Interference Testing” 
>> at
>> White Sands Missile Range. I just happened to be in my home office watching
>> several of my GPS-disciplined NTP servers when this occurred. Thanks, Graham!
>> 
>> :John
>> 
>>> ZDV   DENVER (ARTCC),CO. [Back to Top] !GPS 08/260 (KZDV A0287/18) ZDV NAV
>>> GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL WI A
>>> 359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
>>> RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
>>> RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230
>> 
>> --
>> J. L. SloanDigital Aggregates Corp.
>> +1 303 940 9064 (O)3440 Youngfield St. #209
>> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
>> jsl...@diag.comhttp://www.diag.com 
>> 
>> 
>> ___
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>> and follow the instructions there.
> 
> 
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Bob Martin]

GPS.gov: Selective Availability
https://www.gps.gov/systems/gps/modernization/sa/
Sep 23, 2016 - The United States has no intent to ever use Selective 
Availability again. In September 2007, the U.S. government announced 
its decision to procure the future generation of GPS satellites, 
known as GPS III, without the SA feature.


Navstar: GPS Satellite Network - Space.com
https://www.space.com › Science & Astronomy
Apr 26, 2018 - GPS III's new L1C civil signal also will make it the 
first GPS satellite ... With selective availability not included on 
the latest GPS satellites, the ...


Hopefully this won't devolve into a discussion about whether one can 
trust the US Government.


Bob Martin

On 9/6/2018 3:58 PM, Mark Sims wrote:

I read that the latest GPS sats don't even have the ability to implement 
selective availability...  seems a dubious claim to me, though.

-


Indeed it might get turned back on again.

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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Bob Martin]

I'm sure this has been discussed many times here.

E-Loran - I designed the timing hardware that controlled the 
transmitters for that upgrade while I was at Timing Solutions.


As I remember it, it was funded by the FAA to be a backup for GPS. 
The FAA planned to make more use of GPS in the future (distant 
future given the speed at which the FAA moves).


I'm not sure the Coast Guard was excited about the responsibility
of running LORAN.

Here is a powerpoint presentation arguing for e-loran:

https://www.gps.gov/governance/advisory/meetings/2009-05/doherty.pdf

Bob Martin

On 9/6/2018 4:35 PM, Scott McGrath wrote:

Actually we DID have a radio based system that provided sufficient accuracy it 
was called eLORAN but it was killed by US politicians because they did not want 
a much more inexpensive to operate system ‘competing’ with GPS.Shutting 
down LORAN saved 32m dollars annually the NAVSTAR GPS program costs billions 
annually.

Ironically while LORAN’s absolute accuracy is less than GPS,  repeatability was 
much better so fishermen liked LORAN better.

Once again the empty suits won and the navigation and timing community lost.

Wrt cellsites staying operational i imagine the oscillators in holdover would 
probably remain sufficiently synchronized for a month or so.



On Sep 6, 2018, at 4:56 PM, Bob kb8tq  wrote:

Hi

Well, we *do* have experience with that. It was called selective availability. 
Indeed it might get turned back on again. It’s impact on a properly designed 
GPSDO - not much. It takes a bit longer to get to best stability. System time 
wise, it still works “good enough”.

A four hour long test format also does basically nothing to a GPSDO based 
system. You didn’t read anything in the papers about all cell service in three 
states going away. The devices did what they are supposed to do and everything 
did it’s boringly normal thing ….. it worked fine.

I still don’t quite understand just what people think could replace satellite 
based timing in these systems. None of the “radio based” systems are within a 
factor many thousands to a few million of being adequate.

=

Now, if this is headed off into a “the government is coming to break down the 
doors and take away all my toys sort of thing. That’s very much *not* a Time 
Nuts topic.

Bob


On Sep 6, 2018, at 11:34 AM, Scott McGrath  wrote:

And there is the other significant vulnerability since GPS is a MILITARY system 
the DoD can take it offline for any reason at any time.

Leaving civilian users with nothing,

If its a national security threat its likely the other GNSS systems will be 
unavailable as well.





On Sep 6, 2018, at 9:53 AM, John Sloan  wrote:


Folks:

Well blow me down. It took some Google Maps fu on the web on my part, but
my time and place does indeed coincide with this “GPS Interference Testing” at
White Sands Missile Range. I just happened to be in my home office watching
several of my GPS-disciplined NTP servers when this occurred. Thanks, Graham!

:John


ZDV   DENVER (ARTCC),CO. [Back to Top] !GPS 08/260 (KZDV A0287/18) ZDV NAV
GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL WI A
359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230


--
J. L. SloanDigital Aggregates Corp.
+1 303 940 9064 (O)3440 Youngfield St. #209
+1 303 489 5178 (M)Wheat Ridge CO 80033 USA
jsl...@diag.comhttp://www.diag.com 


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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[David I. Emery]

On Thu, Sep 06, 2018 at 06:35:23PM -0400, Scott McGrath wrote:
> Actually we DID have a radio based system that provided sufficient accuracy 
> it was called eLORAN but it was killed by US politicians because they did not 
> want a much more inexpensive to operate system ???competing??? with GPS.
> Shutting down LORAN saved 32m dollars annually the NAVSTAR GPS program costs 
> billions annually.

> Once again the empty suits won and the navigation and timing community lost.

FWLIW, my brother in law was the USCG admiral who was CFO (and
chief bean counter) of the USCG when that was going down.  I tried, but
ran into the "it's classified" stuff...  I think they had a rationale
other than just cost.   There is an argument that denying GPS to
terrorists in crisis situations is much easier than denying E-Loran... 

He is not an empty suit BTW, though a helo pilot (and MBA) by
training and not a time nut or engineer.   Now long out of the USCG and
executive VP of a Cruise line.


-- 
  Dave Emery N1PRE/AE, d...@dieconsulting.com  DIE Consulting, Weston, Mass 
02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."


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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Scott McGrath]

Actually we DID have a radio based system that provided sufficient accuracy it 
was called eLORAN but it was killed by US politicians because they did not want 
a much more inexpensive to operate system ‘competing’ with GPS.Shutting 
down LORAN saved 32m dollars annually the NAVSTAR GPS program costs billions 
annually.

Ironically while LORAN’s absolute accuracy is less than GPS,  repeatability was 
much better so fishermen liked LORAN better.

Once again the empty suits won and the navigation and timing community lost.

Wrt cellsites staying operational i imagine the oscillators in holdover would 
probably remain sufficiently synchronized for a month or so.



On Sep 6, 2018, at 4:56 PM, Bob kb8tq  wrote:

Hi

Well, we *do* have experience with that. It was called selective availability. 
Indeed it might get turned back on again. It’s impact on a properly designed 
GPSDO - not much. It takes a bit longer to get to best stability. System time 
wise, it still works “good enough”. 

A four hour long test format also does basically nothing to a GPSDO based 
system. You didn’t read anything in the papers about all cell service in three 
states going away. The devices did what they are supposed to do and everything 
did it’s boringly normal thing ….. it worked fine. 

I still don’t quite understand just what people think could replace satellite 
based timing in these systems. None of the “radio based” systems are within a 
factor many thousands to a few million of being adequate. 

=

Now, if this is headed off into a “the government is coming to break down the 
doors and take away all my toys sort of thing. That’s very much *not* a Time 
Nuts topic.

Bob

> On Sep 6, 2018, at 11:34 AM, Scott McGrath  wrote:
> 
> And there is the other significant vulnerability since GPS is a MILITARY 
> system the DoD can take it offline for any reason at any time.  
> 
> Leaving civilian users with nothing, 
> 
> If its a national security threat its likely the other GNSS systems will be 
> unavailable as well.
> 
> 
> 
> 
> 
> On Sep 6, 2018, at 9:53 AM, John Sloan  wrote:
> 
> 
> Folks:
> 
> Well blow me down. It took some Google Maps fu on the web on my part, but
> my time and place does indeed coincide with this “GPS Interference Testing” at
> White Sands Missile Range. I just happened to be in my home office watching
> several of my GPS-disciplined NTP servers when this occurred. Thanks, Graham!
> 
> :John
> 
>> ZDV   DENVER (ARTCC),CO. [Back to Top] !GPS 08/260 (KZDV A0287/18) ZDV NAV
>> GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL WI A
>> 359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
>> RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
>> RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230
> 
> --
> J. L. SloanDigital Aggregates Corp.
> +1 303 940 9064 (O)3440 Youngfield St. #209
> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
> jsl...@diag.comhttp://www.diag.com 
> 
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
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> 
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Bob kb8tq]

Hi

Well, we *do* have experience with that. It was called selective availability. 
Indeed it might get turned back on again. It’s impact on a properly designed 
GPSDO - not much. It takes a bit longer to get to best stability. System time 
wise, it still works “good enough”. 

A four hour long test format also does basically nothing to a GPSDO based 
system. You didn’t read anything in the papers about all cell service in three 
states going away. The devices did what they are supposed to do and everything 
did it’s boringly normal thing ….. it worked fine. 

I still don’t quite understand just what people think could replace satellite 
based timing in these systems. None of the “radio based” systems are within a 
factor many thousands to a few million of being adequate. 

=

Now, if this is headed off into a “the government is coming to break down the 
doors and take away all my toys sort of thing. That’s very much *not* a Time 
Nuts topic.

Bob

> On Sep 6, 2018, at 11:34 AM, Scott McGrath  wrote:
> 
> And there is the other significant vulnerability since GPS is a MILITARY 
> system the DoD can take it offline for any reason at any time.  
> 
> Leaving civilian users with nothing, 
> 
>  If its a national security threat its likely the other GNSS systems will be 
> unavailable as well.
> 
> 
> 
> 
> 
> On Sep 6, 2018, at 9:53 AM, John Sloan  wrote:
> 
> 
> Folks:
> 
> Well blow me down. It took some Google Maps fu on the web on my part, but
> my time and place does indeed coincide with this “GPS Interference Testing” at
> White Sands Missile Range. I just happened to be in my home office watching
> several of my GPS-disciplined NTP servers when this occurred. Thanks, Graham!
> 
> :John
> 
>> ZDV   DENVER (ARTCC),CO. [Back to Top] !GPS 08/260 (KZDV A0287/18) ZDV NAV
>> GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL WI A
>> 359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
>> RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
>> RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230
> 
> --
> J. L. SloanDigital Aggregates Corp.
> +1 303 940 9064 (O)3440 Youngfield St. #209
> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
> jsl...@diag.comhttp://www.diag.com 
> 
> 
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[David Van Horn]

We just put up another GPS antenna for our backup thunderbolt, and now IT is 
blaming that for why our wifi is sluggish.
And it happens whether the new antenna is even connected!

https://www.kb6nu.com/theyll-do-it-every-time/


I should have known.. (KC6ETE here)
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Scott McGrath]

And there is the other significant vulnerability since GPS is a MILITARY system 
the DoD can take it offline for any reason at any time.  

 Leaving civilian users with nothing, 

  If its a national security threat its likely the other GNSS systems will be 
unavailable as well.





On Sep 6, 2018, at 9:53 AM, John Sloan  wrote:


Folks:

Well blow me down. It took some Google Maps fu on the web on my part, but
my time and place does indeed coincide with this “GPS Interference Testing” at
White Sands Missile Range. I just happened to be in my home office watching
several of my GPS-disciplined NTP servers when this occurred. Thanks, Graham!

:John

> ZDV   DENVER (ARTCC),CO. [Back to Top] !GPS 08/260 (KZDV A0287/18) ZDV NAV
> GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL WI A
> 359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
> RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
> RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230

--
J. L. SloanDigital Aggregates Corp.
+1 303 940 9064 (O)3440 Youngfield St. #209
+1 303 489 5178 (M)Wheat Ridge CO 80033 USA
jsl...@diag.comhttp://www.diag.com 


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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Dr. David Kirkby]

On Tue, 4 Sep 2018, 18:35 John Sloan,  wrote:

> Folks:
>
>
>
> Yesterday (2018-09-03) afternoon (about 22:00UTC, 16:00MDT) I noticed one
> of my three home-made GPS-disciplined NTP servers had lost its GPS lock.
> After some forensics on my part, this (2018-09-04) morning (about 16:00UTC,
> 10:00MDT) I replaced the amplified antenna, and the device reacquired its
> lock. I figured it was just an antenna failures; this is an amplified
> filtered antenna so it has active electronics.
>
> Then just an hour or so later, I noticed one of my commercial
> GPS-disciplined NTP servers (TimeMachines) had lost the GPS 1PPS timing
> signal, but indicated it still had GPS lock. (I
>
> No clue what's going on in my suburb near Golden Colorado. But I’m a
> little freaked out. Trying to figure out which rule, [1] It’s something
> stupid I’ve done, or [2] I am not unique, to apply.
>
> :John


I know someone else who had a similar problem. It turned out to be a fault
in one of the active antennas which went into self-oscillation,  which
jammed the other GPS receivers.



Dave.
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[John Sloan]

Folks:

Well blow me down. It took some Google Maps fu on the web on my part, but
my time and place does indeed coincide with this “GPS Interference Testing” at
White Sands Missile Range. I just happened to be in my home office watching
several of my GPS-disciplined NTP servers when this occurred. Thanks, Graham!

:John

> ZDV   DENVER (ARTCC),CO. [Back to Top] !GPS 08/260 (KZDV A0287/18) ZDV NAV
> GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL WI A
> 359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
> RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
> RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230

--
J. L. SloanDigital Aggregates Corp.
+1 303 940 9064 (O)3440 Youngfield St. #209
+1 303 489 5178 (M)Wheat Ridge CO 80033 USA
jsl...@diag.comhttp://www.diag.com 


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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Hal Murray]

I'm in Silicon Valley.  I'm logging some data from a Z3801A and a KS-24361.

I have a poor antenna location.  I'm used to the Z3801A dropping into holdover 
every few days when it can't find any satellites.  Less often for the KS-24361.

I noticed some strange activity in the past few days.  The FFOM is bumping up 
to 1 for a while while it says it has several satellites.  I don't see 
indications of holdover, but maybe I'm not looking in the right place.

-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Scott McGrath]

Actually. I have 6...   And a large assortment of directional antennas of many 
flavors LPDA, Horn etc,I have to get out there and find the interfering 
source.

Cable company has been having problems with ‘booster’ amplifiers installed by 
homeowners to ‘clean up’ noisy DTV signals.   So just imagine a cheap 
unshielded amp driven into clipping.

I live in the sticks so LightSquared or its successor  is unlikely to be the 
source in my case.



On Sep 4, 2018, at 3:18 PM, Dana Whitlow  wrote:

Scott & John,

Do either of you have any activity by "Light Squared" (or whatever it's now
called) in your area.  Jamming does not always have to be in-band to be
effective.

Dana


> On Tue, Sep 4, 2018 at 1:11 PM Scott McGrath  wrote:
> 
> My TrueTime DC-XL has lost lock since yesterday as has my Z3805 and my
> car’s onboard GPS will not lock since the 2’nd.  I need to get about a mile
> from home before Car’s nav system reports ready.
> 
> There has been a great deal of repair work on the local cable system so
> this is almost certainly related to that
> 
> But it proves my point about the fragility of GPS
> 
> 
> 
> 
> 
> On Sep 4, 2018, at 12:31 PM, John Sloan  wrote:
> 
> Folks:
> 
> GPS jamming and spoofing isn't really my area of expertise, but it's
> something I worry about, not just for its impact on geolocation and
> navigation applications, but also because GPS has become critical as a high
> precision timing reference in the telecommunications realm, which *is* my
> area of expertise.
> 
> Yesterday (2018-09-03) afternoon (about 22:00UTC, 16:00MDT) I noticed one
> of my three home-made GPS-disciplined NTP servers had lost its GPS lock.
> After some forensics on my part, this (2018-09-04) morning (about 16:00UTC,
> 10:00MDT) I replaced the amplified antenna, and the device reacquired its
> lock. I figured it was just an antenna failures; this is an amplified
> filtered antenna so it has active electronics.
> 
> Then just an hour or so later, I noticed one of my commercial
> GPS-disciplined NTP servers (TimeMachines) had lost the GPS 1PPS timing
> signal, but indicated it still had GPS lock. (I question now what this
> actually means in the context of this particular device). As a
> troubleshooting step, I power cycled the device, and it reacquired 1PPS.
> But as I did that, the second commercial GPS-disciplined NTP server
> (Uputronics) right next to it lit up with a red warning on its display,
> indicating it had lost GPS lock. A minute or so later it also reacquired
> lock and indicated 1PPS, with no action on my part.
> 
> All of these devices are completely independent, have different software
> (and probably hardware), have separate amplified antennas sitting side by
> side in the window of my home office, and are not all on the same
> electrical outlet (but may be on the same household circuit).
> 
> I lit up the LCD display on my little GPS monitoring tool I built that
> runs Lady Heather 24x7 and see on the graphical display sudden jumps of
> reduced timing accuracy of a factor of 10^2 (from nanoseconds to hundreds
> of nanoseconds) in the recent past. But I’m thinking this can also be
> caused just by the dynamic satellite geometry, and might be normal. It’s
> not like I watch this graph all the time (even though it does sit right in
> front of me on my desk).
> 
> No clue what's going on in my suburb near Golden Colorado. But I’m a
> little freaked out. Trying to figure out which rule, [1] It’s something
> stupid I’ve done, or [2] I am not unique, to apply.
> 
> :John
> 
> --
> J. L. SloanDigital Aggregates Corp.
> +1 303 940 9064 (O)3440 Youngfield St. #209
> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
> jsl...@diag.comhttp://www.diag.com 
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Graham / KE9H]

The following are active GPS NOTAMs.
Data Current as of: Tue, 04 Sep 2018 19:16:00 UTC
GPS   GLOBAL POSITIONING SYSTEM [Back to Top] !GPS 09/009 (KNMH A0020/18)
GPS NAV PRN 02 OUT OF SERVICE 1809061455-1809070255

ZAB   ALBUQUERQUE (ARTCC),NM. [Back to Top] !GPS 08/259 (KZAB A0367/18) ZAB
NAV GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL
WI A 359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230

ZDV   DENVER (ARTCC),CO. [Back to Top] !GPS 08/260 (KZDV A0287/18) ZDV NAV
GPS (WSMR GPS 18-20) (INCLUDING WAAS, GBAS, AND ADS-B) MAY NOT BE AVBL WI A
359NM RADIUS CENTERED AT 45N1063840W (TCS054036) FL400-UNL, 311NM
RADIUS AT FL250, 215NM RADIUS AT 1FT, 223NM RADIUS AT 4000FT AGL, 169NM
RADIUS AT 50FT AGL DLY 1830-2230 1809031830-1809082230

The military does testing that can cause GPS jamming down in New Mexico.
Are you within range of these NOTAMS?
You might have to plot the Lat-Long co-ordinates

--- Graham

==


On Tue, Sep 4, 2018 at 1:10 PM Scott McGrath  wrote:

> My TrueTime DC-XL has lost lock since yesterday as has my Z3805 and my
> car’s onboard GPS will not lock since the 2’nd.  I need to get about a mile
> from home before Car’s nav system reports ready.
>
> There has been a great deal of repair work on the local cable system so
> this is almost certainly related to that
>
> But it proves my point about the fragility of GPS
>
>
>
>
>
> On Sep 4, 2018, at 12:31 PM, John Sloan  wrote:
>
> Folks:
>
> GPS jamming and spoofing isn't really my area of expertise, but it's
> something I worry about, not just for its impact on geolocation and
> navigation applications, but also because GPS has become critical as a high
> precision timing reference in the telecommunications realm, which *is* my
> area of expertise.
>
> Yesterday (2018-09-03) afternoon (about 22:00UTC, 16:00MDT) I noticed one
> of my three home-made GPS-disciplined NTP servers had lost its GPS lock.
> After some forensics on my part, this (2018-09-04) morning (about 16:00UTC,
> 10:00MDT) I replaced the amplified antenna, and the device reacquired its
> lock. I figured it was just an antenna failures; this is an amplified
> filtered antenna so it has active electronics.
>
> Then just an hour or so later, I noticed one of my commercial
> GPS-disciplined NTP servers (TimeMachines) had lost the GPS 1PPS timing
> signal, but indicated it still had GPS lock. (I question now what this
> actually means in the context of this particular device). As a
> troubleshooting step, I power cycled the device, and it reacquired 1PPS.
> But as I did that, the second commercial GPS-disciplined NTP server
> (Uputronics) right next to it lit up with a red warning on its display,
> indicating it had lost GPS lock. A minute or so later it also reacquired
> lock and indicated 1PPS, with no action on my part.
>
> All of these devices are completely independent, have different software
> (and probably hardware), have separate amplified antennas sitting side by
> side in the window of my home office, and are not all on the same
> electrical outlet (but may be on the same household circuit).
>
> I lit up the LCD display on my little GPS monitoring tool I built that
> runs Lady Heather 24x7 and see on the graphical display sudden jumps of
> reduced timing accuracy of a factor of 10^2 (from nanoseconds to hundreds
> of nanoseconds) in the recent past. But I’m thinking this can also be
> caused just by the dynamic satellite geometry, and might be normal. It’s
> not like I watch this graph all the time (even though it does sit right in
> front of me on my desk).
>
> No clue what's going on in my suburb near Golden Colorado. But I’m a
> little freaked out. Trying to figure out which rule, [1] It’s something
> stupid I’ve done, or [2] I am not unique, to apply.
>
> :John
>
> --
> J. L. SloanDigital Aggregates Corp.
> +1 303 940 9064 (O)3440 Youngfield St. #209
> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
> jsl...@diag.comhttp://www.diag.com 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
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Re: [time-nuts] Lost GPS lock or 1PPS recently?

[Dana Whitlow]

Scott & John,

Do either of you have any activity by "Light Squared" (or whatever it's now
called) in your area.  Jamming does not always have to be in-band to be
effective.

Dana


On Tue, Sep 4, 2018 at 1:11 PM Scott McGrath  wrote:

> My TrueTime DC-XL has lost lock since yesterday as has my Z3805 and my
> car’s onboard GPS will not lock since the 2’nd.  I need to get about a mile
> from home before Car’s nav system reports ready.
>
> There has been a great deal of repair work on the local cable system so
> this is almost certainly related to that
>
> But it proves my point about the fragility of GPS
>
>
>
>
>
> On Sep 4, 2018, at 12:31 PM, John Sloan  wrote:
>
> Folks:
>
> GPS jamming and spoofing isn't really my area of expertise, but it's
> something I worry about, not just for its impact on geolocation and
> navigation applications, but also because GPS has become critical as a high
> precision timing reference in the telecommunications realm, which *is* my
> area of expertise.
>
> Yesterday (2018-09-03) afternoon (about 22:00UTC, 16:00MDT) I noticed one
> of my three home-made GPS-disciplined NTP servers had lost its GPS lock.
> After some forensics on my part, this (2018-09-04) morning (about 16:00UTC,
> 10:00MDT) I replaced the amplified antenna, and the device reacquired its
> lock. I figured it was just an antenna failures; this is an amplified
> filtered antenna so it has active electronics.
>
> Then just an hour or so later, I noticed one of my commercial
> GPS-disciplined NTP servers (TimeMachines) had lost the GPS 1PPS timing
> signal, but indicated it still had GPS lock. (I question now what this
> actually means in the context of this particular device). As a
> troubleshooting step, I power cycled the device, and it reacquired 1PPS.
> But as I did that, the second commercial GPS-disciplined NTP server
> (Uputronics) right next to it lit up with a red warning on its display,
> indicating it had lost GPS lock. A minute or so later it also reacquired
> lock and indicated 1PPS, with no action on my part.
>
> All of these devices are completely independent, have different software
> (and probably hardware), have separate amplified antennas sitting side by
> side in the window of my home office, and are not all on the same
> electrical outlet (but may be on the same household circuit).
>
> I lit up the LCD display on my little GPS monitoring tool I built that
> runs Lady Heather 24x7 and see on the graphical display sudden jumps of
> reduced timing accuracy of a factor of 10^2 (from nanoseconds to hundreds
> of nanoseconds) in the recent past. But I’m thinking this can also be
> caused just by the dynamic satellite geometry, and might be normal. It’s
> not like I watch this graph all the time (even though it does sit right in
> front of me on my desk).
>
> No clue what's going on in my suburb near Golden Colorado. But I’m a
> little freaked out. Trying to figure out which rule, [1] It’s something
> stupid I’ve done, or [2] I am not unique, to apply.
>
> :John
>
> --
> J. L. SloanDigital Aggregates Corp.
> +1 303 940 9064 (O)3440 Youngfield St. #209
> +1 303 489 5178 (M)Wheat Ridge CO 80033 USA
> jsl...@diag.comhttp://www.diag.com 
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> time-nuts mailing list -- time-nuts@lists.febo.com
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