Re: [time-nuts] GPS Outage

[Magnus Danielson]

Hi Jim,

On 03/01/2016 03:24 PM, jimlux wrote:

On 2/29/16 10:56 PM, Magnus Danielson wrote:



On 02/29/2016 11:31 AM, Martin Burnicki wrote:

Hal,

Hal Murray wrote:


martin.burni...@burnicki.net said:

Strange that at least 3 independant firmware trees/development
teams should
chose the same magic wk860.



I don't find it strange. If the next firmware version is based on the
previous version and none of the developers has stumbled across this
potential problem earlier ...


That sounds like poor software engineering.  Or poor engineering
management.

The wk860 is supposed to represent the build time of the software ...


Do you *know* this, or are you just *assuming* this? ;-)


so it will
work for 20 years from when it was built rather than 20 years from
when the
10 bit week counter last rolled over or 20 years from when the
constant was
last updated.


There are also approaches where the proper extension of a week number
doesn't just work within a single 1024 week cycle with some hardcoded
limit, like this simple example:

if ( wn < 860 )
   wn += 1024;

There may always be pieces of code which generate a faulty result under
certain conditions, and no stumbles across this even in reviews until it
really happens.

I'm not aware of *any* project where each single line of code is checked
once again whenever a new release is rolled out.


Rather, in all projects I've seen there is a tendency to trust existing
code and only extend it. Re-validating it is usually regarded as money
in the sea. That old code can have incorrect assumptions that you
eventually expose as you change its environment is a re-occurring
learning experience.



Ariane 5...


Indeed. Most of the cases the failure isn't as spectacular.

Cheers,
Magnus
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Re: [time-nuts] GPS Outage

[jimlux]

On 2/29/16 10:56 PM, Magnus Danielson wrote:



On 02/29/2016 11:31 AM, Martin Burnicki wrote:

Hal,

Hal Murray wrote:


martin.burni...@burnicki.net said:

Strange that at least 3 independant firmware trees/development
teams should
chose the same magic wk860.



I don't find it strange. If the next firmware version is based on the
previous version and none of the developers has stumbled across this
potential problem earlier ...


That sounds like poor software engineering.  Or poor engineering
management.

The wk860 is supposed to represent the build time of the software ...


Do you *know* this, or are you just *assuming* this? ;-)


so it will
work for 20 years from when it was built rather than 20 years from
when the
10 bit week counter last rolled over or 20 years from when the
constant was
last updated.


There are also approaches where the proper extension of a week number
doesn't just work within a single 1024 week cycle with some hardcoded
limit, like this simple example:

if ( wn < 860 )
   wn += 1024;

There may always be pieces of code which generate a faulty result under
certain conditions, and no stumbles across this even in reviews until it
really happens.

I'm not aware of *any* project where each single line of code is checked
once again whenever a new release is rolled out.


Rather, in all projects I've seen there is a tendency to trust existing
code and only extend it. Re-validating it is usually regarded as money
in the sea. That old code can have incorrect assumptions that you
eventually expose as you change its environment is a re-occurring
learning experience.



Ariane 5...




 Modern approaches to testing helps, and working on

the backlog of testing can help to disclose such problems, but only if
the test-code writer has the mindset that covers the problem at hand.
It's easy to make bold statements, reality is much more humbling
experience in the long run. Good test-benches will aid you as you want
to make larger clean-ups of old code. Larger clean-ups helps to expose
old bugs as you actually look at the code as a designer again. It is
also humbling to see what errors a younger yourself did and how you now
don't do such design anymore as you have been bitten badly by the bug.





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Re: [time-nuts] GPS Outage

[Bob Camp]

Hi

Take a look at math libraries and things like printf libraries. Each time 
somebody
writes one, there are a group of bugs that come up again and again. Yes, you 
would *think* each group would come up with creative *new* errors … not so 
much. 
There are always obvious assumptions that turn out to be wrong in corner cases.

Bob


> On Mar 1, 2016, at 1:56 AM, Magnus Danielson  
> wrote:
> 
> 
> 
> On 02/29/2016 11:31 AM, Martin Burnicki wrote:
>> Hal,
>> 
>> Hal Murray wrote:
>>> 
>>> martin.burni...@burnicki.net said:
> Strange that at least 3 independant firmware trees/development teams 
> should
> chose the same magic wk860.
>>> 
 I don't find it strange. If the next firmware version is based on the
 previous version and none of the developers has stumbled across this
 potential problem earlier ...
>>> 
>>> That sounds like poor software engineering.  Or poor engineering management.
>>> 
>>> The wk860 is supposed to represent the build time of the software ...
>> 
>> Do you *know* this, or are you just *assuming* this? ;-)
>> 
>>> so it will
>>> work for 20 years from when it was built rather than 20 years from when the
>>> 10 bit week counter last rolled over or 20 years from when the constant was
>>> last updated.
>> 
>> There are also approaches where the proper extension of a week number
>> doesn't just work within a single 1024 week cycle with some hardcoded
>> limit, like this simple example:
>> 
>> if ( wn < 860 )
>>   wn += 1024;
>> 
>> There may always be pieces of code which generate a faulty result under
>> certain conditions, and no stumbles across this even in reviews until it
>> really happens.
>> 
>> I'm not aware of *any* project where each single line of code is checked
>> once again whenever a new release is rolled out.
> 
> Rather, in all projects I've seen there is a tendency to trust existing code 
> and only extend it. Re-validating it is usually regarded as money in the sea. 
> That old code can have incorrect assumptions that you eventually expose as 
> you change its environment is a re-occurring learning experience. Modern 
> approaches to testing helps, and working on the backlog of testing can help 
> to disclose such problems, but only if the test-code writer has the mindset 
> that covers the problem at hand. It's easy to make bold statements, reality 
> is much more humbling experience in the long run. Good test-benches will aid 
> you as you want to make larger clean-ups of old code. Larger clean-ups helps 
> to expose old bugs as you actually look at the code as a designer again. It 
> is also humbling to see what errors a younger yourself did and how you now 
> don't do such design anymore as you have been bitten badly by the bug.
> 
> Cheers,
> Magnus
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Re: [time-nuts] GPS Outage

[Magnus Danielson]

On 02/29/2016 11:31 AM, Martin Burnicki wrote:

Hal,

Hal Murray wrote:


martin.burni...@burnicki.net said:

Strange that at least 3 independant firmware trees/development teams should
chose the same magic wk860.



I don't find it strange. If the next firmware version is based on the
previous version and none of the developers has stumbled across this
potential problem earlier ...


That sounds like poor software engineering.  Or poor engineering management.

The wk860 is supposed to represent the build time of the software ...


Do you *know* this, or are you just *assuming* this? ;-)


so it will
work for 20 years from when it was built rather than 20 years from when the
10 bit week counter last rolled over or 20 years from when the constant was
last updated.


There are also approaches where the proper extension of a week number
doesn't just work within a single 1024 week cycle with some hardcoded
limit, like this simple example:

if ( wn < 860 )
   wn += 1024;

There may always be pieces of code which generate a faulty result under
certain conditions, and no stumbles across this even in reviews until it
really happens.

I'm not aware of *any* project where each single line of code is checked
once again whenever a new release is rolled out.


Rather, in all projects I've seen there is a tendency to trust existing 
code and only extend it. Re-validating it is usually regarded as money 
in the sea. That old code can have incorrect assumptions that you 
eventually expose as you change its environment is a re-occurring 
learning experience. Modern approaches to testing helps, and working on 
the backlog of testing can help to disclose such problems, but only if 
the test-code writer has the mindset that covers the problem at hand. 
It's easy to make bold statements, reality is much more humbling 
experience in the long run. Good test-benches will aid you as you want 
to make larger clean-ups of old code. Larger clean-ups helps to expose 
old bugs as you actually look at the code as a designer again. It is 
also humbling to see what errors a younger yourself did and how you now 
don't do such design anymore as you have been bitten badly by the bug.


Cheers,
Magnus
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Re: [time-nuts] GPS Outage

[Wojciech Owczarek]

Funny how apparently Trimble were involved in the wk860 problem, I thought they 
famously used their leap second based rollover protection: 
http://www.google.co.uk/patents/US5923618 :) Maybe that algorithm isn't that 
smart after all.

Thanks,
Wojciech 

  Original Message  
From:martin.burni...@burnicki.net
Sent:29 February 2016 11:02 am
To:time-nuts@febo.com
Reply to:time-nuts@febo.com
Cc:hmur...@megapathdsl.net
Subject:Re: [time-nuts] GPS Outage

Hal,

Hal Murray wrote:
> 
> martin.burni...@burnicki.net said:
>>> Strange that at least 3 independant firmware trees/development teams should
>>> chose the same magic wk860.
> 
>> I don't find it strange. If the next firmware version is based on the
>> previous version and none of the developers has stumbled across this
>> potential problem earlier ... 
> 
> That sounds like poor software engineering.  Or poor engineering management.
> 
> The wk860 is supposed to represent the build time of the software ...

Do you *know* this, or are you just *assuming* this? ;-)

> so it will 
> work for 20 years from when it was built rather than 20 years from when the 
> 10 bit week counter last rolled over or 20 years from when the constant was 
> last updated.

There are also approaches where the proper extension of a week number
doesn't just work within a single 1024 week cycle with some hardcoded
limit, like this simple example:

if ( wn < 860 )
  wn += 1024;

There may always be pieces of code which generate a faulty result under
certain conditions, and no stumbles across this even in reviews until it
really happens.

I'm not aware of *any* project where each single line of code is checked
once again whenever a new release is rolled out.

Martin

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Re: [time-nuts] GPS Outage

[Martin Burnicki]

Hal,

Hal Murray wrote:
> 
> martin.burni...@burnicki.net said:
>>> Strange that at least 3 independant firmware trees/development teams should
>>> chose the same magic wk860.
> 
>> I don't find it strange. If the next firmware version is based on the
>> previous version and none of the developers has stumbled across this
>> potential problem earlier ... 
> 
> That sounds like poor software engineering.  Or poor engineering management.
> 
> The wk860 is supposed to represent the build time of the software ...

Do you *know* this, or are you just *assuming* this? ;-)

> so it will 
> work for 20 years from when it was built rather than 20 years from when the 
> 10 bit week counter last rolled over or 20 years from when the constant was 
> last updated.

There are also approaches where the proper extension of a week number
doesn't just work within a single 1024 week cycle with some hardcoded
limit, like this simple example:

if ( wn < 860 )
  wn += 1024;

There may always be pieces of code which generate a faulty result under
certain conditions, and no stumbles across this even in reviews until it
really happens.

I'm not aware of *any* project where each single line of code is checked
once again whenever a new release is rolled out.

Martin

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Re: [time-nuts] GPS Outage..

[Magnus Danielson]

Hi Jim,

For Call Data Records (CDR) there isn't no need for significantly better 
precision, and for most logging use not either, but for the air 
interface, timing has shifted from relatively unimportant to very important.


The trouble is that it is so highly dependent on technology, that 
generic statements about cell/mobile technology cannot be made. Time is 
also another aspect, and geography. It used to be that the north america 
ran its own race on mobile standards (AMPS/DAMPS/CDMA). The nordic 
countries ran theirs (NMT), and that converted into the european (GSM) 
and then in the next round the world (UMTS). Some technology got 
inherited into the UMTS from CDMA. Much got inherited from the 
NMT/GSM/UMTS/LTE route. There is also technologies such as DECT and 
TETRA and then some national variants of the international ones.


Cheers,
Magnus

On 02/27/2016 11:09 PM, jimlux wrote:

I was thinking about the dispatch center.  When I worked on software for
the LAPD ECCCS system in the 80s, timing was established by the OS
timing (rsx-11m)  external sync was by wristwatch.

I doubt it's any more precise now.   They would get a feed from the E911
system.  So the tight timing to get caller location would be in that
system, not the PD's system.

The dispatch system needed millisecond response time ( for radio voice
switching) but not absolute timing. It ran with a hot standby for fail
over and used dual port disk drives. The file system (my part) used OS
timestamps.


Sent via the Samsung Galaxy S®6 active, an AT 4G LTE smartphone
 Original message 
From: Magnus Danielson <mag...@rubidium.dyndns.org>
Date: 2/27/2016 10:54 AM (GMT-08:00)
To: time-nuts@febo.com
Cc: mag...@rubidium.se
Subject: Re: [time-nuts] GPS Outage..

Hi Jim,

On 02/27/2016 06:14 PM, jimlux wrote:
 > On 2/26/16 11:34 PM, Hal Murray wrote:
 >>>> How many of them came from E-911 stations?
 >>> E-911 triangulation done on cell towers …
 >>
 >> I was thinking of the stations where they have the dispatchers who
 >> answer the
 >> calls
 >> and pass the info on to the right people.  I think they need good
 >> timing on
 >> the recordings, but don't know any details.  I've always thought some
 >> of them
 >> used GPS.
 >>
 >
 >
 > They need good time, but probably only to the nearest second.

Phase alignment is relevant for TDMA based systems as well as CDMA based
systems, but for a bit different reasons.

GSM for instance actually have phase requirements, but dodges it by
using one of many options to compensate the phase difference between
different towers.

Cheers,
Magnus
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Re: [time-nuts] GPS Outage..

[jimlux]

I was thinking about the dispatch center.  When I worked on software for the 
LAPD ECCCS system in the 80s, timing was established by the OS timing (rsx-11m) 
 external sync was by wristwatch. 
I doubt it's any more precise now.   They would get a feed from the E911 
system.  So the tight timing to get caller location would be in that system, 
not the PD's system.
The dispatch system needed millisecond response time ( for radio voice 
switching) but not absolute timing. It ran with a hot standby for fail over and 
used dual port disk drives. The file system (my part) used OS timestamps.  

Sent via the Samsung Galaxy S®6 active, an AT 4G LTE smartphone 
Original message From: Magnus Danielson <mag...@rubidium.dyndns.org> 
Date: 2/27/2016  10:54 AM  (GMT-08:00) To: time-nuts@febo.com Cc: 
mag...@rubidium.se Subject: Re: [time-nuts] GPS Outage.. 
Hi Jim,

On 02/27/2016 06:14 PM, jimlux wrote:
> On 2/26/16 11:34 PM, Hal Murray wrote:
>>>> How many of them came from E-911 stations?
>>> E-911 triangulation done on cell towers …
>>
>> I was thinking of the stations where they have the dispatchers who
>> answer the
>> calls
>> and pass the info on to the right people.  I think they need good
>> timing on
>> the recordings, but don't know any details.  I've always thought some
>> of them
>> used GPS.
>>
>
>
> They need good time, but probably only to the nearest second.

Phase alignment is relevant for TDMA based systems as well as CDMA based 
systems, but for a bit different reasons.

GSM for instance actually have phase requirements, but dodges it by 
using one of many options to compensate the phase difference between 
different towers.

Cheers,
Magnus
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Re: [time-nuts] GPS Outage..

[Poul-Henning Kamp]

In message , Bob Camp writes:

>(Stratum 1,2,3) is based on various timing sources. It also was
>designed in an era of “top down” timing. That is a very different
>approach than the “bottom up” timing of the over the air codes
>on CDMA or some (but not all) advanced TDMA systems. 

The BSTJ contains some very interesting articles about how
synchronization got introduced and rolled out in the telephone
network originally.

You can find them on archive.org

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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Re: [time-nuts] GPS Outage..

[Bob Camp]

Hi


All CDMA systems are directly locked to GPS time. None of them do the Gold Code
sync based on central office timing. Prior to CDMA, the AMPS system was 
frequency 
domain based not time. Those basestations did not use anything more than an OCXO
to keep them up and running on the wireless side of the system. 

Regardless of the ultimate backhaul sync source above the CO, the basestation 
will keep
talking based on whatever sync pulse it gets on the backhaul link. If the CO 
goes off and away
network wise, that is only a problem for traffic that leaves the local area. 
Indeed much of “that stuff”
(Stratum 1,2,3) is based on various timing sources. It also was designed in an 
era of “top down” 
timing. That is a very different approach than the “bottom up” timing of the 
over the air codes 
on CDMA or some (but not all) advanced TDMA systems. 

Bob

> On Feb 27, 2016, at 9:50 AM, Tom McDermott  wrote:
> 
> The reason many cell sites went to GPS for time and frequency
> synchronization is that in many cases
> it was either less expensive or only possible to backhaul the cell site
> traffic to the MTSO (Mobile Telephone
> Switching Office) via microwave radio rather than wireline copper or fiber
> carrier.
> 
> That microwave backhaul did not always provide sufficiently precise phase
> and frequency reference
> needed at the cell site.
> 
> -- Tom, N5EG
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Re: [time-nuts] GPS Outage..

[Magnus Danielson]

Hi Jim,

On 02/27/2016 06:14 PM, jimlux wrote:

On 2/26/16 11:34 PM, Hal Murray wrote:

How many of them came from E-911 stations?

E-911 triangulation done on cell towers …


I was thinking of the stations where they have the dispatchers who
answer the
calls
and pass the info on to the right people.  I think they need good
timing on
the recordings, but don't know any details.  I've always thought some
of them
used GPS.




They need good time, but probably only to the nearest second.


Phase alignment is relevant for TDMA based systems as well as CDMA based 
systems, but for a bit different reasons.


GSM for instance actually have phase requirements, but dodges it by 
using one of many options to compensate the phase difference between 
different towers.


Cheers,
Magnus
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Re: [time-nuts] GPS Outage..

[Magnus Danielson]

Tom,

On 02/27/2016 03:50 PM, Tom McDermott wrote:

The reason many cell sites went to GPS for time and frequency
synchronization is that in many cases
it was either less expensive or only possible to backhaul the cell site
traffic to the MTSO (Mobile Telephone
Switching Office) via microwave radio rather than wireline copper or fiber
carrier.

That microwave backhaul did not always provide sufficiently precise phase
and frequency reference
needed at the cell site.


For most telecom purposes, the frequency transfer of microwave links 
suffice. Newer links have some basic support for things like PTP.
I run time-transfer over many microwave links, which is a bit of a 
challenge for all the wrong reasons, but it works.


It is only when you push the requirement below +/- 1 us that you start 
to have issues.


Cheers,
Magnus
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Re: [time-nuts] GPS Outage..

[Mark Spencer]

I'd be curious to know how many carriers have a reference source other than GPS 
for their "data line sync."

A few decades ago when I worked with long haul data circuits for a living the 
use of in non GPS timing references still seemed fairly common in my view.

Yes I agree that some systems can run from "line timing" but a reference source 
is still needed some where.  
In my experience there was a common assumption made that the carriers had an 
accurate reference source for the timing that customers would pull "data line 
sync" from.

Later when I entered the time nuts hobby I saw lots of ex Telecom timing  gear 
for sale on the usual auction site.


All the best
Mark Spencer


> On Feb 27, 2016, at 4:51 AM, Bob Camp  wrote:
> 
> Hi
> 
>> On Feb 26, 2016, at 8:01 PM, Majdi S. Abbas  wrote:
>> 
>> On Fri, Feb 26, 2016 at 05:56:59PM -0500, Bob Camp wrote:
>>> Cell phones since they first came out have *never ever* been setup 
>>> to run on anything other than GPS. Retrofitting them to use something 
>>> else would take a decade or more. We didn’t “destroy the backup”, there 
>>> never was one. Pretty much all of our surplus gizmos are cell tower 
>>> surplus (like 99.99%).
>> 
>>Bob,
>> 
>>It depends.  
>> 
>>We're used to thinking of those GPS and oscillator packages
>> as the only timing for a cell site, but that was not the case until
>> fairly recently.
>> 
>>In many of those sites, there was also transport gear that
>> would take line timing from a CO or other site upstream that 
>> typically had diverse reference clocks available.  It might even 
>> have provided a backup BITS T1 as a frequency reference to cell
>> equipment.
>> 
>>Even without a local transport node, prior to the last few
>> years (where things seem to be going Ethernet), most cellular equipment
>> was still taking TDM handoffs, and could revert to taking line timing
>> off its transport circuits, thereby indirectly getting it from 
>> practically anything upstream if its local reference failed.
> 
> Again, the context of the question is an external to the system timing 
> source. In other words Loran-C or something similar. Even today, the network
> sync to the backbone does not come from the GPS. That comes from the 
> carrier’s data line sync. 
> 
> Bob
> 
> 
>> 
>>Certainly, the surplus device pool is all GPS, but that's
>> because of the number of additional devices deployed, not necessarily
>> representative of the full footprint of LORAN and other methods that
>> used to be available as indirect backup references for the sites.
>> 
>>Of course, that's not going to be an option going forwards.
>> I, for one, welcome our new Ethernet overlords.
>> 
>>--msa
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Re: [time-nuts] GPS Outage..

[Bob Camp]

Hi

The time stamps in the recordings have no connection with the triangulation 
part of the system. The audio
tracks are completely independent of the “navigation”.

Bob

> On Feb 27, 2016, at 2:34 AM, Hal Murray  wrote:
> 
>>> How many of them came from E-911 stations?
>> E-911 triangulation done on cell towers …
> 
> I was thinking of the stations where they have the dispatchers who answer the 
> calls
> and pass the info on to the right people.  I think they need good timing on 
> the recordings, but don't know any details.  I've always thought some of them 
> used GPS.
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] GPS Outage..

[jimlux]

On 2/26/16 11:34 PM, Hal Murray wrote:

How many of them came from E-911 stations?

E-911 triangulation done on cell towers …


I was thinking of the stations where they have the dispatchers who answer the
calls
and pass the info on to the right people.  I think they need good timing on
the recordings, but don't know any details.  I've always thought some of them
used GPS.




They need good time, but probably only to the nearest second.


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Re: [time-nuts] GPS Outage..

[Tom McDermott]

The reason many cell sites went to GPS for time and frequency
synchronization is that in many cases
it was either less expensive or only possible to backhaul the cell site
traffic to the MTSO (Mobile Telephone
Switching Office) via microwave radio rather than wireline copper or fiber
carrier.

That microwave backhaul did not always provide sufficiently precise phase
and frequency reference
needed at the cell site.

-- Tom, N5EG
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Re: [time-nuts] GPS Outage

[jimlux]

On 2/26/16 12:39 PM, Hal Murray wrote:


martin.burni...@burnicki.net said:

Strange that at least 3 independant firmware trees/development teams should
chose the same magic wk860.



I don't find it strange. If the next firmware version is based on the
previous version and none of the developers has stumbled across this
potential problem earlier ...


That sounds like poor software engineering.  Or poor engineering management.

The wk860 is supposed to represent the build time of the software so it will
work for 20 years from when it was built rather than 20 years from when the
10 bit week counter last rolled over or 20 years from when the constant was
last updated.

That magic constant has to be pulled out to a module where it is visible
rather than buried deep in some large module.  Then the recipe for releasing
software has to update it, either by having a step in the checklist where the
human does the edit or by running a script that does it.  (Yes, you have to
start by having a formal procedure for releasing software/firmware.)





for something which has a design life of <1024 weeks, I don't know that 
this can be described as poor software engineering. The software meets 
the requirements. It doesn't have extra complexity (needed to deal with 
rollover) that is not required.


For all we know, they have some process at the mfr which would trigger 
an update on new releases of the software (for new models of receiver).


20 years is a very long time for most electronics made in large 
quantities. The people who get "bit" by this kind of thing are folks 
using old surplus equipment (time-nuts, etc.) and deep space missions 
(lots of inheritance, long mission durations).




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Re: [time-nuts] GPS Outage..

[Bob Camp]

Hi

Since there are at least a few hundred TBolts running around in the red cases
with the horrible switching power supplies, it’s technically only “most”. The 
quick
way to tell if it’s an Andrew unit is the connectors. They are upside down on 
the 
Andrew units compared to the “Trimble Standard” design. 

Bob
 
> On Feb 26, 2016, at 9:21 PM, Arthur Dent  wrote:
> 
>> kb8tq at n1k.org said: Pretty much all of our surplus
> gizmos are cell tower surplus (like 99.99%).
> 
> True - I believe all the Trimble Thunderbolts came from
> Andrew/Grayson/Geometrix WLS2A-24-G or similar Wireless
> Location Sensors. I know I removed over 200 T-bolts from
> these units personally.
> 
> -Arthur
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Re: [time-nuts] GPS Outage..

[Bob Camp]

Hi

> On Feb 26, 2016, at 8:01 PM, Majdi S. Abbas  wrote:
> 
> On Fri, Feb 26, 2016 at 05:56:59PM -0500, Bob Camp wrote:
>> Cell phones since they first came out have *never ever* been setup 
>> to run on anything other than GPS. Retrofitting them to use something 
>> else would take a decade or more. We didn’t “destroy the backup”, there 
>> never was one. Pretty much all of our surplus gizmos are cell tower 
>> surplus (like 99.99%). 
> 
>   Bob,
> 
>   It depends.  
> 
>   We're used to thinking of those GPS and oscillator packages
> as the only timing for a cell site, but that was not the case until
> fairly recently.
> 
>   In many of those sites, there was also transport gear that
> would take line timing from a CO or other site upstream that 
> typically had diverse reference clocks available.  It might even 
> have provided a backup BITS T1 as a frequency reference to cell
> equipment.
> 
>   Even without a local transport node, prior to the last few
> years (where things seem to be going Ethernet), most cellular equipment
> was still taking TDM handoffs, and could revert to taking line timing
> off its transport circuits, thereby indirectly getting it from 
> practically anything upstream if its local reference failed.

Again, the context of the question is an external to the system timing 
source. In other words Loran-C or something similar. Even today, the network
sync to the backbone does not come from the GPS. That comes from the 
carrier’s data line sync. 

Bob


> 
>   Certainly, the surplus device pool is all GPS, but that's
> because of the number of additional devices deployed, not necessarily
> representative of the full footprint of LORAN and other methods that
> used to be available as indirect backup references for the sites.
> 
>   Of course, that's not going to be an option going forwards.
> I, for one, welcome our new Ethernet overlords.
> 
>   --msa
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Re: [time-nuts] GPS Outage..

[Hal Murray]

>> How many of them came from E-911 stations?
> E-911 triangulation done on cell towers …

I was thinking of the stations where they have the dispatchers who answer the 
calls
and pass the info on to the right people.  I think they need good timing on 
the recordings, but don't know any details.  I've always thought some of them 
used GPS.

-- 
These are my opinions.  I hate spam.



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[time-nuts] GPS Outage..

[Arthur Dent]

>kb8tq at n1k.org said: Pretty much all of our surplus
gizmos are cell tower surplus (like 99.99%).

True - I believe all the Trimble Thunderbolts came from
Andrew/Grayson/Geometrix WLS2A-24-G or similar Wireless
Location Sensors. I know I removed over 200 T-bolts from
these units personally.

-Arthur
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Re: [time-nuts] GPS Outage..

[Bob Camp]

Hi

So in the context of the original post, exactly how many Loran-C disciplined 
cell phone systems were there? … errr .. none. 

The *only* systems that use any sort of external disciplining are GPS based. 

Self contained or “not disciplined” does not count in this case. 

Bob

> On Feb 26, 2016, at 7:19 PM, Magnus Danielson  
> wrote:
> 
> Bob,
> 
> Nope. Cell phones have been using land-lines for ages to sync up. It was with 
> the CDMA stuff that GPS phase was starting to be used to coordinate. GSM for 
> instance does not need GPS on the base-stations, it even goes to lengthy 
> extends to avoid it. CDMA didn't come into much use over here. GPS wasn't 
> even there when cell phones got started. It is only lately that GPS have 
> become a more integrated part of the system, but as GLONASS has become more 
> popular more base-stations support that too, in order to support AGNSS. 
> Landlines still provide an interesting backup and big efforts is invested on 
> the sync-networks.
> 
> Cheers,
> Magnus
> 
> On 02/26/2016 11:56 PM, Bob Camp wrote:
>> Hi
>> 
>> ….. ummm ….. errr …..
>> 
>> Cell phones since they first came out have *never ever* been setup to run on 
>> anything other than GPS. Retrofitting them to use something else would take 
>> a decade or more. We didn’t “destroy the backup”, there never was one. 
>> Pretty much all of our surplus gizmos are cell tower surplus (like 99.99%).
>> 
>> Bob
>> 
>>> On Feb 26, 2016, at 11:57 AM, Burt I. Weiner  wrote:
>>> 
>>> Maybe I'm misreading what you're saying, but no matter the cause, it points 
>>> out what can and does happen when you put all the mission critical eggs in 
>>> one basket.  That we don't have as reliable as possible a backup system, or 
>>> why we destroyed the one we had, is mind boggling.  This is a perfect 
>>> example of what happens when you have people who don't understand the 
>>> problem/s making the wrong final decisions in spite of having been warned.
>>> 
>>> It is my belief that if we are to be so reliant on these systems for so 
>>> many things, we need to have a functioning backup system in place.
>>> 
>>> Burt, K6OQK
>>> 
>>> 
>>> 
 Mark Sims wrote:
>> When is some organization going to explain what happened in February for 
>> almost two hours starting at 00:16 GMT?  That subject has gone silent.  
>> Rob, NC0B
> I heard back from NAVCEN.  They said it was a Trimble issue and that 
> Trimble would contact me (they didn't).   But that does not jive with 
> reports of failures in Motorola, Navman, etc receivers.
 
 I think we need to distinguish here.
 
 The January 26 issue was due to faulty data sent by the satellites,
 which caused GPS receivers to apply a wrong UTC correction which caused
 the UTC time to be off by 13.7 us.
 
 As explained by Luc Gaudin from http://naelcom.com (who obviously sell
 Trimble GPS receivers) the February 13 issue was indeed just a Trimble
 firmware problem. See:
 https://www.febo.com/pipermail/time-nuts/2016-February/096042.html
 https://www.febo.com/pipermail/time-nuts/2016-February/096050.html
 
 Martin
>>> 
>>> Burt I. Weiner Associates
>>> Broadcast Technical Services
>>> Glendale, California  U.S.A.
>>> b...@att.net
>>> www.biwa.cc
>>> K6OQK
>>> ___
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>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>> 
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Re: [time-nuts] GPS Outage..

[Majdi S. Abbas]

On Fri, Feb 26, 2016 at 05:56:59PM -0500, Bob Camp wrote:
> Cell phones since they first came out have *never ever* been setup 
> to run on anything other than GPS. Retrofitting them to use something 
> else would take a decade or more. We didn’t “destroy the backup”, there 
> never was one. Pretty much all of our surplus gizmos are cell tower 
> surplus (like 99.99%). 

Bob,

It depends.  

We're used to thinking of those GPS and oscillator packages
as the only timing for a cell site, but that was not the case until
fairly recently.

In many of those sites, there was also transport gear that
would take line timing from a CO or other site upstream that 
typically had diverse reference clocks available.  It might even 
have provided a backup BITS T1 as a frequency reference to cell
equipment.

Even without a local transport node, prior to the last few
years (where things seem to be going Ethernet), most cellular equipment
was still taking TDM handoffs, and could revert to taking line timing
off its transport circuits, thereby indirectly getting it from 
practically anything upstream if its local reference failed.

Certainly, the surplus device pool is all GPS, but that's
because of the number of additional devices deployed, not necessarily
representative of the full footprint of LORAN and other methods that
used to be available as indirect backup references for the sites.

Of course, that's not going to be an option going forwards.
I, for one, welcome our new Ethernet overlords.

--msa
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Re: [time-nuts] GPS Outage..

[Bob Camp]

HI

E-911 triangulation done on cell towers …

Bob

> On Feb 26, 2016, at 7:25 PM, Hal Murray  wrote:
> 
> 
> kb...@n1k.org said:
>> Pretty much all of our surplus gizmos are cell tower surplus (like 99.99%).
> 
> How many of them came from E-911 stations?
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] GPS Outage..

[Hal Murray]

kb...@n1k.org said:
> Pretty much all of our surplus gizmos are cell tower surplus (like 99.99%).

How many of them came from E-911 stations?


-- 
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Re: [time-nuts] GPS Outage..

[Magnus Danielson]

Bob,

Nope. Cell phones have been using land-lines for ages to sync up. It was 
with the CDMA stuff that GPS phase was starting to be used to 
coordinate. GSM for instance does not need GPS on the base-stations, it 
even goes to lengthy extends to avoid it. CDMA didn't come into much use 
over here. GPS wasn't even there when cell phones got started. It is 
only lately that GPS have become a more integrated part of the system, 
but as GLONASS has become more popular more base-stations support that 
too, in order to support AGNSS. Landlines still provide an interesting 
backup and big efforts is invested on the sync-networks.


Cheers,
Magnus

On 02/26/2016 11:56 PM, Bob Camp wrote:

Hi

….. ummm ….. errr …..

Cell phones since they first came out have *never ever* been setup to run on 
anything other than GPS. Retrofitting them to use something else would take a 
decade or more. We didn’t “destroy the backup”, there never was one. Pretty 
much all of our surplus gizmos are cell tower surplus (like 99.99%).

Bob


On Feb 26, 2016, at 11:57 AM, Burt I. Weiner  wrote:

Maybe I'm misreading what you're saying, but no matter the cause, it points out 
what can and does happen when you put all the mission critical eggs in one 
basket.  That we don't have as reliable as possible a backup system, or why we 
destroyed the one we had, is mind boggling.  This is a perfect example of what 
happens when you have people who don't understand the problem/s making the 
wrong final decisions in spite of having been warned.

It is my belief that if we are to be so reliant on these systems for so many 
things, we need to have a functioning backup system in place.

Burt, K6OQK




Mark Sims wrote:

When is some organization going to explain what happened in February for almost 
two hours starting at 00:16 GMT?  That subject has gone silent.  Rob, NC0B

I heard back from NAVCEN.  They said it was a Trimble issue and that Trimble 
would contact me (they didn't).   But that does not jive with reports of 
failures in Motorola, Navman, etc receivers.


I think we need to distinguish here.

The January 26 issue was due to faulty data sent by the satellites,
which caused GPS receivers to apply a wrong UTC correction which caused
the UTC time to be off by 13.7 us.

As explained by Luc Gaudin from http://naelcom.com (who obviously sell
Trimble GPS receivers) the February 13 issue was indeed just a Trimble
firmware problem. See:
https://www.febo.com/pipermail/time-nuts/2016-February/096042.html
https://www.febo.com/pipermail/time-nuts/2016-February/096050.html

Martin


Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK
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Re: [time-nuts] GPS Outage..

[Alex Pummer]

Hi Burt,
you are more than right, but don't forget the bean counters! they have 
power over everything even logical thinking.

73
KJ6UHN
Alex

On 2/26/2016 8:57 AM, Burt I. Weiner wrote:
Maybe I'm misreading what you're saying, but no matter the cause, it 
points out what can and does happen when you put all the mission 
critical eggs in one basket.  That we don't have as reliable as 
possible a backup system, or why we destroyed the one we had, is mind 
boggling.  This is a perfect example of what happens when you have 
people who don't understand the problem/s making the wrong final 
decisions in spite of having been warned.


It is my belief that if we are to be so reliant on these systems for 
so many things, we need to have a functioning backup system in place.


Burt, K6OQK




Mark Sims wrote:
>> When is some organization going to explain what happened in 
February for almost two hours starting at 00:16 GMT?  That subject 
has gone silent.  Rob, NC0B
> I heard back from NAVCEN.  They said it was a Trimble issue and 
that Trimble would contact me (they didn't).   But that does not jive 
with reports of failures in Motorola, Navman, etc receivers.


I think we need to distinguish here.

The January 26 issue was due to faulty data sent by the satellites,
which caused GPS receivers to apply a wrong UTC correction which caused
the UTC time to be off by 13.7 us.

As explained by Luc Gaudin from http://naelcom.com (who obviously sell
Trimble GPS receivers) the February 13 issue was indeed just a Trimble
firmware problem. See:
https://www.febo.com/pipermail/time-nuts/2016-February/096042.html
https://www.febo.com/pipermail/time-nuts/2016-February/096050.html

Martin


Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK
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-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7442 / Virus Database: 4537/11699 - Release Date: 
02/26/16


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Re: [time-nuts] GPS Outage

[Magnus Danielson]

Hal,

On 02/26/2016 09:39 PM, Hal Murray wrote:


martin.burni...@burnicki.net said:

Strange that at least 3 independant firmware trees/development teams should
chose the same magic wk860.



I don't find it strange. If the next firmware version is based on the
previous version and none of the developers has stumbled across this
potential problem earlier ...


That sounds like poor software engineering.  Or poor engineering management.


It's easy to say, but as work progresses over the years, it is hard to 
revisit all aspects of the code and re-evaluate it. One has to adapt 
humbleness to the task, try to check as much as possible, but still 
accept that you can't find all the bugs. Often the need to finish new 
products on time comes before, flushing out all the new bugs.



The wk860 is supposed to represent the build time of the software so it will
work for 20 years from when it was built rather than 20 years from when the
10 bit week counter last rolled over or 20 years from when the constant was
last updated.


Indeed. Just not quite the full 20 years.


That magic constant has to be pulled out to a module where it is visible
rather than buried deep in some large module.  Then the recipe for releasing
software has to update it, either by having a step in the checklist where the
human does the edit or by running a script that does it.  (Yes, you have to
start by having a formal procedure for releasing software/firmware.)


That assumes one can foresee this to become a problem. Most doesn't 
consider it to be a recent problem. However, just updating the constant 
won't work for the type of products we have here, as the boxes we now 
see have problems was never updated. A battery-backed RTC clock would 
have helped, but the battery would probably fail around now. EEPROM 
updates in the boxes would have helped, but 20 years back EEPROMS 
wheren't too happy about many updates.


I think it is better to realize that the solution was good enough for 
the expected lifetime of the product.


I've made some design choices like this. Some of them have survived the 
complete re-writes and still not greatly failed the assumptions. Some 
have faired less well. Some of the design decisions I make can easily 
live for 20 years, and the one thing I've learned is that it is hard to 
balance longterm with practical design for the expected lifetime.


I think they did fairly well. For most systems, the remaining problem is 
showing the time as being exactly 1024 weeks off, but all other aspects 
working correctly. We can apply prior knowledge to correct the 1024 
weeks offset and keep these receivers running way beyond their designed 
lifetime. That's actually quite respectable in my book.


Best Regards,
Magnus
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Re: [time-nuts] GPS Outage..

[Bob Camp]

Hi

….. ummm ….. errr …..

Cell phones since they first came out have *never ever* been setup to run on 
anything other than GPS. Retrofitting them to use something else would take a 
decade or more. We didn’t “destroy the backup”, there never was one. Pretty 
much all of our surplus gizmos are cell tower surplus (like 99.99%). 

Bob

> On Feb 26, 2016, at 11:57 AM, Burt I. Weiner  wrote:
> 
> Maybe I'm misreading what you're saying, but no matter the cause, it points 
> out what can and does happen when you put all the mission critical eggs in 
> one basket.  That we don't have as reliable as possible a backup system, or 
> why we destroyed the one we had, is mind boggling.  This is a perfect example 
> of what happens when you have people who don't understand the problem/s 
> making the wrong final decisions in spite of having been warned.
> 
> It is my belief that if we are to be so reliant on these systems for so many 
> things, we need to have a functioning backup system in place.
> 
> Burt, K6OQK
> 
> 
> 
>> Mark Sims wrote:
>> >> When is some organization going to explain what happened in February for 
>> >> almost two hours starting at 00:16 GMT?  That subject has gone silent.  
>> >> Rob, NC0B
>> > I heard back from NAVCEN.  They said it was a Trimble issue and that 
>> > Trimble would contact me (they didn't).   But that does not jive with 
>> > reports of failures in Motorola, Navman, etc receivers.
>> 
>> I think we need to distinguish here.
>> 
>> The January 26 issue was due to faulty data sent by the satellites,
>> which caused GPS receivers to apply a wrong UTC correction which caused
>> the UTC time to be off by 13.7 us.
>> 
>> As explained by Luc Gaudin from http://naelcom.com (who obviously sell
>> Trimble GPS receivers) the February 13 issue was indeed just a Trimble
>> firmware problem. See:
>> https://www.febo.com/pipermail/time-nuts/2016-February/096042.html
>> https://www.febo.com/pipermail/time-nuts/2016-February/096050.html
>> 
>> Martin
> 
> Burt I. Weiner Associates
> Broadcast Technical Services
> Glendale, California  U.S.A.
> b...@att.net
> www.biwa.cc
> K6OQK 
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Re: [time-nuts] GPS Outage

[Tom Van Baak]

The official word, released a few minutes ago:


NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2016016 NANU TYPE: GENERAL
*** GENERAL MESSAGE TO ALL GPS USERS ***
NAVCEN has determined that the event referenced by GPS NANU 2016012 was not a 
GPS time transfer anomaly but was a user equipment issue.  GPS users that 
continue to experience equipment problems are encouraged to contact their 
equipment manufacturer for assistance.
*** GENERAL MESSAGE TO ALL GPS USERS ***

   POC: CIVILIAN - NAVCEN AT 703-313-5900, HTTP://WWW.NAVCEN.USCG.GOV
   MILITARY - GPS OPERATIONS CENTER at HTTPS://GPS.AFSPC.AF.MIL/GPSOC, DSN 
560-2541,
   COMM 719-567-2541, gpsoperationscen...@us.af.mil, HTTPS://GPS.AFSPC.AF.MIL 
   MILITARY ALTERNATE - JOINT SPACE OPERATIONS CENTER, DSN276-3514, 
   COMM 805-606-3514, jspoccombat...@vandenberg.af.mil


Sources:
http://www.navcen.uscg.gov/?pageName=gpsAlmanacs
https://celestrak.com/GPS/NANU/2016/nanu.2016016.txt

/tvb


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Re: [time-nuts] GPS Outage

[Hal Murray]

martin.burni...@burnicki.net said:
>> Strange that at least 3 independant firmware trees/development teams should
>> chose the same magic wk860.

> I don't find it strange. If the next firmware version is based on the
> previous version and none of the developers has stumbled across this
> potential problem earlier ... 

That sounds like poor software engineering.  Or poor engineering management.

The wk860 is supposed to represent the build time of the software so it will 
work for 20 years from when it was built rather than 20 years from when the 
10 bit week counter last rolled over or 20 years from when the constant was 
last updated.

That magic constant has to be pulled out to a module where it is visible 
rather than buried deep in some large module.  Then the recipe for releasing 
software has to update it, either by having a step in the checklist where the 
human does the edit or by running a script that does it.  (Yes, you have to 
start by having a formal procedure for releasing software/firmware.)


-- 
These are my opinions.  I hate spam.



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[time-nuts] GPS Outage..

[Burt I. Weiner]

Maybe I'm misreading what you're saying, but no matter the cause, it 
points out what can and does happen when you put all the mission 
critical eggs in one basket.  That we don't have as reliable as 
possible a backup system, or why we destroyed the one we had, is mind 
boggling.  This is a perfect example of what happens when you have 
people who don't understand the problem/s making the wrong final 
decisions in spite of having been warned.


It is my belief that if we are to be so reliant on these systems for 
so many things, we need to have a functioning backup system in place.


Burt, K6OQK




Mark Sims wrote:
>> When is some organization going to explain what happened in 
February for almost two hours starting at 00:16 GMT?  That subject 
has gone silent.  Rob, NC0B
> I heard back from NAVCEN.  They said it was a Trimble issue and 
that Trimble would contact me (they didn't).   But that does not 
jive with reports of failures in Motorola, Navman, etc receivers.


I think we need to distinguish here.

The January 26 issue was due to faulty data sent by the satellites,
which caused GPS receivers to apply a wrong UTC correction which caused
the UTC time to be off by 13.7 us.

As explained by Luc Gaudin from http://naelcom.com (who obviously sell
Trimble GPS receivers) the February 13 issue was indeed just a Trimble
firmware problem. See:
https://www.febo.com/pipermail/time-nuts/2016-February/096042.html
https://www.febo.com/pipermail/time-nuts/2016-February/096050.html

Martin


Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK 


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Re: [time-nuts] GPS Outage

[Magnus Danielson]

Hi,

On 02/26/2016 02:39 PM, jimlux wrote:

On 2/26/16 3:34 AM, Björn wrote:

"The product will not report the correct extended GPS week number
after the Feb,13th 2016.
After the rollover to week #860, the thunderbolt will not make
position for 2 hours, because the Ephemeris data on the GPS receiver
being consider incorrect.
The module will work fine after this 2 hours."

Have the Motorola Oncore/Navman/Jupiter receivers also been checked
for this condition?

Strange that at least 3 independant firmware trees/development teams
should chose the same magic wk860.


Actually not that weird.
They might all have inherited a published code snippet.  There's a
little table driven chunk of code to compute CRCs that pretty much
everybody uses, and it derives from some article published in the 70s or
early 80s for an 8 bit micro.


Indeed. I know of at least one GPS chip vendor that with their developer 
kit provided code. Some code inheritance might be proper, but some might 
be unintentional or not even valid license-wise. Very nice way to 
inherit bugs, as we know what they are... eventually.


Would still love to see some of that code. Somebody got a copy of the 
Marconi/Zarlink code?


Cheers,
Magnus
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Re: [time-nuts] GPS Outage

[Artek Manuals]

I have  an ONCORE and VP-ONCORE neither were affected by the week 860 
problem


Dave
NR1DX

On 2/26/2016 6:34 AM, Björn wrote:

"The product will not report the correct extended GPS week number after the 
Feb,13th 2016.
After the rollover to week #860, the thunderbolt will not make position for 2 
hours, because the Ephemeris data on the GPS receiver being consider incorrect.
The module will work fine after this 2 hours."

Have the Motorola Oncore/Navman/Jupiter receivers also been checked for this 
condition?

Strange that at least 3 independant firmware trees/development teams should 
chose the same magic wk860.

I guess that someone with both affected non-trimble receivers and a gps rf 
simulator would need to spend some time on this.

--
   Björn


Dave
manu...@artekmanuals.com
www.ArtekManuals.com

---
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Re: [time-nuts] GPS Outage

[Martin Burnicki]

Björn wrote:
> "The product will not report the correct extended GPS week number after the 
> Feb,13th 2016.
> After the rollover to week #860, the thunderbolt will not make position for 2 
> hours, because the Ephemeris data on the GPS receiver being consider 
> incorrect.
> The module will work fine after this 2 hours."
> 
> Have the Motorola Oncore/Navman/Jupiter receivers also been checked for this 
> condition? 

Hm, if this is a bug in the Trimble firmware, why should Motorola or
other brands be affected?

I don't remember I have heard about *this* problem with other GPS
receiver models.

> Strange that at least 3 independant firmware trees/development teams should 
> chose the same magic wk860.

I don't find it strange. If the next firmware version is based on the
previous version and none of the developers has stumbled across this
potential problem earlier ...

Martin

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Re: [time-nuts] GPS Outage

[jimlux]

On 2/26/16 3:34 AM, Björn wrote:

"The product will not report the correct extended GPS week number after the 
Feb,13th 2016.
After the rollover to week #860, the thunderbolt will not make position for 2 
hours, because the Ephemeris data on the GPS receiver being consider incorrect.
The module will work fine after this 2 hours."

Have the Motorola Oncore/Navman/Jupiter receivers also been checked for this 
condition?

Strange that at least 3 independant firmware trees/development teams should 
chose the same magic wk860.


Actually not that weird.
They might all have inherited a published code snippet.  There's a 
little table driven chunk of code to compute CRCs that pretty much 
everybody uses, and it derives from some article published in the 70s or 
early 80s for an 8 bit micro.



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Re: [time-nuts] GPS Outage

[Björn]

"The product will not report the correct extended GPS week number after the 
Feb,13th 2016.
After the rollover to week #860, the thunderbolt will not make position for 2 
hours, because the Ephemeris data on the GPS receiver being consider incorrect.
The module will work fine after this 2 hours."

Have the Motorola Oncore/Navman/Jupiter receivers also been checked for this 
condition? 

Strange that at least 3 independant firmware trees/development teams should 
chose the same magic wk860.

I guess that someone with both affected non-trimble receivers and a gps rf 
simulator would need to spend some time on this.

--
      Björn

 Originalmeddelande Från: Martin Burnicki 
<martin.burni...@burnicki.net> Datum:2016-02-26  09:32  (GMT+01:00) 
Till: time-nuts@febo.com Rubrik: Re: [time-nuts] GPS 
Outage 
Mark Sims wrote:
>> When is some organization going to explain what happened in February for 
>> almost two hours starting at 00:16 GMT?  That subject has gone silent.  Rob, 
>> NC0B
> I heard back from NAVCEN.  They said it was a Trimble issue and that Trimble 
> would contact me (they didn't).   But that does not jive with reports of 
> failures in Motorola, Navman, etc receivers.

I think we need to distinguish here.

The January 26 issue was due to faulty data sent by the satellites,
which caused GPS receivers to apply a wrong UTC correction which caused
the UTC time to be off by 13.7 us.

As explained by Luc Gaudin from http://naelcom.com (who obviously sell
Trimble GPS receivers) the February 13 issue was indeed just a Trimble
firmware problem. See:
https://www.febo.com/pipermail/time-nuts/2016-February/096042.html
https://www.febo.com/pipermail/time-nuts/2016-February/096050.html

Martin

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Re: [time-nuts] GPS Outage

[Martin Burnicki]

Mark Sims wrote:
>> When is some organization going to explain what happened in February for 
>> almost two hours starting at 00:16 GMT?  That subject has gone silent.  Rob, 
>> NC0B
> I heard back from NAVCEN.  They said it was a Trimble issue and that Trimble 
> would contact me (they didn't).   But that does not jive with reports of 
> failures in Motorola, Navman, etc receivers.

I think we need to distinguish here.

The January 26 issue was due to faulty data sent by the satellites,
which caused GPS receivers to apply a wrong UTC correction which caused
the UTC time to be off by 13.7 us.

As explained by Luc Gaudin from http://naelcom.com (who obviously sell
Trimble GPS receivers) the February 13 issue was indeed just a Trimble
firmware problem. See:
https://www.febo.com/pipermail/time-nuts/2016-February/096042.html
https://www.febo.com/pipermail/time-nuts/2016-February/096050.html

Martin

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[time-nuts] GPS Outage

[Mark Sims]

> When is some organization going to explain what happened in February for 
> almost two hours starting at 00:16 GMT?  That subject has gone silent.  Rob, 
> NC0B
I heard back from NAVCEN.  They said it was a Trimble issue and that Trimble 
would contact me (they didn't).   But that does not jive with reports of 
failures in Motorola, Navman, etc receivers.

  
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Re: [time-nuts] GPS Outage

[Rob Sherwood .]

When is some organization going to explain what happened in February for almost 
two hours starting at 00:16 GMT?  That subject has gone silent.  Rob, NC0B

Sent from my iPad

> On Feb 25, 2016, at 2:03 AM, "Michael Perrett"  wrote:
> 
> 
> 
> I think the following might be relief to all the traffic regards "bad GPS"
> ref  January 26th.
> http://gpsworld.com/world-dodges-gps-bullet/
> 
> Michael / K7HIL
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> 
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> 
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[time-nuts] GPS Outage

[Michael Perrett]

I think the following might be relief to all the traffic regards "bad GPS"
ref  January 26th.
http://gpsworld.com/world-dodges-gps-bullet/

Michael / K7HIL
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Re: [time-nuts] GPS outage? 19:00-2100 UTC Tue

[Hal Murray]

t...@radio.sent.com said:
 I think that Menlo Park is somewhat under 300 NM (nautical miles) from China
 Lake (depending on exactly where the test was located), and the expected
 interference range was about 252 NM. So you might have been at the edge of
 the affected area. See: http://www.navcen.uscg.gov/pdf/gps/gpsnotices/
 GPS_Interference.pdf

Thanks.  My measurements on Google maps are are close to 250 miles.  That's 
to the town rather than the boonies out back.

My antennas are all in poor locations (indoors) rather than good locations so 
I'm probably more sensitive than some of their target users.

What's the BNM column on that chart?

What sort of gear would I need to detect a local jammer?


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] GPS outage? 19:00-2100 UTC Tue

[Bill Byrom]

The term BNM also initially confused me. It appears to be Broadcast
Notice to Mariner, a report produced by the US Coast Guard with
important warnings for ship navigation.
http://pdept.cgaux.org/Documents/Active/NS/LocalNoticeToMariners/lnm14022011.pdf

Detecting GPS interference is an interesting topic. I work as an RF
Application Engineer for Tektronix, so I'm biased about this topic.
Different types of interference will show up in different manners on
various types of spectrum analyzers. I would use a directional antenna
with low noise preamplifier with a Real-Time Spectrum Analyzer (RTSA
like the low cost Tektronix RSA306 USB 3 analyzer) so you can see the
statistics of signals at or below the thermal noise floor. The jamming
signal might be wideband Gaussian noise, band-filtered Gaussian noise,
BPSK or QPSK or QAM modulated signals, frequency chirped signals, or
other RF signals people might come up with to create interference. I'm
purposely not going to suggest which of these would be better or worse
at interfering, but a RTSA can see weak signals near the thermal noise
floor which might be unintentionally or purposefully causing
interference.

Some people assume you can't use a spectrum analyzer to see the GPS
constellation from a good GPS amplified antenna because each GPS
received satellite signal is over 10 dB below the thermal noise floor
and a normal received GPS constellation is still below the kTB thermal
noise floor (-174 dBm/Hz). But the uncorrelated combination of a typical
GPS constellation with an antenna at a good location will sum with the
background noise and will be sufficient to push the noise floor up maybe
0.5 dB (depending on how many satellites can be seen) above the thermal
noise floor, and this is easy to see if you use 10,000 or more
averages/sec using a RTSA or a bitmap statistical display. Again, I'm
not trying to advertise anything in this forum but just give you a
technical answer to your question.

--
Bill Byrom N5BB
 
 
 
On Thu, Aug 20, 2015, at 12:12 AM, Hal Murray wrote:
  
 What's the BNM column on that chart?
  
 What sort of gear would I need to detect a local jammer?
  
 
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Re: [time-nuts] GPS outage? 19:00-2100 UTC Tue

[Björn Gabrielsson]

 What sort of gear would I need to detect a local jammer?

A GPS receiver where you can get AGC data, to see if the power in the GPS
band increased - or a SDR-radio, like the SDR-RTL at sub $20 or a
commercial GPS jamming detector.

--

 Björn

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Re: [time-nuts] GPS outage? 19:00-2100 UTC Tue

[Hal Murray]

t...@radio.sent.com said:
 The term BNM also initially confused me. It appears to be Broadcast
 Notice to Mariner

Thanks.

There was another similar event Wed morning:
  08:15-10:00 UTC, Wed
  01:15-03:00 PDT

and a shorter one from:
  13:30-14:00 UTC
  06:30-07:00 PDT


-- 
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Re: [time-nuts] GPS outage? 19:00-2100 UTC Tue

[Jim Lux]

On 8/19/15 10:12 PM, Hal Murray wrote:


t...@radio.sent.com said:

I think that Menlo Park is somewhat under 300 NM (nautical miles) from China
Lake (depending on exactly where the test was located), and the expected
interference range was about 252 NM. So you might have been at the edge of
the affected area. See: http://www.navcen.uscg.gov/pdf/gps/gpsnotices/
GPS_Interference.pdf




On the other hand, there is a 4000 m tall mountain range (Sierra Nevada) 
and a lot of other stuff between the two. I'm pretty sure that the 
radius of the circle is for *airborne* platforms, where the jammers are 
in line of sight.  (radar horizon at 30,000 ft is about 250 miles)


It would be truly amazing to get L-band propagation from China Lake to 
Menlo Park.


I'd go for the trucker with a jammer scenario
http://gpsworld.com/personal-privacy-jammers-12837/

or malfunctioning equipment oscillating in band scenario (like the 
Monterey Bay event)


http://gpsworld.com/the-hunt-rfi/



Thanks.  My measurements on Google maps are are close to 250 miles.  That's
to the town rather than the boonies out back.

My antennas are all in poor locations (indoors) rather than good locations so
I'm probably more sensitive than some of their target users.

What's the BNM column on that chart?

What sort of gear would I need to detect a local jammer?




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Re: [time-nuts] GPS outage? 19:00-2100 UTC Tue

[Brent Gordon]

No problems in Albuquerque, NM.


On 8/19/2015 2:11 AM, Hal Murray wrote:


Most/all of my GPS toys stopped working for a few hours late Tue evening.  A
few where I have good logging ran out of satellites.

Did anybody else notice anything similar?

Was it local interference, or something at the GPS level?

I'm in Menlo Park California.  That was mid afternoon local time, PDT


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Re: [time-nuts] GPS outage? 19:00-2100 UTC Tue

[David J Taylor]

From: Hal Murray

Most/all of my GPS toys stopped working for a few hours late Tue evening.  A
few where I have good logging ran out of satellites.

Did anybody else notice anything similar?

Was it local interference, or something at the GPS level?

I'm in Menlo Park California.  That was mid afternoon local time, PDT
=

Any GPS outages I've seen due to poor satellite configuration usually last 
far less than two hours.  Local jamming would be my first guess.


David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk 


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[time-nuts] GPS outage? 19:00-2100 UTC Tue

[Hal Murray]

Most/all of my GPS toys stopped working for a few hours late Tue evening.  A 
few where I have good logging ran out of satellites.

Did anybody else notice anything similar?

Was it local interference, or something at the GPS level?

I'm in Menlo Park California.  That was mid afternoon local time, PDT



-- 
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Re: [time-nuts] GPS outage? 19:00-2100 UTC Tue

[Poul-Henning Kamp]

In message 20150819081108.08ebd406...@ip-64-139-1-69.sjc.megapath.net, Hal Mu
rray writes:

Most/all of my GPS toys stopped working for a few hours late Tue evening.  A 
few where I have good logging ran out of satellites.

Did anybody else notice anything similar?

Was it local interference, or something at the GPS level?

Nothing on my side of the planet.

Most likely a White Van Man who doesn't want the boss to track his
use of the company car outside business-hours.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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Re: [time-nuts] GPS outage? 19:00-2100 UTC Tue

[Bill Byrom]

According to the official GPS testing (interference) website, there were tests 
at China Lake scheduled for sometime(s) on August 18-20, 2015. I think that 
Menlo Park is somewhat under 300 NM (nautical miles) from China Lake (depending 
on exactly where the test was located), and the expected interference range was 
about 252 NM. So you might have been at the edge of the affected area. See:
http://www.navcen.uscg.gov/pdf/gps/gpsnotices/GPS_Interference.pdf
http://www.gps.gov/support/user/

I don't see any satellite outages in the official report:
http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx

And note that except for certain government tests and operations, GPS
jamming is illegal, and violations are prosecuted:
http://www.gps.gov/spectrum/jamming/
--
Bill Byrom N5BB

On Wed, Aug 19, 2015, at 03:11 AM, Hal Murray wrote:
  
 Most/all of my GPS toys stopped working for a few hours late Tue evening.
 A
 few where I have good logging ran out of satellites.
  
 Did anybody else notice anything similar?
  
 Was it local interference, or something at the GPS level?
  
 I'm in Menlo Park California.  That was mid afternoon local time, PDT
  
  
  
 --
 These are my opinions.  I hate spam.
  
  
  
 _
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Re: [time-nuts] GPS outage?

[Bob Camp]

Hi

I'd say that:

HiNOTICE ADVISORY TO NAVSTAR USERS (NANU) 2013053
SUBJ: SVN34 (PRN04) FORECAST OUTAGE SUMMARY JDAY 246/1717 - JDAY 247/0029
1. NANU TYPE: FCSTSUMM
   NANU NUMBER: 2013053
   NANU DTG: 040030Z SEP 2013
   REFERENCE NANU: 2013052
   REF NANU DTG: 291526Z AUG 2013
   SVN: 34
   PRN: 04
   START JDAY: 246
   START TIME ZULU: 1717
   START CALENDAR DATE: 03 SEP 2013
   STOP JDAY: 247
   STOP TIME ZULU: 0029
   STOP CALENDAR DATE: 04 SEP 2013

2.  CONDITION: GPS SATELLITE SVN34 (PRN04) WAS UNUSABLE ON JDAY 246
(03 SEP 2013) BEGINNING 1717 ZULU UNTIL JDAY 247 (04 SEP 2013)
ENDING 0029 ZULU.

3.  POC: CIVILIAN - NAVCEN AT 703-313-5900, HTTP://WWW.NAVCEN.USCG.GOV
MILITARY - GPS OPERATIONS CENTER at HTTPS://GPS.AFSPC.AF.MIL/GPSOC, DSN 
560-2541,
COMM 719-567-2541, gpsoperationscen...@us.af.mil, HTTPS://GPS.AFSPC.AF.MIL
MILITARY ALTERNATE - JOINT SPACE OPERATIONS CENTER, DSN 276-3514,
COMM 805-606-3514, jspoccombat...@vandenberg.af.mil

is indeed trustworthy. 


It could / might cause issues world wide. A lot depends on how people write 
their firmware and how many sats are in view. Apparently it was not an issue to 
normal navigation firmware. The basic question being - did they write the 
firmware to take the best 2 out of 3 if things looked odd. Given all the 
issues with multi path I would think they would.

Bob




On Sep 6, 2013, at 11:36 PM, John C. Westmoreland, P.E. 
j...@westmorelandengineering.com wrote:

 Fellow Time Nuts:
 
 Is this a site to be trusted?:
 
 http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx
 
 Regards,
 John W.
 
 
 On Fri, Sep 6, 2013 at 6:41 PM, John C. Westmoreland, P.E. 
 j...@westmorelandengineering.com wrote:
 
 Lisa,
 
 Thanks for this update.  How many Resolution-T receivers are out there?
 
 Not to go off on another tangent - but I have heard something about 'GPS
 jamming during the America's Cup'.  Hmmm.
 
 Regards,
 John Westmoreland
 
 
 
 On Fri, Sep 6, 2013 at 8:54 AM, Lisa Perdue perdue.l...@gmail.com wrote:
 
 Trimble has confirmed to us that the nonstandard outage on PRN 4 (SVN 34)
 may have caused the Resolution-T receivers to perform a reset and then
 return to normal operation. They are investigating the cause but it does
 explain why only some people experienced the event. Other Trimble
 receivers
 and other manufacturers seem unaffected.
 
 
 On Thu, Sep 5, 2013 at 10:34 PM, Brian, WA1ZMS wa1...@att.net wrote:
 
 Guys-
 
 Please forgive me for the BW..
 
 My day-job mgmt. has also asked me today if I knew of any US regional
 GPS
 issues, as we too have had several reports of
 our customers systems going into Rb hold-over on or about the 4th of
 Sept.
 Only fact I can find is that SVN 4 was noted as
 an issue via:
 http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx
 But that can't be the root cause.
 
 At work, I am now the go-to-guy for ANYTHING GPS related since I'm a
 Time-Nut and we have customers who depend on
 GPS timing for their  comm. systems;  and for reasons I cannot go into
 here
 on this reflector.
 
 So like Brad.I too have anecdotal reports of issues.  The sky is not
 falling, nor was it a serious issue.
 However if anyone has info that they cannot share via the reflector, a
 private reply would be much appreciated.
 I am not looking for info that cannot be openly shared. But if anyone
 has
 hint or clue, I would much appreciate it.
 
 BTWmy GPS receivers here in VA seemed to have had no issue. Go
 figure.
 
 -Brian, WA1ZMS
 
 
 
 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
 Behalf Of Brad Dye
 Sent: Wednesday, September 04, 2013 6:14 PM
 To: Time Nuts
 Subject: [time-nuts] GPS outage?
 
 Readers of my newsletter are reporting a strange interruption of their
 GPS
 reception yesterday -- mainly in the northeastern US but also in SC.
 This
 is
 my first day on this mailing list -- for a while -- so I don't know if
 this
 has been discussed or reported previously. Has anyone else noticed
 this? We
 are trying to find out is there was some sort of system-wide issue or
 maybe
 if it was local interference possibly caused by those GPS jammers that
 some
 of the truckers have been using.
 
 By the way, my newsletter is mostly about Paging, and we use GPS/DOs to
 keep
 the paging transmitters (in simulcast mode) synchronized and on
 frequency.
 
 Best regards,
 
 Brad Dye, K9IQY
 Editor, Wireless Messaging News
 P.O. Box 266
 Fairfield, IL  62837 USA
 Telephone: 618-599-7869
 Skype: braddye
 http://www.braddye.com
 
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Re: [time-nuts] GPS outage?

[Jim Lux]

On 9/6/13 8:36 PM, John C. Westmoreland, P.E. wrote:

Fellow Time Nuts:

Is this a site to be trusted?:

http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx

Regards,
John W.



AGI are the folks who make and sell STK (Satellite Took Kit, I believe) 
which has a dominant position in the marketplace for doing analyses of 
satellite orbits, visibility, planning, etc.  They have all sorts of 
hooks for their product: antenna patterns, link calculations, etc.


I prefer SOAP (Satellite Orbit Analysis Program) from Aerospace 
Corporation (free for government use, maybe even for non-profits), but 
STK is a much, much bigger commercial player.


Both products have fairly steep learning curves.



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Re: [time-nuts] GPS outage?

[Magnus Danielson]

On 09/06/2013 05:06 AM, Chris Albertson wrote:
 Can anyone estimate how many GPS jammers there are in the New England
 area?   There just might be thousands.  I don't know.

 I think the reason most people are not effected is that most GPS user
 are mobile and if they are near a jammer it is only for a few minutes
Let me tell you that FAA and DHS has serious concerns regarding GPS jammers.

They will happily inform you of just how much trouble they went through
to identify the GPS jammer that regularly caused problems for a New
Jersey airport. They will also tell you that they saw 5 other GPS
jammers, but none of those affected the airport. It was a painful
learning experience for them.

Cheers,
Magnus
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Re: [time-nuts] GPS outage?

[Bob Camp]

Hi

A truck jammer isn't what you would use to take out a large area, you would 
need  100,000 of that sort of jammer. Since the truckers that use them get 
fired, there's a limited number of them in use….

That said, if the event is simply toggling into holdover and then immediately 
popping back out, there's a lot of things that can cause that. Exactly what 
depends a bit on how long the firmware takes to declare a loss / recovery of 
GPS. 

Bob

On Sep 5, 2013, at 11:06 PM, Chris Albertson albertson.ch...@gmail.com wrote:

 Can anyone estimate how many GPS jammers there are in the New England
 area?   There just might be thousands.  I don't know.
 
 I think the reason most people are not effected is that most GPS user
 are mobile and if they are near a jammer it is only for a few minutes
 
 On Thu, Sep 5, 2013 at 4:59 PM, Bob Camp li...@rtty.us wrote:
 Hi
 
 You could indeed deploy a few thousand gizmos and have a pretty significant 
 impact. I'm not at all sure that would be the easier task ….
 
 
 -- 
 
 Chris Albertson
 Redondo Beach, California
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Re: [time-nuts] GPS outage?

[Jim Lux]

On 9/6/13 4:00 AM, Bob Camp wrote:

Hi

A truck jammer isn't what you would use to take out a large area,
you would need  100,000 of that sort of jammer. Since the truckers
that use them get fired, there's a limited number of them in use….


Considering they cost $30, and they're not that easy to detect, I think 
it's a bigger problem than that.  If the trucking company's GPS logging 
system is always failing, they may *think* the driver is using a jammer, 
but they probably don't *know*, so the driver just winds up not getting 
called for trips.  But that same driver will go work for another 
company, carrying the jammer in his/her pocket.


In fact, even if the driver were caught by the FCC, AND they filed an 
enforcement action, I doubt it would show up in the usual background 
check.  It's not on your driving record or criminal record, which 
are the things that people hiring drivers check.


If the driver were actually caught by the trucking company, I doubt 
they'd tell the FCC (since the FCC will come after the company too), and 
there's probably no law enforcement involvement.  The driver is 
terminated, and if someone were to ask, the company would just reply 
yes, they worked as a driver from %date% to %date%.  I can't imagine a 
company telling someone calling for a reference about a driver using a 
jammer: there's too many downsides.  It's not cut and dried like oh, 
Bob was terminated when he wrecked 3 trucks or came into work after 
being awake for 3 days straight waving a sword.  Those kinds of things 
are objective and easy to report.



But as you say, you'd need a lot of eBay GPS jammers to cause a large 
area outage.  We here on Time-Nuts, of course, are far more 
sophisticated, and with the thousands of dollars worth of equipment, and 
millions of hours of experience (cumulatively), it would be short work 
for one of us to deny GPS to a significant area.  Just sayin'... {Let me 
go out to my garage and start warming up the filaments and start the 
water cooling system on the L-band Klystron. I need to drive up to the 
top of Mt. Wilson where I have a good view of the LA basin, bwa-ha-ha-ha...}





That said, if the event is simply toggling into holdover and then
immediately popping back out, there's a lot of things that can cause
that. Exactly what depends a bit on how long the firmware takes to
declare a loss / recovery of GPS.

Bob


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Re: [time-nuts] GPS outage?

[George Sintchak]

Hi Brian,
No unusual GPS blips noticed here with my Z3801a on Long Island, NY either. 
The SVN 4 may have caused a holdover event to download a new almanac and 
some receivers were not happy doing that if only seeing a few birds and/or 
poor geometry in NE area at that time.


FCSTDV, or Forecast Delta-V, gives scheduled outage times for Delta-V 
maneuvers. The satellite is moved during this maintenance and the user may 
be required to download a new almanac.


George, WA2VNV



Message: 4
Date: Fri, 6 Sep 2013 01:06:30 -0400
From: Brian, WA1ZMS wa1...@att.net
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] GPS outage?
Message-ID: 27563b77-e8c5-440c-bbba-4d118d885...@att.net
Content-Type: text/plain; charset=utf-8

John-

I agree. We all should/would have seen
even a minor outage. That's what makes the event from early this week a 
rather odd event.


I have personally observed GPS jamming events from truck drivers trying to 
prevent being tracked. But those events are very localized it seems and 
are well bounded.


I cannot speak for others, but I am on
a presumption/ theory for our vendor supplied gear that the GPS engines 
may not have dealt very well with SVN 4 being tagged as not for use on
Sept 3  4.  Just a theory from an RF guy since I have no other 
explanation why some gear had issues yet 99% of us Time-Nuts never noticed 
an issue.


Oh well..

-Brian, WA1ZMS


SNIP 


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Re: [time-nuts] GPS outage?

[Lisa Perdue]

Trimble has confirmed to us that the nonstandard outage on PRN 4 (SVN 34)
may have caused the Resolution-T receivers to perform a reset and then
return to normal operation. They are investigating the cause but it does
explain why only some people experienced the event. Other Trimble receivers
and other manufacturers seem unaffected.


On Thu, Sep 5, 2013 at 10:34 PM, Brian, WA1ZMS wa1...@att.net wrote:

 Guys-

 Please forgive me for the BW..

 My day-job mgmt. has also asked me today if I knew of any US regional GPS
 issues, as we too have had several reports of
 our customers systems going into Rb hold-over on or about the 4th of Sept.
 Only fact I can find is that SVN 4 was noted as
 an issue via: http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx
 But that can't be the root cause.

 At work, I am now the go-to-guy for ANYTHING GPS related since I'm a
 Time-Nut and we have customers who depend on
 GPS timing for their  comm. systems;  and for reasons I cannot go into here
 on this reflector.

 So like Brad.I too have anecdotal reports of issues.  The sky is not
 falling, nor was it a serious issue.
 However if anyone has info that they cannot share via the reflector, a
 private reply would be much appreciated.
 I am not looking for info that cannot be openly shared. But if anyone has
 hint or clue, I would much appreciate it.

 BTWmy GPS receivers here in VA seemed to have had no issue. Go figure.

 -Brian, WA1ZMS



 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
 Behalf Of Brad Dye
 Sent: Wednesday, September 04, 2013 6:14 PM
 To: Time Nuts
 Subject: [time-nuts] GPS outage?

 Readers of my newsletter are reporting a strange interruption of their GPS
 reception yesterday -- mainly in the northeastern US but also in SC. This
 is
 my first day on this mailing list -- for a while -- so I don't know if this
 has been discussed or reported previously. Has anyone else noticed this? We
 are trying to find out is there was some sort of system-wide issue or maybe
 if it was local interference possibly caused by those GPS jammers that some
 of the truckers have been using.

 By the way, my newsletter is mostly about Paging, and we use GPS/DOs to
 keep
 the paging transmitters (in simulcast mode) synchronized and on frequency.

 Best regards,

 Brad Dye, K9IQY
 Editor, Wireless Messaging News
 P.O. Box 266
 Fairfield, IL  62837 USA
 Telephone: 618-599-7869
 Skype: braddye
 http://www.braddye.com

 ___
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 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

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 To unsubscribe, go to
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Re: [time-nuts] GPS outage?

[Bill Hawkins]

You bet I'm outraged by GPS causing the death of simpler, more secure
systems like Loran. GPS has many ways to fail, but vacuum tube
transmitters
just required new tubes.

Aren't you outraged too?

Wait - this is about outages?

Never mind.

(Remembering Emily Litella / Gilda Ratner - violins in the streets)

Bill Hawkins

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Re: [time-nuts] GPS outage?

[Ed Palmer]

Bill, did you forget your meds or double up on the dosage or something? ;-)

Ed

On 9/6/2013 1:07 PM, Bill Hawkins wrote:

You bet I'm outraged by GPS causing the death of simpler, more secure
systems like Loran. GPS has many ways to fail, but vacuum tube
transmitters
just required new tubes.

Aren't you outraged too?

Wait - this is about outages?

Never mind.

(Remembering Emily Litella / Gilda Ratner - violins in the streets)

Bill Hawkins



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Re: [time-nuts] GPS outage?

[Bob Camp]

Hi

Ok, here's why the guy gets fired:

The trucking company doesn't do the GPS thing to catch the trucker goofing off. 
They do it because they get paid to do it. A number of companies will only ship 
with you *if* you can real time track the cargo and tell them when it'll get to 
their dock. Why - they only have to pay the unload crew to be there when 
there's cargo coming in. They only schedule production when all the parts will 
be there. No parts / no delivery  - everybody stay home and we don't pay you. 

When the tracking goes blank on the truck, the company does not pay the agreed 
on premium for the service. If the percentage of loads without tracking goes 
above a (quite low) threshold the truck line gets significantly less business 
than their competitor. 

The trucking companies go after this stuff because it costs them a lot of 
money, not because of any law that may be broken. 

Bob

On Sep 6, 2013, at 9:25 AM, Jim Lux jim...@earthlink.net wrote:

 On 9/6/13 4:00 AM, Bob Camp wrote:
 Hi
 
 A truck jammer isn't what you would use to take out a large area,
 you would need  100,000 of that sort of jammer. Since the truckers
 that use them get fired, there's a limited number of them in use….
 
 Considering they cost $30, and they're not that easy to detect, I think it's 
 a bigger problem than that.  If the trucking company's GPS logging system is 
 always failing, they may *think* the driver is using a jammer, but they 
 probably don't *know*, so the driver just winds up not getting called for 
 trips.  But that same driver will go work for another company, carrying the 
 jammer in his/her pocket.
 
 In fact, even if the driver were caught by the FCC, AND they filed an 
 enforcement action, I doubt it would show up in the usual background check.  
 It's not on your driving record or criminal record, which are the things 
 that people hiring drivers check.
 
 If the driver were actually caught by the trucking company, I doubt they'd 
 tell the FCC (since the FCC will come after the company too), and there's 
 probably no law enforcement involvement.  The driver is terminated, and if 
 someone were to ask, the company would just reply yes, they worked as a 
 driver from %date% to %date%.  I can't imagine a company telling someone 
 calling for a reference about a driver using a jammer: there's too many 
 downsides.  It's not cut and dried like oh, Bob was terminated when he 
 wrecked 3 trucks or came into work after being awake for 3 days straight 
 waving a sword.  Those kinds of things are objective and easy to report.
 
 
 But as you say, you'd need a lot of eBay GPS jammers to cause a large area 
 outage.  We here on Time-Nuts, of course, are far more sophisticated, and 
 with the thousands of dollars worth of equipment, and millions of hours of 
 experience (cumulatively), it would be short work for one of us to deny GPS 
 to a significant area.  Just sayin'... {Let me go out to my garage and start 
 warming up the filaments and start the water cooling system on the L-band 
 Klystron. I need to drive up to the top of Mt. Wilson where I have a good 
 view of the LA basin, bwa-ha-ha-ha...}
 
 
 
 That said, if the event is simply toggling into holdover and then
 immediately popping back out, there's a lot of things that can cause
 that. Exactly what depends a bit on how long the firmware takes to
 declare a loss / recovery of GPS.
 
 Bob
 
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Re: [time-nuts] GPS outage?

[John C. Westmoreland, P.E.]

Lisa,

Thanks for this update.  How many Resolution-T receivers are out there?

Not to go off on another tangent - but I have heard something about 'GPS
jamming during the America's Cup'.  Hmmm.

Regards,
John Westmoreland



On Fri, Sep 6, 2013 at 8:54 AM, Lisa Perdue perdue.l...@gmail.com wrote:

 Trimble has confirmed to us that the nonstandard outage on PRN 4 (SVN 34)
 may have caused the Resolution-T receivers to perform a reset and then
 return to normal operation. They are investigating the cause but it does
 explain why only some people experienced the event. Other Trimble receivers
 and other manufacturers seem unaffected.


 On Thu, Sep 5, 2013 at 10:34 PM, Brian, WA1ZMS wa1...@att.net wrote:

  Guys-
 
  Please forgive me for the BW..
 
  My day-job mgmt. has also asked me today if I knew of any US regional GPS
  issues, as we too have had several reports of
  our customers systems going into Rb hold-over on or about the 4th of
 Sept.
  Only fact I can find is that SVN 4 was noted as
  an issue via:
 http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx
  But that can't be the root cause.
 
  At work, I am now the go-to-guy for ANYTHING GPS related since I'm a
  Time-Nut and we have customers who depend on
  GPS timing for their  comm. systems;  and for reasons I cannot go into
 here
  on this reflector.
 
  So like Brad.I too have anecdotal reports of issues.  The sky is not
  falling, nor was it a serious issue.
  However if anyone has info that they cannot share via the reflector, a
  private reply would be much appreciated.
  I am not looking for info that cannot be openly shared. But if anyone has
  hint or clue, I would much appreciate it.
 
  BTWmy GPS receivers here in VA seemed to have had no issue. Go
 figure.
 
  -Brian, WA1ZMS
 
 
 
  -Original Message-
  From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
  Behalf Of Brad Dye
  Sent: Wednesday, September 04, 2013 6:14 PM
  To: Time Nuts
  Subject: [time-nuts] GPS outage?
 
  Readers of my newsletter are reporting a strange interruption of their
 GPS
  reception yesterday -- mainly in the northeastern US but also in SC. This
  is
  my first day on this mailing list -- for a while -- so I don't know if
 this
  has been discussed or reported previously. Has anyone else noticed this?
 We
  are trying to find out is there was some sort of system-wide issue or
 maybe
  if it was local interference possibly caused by those GPS jammers that
 some
  of the truckers have been using.
 
  By the way, my newsletter is mostly about Paging, and we use GPS/DOs to
  keep
  the paging transmitters (in simulcast mode) synchronized and on
 frequency.
 
  Best regards,
 
  Brad Dye, K9IQY
  Editor, Wireless Messaging News
  P.O. Box 266
  Fairfield, IL  62837 USA
  Telephone: 618-599-7869
  Skype: braddye
  http://www.braddye.com
 
  ___
  time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
  and follow the instructions there.
 
  ___
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  To unsubscribe, go to
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  and follow the instructions there.
 
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 To unsubscribe, go to
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Re: [time-nuts] GPS outage?

[John C. Westmoreland, P.E.]

Fellow Time Nuts:

Is this a site to be trusted?:

http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx

Regards,
John W.


On Fri, Sep 6, 2013 at 6:41 PM, John C. Westmoreland, P.E. 
j...@westmorelandengineering.com wrote:

 Lisa,

 Thanks for this update.  How many Resolution-T receivers are out there?

 Not to go off on another tangent - but I have heard something about 'GPS
 jamming during the America's Cup'.  Hmmm.

 Regards,
 John Westmoreland



 On Fri, Sep 6, 2013 at 8:54 AM, Lisa Perdue perdue.l...@gmail.com wrote:

 Trimble has confirmed to us that the nonstandard outage on PRN 4 (SVN 34)
 may have caused the Resolution-T receivers to perform a reset and then
 return to normal operation. They are investigating the cause but it does
 explain why only some people experienced the event. Other Trimble
 receivers
 and other manufacturers seem unaffected.


 On Thu, Sep 5, 2013 at 10:34 PM, Brian, WA1ZMS wa1...@att.net wrote:

  Guys-
 
  Please forgive me for the BW..
 
  My day-job mgmt. has also asked me today if I knew of any US regional
 GPS
  issues, as we too have had several reports of
  our customers systems going into Rb hold-over on or about the 4th of
 Sept.
  Only fact I can find is that SVN 4 was noted as
  an issue via:
 http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx
  But that can't be the root cause.
 
  At work, I am now the go-to-guy for ANYTHING GPS related since I'm a
  Time-Nut and we have customers who depend on
  GPS timing for their  comm. systems;  and for reasons I cannot go into
 here
  on this reflector.
 
  So like Brad.I too have anecdotal reports of issues.  The sky is not
  falling, nor was it a serious issue.
  However if anyone has info that they cannot share via the reflector, a
  private reply would be much appreciated.
  I am not looking for info that cannot be openly shared. But if anyone
 has
  hint or clue, I would much appreciate it.
 
  BTWmy GPS receivers here in VA seemed to have had no issue. Go
 figure.
 
  -Brian, WA1ZMS
 
 
 
  -Original Message-
  From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
  Behalf Of Brad Dye
  Sent: Wednesday, September 04, 2013 6:14 PM
  To: Time Nuts
  Subject: [time-nuts] GPS outage?
 
  Readers of my newsletter are reporting a strange interruption of their
 GPS
  reception yesterday -- mainly in the northeastern US but also in SC.
 This
  is
  my first day on this mailing list -- for a while -- so I don't know if
 this
  has been discussed or reported previously. Has anyone else noticed
 this? We
  are trying to find out is there was some sort of system-wide issue or
 maybe
  if it was local interference possibly caused by those GPS jammers that
 some
  of the truckers have been using.
 
  By the way, my newsletter is mostly about Paging, and we use GPS/DOs to
  keep
  the paging transmitters (in simulcast mode) synchronized and on
 frequency.
 
  Best regards,
 
  Brad Dye, K9IQY
  Editor, Wireless Messaging News
  P.O. Box 266
  Fairfield, IL  62837 USA
  Telephone: 618-599-7869
  Skype: braddye
  http://www.braddye.com
 
  ___
  time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
  and follow the instructions there.
 
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Re: [time-nuts] GPS outage?

[Magnus Danielson]

On 09/05/2013 03:37 AM, Bob Camp wrote:
 Hi

 My guess is that if GPS was down over the northeastern part of the US for 
 most of a day, you would not have to check with TimeNuts. It would be on the 
 evening news. Since your typical mobile GPS needs more sats than a timing 
 receiver, they should drop out first. When the entire car / truck / bus / 
 ambulance driving population of a couple dozen states all gets lost at once - 
 you'll hear about it…..
Each bird illuminate about one third of the earth surface, so if about
one third of the constellation would be off line it would have been a
major event and seen over more than half the earth as a drop too. I see
no strange notes in the GPS OPS Advisory, just the normal maintenance
with nominally 32 birds on air.

There are ways by which GPS reception is disrupted, for instance by
other transmitters. A few other causes like solare flares is said to
cause it, and I think I've heard about issues around vulcanos.

Cheers,
Magnus
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Re: [time-nuts] GPS outage?

[Bob Camp]

Hi

Ok, I'll also mention that I haven't heard of any major volcanic eruptions in 
the north eastern US. GPS outages would not make it on the news if there was a 
major Volcano doing it's thing outside Cleveland ….

If a sat went down, and did so in a pathogenic fashion, you would have an issue 
world wide. To keep the problem local, some sort of local jamming is about the 
only thing that could do it. To take out an area like New England all at once 
you would need a fairly high flying platform with a fairly powerful transmitter.

Bob

On Sep 5, 2013, at 2:29 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote:

 On 09/05/2013 03:37 AM, Bob Camp wrote:
 Hi
 
 My guess is that if GPS was down over the northeastern part of the US for 
 most of a day, you would not have to check with TimeNuts. It would be on the 
 evening news. Since your typical mobile GPS needs more sats than a timing 
 receiver, they should drop out first. When the entire car / truck / bus / 
 ambulance driving population of a couple dozen states all gets lost at once 
 - you'll hear about it…..
 Each bird illuminate about one third of the earth surface, so if about
 one third of the constellation would be off line it would have been a
 major event and seen over more than half the earth as a drop too. I see
 no strange notes in the GPS OPS Advisory, just the normal maintenance
 with nominally 32 birds on air.
 
 There are ways by which GPS reception is disrupted, for instance by
 other transmitters. A few other causes like solare flares is said to
 cause it, and I think I've heard about issues around vulcanos.
 
 Cheers,
 Magnus
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Re: [time-nuts] GPS outage?

[Magnus Danielson]

On 09/05/2013 01:08 PM, Bob Camp wrote:
 Hi

 Ok, I'll also mention that I haven't heard of any major volcanic eruptions in 
 the north eastern US. GPS outages would not make it on the news if there was 
 a major Volcano doing it's thing outside Cleveland ….
Indeed. I think the problems could occur even when there is no eruption.
However, my memory is fuzzy on the details.
 If a sat went down, and did so in a pathogenic fashion, you would have an 
 issue world wide.
Indeed. It would also show up in the GPS operational logs.
 To keep the problem local, some sort of local jamming is about the only thing 
 that could do it. To take out an area like New England all at once you would 
 need a fairly high flying platform with a fairly powerful transmitter.
Well, it could also be deployment of a system that does the same thing
spread out.

Cheers,
Magnus
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Re: [time-nuts] GPS outage?

[Chris Albertson]

Another scenario that would result in many reports from an area like
New England is if only about a dozen people happened to be affected by
one truck that was carrying a jammer.  These dozen people would
complain and from those few complaints you'd say we have a dozen
reports from all over New England of GPS outage.   I suspect this is
the kind of thing that happened.

Each satellite serves the entire Earth so a system failure would be
global, not regional.  I suspect the problem is that the data were
collected from people who self-report a problem.   You only heard from
them and not the millions of others who had no problem.   A rather
extreme case of sample bias.   A better method is to pool random GPS
users and ask if their systems work.  This would be hard work but now
we have GPS inside cell phones so the polling can be automated.



On Thu, Sep 5, 2013 at 4:08 AM, Bob Camp li...@rtty.us wrote:
 To keep the problem local, some sort of local jamming is about the only thing 
 that could do it.
 To take out an area like New England all at once you would need a fairly high 
 flying platform with a fairly powerful transmitter.




-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] GPS outage?

[Bob Camp]

Hi

You could indeed deploy a few thousand gizmos and have a pretty significant 
impact. I'm not at all sure that would be the easier task ….

Bob

On Sep 5, 2013, at 4:18 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote:

 On 09/05/2013 01:08 PM, Bob Camp wrote:
 Hi
 
 Ok, I'll also mention that I haven't heard of any major volcanic eruptions 
 in the north eastern US. GPS outages would not make it on the news if there 
 was a major Volcano doing it's thing outside Cleveland ….
 Indeed. I think the problems could occur even when there is no eruption.
 However, my memory is fuzzy on the details.
 If a sat went down, and did so in a pathogenic fashion, you would have an 
 issue world wide.
 Indeed. It would also show up in the GPS operational logs.
 To keep the problem local, some sort of local jamming is about the only 
 thing that could do it. To take out an area like New England all at once you 
 would need a fairly high flying platform with a fairly powerful transmitter.
 Well, it could also be deployment of a system that does the same thing
 spread out.
 
 Cheers,
 Magnus
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Re: [time-nuts] GPS outage?

[Brian, WA1ZMS]

Guys-

Please forgive me for the BW..

My day-job mgmt. has also asked me today if I knew of any US regional GPS
issues, as we too have had several reports of
our customers systems going into Rb hold-over on or about the 4th of Sept.
Only fact I can find is that SVN 4 was noted as
an issue via: http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx
But that can't be the root cause.

At work, I am now the go-to-guy for ANYTHING GPS related since I'm a
Time-Nut and we have customers who depend on
GPS timing for their  comm. systems;  and for reasons I cannot go into here
on this reflector.

So like Brad.I too have anecdotal reports of issues.  The sky is not
falling, nor was it a serious issue.
However if anyone has info that they cannot share via the reflector, a
private reply would be much appreciated.
I am not looking for info that cannot be openly shared. But if anyone has
hint or clue, I would much appreciate it.

BTWmy GPS receivers here in VA seemed to have had no issue. Go figure.

-Brian, WA1ZMS



-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Brad Dye
Sent: Wednesday, September 04, 2013 6:14 PM
To: Time Nuts
Subject: [time-nuts] GPS outage?

Readers of my newsletter are reporting a strange interruption of their GPS
reception yesterday -- mainly in the northeastern US but also in SC. This is
my first day on this mailing list -- for a while -- so I don't know if this
has been discussed or reported previously. Has anyone else noticed this? We
are trying to find out is there was some sort of system-wide issue or maybe
if it was local interference possibly caused by those GPS jammers that some
of the truckers have been using.

By the way, my newsletter is mostly about Paging, and we use GPS/DOs to keep
the paging transmitters (in simulcast mode) synchronized and on frequency.

Best regards,

Brad Dye, K9IQY
Editor, Wireless Messaging News
P.O. Box 266
Fairfield, IL  62837 USA
Telephone: 618-599-7869
Skype: braddye
http://www.braddye.com

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Re: [time-nuts] GPS outage?

[Chris Albertson]

Can anyone estimate how many GPS jammers there are in the New England
area?   There just might be thousands.  I don't know.

I think the reason most people are not effected is that most GPS user
are mobile and if they are near a jammer it is only for a few minutes

On Thu, Sep 5, 2013 at 4:59 PM, Bob Camp li...@rtty.us wrote:
 Hi

 You could indeed deploy a few thousand gizmos and have a pretty significant 
 impact. I'm not at all sure that would be the easier task ….


-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] GPS outage?

[John C. Westmoreland, P.E.]

Hello All,

Not to go off on a tangent here but are there 'time nuts' distributed
around the globe in such a way as we'd know about an outage?

One good hiccup by the Sun and it could cause an outage - correct?  (
http://www.spaceweather.com)

It wasn't so long ago we were told the Iridium 'Flares' were all that were
left of Motorola's project and now you can go buy a phone here:
http://iridium.com/default.aspx

Regards,
John W.






On Thu, Sep 5, 2013 at 8:06 PM, Chris Albertson
albertson.ch...@gmail.comwrote:

 Can anyone estimate how many GPS jammers there are in the New England
 area?   There just might be thousands.  I don't know.

 I think the reason most people are not effected is that most GPS user
 are mobile and if they are near a jammer it is only for a few minutes

 On Thu, Sep 5, 2013 at 4:59 PM, Bob Camp li...@rtty.us wrote:
  Hi
 
  You could indeed deploy a few thousand gizmos and have a pretty
 significant impact. I'm not at all sure that would be the easier task ….


 --

 Chris Albertson
 Redondo Beach, California
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Re: [time-nuts] GPS outage?

[Brian, WA1ZMS]

John-

I agree. We all should/would have seen
even a minor outage. That's what makes the event from early this week a rather 
odd event.

I have personally observed GPS jamming events from truck drivers trying to 
prevent being tracked. But those events are very localized it seems and are 
well bounded.

I cannot speak for others, but I am on
a presumption/ theory for our vendor supplied gear that the GPS engines may not 
have dealt very well with SVN 4 being tagged as not for use on
Sept 3  4.  Just a theory from an RF guy since I have no other explanation why 
some gear had issues yet 99% of us Time-Nuts never noticed an issue.

Oh well..

-Brian, WA1ZMS

On Sep 6, 2013, at 12:23 AM, John C. Westmoreland, P.E. 
j...@westmorelandengineering.com wrote:

 Hello All,
 
 Not to go off on a tangent here but are there 'time nuts' distributed
 around the globe in such a way as we'd know about an outage?
 
 One good hiccup by the Sun and it could cause an outage - correct?  (
 http://www.spaceweather.com)
 
 It wasn't so long ago we were told the Iridium 'Flares' were all that were
 left of Motorola's project and now you can go buy a phone here:
 http://iridium.com/default.aspx
 
 Regards,
 John W.
 
 
 
 
 
 
 On Thu, Sep 5, 2013 at 8:06 PM, Chris Albertson
 albertson.ch...@gmail.comwrote:
 
 Can anyone estimate how many GPS jammers there are in the New England
 area?   There just might be thousands.  I don't know.
 
 I think the reason most people are not effected is that most GPS user
 are mobile and if they are near a jammer it is only for a few minutes
 
 On Thu, Sep 5, 2013 at 4:59 PM, Bob Camp li...@rtty.us wrote:
 Hi
 
 You could indeed deploy a few thousand gizmos and have a pretty
 significant impact. I'm not at all sure that would be the easier task ….
 
 
 --
 
 Chris Albertson
 Redondo Beach, California
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[time-nuts] GPS outage?

[Brad Dye]

Readers of my newsletter are reporting a strange interruption of their GPS 
reception yesterday -- mainly in the northeastern US but also in SC. This is my 
first day on this mailing list -- for a while -- so I don't know if this has 
been discussed or reported previously. Has anyone else noticed this? We are 
trying to find out is there was some sort of system-wide issue or maybe if it 
was local interference possibly caused by those GPS jammers that some of the 
truckers have been using.

By the way, my newsletter is mostly about Paging, and we use GPS/DOs to keep 
the paging transmitters (in simulcast mode) synchronized and on frequency.

Best regards,

Brad Dye, K9IQY
Editor, Wireless Messaging News
P.O. Box 266
Fairfield, IL  62837 USA
Telephone: 618-599-7869
Skype: braddye
http://www.braddye.com

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Re: [time-nuts] GPS outage?

[Bob Camp]

Hi

My guess is that if GPS was down over the northeastern part of the US for most 
of a day, you would not have to check with TimeNuts. It would be on the evening 
news. Since your typical mobile GPS needs more sats than a timing receiver, 
they should drop out first. When the entire car / truck / bus / ambulance 
driving population of a couple dozen states all gets lost at once - you'll hear 
about it…..

Bob

On Sep 4, 2013, at 6:14 PM, Brad Dye b...@braddye.com wrote:

 Readers of my newsletter are reporting a strange interruption of their GPS 
 reception yesterday -- mainly in the northeastern US but also in SC. This is 
 my first day on this mailing list -- for a while -- so I don't know if this 
 has been discussed or reported previously. Has anyone else noticed this? We 
 are trying to find out is there was some sort of system-wide issue or maybe 
 if it was local interference possibly caused by those GPS jammers that some 
 of the truckers have been using.
 
 By the way, my newsletter is mostly about Paging, and we use GPS/DOs to keep 
 the paging transmitters (in simulcast mode) synchronized and on frequency.
 
 Best regards,
 
 Brad Dye, K9IQY
 Editor, Wireless Messaging News
 P.O. Box 266
 Fairfield, IL  62837 USA
 Telephone: 618-599-7869
 Skype: braddye
 http://www.braddye.com
 
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