Re: [time-nuts] Garmin GPS12XL V3.51

[Tim Shoppa]

Beyond the predictability of physical variation, there is also the unknown
probability of a human decision to abolish leap seconds, while also
continuing to satisfy the various legal requirements around the world that
civil time be tied to the Sun.
https://en.wikipedia.org/wiki/Leap_second#Proposal_to_abolish_leap_seconds

Tim N3QE

On Thu, Apr 11, 2019 at 3:01 PM Adrian Godwin  wrote:

> Thanks. So the current estimate of 13 is towards the high end and variation
> is large enough that 40 years with might be sufficiently low that only 1
> rollover is assumed. Not likely to overflow the leap second count early
> either.
>
>
> On Thu, Apr 11, 2019 at 3:01 PM Tony Finch  wrote:
>
> > Adrian Godwin  wrote:
> > >
> > > How much variation in the rate of leap second insertion is there?
> >
> > 1972-01-01 - 1992-01-01 : 17
> > 1973-01-01 - 1993-01-01 : 16
> > 1974-01-01 - 1994-01-01 : 16
> > 1975-01-01 - 1995-01-01 : 16
> > 1976-01-01 - 1996-01-01 : 15
> > 1977-01-01 - 1997-01-01 : 15
> > 1978-01-01 - 1998-01-01 : 15
> > 1979-01-01 - 1999-01-01 : 14
> > 1980-01-01 - 2000-01-01 : 14
> > 1981-01-01 - 2001-01-01 : 13
> > 1982-01-01 - 2002-01-01 : 12
> > 1983-01-01 - 2003-01-01 : 11
> > 1984-01-01 - 2004-01-01 : 10
> > 1985-01-01 - 2005-01-01 : 10
> > 1986-01-01 - 2006-01-01 :  9
> > 1987-01-01 - 2007-01-01 : 10
> > 1988-01-01 - 2008-01-01 : 10
> > 1989-01-01 - 2009-01-01 :  9
> > 1990-01-01 - 2010-01-01 : 10
> > 1991-01-01 - 2011-01-01 :  9
> > 1992-01-01 - 2012-01-01 :  8
> > 1993-01-01 - 2013-01-01 :  8
> > 1994-01-01 - 2014-01-01 :  7
> > 1995-01-01 - 2015-01-01 :  6
> > 1996-01-01 - 2016-01-01 :  7
> > 1997-01-01 - 2017-01-01 :  6
> > 1998-01-01 - 2018-01-01 :  6
> > 1999-01-01 - 2019-01-01 :  6
> > 2000-01-01 - 2020-01-01 :  6
> >
> > Tony.
> > --
> > f.anthony.n.finchhttp://dotat.at/
> > Trafalgar: In east, northerly 5 or 6. In west, variable 3 or 4. In east,
> > moderate, occasionally rough. in west, moderate, occasionally rough in
> > north.
> > In east, fair. In west, mainly fair. In east, good. In west, good.
> >
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to
> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
> >
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Re: [time-nuts] Garmin GPS12XL V3.51

[Adrian Godwin]

Thanks. So the current estimate of 13 is towards the high end and variation
is large enough that 40 years with might be sufficiently low that only 1
rollover is assumed. Not likely to overflow the leap second count early
either.


On Thu, Apr 11, 2019 at 3:01 PM Tony Finch  wrote:

> Adrian Godwin  wrote:
> >
> > How much variation in the rate of leap second insertion is there?
>
> 1972-01-01 - 1992-01-01 : 17
> 1973-01-01 - 1993-01-01 : 16
> 1974-01-01 - 1994-01-01 : 16
> 1975-01-01 - 1995-01-01 : 16
> 1976-01-01 - 1996-01-01 : 15
> 1977-01-01 - 1997-01-01 : 15
> 1978-01-01 - 1998-01-01 : 15
> 1979-01-01 - 1999-01-01 : 14
> 1980-01-01 - 2000-01-01 : 14
> 1981-01-01 - 2001-01-01 : 13
> 1982-01-01 - 2002-01-01 : 12
> 1983-01-01 - 2003-01-01 : 11
> 1984-01-01 - 2004-01-01 : 10
> 1985-01-01 - 2005-01-01 : 10
> 1986-01-01 - 2006-01-01 :  9
> 1987-01-01 - 2007-01-01 : 10
> 1988-01-01 - 2008-01-01 : 10
> 1989-01-01 - 2009-01-01 :  9
> 1990-01-01 - 2010-01-01 : 10
> 1991-01-01 - 2011-01-01 :  9
> 1992-01-01 - 2012-01-01 :  8
> 1993-01-01 - 2013-01-01 :  8
> 1994-01-01 - 2014-01-01 :  7
> 1995-01-01 - 2015-01-01 :  6
> 1996-01-01 - 2016-01-01 :  7
> 1997-01-01 - 2017-01-01 :  6
> 1998-01-01 - 2018-01-01 :  6
> 1999-01-01 - 2019-01-01 :  6
> 2000-01-01 - 2020-01-01 :  6
>
> Tony.
> --
> f.anthony.n.finchhttp://dotat.at/
> Trafalgar: In east, northerly 5 or 6. In west, variable 3 or 4. In east,
> moderate, occasionally rough. in west, moderate, occasionally rough in
> north.
> In east, fair. In west, mainly fair. In east, good. In west, good.
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
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Re: [time-nuts] Garmin GPS12XL V3.51

[Tony Finch]

Adrian Godwin  wrote:
>
> How much variation in the rate of leap second insertion is there?

1972-01-01 - 1992-01-01 : 17
1973-01-01 - 1993-01-01 : 16
1974-01-01 - 1994-01-01 : 16
1975-01-01 - 1995-01-01 : 16
1976-01-01 - 1996-01-01 : 15
1977-01-01 - 1997-01-01 : 15
1978-01-01 - 1998-01-01 : 15
1979-01-01 - 1999-01-01 : 14
1980-01-01 - 2000-01-01 : 14
1981-01-01 - 2001-01-01 : 13
1982-01-01 - 2002-01-01 : 12
1983-01-01 - 2003-01-01 : 11
1984-01-01 - 2004-01-01 : 10
1985-01-01 - 2005-01-01 : 10
1986-01-01 - 2006-01-01 :  9
1987-01-01 - 2007-01-01 : 10
1988-01-01 - 2008-01-01 : 10
1989-01-01 - 2009-01-01 :  9
1990-01-01 - 2010-01-01 : 10
1991-01-01 - 2011-01-01 :  9
1992-01-01 - 2012-01-01 :  8
1993-01-01 - 2013-01-01 :  8
1994-01-01 - 2014-01-01 :  7
1995-01-01 - 2015-01-01 :  6
1996-01-01 - 2016-01-01 :  7
1997-01-01 - 2017-01-01 :  6
1998-01-01 - 2018-01-01 :  6
1999-01-01 - 2019-01-01 :  6
2000-01-01 - 2020-01-01 :  6

Tony.
-- 
f.anthony.n.finchhttp://dotat.at/
Trafalgar: In east, northerly 5 or 6. In west, variable 3 or 4. In east,
moderate, occasionally rough. in west, moderate, occasionally rough in north.
In east, fair. In west, mainly fair. In east, good. In west, good.

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Re: [time-nuts] Garmin GPS12XL V3.51

[Adrian Godwin]

The references I found in those archived postings explain that the problem
was that the GPS receiver had been 'fixed' in 2011 but that the fix only
worked until 2015. The solution was to replace the receiver.

I wasn't able to find any discussion of why the fix lasted such a short
time, but it seems far too short to be due to variation in the rate of leap
second insertions.

Assuming that the reason for that algorithm's failure is correct though, it
implies that leap second insertion rate might vary by at least 13
insertions in 20 years in order that an estimate of week counter cycles
produced from leap second count would be wrong.

This carries a further implication that the 7 bit count of leap seconds
will last not for 175 years but half that or perhaps worse. Or, if the
problem is with a lower than assumed rate of insertions, better.

How much variation in the rate of leap second insertion is there?

On Tue, 9 Apr 2019, 14:01 Tom Van Baak,  wrote:

> > There's another relatively simple clue in the old GPS signal: the leap
> > second count! A device manufacturer could teach it what the leap second
> > count was at manufacturing time, and how to predict a lower bound on the
> > leap second count in the future (with a suitable safety margin / fudge
> > factor) which should allow it to live a bit more than 20 years.
>
> The idea was proposed 20+ years ago, Trimble even has a patent on it.
> Details here:
>
> http://leapsecond.com/notes/gpswnro.htm
>
> But it turns out not to work. Earth rotation is too difficult to predict
> 20, 40, or 60 years into the future. There was talk that the GPS receiver
> failures in 2015 were related to this algorithm. Look for any threads with
> subjects like: TS2100, TymServe 2100, 1995 rollover, Trimble ACE, Heol
> Design in:
>
> http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2015-May/
> http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2015-June/
>
> /tvb
>
> - Original Message -
> From: "Tony Finch" 
> To: "Discussion of precise time and frequency measurement" <
> time-nuts@lists.febo.com>
> Sent: Tuesday, April 09, 2019 4:08 AM
> Subject: Re: [time-nuts] Garmin GPS12XL V3.51
>
>
> > Leo Bodnar  wrote:
> >
> >> Assume that the device does not have any reliable long term non-volatile
> >> memory that you can update.
> >
> >> In the absence of any clues your only reliable piece of knowledge is
> >> that the cold start date is somewhere after the date of manufacturing
> >> or, most often, firmware compilation date.
> >
> > There's another relatively simple clue in the old GPS signal: the leap
> > second count! A device manufacturer could teach it what the leap second
> > count was at manufacturing time, and how to predict a lower bound on the
> > leap second count in the future (with a suitable safety margin / fudge
> > factor) which should allow it to live a bit more than 20 years.
> >
> > Tony.
> > --
> > f.anthony.n.finchhttp://dotat.at/
> > Gibraltar Point to North Foreland: Northeasterly 5 or 6, occasionally 7
> in
> > south. Moderate. Showers at first in south. Good, occasionally moderate
> at
> > first.
> >
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
>
>
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Re: [time-nuts] Garmin GPS12XL V3.51

[Bob kb8tq]

Hi

The “fix” for this (adding 3 more bits) was worked out and announced back in 
2004. The new
generation of sats will be transmitting a longer week number. The gotcha is 
that the old sats
are still up there doing their thing. They are built in a way that you can’t 
just shoot a firmware
patch into space and add more bits to the transmitted message. 

The original plan was that the new message would be on the air well before the 
rollover event
that just happened. Even then, there was some debate about how many devices 
would be able
to use the “new” message. The whole implement / debug / deploy / patch cycle is 
not something
that happens overnight. 

On all of our older gear, there pretty much are no patches for any of this. 
Doing a patch that 
resets the magic “built on” date is pretty trivial compared to doing more bits 
in the message. 
We don’t even have simple patches for this gear …..

Bob


> On Apr 10, 2019, at 1:49 AM, Forrest Christian (List Account) 
>  wrote:
> 
> I realize that this doesn't help old receivers, but I'm sort of
> surprised that this wasn't addressed as the GPS system has had various
> additions made to it such as WAAS.  Even 3-4 bits allocated to this
> purpose in one of the datastreams would move us out beyond any
> reasonable expectation of the life of the current GPS protocol.
> 
> Does anyone know if any of the global GNSS alternatives (aka GLONASS,
> etc.) have similar limitations?
> 
> On Tue, Apr 9, 2019 at 7:01 AM Tom Van Baak  wrote:
>> 
>>> There's another relatively simple clue in the old GPS signal: the leap
>>> second count! A device manufacturer could teach it what the leap second
>>> count was at manufacturing time, and how to predict a lower bound on the
>>> leap second count in the future (with a suitable safety margin / fudge
>>> factor) which should allow it to live a bit more than 20 years.
>> 
>> The idea was proposed 20+ years ago, Trimble even has a patent on it. 
>> Details here:
>> 
>> http://leapsecond.com/notes/gpswnro.htm
>> 
>> But it turns out not to work. Earth rotation is too difficult to predict 20, 
>> 40, or 60 years into the future. There was talk that the GPS receiver 
>> failures in 2015 were related to this algorithm. Look for any threads with 
>> subjects like: TS2100, TymServe 2100, 1995 rollover, Trimble ACE, Heol 
>> Design in:
>> 
>> http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2015-May/
>> http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2015-June/
>> 
>> /tvb
>> 
>> - Original Message -
>> From: "Tony Finch" 
>> To: "Discussion of precise time and frequency measurement" 
>> 
>> Sent: Tuesday, April 09, 2019 4:08 AM
>> Subject: Re: [time-nuts] Garmin GPS12XL V3.51
>> 
>> 
>>> Leo Bodnar  wrote:
>>> 
>>>> Assume that the device does not have any reliable long term non-volatile
>>>> memory that you can update.
>>> 
>>>> In the absence of any clues your only reliable piece of knowledge is
>>>> that the cold start date is somewhere after the date of manufacturing
>>>> or, most often, firmware compilation date.
>>> 
>>> There's another relatively simple clue in the old GPS signal: the leap
>>> second count! A device manufacturer could teach it what the leap second
>>> count was at manufacturing time, and how to predict a lower bound on the
>>> leap second count in the future (with a suitable safety margin / fudge
>>> factor) which should allow it to live a bit more than 20 years.
>>> 
>>> Tony.
>>> --
>>> f.anthony.n.finchhttp://dotat.at/
>>> Gibraltar Point to North Foreland: Northeasterly 5 or 6, occasionally 7 in
>>> south. Moderate. Showers at first in south. Good, occasionally moderate at
>>> first.
>>> 
>>> ___
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to 
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>> 
>> 
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to 
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> 
> 
> 
> -- 
> - Forrest
> 
> ___
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Re: [time-nuts] Garmin GPS12XL V3.51

[Tony Finch]

Tom Van Baak  wrote:

> > There's another relatively simple clue in the old GPS signal: the leap
> > second count!
>
> The idea was proposed 20+ years ago, Trimble even has a patent on it.
> Details here:
>
> http://leapsecond.com/notes/gpswnro.htm

Oh, wonderful :-)

> But it turns out not to work. Earth rotation is too difficult to predict
> 20, 40, or 60 years into the future.

I was thinking in terms of getting a bit more lifetime than 20 years from
the firmware compilation date, but as you say it isn't reliable enough to
get much more than 20 years.

Tony.
-- 
f.anthony.n.finchhttp://dotat.at/
Biscay: Northerly 3 or 4, occasionally 5 in east. Moderate. Showers, thundery
at first in south. Good, occasionally poor until later.

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Re: [time-nuts] Garmin GPS12XL V3.51

[Forrest Christian (List Account)]

I realize that this doesn't help old receivers, but I'm sort of
surprised that this wasn't addressed as the GPS system has had various
additions made to it such as WAAS.  Even 3-4 bits allocated to this
purpose in one of the datastreams would move us out beyond any
reasonable expectation of the life of the current GPS protocol.

Does anyone know if any of the global GNSS alternatives (aka GLONASS,
etc.) have similar limitations?

On Tue, Apr 9, 2019 at 7:01 AM Tom Van Baak  wrote:
>
> > There's another relatively simple clue in the old GPS signal: the leap
> > second count! A device manufacturer could teach it what the leap second
> > count was at manufacturing time, and how to predict a lower bound on the
> > leap second count in the future (with a suitable safety margin / fudge
> > factor) which should allow it to live a bit more than 20 years.
>
> The idea was proposed 20+ years ago, Trimble even has a patent on it. Details 
> here:
>
> http://leapsecond.com/notes/gpswnro.htm
>
> But it turns out not to work. Earth rotation is too difficult to predict 20, 
> 40, or 60 years into the future. There was talk that the GPS receiver 
> failures in 2015 were related to this algorithm. Look for any threads with 
> subjects like: TS2100, TymServe 2100, 1995 rollover, Trimble ACE, Heol Design 
> in:
>
> http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2015-May/
> http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2015-June/
>
> /tvb
>
> - Original Message -
> From: "Tony Finch" 
> To: "Discussion of precise time and frequency measurement" 
> 
> Sent: Tuesday, April 09, 2019 4:08 AM
> Subject: Re: [time-nuts] Garmin GPS12XL V3.51
>
>
> > Leo Bodnar  wrote:
> >
> >> Assume that the device does not have any reliable long term non-volatile
> >> memory that you can update.
> >
> >> In the absence of any clues your only reliable piece of knowledge is
> >> that the cold start date is somewhere after the date of manufacturing
> >> or, most often, firmware compilation date.
> >
> > There's another relatively simple clue in the old GPS signal: the leap
> > second count! A device manufacturer could teach it what the leap second
> > count was at manufacturing time, and how to predict a lower bound on the
> > leap second count in the future (with a suitable safety margin / fudge
> > factor) which should allow it to live a bit more than 20 years.
> >
> > Tony.
> > --
> > f.anthony.n.finchhttp://dotat.at/
> > Gibraltar Point to North Foreland: Northeasterly 5 or 6, occasionally 7 in
> > south. Moderate. Showers at first in south. Good, occasionally moderate at
> > first.
> >
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to 
> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.



-- 
- Forrest

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Re: [time-nuts] Garmin GPS12XL V3.51

[Tom Van Baak]

> There's another relatively simple clue in the old GPS signal: the leap
> second count! A device manufacturer could teach it what the leap second
> count was at manufacturing time, and how to predict a lower bound on the
> leap second count in the future (with a suitable safety margin / fudge
> factor) which should allow it to live a bit more than 20 years.

The idea was proposed 20+ years ago, Trimble even has a patent on it. Details 
here:

http://leapsecond.com/notes/gpswnro.htm

But it turns out not to work. Earth rotation is too difficult to predict 20, 
40, or 60 years into the future. There was talk that the GPS receiver failures 
in 2015 were related to this algorithm. Look for any threads with subjects 
like: TS2100, TymServe 2100, 1995 rollover, Trimble ACE, Heol Design in:

http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2015-May/
http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2015-June/

/tvb

- Original Message - 
From: "Tony Finch" 
To: "Discussion of precise time and frequency measurement" 

Sent: Tuesday, April 09, 2019 4:08 AM
Subject: Re: [time-nuts] Garmin GPS12XL V3.51


> Leo Bodnar  wrote:
> 
>> Assume that the device does not have any reliable long term non-volatile
>> memory that you can update.
> 
>> In the absence of any clues your only reliable piece of knowledge is
>> that the cold start date is somewhere after the date of manufacturing
>> or, most often, firmware compilation date.
> 
> There's another relatively simple clue in the old GPS signal: the leap
> second count! A device manufacturer could teach it what the leap second
> count was at manufacturing time, and how to predict a lower bound on the
> leap second count in the future (with a suitable safety margin / fudge
> factor) which should allow it to live a bit more than 20 years.
> 
> Tony.
> -- 
> f.anthony.n.finchhttp://dotat.at/
> Gibraltar Point to North Foreland: Northeasterly 5 or 6, occasionally 7 in
> south. Moderate. Showers at first in south. Good, occasionally moderate at
> first.
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.


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Re: [time-nuts] Garmin GPS12XL V3.51

[Tony Finch]

Leo Bodnar  wrote:

> Assume that the device does not have any reliable long term non-volatile
> memory that you can update.

> In the absence of any clues your only reliable piece of knowledge is
> that the cold start date is somewhere after the date of manufacturing
> or, most often, firmware compilation date.

There's another relatively simple clue in the old GPS signal: the leap
second count! A device manufacturer could teach it what the leap second
count was at manufacturing time, and how to predict a lower bound on the
leap second count in the future (with a suitable safety margin / fudge
factor) which should allow it to live a bit more than 20 years.

Tony.
-- 
f.anthony.n.finchhttp://dotat.at/
Gibraltar Point to North Foreland: Northeasterly 5 or 6, occasionally 7 in
south. Moderate. Showers at first in south. Good, occasionally moderate at
first.

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Re: [time-nuts] Garmin GPS12XL V3.51

[Joe Leikhim]

Thanks Peter; I will give that a whirl. It seems Garmin must have made this 
tool to push the EOW out for maintenance purposes. Good thing I have the cable!

"Message: 12
Date: Mon, 8 Apr 2019 14:09:55 +0100
From: Peter Vince
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] Garmin GPS12XL V3.51
Message-ID:

Content-Type: text/plain; charset="UTF-8"

I dug out my old Garmin GPS-III's (mid 1990's vintage !).  The internal
backup batteries had completely died after many years of non-use, so it
took a while for them to find the satellites, but when they did, they, of
course, came up with an August 1999 date.  A quick "Google" found that
someone is hosting a zipped Windows executable (apparently originally from
Garmin) that you run when the satnav is connected to your PC via a serial
cable, and it corrects whatever internally so that the date is reported
correctly.  Works like an absolute charm!  The program doesn't say it is
specifically for the GPS-III, so it might be using a standard
(undocumented, of course!) message that will work on a whole bunch of
receivers.  Might be worth giving it a try?  See:

 https://sites.google.com/site/gnbaddeley/GpsEow_V1.20_PC_Software.zip

Regards,

 Peter
"

--
Joe Leikhim


Leikhim and Associates

Communications Consultants

Oviedo, Florida

jleik...@leikhim.com

407-982-0446

WWW.LEIKHIM.COM

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Re: [time-nuts] Garmin GPS12XL V3.51

[Joe Leikhim]

John; Try the tool Peter found.
I thought the GPS-12 lacked a serial port and the GPS-12XL had both a serial 
port and external antenna port. Both good to have for a differential station.

"Message: 9
Date: Mon, 8 Apr 2019 01:52:20 +
From: John Reid
To:"time-nuts@lists.febo.com"  
Subject: Re: [time-nuts] Garmin GPS12XL V3.51
Message-ID:



Content-Type: text/plain; charset="utf-8"

I checked today the GPS12XL I have, and that came up with a date in
August 99, before dying a few minutes later. Firmware 4.57.


The only thought I had was that the GPS 12 (still working, still showing
"19" as the year) was bought new around 2002 with a differential
receiver. Perhaps there was something different for that?


John"

--
Joe Leikhim


Leikhim and Associates

Communications Consultants

Oviedo, Florida

jleik...@leikhim.com

407-982-0446

WWW.LEIKHIM.COM

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Re: [time-nuts] Garmin GPS12XL V3.51

[Esa Heikkinen]

course, came up with an August 1999 date.  A quick "Google" found that
someone is hosting a zipped Windows executable (apparently originally from
Garmin) that you run when the satnav is connected to your PC via a serial
cable, and it corrects whatever internally so that the date is reported
correctly.  Works like an absolute charm!  The program doesn't say it is


Amazing! Now my GPS12 shows correct date again! Time is still not 
exactly synced, but inside same second. Maybe it's display issue; too 
slow rerfresh rate for accurate seconds.


My GPS12 was unused many years and had lost all settings. Last time I 
used it in geocaching because it seems to perform better than smartphone 
GPS in some difficult places like in forest.


--
73s!
Esa
OH4KJU

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Re: [time-nuts] Garmin GPS12XL V3.51

[Leo Bodnar]

Assume that the device does not have any reliable long term non-volatile memory 
that you can update.
In the absence of any clues your only reliable piece of knowledge is that the 
cold start date is somewhere after the date of manufacturing or, most often, 
firmware compilation date.
This is the simplest strategy - one that provides 20 years of device lifespan.  
"Device" in this case can be anything, including a single chip module that only 
has mask ROM and 128bytes of OTP memory like most Ublox modules.

If you have NVRAM, you can store last seen full week number periodically.  
Unless you don't power up the device for 20 years since last update you should 
be fine too.

Of course, if you have the ability to decode CNAV messages you can kick the can 
much further down the road.
Leo

> From: Joe Leikhim 
> My question is this. Why would the receivers be hard coded to a start date 
> for the 1023 week register?
> Why doesn't the receiver restart that date whenever reset or turned on after 
> a period of time?
> It seems like faulty logic to build in a defect like this.

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Re: [time-nuts] Garmin GPS12XL V3.51

[Peter Vince]

I dug out my old Garmin GPS-III's (mid 1990's vintage !).  The internal
backup batteries had completely died after many years of non-use, so it
took a while for them to find the satellites, but when they did, they, of
course, came up with an August 1999 date.  A quick "Google" found that
someone is hosting a zipped Windows executable (apparently originally from
Garmin) that you run when the satnav is connected to your PC via a serial
cable, and it corrects whatever internally so that the date is reported
correctly.  Works like an absolute charm!  The program doesn't say it is
specifically for the GPS-III, so it might be using a standard
(undocumented, of course!) message that will work on a whole bunch of
receivers.  Might be worth giving it a try?  See:

 https://sites.google.com/site/gnbaddeley/GpsEow_V1.20_PC_Software.zip

Regards,

 Peter


On Mon, 8 Apr 2019 at 14:01, David J Taylor via time-nuts <
time-nuts@lists.febo.com> wrote:

> I checked today the GPS12XL I have, and that came up with a date in
> August 99, before dying a few minutes later. Firmware 4.57.
> []
> John
> 
>
> John,
>
> I think my 12XL firmware 4.60 is OK.  Perhaps you can update the firmware?
>
> Cheers,
> David
> --
> SatSignal Software - Quality software for you
> Web: http://www.satsignal.eu
> Email: david-tay...@blueyonder.co.uk
> Twitter: @gm8arv
>
>
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Re: [time-nuts] Garmin GPS12XL V3.51

[David J Taylor via time-nuts]

I checked today the GPS12XL I have, and that came up with a date in 
August 99, before dying a few minutes later. Firmware 4.57.

[]
John


John,

I think my 12XL firmware 4.60 is OK.  Perhaps you can update the firmware?

Cheers,
David
--
SatSignal Software - Quality software for you
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv

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Re: [time-nuts] Garmin GPS12XL V3.51

[John Reid]

I checked today the GPS12XL I have, and that came up with a date in 
August 99, before dying a few minutes later. Firmware 4.57.


The only thought I had was that the GPS 12 (still working, still showing 
"19" as the year) was bought new around 2002 with a differential 
receiver. Perhaps there was something different for that?


John

On 7/4/19 6:42 pm, John wrote:

> I switched my GPS12 on, and it comes up with 07 Apr 19, time correct, 
> too.
>
> Firmware is 4.58, 1996-2000.
>
>
> John
>
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Re: [time-nuts] Garmin GPS12XL V3.51

[Esa Heikkinen]

I switched my GPS12 on, and it comes up with 07 Apr 19, time correct, too.
Firmware is 4.58, 1996-2000.
But Garmin GPS12 (not XL) with 4.58 seems to fail! It shows 22 Aug 99, 
also with about one second time error. Otherwise the navigation was OK 
at least with quick test.


--
73s!
Esa
OH4KJU

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Re: [time-nuts] Garmin GPS12XL V3.51

[Joe Leikhim]

John;
I read somewhere and I could be wrong, that if you select the autolocate mode 
it should correct itself. I did so on my older unit and it did not. Now I 
cannot get that screen back because it is synched. Also is yours a GPS12 or a 
12XL? The comments on the Garmin site are more specific for the 12 model that 
it will fail and not supported while the 12XL is sort of weasel worded and does 
not specifically say it will fail hard.

There were suggestions elsewhere online to do a factory fresh restart somehow, 
but that the TCXO could be so far off the receiver won't reacquire a signal. 
Mine has low operating hours so maybe that would work.

My question is this. Why would the receivers be hard coded to a start date for 
the 1023 week register? Why doesn't the receiver restart that date whenever 
reset or turned on after a period of time? It seems like faulty logic to build 
in a defect like this.


"Message: 27
Date: Sun, 7 Apr 2019 08:42:25 +
From: John Reid
To:"time-nuts@lists.febo.com"  
Subject: Re: [time-nuts] Garmin GPS12XL V3.51
Message-ID:



Content-Type: text/plain; charset="utf-8"

I switched my GPS12 on, and it comes up with 07 Apr 19, time correct, too.

Firmware is 4.58, 1996-2000.


John"

--
Joe Leikhim


Leikhim and Associates

Communications Consultants

Oviedo, Florida

jleik...@leikhim.com

407-982-0446

WWW.LEIKHIM.COM

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Re: [time-nuts] Garmin GPS12XL V3.51

[John Reid]

I switched my GPS12 on, and it comes up with 07 Apr 19, time correct, too.

Firmware is 4.58, 1996-2000.


John

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Re: [time-nuts] Garmin GPS12XL V3.51

[Joe Leikhim]

I just checked the Garmin site and indeed there are upgrades to versions 4.60 
and 3.53. It seems that since I have V3.51 I can jump to 3.53 but not 4.60. I 
assume my hardware precedes yours.

"Mine had the batteries out for about a year.? Put some fresh ones in, turned it
on and set it outside for several minutes. It located position and is showing
today's date and time just fine.? Software version on mine is 4.58.

Wes"

--
Joe Leikhim


Leikhim and Associates

Communications Consultants

Oviedo, Florida

jleik...@leikhim.com

407-982-0446

WWW.LEIKHIM.COM


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Re: [time-nuts] Garmin GPS12XL V3.51

[Wes]

Mine had the batteries out for about a year.  Put some fresh ones in, turned it 
on and set it outside for several minutes. It located position and is showing 
today's date and time just fine.  Software version on mine is 4.58.


Wes

  It had to On 4/6/2019 12:10 AM, David J Taylor via time-nuts wrote:

Just checked my wonderful Garmin GPS12XL tonight. before midnight UTC I
checked navigation and UTC time and all was well. I did not bother to
check date for some reason. Well now April 6 2019 at 03:39:19 UTC I see
the time is 21 August 99 and no apparent way to change. The navigation
and time seem correct.

I heard there was a way to reset these to current date. Any thoughts?
Can I still use this as a tool for gathering waypoints with precision?

Joe Leikhim
==

Joe,

My 12 XL runs 24x7 so I tried switching it off and on, and the date and time 
are still correct, but maybe that's stored data it's using?


When it boots, it shows 4.60 (1966-2003) as the software, so perhaps you can 
update?  Whether that fixes the issue I don't know


Cheers,
David




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Re: [time-nuts] Garmin GPS12XL V3.51

[Joe Leikhim]

Thanks! I don't ever think I relied on the date in the unit.  It is 
going to get some use soon. I would have no idea what to replace it with.


Next I need to check out my Symmetricom / /Datum 9390/-/6000/ EXACTIME 
next. The antenna has been off \for a while. It was updated some years 
back to what was the latest and last version.



On 4/6/2019 1:04 AM, Peter Putnam wrote:

From the Garmin web-site at:
https://support.garmin.com/en-US/?faq=jXw3hvTdo24PunZy4yOpX8&productID=87&searchQuery=date%20error&tab=topics


  GPS 12 Time and Date are Incorrect

We’ve identified an issue with this product that causes the date 
and/or time to be wrong after the GPS Rollover on April 6th, 
2019. However, all functions not dependent on date and/or time will 
continue to work normally. Due to the age of the device we have 
determined we will not fix this issue.


*What does that mean for my Garmin**?*

  * The date and/or time determined by the GPS will be wrong
  * Position, velocity, navigation, and all other functionality not
dependent on date and/or time will continue to work normally

*What is GPS Week Rollover?*

The GPS satellite system communicates the date via a week number that 
is limited to 1024 weeks (about 20 years). On April 6th, 2019 the week 
numbers broadcast by the satellites will “rollover” to zero. If GPS 
receivers don’t account for this rollover in their software, it will 
calculate the wrong date and/or time.




On 4/5/2019 8:40 PM, Joe Leikhim wrote:
Just checked my wonderful Garmin GPS12XL tonight. before midnight UTC 
I checked navigation and UTC time and all was well. I did not bother 
to check date for some reason. Well now April 6 2019 at 03:39:19 UTC 
I see the time is 21 August 99 and no apparent way to change. The 
navigation and time seem correct.


I heard there was a way to reset these to current date. Any thoughts? 
Can I still use this as a tool for gathering waypoints with precision?





 
	Virus-free. www.avg.com 
 



<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>


--
Joe Leikhim


Leikhim and Associates

Communications Consultants

Oviedo, Florida

jleik...@leikhim.com

407-982-0446

WWW.LEIKHIM.COM

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Re: [time-nuts] Garmin GPS12XL V3.51

[Björn]

If you ignore date/year, everything else should be just as before.

—

Björn 

Sent from my iPhone

> On 6 Apr 2019, at 05:40, Joe Leikhim  wrote:
> 
> Just checked my wonderful Garmin GPS12XL tonight. before midnight UTC I 
> checked navigation and UTC time and all was well. I did not bother to check 
> date for some reason. Well now April 6 2019 at 03:39:19 UTC I see the time is 
> 21 August 99 and no apparent way to change. The navigation and time seem 
> correct.
> 
> I heard there was a way to reset these to current date. Any thoughts? Can I 
> still use this as a tool for gathering waypoints with precision?
> 
> -- 
> Joe Leikhim
> 
> 
> Leikhim and Associates
> 
> Communications Consultants
> 
> Oviedo, Florida
> 
> jleik...@leikhim.com
> 
> 407-982-0446
> 
> WWW.LEIKHIM.COM
> 
> 
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Re: [time-nuts] Garmin GPS12XL V3.51

[David J Taylor via time-nuts]

Just checked my wonderful Garmin GPS12XL tonight. before midnight UTC I
checked navigation and UTC time and all was well. I did not bother to
check date for some reason. Well now April 6 2019 at 03:39:19 UTC I see
the time is 21 August 99 and no apparent way to change. The navigation
and time seem correct.

I heard there was a way to reset these to current date. Any thoughts?
Can I still use this as a tool for gathering waypoints with precision?

Joe Leikhim
==

Joe,

My 12 XL runs 24x7 so I tried switching it off and on, and the date and time 
are still correct, but maybe that's stored data it's using?


When it boots, it shows 4.60 (1966-2003) as the software, so perhaps you can 
update?  Whether that fixes the issue I don't know


Cheers,
David
--
SatSignal Software - Quality software for you
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 



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