[time-nuts] Warped back to 1993

[Tammy A Wisdom]

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It looks like it affects truetime XL-DC's I just noticed it at my
house as well :(

On 8/11/13 07:09:40, Magnus Danielson wrote:
> If Furuno can supply the FW to update with, we would be more than
> happy.
> 
> A slight alteration of the code would suffice...
> 
> if (week < 729) week += 2048; else week += 1024;
> 
> Which would keep them floating for another 1024 weeks. If they then
> let us know where the two constats is located so we could modify it
> again ourselves we be very happy.
> 
> Cheers, Magnus
> 
> On 08/11/2013 01:29 PM, Azelio Boriani wrote:
>> OK, good, found the bug. Now, iwe wish it were possible to
>> download the firmware, make the correction and then upload...
>> 
>> On Sun, Aug 11, 2013 at 1:14 PM, Magnus Danielson 
>> <magnus at rubidium.dyndns.org> wrote:
>>> On 08/11/2013 05:18 AM, Mark C. Stephens wrote:
>>>> Okay this is what worked for me:
>>>> 
>>>> 1. Removed power and antenna. 2. apply power with no
>>>> antenna. 3. send :GPS:INIT:DATE 2007,08,11 4. plug antenna
>>>> back in.
>>>> 
>>>> For some reason if I used the correct date, the Z3815A warped
>>>> back to 1993.
>>>> 
>>>> But I am curious why did this happen today?
>>> GPS weeks begin on sundays. Today is first day of week 1753:
>>> 
>>> http://csrc.ucsd.edu/scripts/convertDate.cgi?time=2013+08+11
>>> 
>>> Going back 1024 days gives you week 729 day 0, which occurs on
>>> 1993 12 26: 
>>> http://csrc.ucsd.edu/scripts/convertDate.cgi?time=1993+12+26
>>> 
>>> A simple way to compensate for the lack of bits is to assume
>>> wrapping occurs, so week numbers lower than som value actually
>>> lacks 1024 weeks. A trivial code like this fixes this:
>>> 
>>> if (week < 729) week += 1024;
>>> 
>>> Brilliant until you reach week 1753.
>>> 
>>> I've seen this happen at 500 and 512.
>>> 
>>> Cheers, Magnus
>>> 
>>>> 
>>>> --marki
>>>> 
>>>> -----Original Message----- From: time-nuts-bounces at febo.com
>>>> [mailto:time-nuts-bounces at febo.com] On Behalf Of Mark C.
>>>> Stephens Sent: Sunday, 11 August 2013 1:06 PM To: Discussion
>>>> of precise time and frequency measurement Subject: Re:
>>>> [time-nuts] Warped back to 1993
>>>> 
>>>> Hal, I can't get it to take, I keep getting E-350 and the
>>>> time does not change. Did you unplug the antenna or anything
>>>> while you changed date?
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> -----Original Message----- From: time-nuts-bounces at febo.com
>>>> [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal Murray 
>>>> Sent: Sunday, 11 August 2013 12:54 PM To: Discussion of
>>>> precise time and frequency measurement Subject: Re:
>>>> [time-nuts] Warped back to 1993
>>>> 
>>>> 
>>>> marks at non-stop.com.au said:
>>>>> A Z3805A, a Z3815A and 58534A integrated timing antenna all
>>>>> think it's 26 Dec 1993. What happened?!
>>>>> _______________________________________________
>>>> Is that off by 1024 weeks?  (Looks close, but I haven't
>>>> checked the details.)
>>>> 
>>>> There is a week field in the GPS data stream.  It's only 10
>>>> bits.
>>>> 
>>>> I had that problem on a Z3801A.  It did the right thing after
>>>> I told it the date. :GPS:INIT:DATE 2011,12,26
>>>> 
>>>> 
>>>> 
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> 
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