LTE Lite time error
I see a one second error in the NMEA string from my LTE Lite.
It lost a second between 23:33:34 and 23:33:42 21-Jan-2015 UTC.
I happened to check because a report of a one second error in some NTP pool
servers.
Just a heads up -- I'll be following up with JL directly.
--
Paul
Hi Paul,
Odd, my LTE-Lite appears spot on. Let's take this off-list and see what's going on.
If anyone else has been logging SkyTraq NMEA or binary from the LTE-Lite let us know.
Thanks,
/tvb
$SkyTraq,Venus8
$Kernel,v2.0.2,00001C92,1426,00006005,I,16.367667MHz
$ver,010827,rev,130221
----- Original Message -----
From: "Paul" tic-toc@bodosom.net
To: "Discussion of precise time and frequency measurement" time-nuts@febo.com
Sent: Friday, January 23, 2015 8:58 PM
Subject: [time-nuts] LTE Lite time error
I see a one second error in the NMEA string from my LTE Lite.
It lost a second between 23:33:34 and 23:33:42 21-Jan-2015 UTC.
I happened to check because a report of a one second error in some NTP pool
servers.
Just a heads up -- I'll be following up with JL directly.
--
Paul
Odd indeed. My LTE-lite is one second late, appears to have already added the pending leap second.
I can compare with four other GPS timeing receivers using time pulse on DCD line. The NMEA data
reports in error. I am awaiting reply from JL. This is not good for an eBay sniper....
Bill, NL7F
On Sun, 25 Jan 2015 12:12:55 -0800, Tom Van Baak wrote:
Hi Paul,
Odd, my LTE-Lite appears spot on. Let's take this off-list and see what's going on.
If anyone else has been logging SkyTraq NMEA or binary from the LTE-Lite let us know.
Bill Beam
NL7F
We have confirmed this issue with the Skytraq firmware on the LTE-Lite and
are working with Skytraq to obtain a firmware update. I will post again
when a firmware update is available.
Keith
Keith
On Sun, Jan 25, 2015 at 5:47 PM, Bill Beam wbeam@gci.net wrote:
Odd indeed. My LTE-lite is one second late, appears to have already added
the pending leap second.
I can compare with four other GPS timeing receivers using time pulse on
DCD line. The NMEA data
reports in error. I am awaiting reply from JL. This is not good for an
eBay sniper....
Bill, NL7F
On Sun, 25 Jan 2015 12:12:55 -0800, Tom Van Baak wrote:
Hi Paul,
Odd, my LTE-Lite appears spot on. Let's take this off-list and see what's
going on.
If anyone else has been logging SkyTraq NMEA or binary from the LTE-Lite
let us know.
Bill Beam
NL7F
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.
Yes there is certainly an error here:
With my timing module I was just eyeballing the output on a windows platform , comparing GUI data.
I have just linked the module up to a BeagleBone Black sync’d with NTP and this is the NMEA msg log:
root@bb3:/home/mike/serial-ports# while read GGA; do echo date $GGA; done < /dev/ttyO4
Mon Jan 26 21:51:07 UTC 2015 $GPGGA,215106.000,4847.3526,N,00216.3005,E,1,04,2.8,192.8,M,47.0,M,,00005C
Mon Jan 26 21:51:07 UTC 2015 $GPGLL,4847.3526,N,00216.3005,E,215106.000,A,A56
Mon Jan 26 21:51:07 UTC 2015 $GPGSA,A,3,25,12,06,31,,,,,,,,,3.0,2.8,1.03A
Mon Jan 26 21:51:07 UTC 2015 $GPRMC,215106.000,A,4847.3526,N,00216.3005,E,000.0,173.5,260115,,,A60
Mon Jan 26 21:51:07 UTC 2015 $GPVTG,173.5,T,,M,000.0,N,000.0,K,A0D
Mon Jan 26 21:51:07 UTC 2015 $GPZDA,215106.000,26,01,2015,00,0054
Mon Jan 26 21:51:07 UTC 2015 $PSTI,00,2,0,4.6,,30
Mon Jan 26 21:51:08 UTC 2015 $GPGGA,215107.000,4847.3526,N,00216.3005,E,1,04,2.8,192.8,M,47.0,M,,00005D
Mon Jan 26 21:51:08 UTC 2015 $GPGLL,4847.3526,N,00216.3005,E,215107.000,A,A57
Mon Jan 26 21:51:08 UTC 2015 $GPGSA,A,3,25,12,06,31,,,,,,,,,3.0,2.8,1.03A
Mon Jan 26 21:51:08 UTC 2015 $GPGSV,3,1,10,25,73,294,42,12,59,063,44,14,45,264,20,29,41,196,257B
Mon Jan 26 21:51:08 UTC 2015 $GPGSV,3,2,10,24,34,136,13,02,28,091,21,31,22,306,34,06,19,047,3774
Mon Jan 26 21:51:08 UTC 2015 $GPGSV,3,3,10,32,03,310,,03,01,347,7A
Mon Jan 26 21:51:08 UTC 2015 $GPRMC,215107.000,A,4847.3526,N,00216.3005,E,000.0,173.5,260115,,,A61
Mon Jan 26 21:51:08 UTC 2015 $GPVTG,173.5,T,,M,000.0,N,000.0,K,A0D
Mon Jan 26 21:51:08 UTC 2015 $GPZDA,215107.000,26,01,2015,00,0055
Mon Jan 26 21:51:08 UTC 2015 $PSTI,00,2,0,-3.9,,*15
The time data is all a second late so they appear to have a serious issue.
I module I have is the NS-T from NavSpark, so I will get on to them to see if they have a fix. Updates later.
"Ceux qui sont prêts à abandonner une liberté essentielle pour obtenir une petite et provisoire sécurité, ne méritent ni liberté ni sécurité."
Benjimin Franklin
Le 26 janv. 2015 à 02:47, Bill Beam wbeam@gci.net a écrit :
Odd indeed. My LTE-lite is one second late, appears to have already added the pending leap second.
I can compare with four other GPS timeing receivers using time pulse on DCD line. The NMEA data
reports in error. I am awaiting reply from JL. This is not good for an eBay sniper....
Bill, NL7F
On Sun, 25 Jan 2015 12:12:55 -0800, Tom Van Baak wrote:
Hi Paul,
Odd, my LTE-Lite appears spot on. Let's take this off-list and see what's going on.
If anyone else has been logging SkyTraq NMEA or binary from the LTE-Lite let us know.
Bill Beam
NL7F
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.
Skytraq has also confirmed the issue and is working on a firmware update.
Updating the Skytraq firmware on the LTE-Lite Eval Board requires the unit
be returned to Jackson Labs for reprogramming. We will update the Skytraq
firmware on units at no charge if units are returned to us. Please contact
us off list to make arrangements for returns.
Also, the ROM firmware in the Skytraq does not exhibit this issue, so
selecting the ROM boot with a jumper between pins 1 and 2 of J3 is a
work-around. When making the J3 connection, be sure to remove power to the
board to avoid corrupting the flash. The LTE-Lite will operate in a mobile
mode without sawtooth correction when the Skytraq is booted from ROM.
Thanks,
Keith
Keith
On Mon, Jan 26, 2015 at 10:43 AM, Keith Loiselle keith.loiselle@gmail.com
wrote:
We have confirmed this issue with the Skytraq firmware on the LTE-Lite and
are working with Skytraq to obtain a firmware update. I will post again
when a firmware update is available.
Keith
Keith
On Sun, Jan 25, 2015 at 5:47 PM, Bill Beam wbeam@gci.net wrote:
Odd indeed. My LTE-lite is one second late, appears to have already
added the pending leap second.
I can compare with four other GPS timeing receivers using time pulse on
DCD line. The NMEA data
reports in error. I am awaiting reply from JL. This is not good for an
eBay sniper....
Bill, NL7F
On Sun, 25 Jan 2015 12:12:55 -0800, Tom Van Baak wrote:
Hi Paul,
Odd, my LTE-Lite appears spot on. Let's take this off-list and see
what's going on.
If anyone else has been logging SkyTraq NMEA or binary from the LTE-Lite
let us know.
Bill Beam
NL7F
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.
Be careful with 'eyeball data'. GPS receiver does not generate NMEA time data and the leading edge of PPS at the same time.
Programs like Tac32 (totally accurate clock) and Lady Heather increment the time display at the leading edge of PPS with a
value 1 second greater than the previous NMEA data time.
I am able to run multiple GPS receivers into multiple computers running Tac32. The LTE-lite displays one second earlier than
all the others.
Prior to the announcement of "Leap Second Pending" in the GPS data stream the LTE-lite agreed with all other units. Now it does not.
On Mon, 26 Jan 2015 22:59:36 +0100, Mike Cook wrote:
Yes there is certainly an error here:
With my timing module I was just eyeballing the output on a windows platform , comparing GUI data.
I have just linked the module up to a BeagleBone Black syncG��d with NTP and this is the NMEA msg log:
root@bb3:/home/mike/serial-ports# while read GGA; do echo date $GGA; done < /dev/ttyO4
Mon Jan 26 21:51:07 UTC 2015 $GPGGA,215106.000,4847.3526,N,00216.3005,E,1,04,2.8,192.8,M,47.0,M,,00005C
Mon Jan 26 21:51:07 UTC 2015 $GPGLL,4847.3526,N,00216.3005,E,215106.000,A,A56
Mon Jan 26 21:51:07 UTC 2015 $GPGSA,A,3,25,12,06,31,,,,,,,,,3.0,2.8,1.03A
Mon Jan 26 21:51:07 UTC 2015 $GPRMC,215106.000,A,4847.3526,N,00216.3005,E,000.0,173.5,260115,,,A60
Mon Jan 26 21:51:07 UTC 2015 $GPVTG,173.5,T,,M,000.0,N,000.0,K,A0D
Mon Jan 26 21:51:07 UTC 2015 $GPZDA,215106.000,26,01,2015,00,0054
Mon Jan 26 21:51:07 UTC 2015 $PSTI,00,2,0,4.6,,*30
snip
The time data is all a second late so they appear to have a serious issue.
Le 26 janv. 2015 +� 02:47, Bill Beam wbeam@gci.net a +�crit :
snip
Odd indeed. My LTE-lite is one second late, appears to have already added the pending leap second.
I can compare with four other GPS timeing receivers using time pulse on DCD line. The NMEA data
reports in error.
snip
Bill Beam
NL7F
Hi, fellow time nuts,
I have some questions regarding the Stanford SR620:
- Is it a drawback wrt ADEV when a SR620 does not have have the opt. oven
if I have an ultra clean external reference? Does it use the external
ref directly
or does it just pull the own reference to the external value in the long
run,
no matter if it's the good or the bad oscilator?
2 I have seen that the manual has a parts list and references the circuit
diagrams, but they are not included in the pdf. Are the circuits somewhere
out there?
My 5370A has become so unreliable that it needs replacement.
regards, Gerhard
Gerhard,
On 01/27/2015 09:00 PM, Gerhard Hoffmann wrote:
Hi, fellow time nuts,
I have some questions regarding the Stanford SR620:
- Is it a drawback wrt ADEV when a SR620 does not have have the opt. oven
if I have an ultra clean external reference? Does it use the external
ref directly
or does it just pull the own reference to the external value in the long
run,
no matter if it's the good or the bad oscilator?
It locks it up with a PLL. See page 9 in PDF below, smack in the middle
is the input circuit and PLL.
This page also gives you all the hints of how to wire in a better
oscillator if you wish.
2 I have seen that the manual has a parts list and references the circuit
diagrams, but they are not included in the pdf. Are the circuits somewhere
out there?
My 5370A has become so unreliable that it needs replacement.
What issues do you see?
Cheers,
Magnus
Gerhard wrote:
- Is it a drawback wrt ADEV when a SR620 does not have have the opt. oven
if I have an ultra clean external reference? Does it use the
external ref directly
or does it just pull the own reference to the external value in the long run,
no matter if it's the good or the bad oscilator?
The SR620 phase locks its internal oscillator (either the standard
TCXO or the optional OCXO) to the external oscillator if the external
reference is selected.
2 I have seen that the manual has a parts list and references the circuit
diagrams, but they are not included in the pdf. Are the circuits somewhere
out there?
If you go to http://www.ko4bb.com/manuals/ and search for SR620,
you will find manuals from 1999, 2004, and 2006, as well.
Best regards,
Charles