Re: [time-nuts] thunderbolt no UTC offset
On 05/02/2012 03:50 AM, Dennis Ferguson wrote: On 2 May, 2012, at 04:30 , Tom Van Baak wrote: The UTC offset is in words 6-10, page 18, subframe 4 -- every 12.5 minutes. /tvb The leap second warning is also in the same place. How the unit could know that a leap second is pending but not know the UTC offset is a mystery. Well, there is such things as software bugs. The upcoming leapsecond is kind of unique as it has been a very long time since the last in June, which was June 1997. http://en.wikipedia.org/wiki/Leap_second So, it is not surprising that there can be some issues with it. As I recall, the format of the GPS message is such that one should be able to execute it correctly even if one does not know the rules. The bugs I have seen comes from software trying to apply the rules, but does it incorrectly. Cheers, Magnus ___ 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.
Re: [time-nuts] thunderbolt no UTC offset
In my opinion nothing has to be changed. It is working OK this way. To improve performance it is worth to use linear regulators for the power supply +12V and -12V that are related to the OCXO supply and EFC. On Wed, May 2, 2012 at 9:24 AM, francesco messineo francesco.messi...@gmail.com wrote: On 5/2/12, Dennis Ferguson dennis.c.fergu...@gmail.com wrote: On 2 May, 2012, at 04:30 , Tom Van Baak wrote: The UTC offset is in words 6-10, page 18, subframe 4 -- every 12.5 minutes. /tvb The leap second warning is also in the same place. How the unit could know that a leap second is pending but not know the UTC offset is a mystery. that's why I asked in the first place... all was green but the leap second pending which I'd expected to be there anyway. The UTC offset came much time later anyway. I don't know if the tbolt could be confused or had some firmware issue after being unpowered for some months. By the way, attached is a plot of signal levels with the new antenna, I'm interested in opinions about what can be changed in the settings to maybe improve performance. Thanks Frank IZ8DWF Dennis Ferguson ___ 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. ___ 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. ___ 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.
[time-nuts] thunderbolt no UTC offset
I think the tbolt may need to go through two 12.5 minute almanac cycles before it updates/outputs all its data... The first thing to do to improve performance is to run the a oscillator autotune command. This will determine the correct osc gain and initial DAC settings. It will also set the TC and damping values and the antenna elevation and signal level filter values. Before running the a command you should set the antenna elevation filter to a low value, clear the signal level history, and let the unit collect signal data for a few hours. That way it can determine the angle where your antenna begins to lose data. The other thing to do is to run the 48 hour precision antenna position survey. Finally, you may want to implement the active temperature control. -- I'm interested in opinions about what can be changed in the settings to maybe improve performance. ___ 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.
Re: [time-nuts] thunderbolt no UTC offset
Correction: the UTC offset is part of the *primary* data packet that is sent every second from the Thunderbolt, but as Tom pointed out, it has to receive the information from the satellite(s) first, which can take 12.5 minutes (Thunderbolt Users Guide, version 5, 2003, page A-56, paragraph Report Packet 0x8F-AB Primary Timing Packet) Until it has received the information, the UTC offset is represented as 0, which can certainly be confusing. The Leap Second Pending bit is part of the *secondary* data packet sent by the Thunderbolt every second as well. The manual does not say how often the leap second pending information is sent from the birds. Since I rarely turn my Thunderbolts off, and I display GPS time by default, I had not noticed the delay after power up. On Tue, May 1, 2012 at 3:17 PM, shali...@gmail.com wrote: From memory, the UTC offset is part of the Supplemental data packet that is sent every second by default. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Hal Murray hmur...@megapathdsl.net Sender: time-nuts-boun...@febo.com Date: Tue, 01 May 2012 11:41:22 To: Discussion of precise time and frequency measurement time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] thunderbolt no UTC offset francesco.messi...@gmail.com said: I just powered on again my trimble thunderbolt after some time without antenna. All alarms are green but the obvious leap second pending. BUT: I can't use UTC time as both tboltmon and lady heather display a No UTC offset message. I don't remember having seen this in the past. What's wrong with the thunderbolt now? How long has it been on? The UTC offset comes from the satellites. I think it is only sent every hour. -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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. ___ 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.
[time-nuts] thunderbolt no UTC offset
Hi all, I just powered on again my trimble thunderbolt after some time without antenna. All alarms are green but the obvious leap second pending. BUT: I can't use UTC time as both tboltmon and lady heather display a No UTC offset message. I don't remember having seen this in the past. What's wrong with the thunderbolt now? Many thanks in advance Frank IZ8DWF ___ 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.
Re: [time-nuts] thunderbolt no UTC offset
francesco.messi...@gmail.com said: I just powered on again my trimble thunderbolt after some time without antenna. All alarms are green but the obvious leap second pending. BUT: I can't use UTC time as both tboltmon and lady heather display a No UTC offset message. I don't remember having seen this in the past. What's wrong with the thunderbolt now? How long has it been on? The UTC offset comes from the satellites. I think it is only sent every hour. -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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.
Re: [time-nuts] thunderbolt no UTC offset
Hi Hal, On 5/1/12, Hal Murray hmur...@megapathdsl.net wrote: francesco.messi...@gmail.com said: I just powered on again my trimble thunderbolt after some time without antenna. All alarms are green but the obvious leap second pending. BUT: I can't use UTC time as both tboltmon and lady heather display a No UTC offset message. I don't remember having seen this in the past. What's wrong with the thunderbolt now? How long has it been on? The UTC offset comes from the satellites. I think it is only sent every hour. yes indeed, it was ok after about 1 hour of the power up. Sorry but I didn't remember I had ever waited so long for the UTC to come on. I'm now plotting the signal strength vs AZ/EL map, I'll post the result tomorrow so maybe someone can tell me how the new antenna is working. Thanks Frank IZ8DWF ___ 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.
Re: [time-nuts] thunderbolt no UTC offset
Incorrect, the UTC offset should be sent in the Almanac, the Almanac having a period of 12.5 minutes max. Not one hour. It should take no more than 12.5 minutes to get the UTC offset when sats are properly being received. bye, Said In a message dated 5/1/2012 11:45:06 Pacific Daylight Time, francesco.messi...@gmail.com writes: Hi Hal, On 5/1/12, Hal Murray hmur...@megapathdsl.net wrote: francesco.messi...@gmail.com said: I just powered on again my trimble thunderbolt after some time without antenna. All alarms are green but the obvious leap second pending. BUT: I can't use UTC time as both tboltmon and lady heather display a No UTC offset message. I don't remember having seen this in the past. What's wrong with the thunderbolt now? How long has it been on? The UTC offset comes from the satellites. I think it is only sent every hour. yes indeed, it was ok after about 1 hour of the power up. Sorry but I didn't remember I had ever waited so long for the UTC to come on. I'm now plotting the signal strength vs AZ/EL map, I'll post the result tomorrow so maybe someone can tell me how the new antenna is working. Thanks Frank IZ8DWF ___ 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.
Re: [time-nuts] thunderbolt no UTC offset
On 5/1/12, saidj...@aol.com saidj...@aol.com wrote: Incorrect, the UTC offset should be sent in the Almanac, the Almanac having a period of 12.5 minutes max. Not one hour. It should take no more than 12.5 minutes to get the UTC offset when sats are properly being received. when I posted my original enquiry, the almanac alarm had turned green since quite some time already, that's why I was wondering what could be wrong. Best regards Frank ___ 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.
Re: [time-nuts] thunderbolt no UTC offset
From memory, the UTC offset is part of the Supplemental data packet that is sent every second by default. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Hal Murray hmur...@megapathdsl.net Sender: time-nuts-boun...@febo.com Date: Tue, 01 May 2012 11:41:22 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] thunderbolt no UTC offset francesco.messi...@gmail.com said: I just powered on again my trimble thunderbolt after some time without antenna. All alarms are green but the obvious leap second pending. BUT: I can't use UTC time as both tboltmon and lady heather display a No UTC offset message. I don't remember having seen this in the past. What's wrong with the thunderbolt now? How long has it been on? The UTC offset comes from the satellites. I think it is only sent every hour. -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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. ___ 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.
Re: [time-nuts] thunderbolt no UTC offset
The UTC offset is in words 6-10, page 18, subframe 4 -- every 12.5 minutes. /tvb ___ 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.
Re: [time-nuts] thunderbolt no UTC offset
On 05/01/2012 10:30 PM, Tom Van Baak wrote: The UTC offset is in words 6-10, page 18, subframe 4 -- every 12.5 minutes. It was added to the broadcast signal as an after-thought, as a separate upgrade package if you wish. At least back then, I believe they had USNO to measure the GPS time and provide corrections to match up with USNO UTC scale. It makes sense that they still do that. The publish differences is really just a hand-full of ns. The GPS time is to be maintained within +/- 1 us of the USNO UTC time-scale according to original setup. Does anyone has any more recent descriptions on this? Besides the track record being available from USNO or for that matter the BIPM. Cheers, Magnus ___ 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.
Re: [time-nuts] thunderbolt no UTC offset
On 2 May, 2012, at 04:30 , Tom Van Baak wrote: The UTC offset is in words 6-10, page 18, subframe 4 -- every 12.5 minutes. /tvb The leap second warning is also in the same place. How the unit could know that a leap second is pending but not know the UTC offset is a mystery. Dennis Ferguson ___ 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.
