From: "Larry Cochrane" <cochrane@..............> Subject: Re: GPS time error Date: Sat, 8 Dec 2001 21:18:50 -0800
Tom,
There is something very wrong with either the GPS time or your computers time or timezone information. From the log file you sent me:
12/08/01 14:25:59 Sending Configuration Information
12/07/01 22:26:05 Remote: GPS New Time: Diff:57598162 VSat:11 TSat:4
This is saying that the time difference between the computer time and the GPS time is 57,598,162 ms or around 16 hours. Either the GPS receiver is sending out the wrong time or your computer time or timezone setting is not correct (more likely). This is how it works. When WinSDR first starts up it send the computer time converted to UTC, timezone and daylight savings time information to the A/D board. The A/D board uses this information to seed it's time and then it tries to lock to GPS or WWV. Normally the difference between the computer and GPS time is a few seconds at startup.
12/07/01 22:27:05 Remote: GPS Not Set: Lck:15:58 Diff:0 Adj:0 VSat:11 TSat:4
12/07/01 22:32:05 Remote: GPS Not Set: Lck:15:53 Diff:-1 Adj:1 VSat:10 TSat:4
This is saying the time has been locked for 15 hours 53 minutes. This can't be since you just started up WinSDR. This happened because of the large time change that happened above.
12/08/01 14:34:43 Settings Local Computer Time: 57599163
Here WinSDR is trying to set the computer time since the A/D board is locked to GPS time. Again the difference between the two times is ~16 hours. Not good.....
12/07/01 22:37:05 Remote: GPS Not Set: Lck:15:48 Diff:-1 Adj:2 VSat:9 TSat:4
12/07/01 22:42:05 Remote: GPS Not Set: Lck:15:43 Diff:0 Adj:4 VSat:9 TSat:4
12/08/01 14:44:44 Settings Local Computer Time: 57552570
Once again WinSDR is trying to set the time. It looks like it was not able to change the computer time at 14:34:43. If you are running NT or Win2K (what OS are you using?) make sure you run the program as Administrator or change your user account to have Admin privileges. If you run WinSDR as a regular user it may not be able to set the computer time. The other thing to check is that your timezone information for your computer is set properly. You can check this in the Date/Time dialog box that can be opened from the Control Panel.
If everything looks fine with your computer you can try and reset your GPS receiver. This can be done by removing the power to the receiver including the battery backup. I think you have one of the used receivers with the battery mounted on the receiver. What you can do is short out the battery for about 5 seconds. After resetting the receiver it should take 10 to 15 minutes to relock to GPS time. You should also see this error message in the log file "Not enough GPS info" as the receiver downloads information it needs to operate properly.
If you still can't get the time correct I will have to send you a version of WinSDR with more debug information.
A note about the display time in the real-time window. Unlike SDR, WinSDR displays the time of the current data packet from the A/D board. Since the A/D board buffers data for 1 second before sending it out there will be a 1 + second delay in time on the real-time window.
-Larry
----- Original Message -----
From: Tom Frey
To: winsdr@..............
Sent: Saturday, December 08, 2001 3:47 PM
Subject: Re: GPS time error
Thanks for the Reply Larry...
I'm afraid I used some high tech methods to determine the error...i listened for the top of the minute WWV tone and watched the display compared the two and they were around 11 seconds off. I reset the 'puters clock to WWV (again by ear) and now the error is only about two seconds off, with WinSdr lagging by about 2 seconds.
I'll dig out the scope and continue the quest for lost time..heheheh
thanks again
tom