Re: [time-nuts] PPS delay on rockwell
On 2015-02-16 02:57, Hal Murray wrote: francesco.messi...@gmail.com said: I can only suspect it was unlocked, but I need to setup all the test in another place closer to the window, since I don't have a splitter to use the same antenna of the thunderbolt. If one or both are unlocked, I'd expect them to drift, not rapidly, but I'll bet it's easy to measure if you wait a day. There is software to talk to TBolts so it should be easy to find out if it is locked. Have you tried any software on the Rockwell? It may even talk NMEA so all you have to do is connect it to a PC and guess the baud rate. Or maybe upload a picture and somebody will recognize the model so you can google for details. See http://gpskit.nl for Rockwell commercial GPS module info. Those modules have an MCX/OSX antenna connector to connect a passive ceramic patch or active GPS antenna. They talk NMEA @ 4800,N,8,1 or Rockwell Zodiac binary @ 9600,N,8,1, depending on jumper settings. Rockwell Zodiac binary may be like SiRF binary as those appear to originally have been designed as Zodiac/Jupiter replacements. PPS accuracy is stated as 1us. There are instructions on the web to make a dipole GPS antenna from a length of coax cable: remove the outer insulation, trim the outer shield and inner conductor to 46mm, and heat shrink tubing (or tape?) to form the T shape. You could stick that out of a gap in a window facing towards the equator with a clear view of the sky. -- Take care. Thanks, Brian Inglis ___ 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] PPS delay on rockwell
francesco.messi...@gmail.com said: I can only suspect it was unlocked, but I need to setup all the test in another place closer to the window, since I don't have a splitter to use the same antenna of the thunderbolt. If one or both are unlocked, I'd expect them to drift, not rapidly, but I'll bet it's easy to measure if you wait a day. There is software to talk to TBolts so it should be easy to find out if it is locked. Have you tried any software on the Rockwell? It may even talk NMEA so all you have to do is connect it to a PC and guess the baud rate. Or maybe upload a picture and somebody will recognize the model so you can google for details. -- These are my opinions. 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] PPS delay on rockwell
On Sun, Feb 15, 2015 at 10:34 PM, Hal Murray hmur...@megapathdsl.net wrote: francesco.messi...@gmail.com said: I measured the PPS output with an HP-5328B, PPS of the thunderbolt as start, rising edge, rockwell PPS as stop, rising edge. The delay is 406.3 ms +/- 30 uS. Are those numbers normal for a rockwell chipset? Any idea why the two PPS are so far apart? PPS offset on the thunderbolt is set to 0. Do you have a scope? What's the width of the Rockwell PPS? yes, I have looked at the PPS shape, it's a 20ms positive pulse Are you triggering on the correct edge? Is there an inverter in there someplace? I would try all 4 combinations of rising/falling edges and see if any of them match cleanly. That could happen if the Rockwell PPS is 500 ms wide. I tried all 4 combinations (besides, the thunderbolt is set for positive PPS), the positive thunderbolt to positive rockwell is the closest of all at 406 ms. I can only suspect it was unlocked, but I need to setup all the test in another place closer to the window, since I don't have a splitter to use the same antenna of the thunderbolt. Thanks 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.
[time-nuts] PPS delay on rockwell
Hi all, I'm testing a custom (and unknown to me) GPS board I had for free some years ago. It has a 10 KHz output and 1 PPS output. Using a thunderbolt as reference, 10 KHz output is abut 13 mHz higher (10 MHz output of the thunderbolt is the time base of the counter, HP-5386A). I measured the PPS output with an HP-5328B, PPS of the thunderbolt as start, rising edge, rockwell PPS as stop, rising edge. The delay is 406.3 ms +/- 30 uS. Are those numbers normal for a rockwell chipset? Any idea why the two PPS are so far apart? PPS offset on the thunderbolt is set to 0. Thanks 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] PPS delay on rockwell
francesco.messi...@gmail.com said: I measured the PPS output with an HP-5328B, PPS of the thunderbolt as start, rising edge, rockwell PPS as stop, rising edge. The delay is 406.3 ms +/- 30 uS. Are those numbers normal for a rockwell chipset? Any idea why the two PPS are so far apart? PPS offset on the thunderbolt is set to 0. Do you have a scope? What's the width of the Rockwell PPS? Are you triggering on the correct edge? Is there an inverter in there someplace? I would try all 4 combinations of rising/falling edges and see if any of them match cleanly. That could happen if the Rockwell PPS is 500 ms wide. -- These are my opinions. 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.
