Good day, *********** REPLY SEPARATOR ***********
On 21-Oct-11 at 13:18 Dennis Ferguson wrote: >On 21 Oct, 2011, at 11:53 , [email protected] wrote: >> Bruce, the most common cause of a GPS receiver getting the date >incorrect is due to cross-correlation. And cross-correlation is usually >the result of too much gain in the GPS antenna's LNA. (snippage) I would be more likely to believe this if the setup had not been working just fine for the last four years. ;-) No, based on what I've read, I'm definitely inclined to believe it's a 1024-week rollover thing. (more snippage) >Some of the heuristics I've heard of are these (or maybe combinations of >these): > >- Assume the date must be more recent than when the firmware was compiled. > By itself this leaves the device with a 1024 week rollover problem, but > the 1024 weeks are counted from the date the firmware was compiled rather > than from the GPS epoch. (still more...) This idea fascinates me, as it is, potentially, the easiest to correct AND the unit itself is vintage mid-90's. This would also explain why the thing stayed working for a while after the last 1024-week roll. I think I'll pull out the firmware, see if I can find the compile date in a dump of the EPROM, change said date, and put the whole thing back together. At worst, I'll end up with the same situation I have now. At best, it'll fix it. No matter what, I'll post the results. Dennis, thanks much! I hadn't even considered that line of thinking. Bruce Lane, Owner & Head Hardware Heavy, Blue Feather Technologies (http://www.bluefeathertech.com) Assoc. member, AZA & AAZK for many moons. "Salvadore Dali's computer has surreal ports..." _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
