Ed what tool are you using to monitor the 3801. LadyHeather remembers these bits of good stuff. Regards Paul. WB8TSL
On Thu, Feb 24, 2022 at 2:46 PM ed breya <[email protected]> wrote: > Last night I told it to do a survey, and let it slog through it > overnight. This morning it seemed to be working fine, and apparently in > position hold mode. > > Then I shut it down for about 45 min to let things cool down to nearly a > fresh cold-start condition. On power up, it went through the usual power > routine, and almost immediately began tracking satellites after the > inner oven warmup, then within a few minutes, the GPS lock indicator > came on. Also, before tracking even started, the position coordinates > reported exactly the same as before power down. So, now this RX unit > appears to be behaving "properly," just like the other. > > This RX unit was probably OK all along as it was, but I just didn't give > it enough of a chance to catch up with everything. The question is why > these two units, virtually identical, and neither having any long term > memory, and operated in the same setup and location, would act so > differently at first. There's no battery backup of the big SRAM, and I > don't see any NVRAM evident. There are two big Flash RAMs, but I believe > they only hold the firmware, so are not written to in normal operation. > Maybe they are? > > I've been wondering where the actual, necessary data must be kept in > order to get things working quickly like this. Since after a power down > and up, the exact same location was recovered before any tracking was > possible, it has to be stored somewhere in the RX or the Z3801A. I > suppose the Z3801A could have some NVRAM - I haven't looked closely > enough yet to see, but I will next time it's opened up. > > Now that this spare RX seems to be verified OK, my next experiment will > be to swap them again and see how the original works first time up, with > the Z3801A used to working with the spare. If it acts very slowly, then > I'd surmise that the Z3801A treats it differently, because its ID number > is different, and has to figure everything out again. If it still runs > easy and quickly, then I'd have to think the data is in the RX, or that > the Z3801A doesn't care, and it is the keeper of the data. If the latter > though, then it's a mystery again - the Z3801A should have told the > spare RX right away the location, quite accurately, and whatever else > was necessary, so it should have been able to get up and go quickly, > right from the first time. > > Ed > _______________________________________________ > time-nuts mailing list -- [email protected] -- To unsubscribe send > an email to [email protected] > To unsubscribe, go to and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
