Hi Charles Thanks for your comments, the surveyed position on this is looking pretty good but what I have now realised is that the severity of the jumps seems very much related to the number of sattelites being tracked. Switching from 8 to 7, or 7 to 8, sats seems to produce the biggest step change whilst switching in either direction between 5 and 6, for example, doesn't seem to show up at all on the monitored DAC voltage. Ok, I take that back, it does still seem to depend on the number of sats being switched between but I've just seen a switch from 5 to 4 sats induce a very noticeable step change in DAC voltage, so the relationship doesn't appear to be linear. Unfortunately I need to power this down now for a few days but will investigate more later. Regards Nigel GM8PZR In a message dated 01/08/2013 09:45:24 GMT Daylight Time, charles_steinm...@lavabit.com writes:
Nigel wrote: >at times I'm seeing very noticeable step changes in the DAC voltage >on this one as that happens. > * * * >I am a bit surprised by the extent, a Mark Sims online plot from >2012 shows some correlation on an NTGS50AA but not as noticeable as >this, and I don't recall seeing anything quite so pronounced on a Thunderbolt. IME (with TBolts), the magnitude of the DAC steps with constellation changes varies with the accuracy of the positional data used by the GPS. To a point, the more accurate the survey, the smaller the DAC jumps will be. (Other errors prevent reducing the constellation-change DAC steps to zero.) Mark has commented here on survey accuracy, and the methods he used in Lady Heather to maximize it. Best regards, Charles _______________________________________________ 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.