Hi You may have your elevation mask set to low for your antenna or a multi path issue from some other source. If the survey location is good to under a meter and the signals are good, there should be very little shift as sats are picked up or dropped.
Bob On Aug 1, 2013, at 5:09 AM, [email protected] wrote: > 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, > [email protected] 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 -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ > 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. _______________________________________________ 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.
