Dave, Plot the #SV tracked and signal strength(s) over a couple of days. See if your once or twice a day glitches correlate to periods of low reception.
To see what the reception of other z3801a owners look like: http://www.realhamradio.com/GPS_websites_list.htm You may even want to try a lower mask instead of a higher mask. It's a trade-off between fewer SV with solid reception and more SV with possibly spotty reception. Easy experiment: try 0 degrees for two days, then 15 degrees, then 30 degrees. What I do is issue a syst:stat? command every 30 seconds. It's easy then to go back to the log files and check things like constellation changes and elevation, or brief or prolonged periods of holdover, etc. /tvb > On Jan 28, 2016, at 8:49 AM, Artek Manuals <manu...@artekmanuals.com> wrote: > > OK > > My Z3801A came out of mothballs after 15 years in controlled storage and > appears to be behaving. now I am curious as to what I am seeing > > First I am not truly a "time" nut ( I am semi retired and have not worn a > watch since October 12th 2008 :-) ). I am probably more of "frequency" nut . > I use the Z3801A as my 10MHz reference. Having a reference source that is > good to .1Hz at 10MHz is more than adequate as a reference for my counters, > signal generators and and spectrum analyzers. But like all engineers if you > give me the numbers I an drawn to trying to figure out what they are telling > me. > > My Z3801A has been on for about 2 weeks now and typically reports 1PPS +/- > 20ns readings 20 hours/day. Then all of a sudden once or twice a day it will > go nuts and the variation increases to +/- 80ns for an hour or two before > settling back down. Watching the 10mhz on a 10 digit counter shows no short > term change in the frequency of the OCXO when the thing goes nuts there are > slight changes in EFC but nothing dramatic vs any other hour to hour > variation. The Allen and modified Allen deviation is around 2e-13 as it > approaches 1e5 samples > > Here is the setup > 1) Z3801A > 2) Symmetricom 58532A antenna, just above the roof, with 8 feet of RG213 to > the Z3801A > 3) Running on a lab grade power supply at 48.5 volts (voltage variation over > time is less .05 volts) > 4) Lab runs at 73deg F +/- 2 degrees , humidity is NOT closely controlled > 5) Running Z38xx software > 6) Elevation cutoff on satellites is set for 15 degrees > > And here is the question is the sudden jump in the pps deviation due to > ionospheric and the satellite constellation change? IS there anything I can > do to minimize it (or is it even necessary to worry/ wonder about) This > behavior has going on since the beginning so it is not likely related to > events earlier in the week. But that set me to wondering could I minimize it > by say raising the elevation mask? Are there satellites in the constellation > that are notorious for noise etc that could be excluded from the tracking > list ...etc etc > > Dave > NR1DX > ArtekManuals.com > > A man with a watch always knows what time it is > A man with two watches is never quite sure > > -- > Dave > manu...@artekmanuals.com > www.ArtekManuals.com > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > _______________________________________________ > 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.
