Azelio, I had an interesting experience with the same symptoms tonight. I inserted a 6 dB pad on the antenna input and it appears to alleviated the problem. Perhaps the GPS module is being overloaded with too much signal?
--marki -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani Sent: Tuesday, 16 July 2013 5:57 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Advice Z3816A jumping to Holdover: 1PPS TI exceeds hold threshold, then Recovery: phase alignment for 3-4 hours. I have a 58503 that occasionally is not able to track satellites. Usually I wait until the holdover expires but then the only fix seems to restart the 58503 (SYST:PRESET) better than power cycle. It seems there is a command to reset only the GPS receiver but it is not in the 58503 manual. On Tue, Jul 16, 2013 at 6:33 AM, Mark C. Stephens <ma...@non-stop.com.au> wrote: > I have a Z3816A and it periodically jumps into holdover with error message: > Holdover: 1PPS TI exceeds hold threshold Then for the next 3-4 hours > it gradually adjusts the phase alignment. > The error message is Recovery: phase alignment [TI +435.5 us] (when I > noticed it had changed, they figure was likely to have been much > higher) The TI then gradually decreases, currently it is sitting on: > Recovery: phase alignment [TI +129.9 us] > > I am hoping that I won't have to power cycle the GPSDO to get it locked again. > > I emailed the seller (Yixun HK) and they are trying to tell me power cycle is > only fix. > They also claim the cause is due to weather? > > I explained to Yixun I have a lot of smart clocks here and none have > exhibited the same problem ever. > This is the 3rd defective Z3816A I have got off Yixun and it is costing me a > small fortune to send these back. > The first was reporting the 12v Supply was out of tolerance, a quick jump > into pForth confirmed the A, B and C 12v supplies were over 12.5v. > I ended up sending it back to Yixun. > The second I was able to fix myself, apparently someone had changed the OCXO > but left the insulating-spacing washers out from the pins of the OCXO. > This was causing a short on the EFC. > That Z3816A unit and now appears to be running normally except the PU is > terrible, I'll run Cal for 24 hours and see if it improves. > > However, Now the 3rd unit is getting this TI exceeded error. > I think I have had enough of shipping things back to these guys - they won't > replace anything, including parts, unless you ship back to them first. > > > I would just like to get some informed opinions, could the issue be with: > > a) Antenna > > b) GPS Module > > c) OCXO > > d) PLL circuit on main board. > > Many thanks, > --marki > _______________________________________________ > 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. _______________________________________________ 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.