Bob - Pad is connected between Distribution amp that powers antenna from separate supply. Good idea.
I haven't bothered measuring the voltage at the output of the pad, perhaps a simple calculation for you? --marki -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Sunday, 21 July 2013 12:06 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. Hi Pad = resistor in series with the dc. That will drop the voltage on the amp in the antenna. Not a good idea. Bob Sent from my iPhone On Jul 20, 2013, at 9:26 PM, "Mark C. Stephens" <ma...@non-stop.com.au> wrote: > I did a quick check of the antenna current on a normal (un-attenuated) vs. > the attenuated receiver: > > Normal: > Antenna current: 26.470589 > > Attenuated: > Antenna current: 32.352940 > > Slightly higher, but well within range. > > > --marki > > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] > On Behalf Of Azelio Boriani > Sent: Sunday, 21 July 2013 8:24 AM > 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. > > OK, interesting but putting an attenuator on the antenna input seems not a > good idea when there are 5V present... > > On Sat, Jul 20, 2013 at 6:01 PM, Mark C. Stephens <ma...@non-stop.com.au> > wrote: >> 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. > _______________________________________________ > 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. _______________________________________________ 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.