From vom513 at gmail.com Tue Aug 12 22:52:39 2025 From: vom513 at gmail.com (Brandon Applegate) Date: Tue, 12 Aug 2025 18:52:39 -0400 Subject: Need help with NMEA + PPS refclock Message-ID: Hello all, So previously - I had Debian 11 or 12 (?) and ntp.org ntpd built from source (NOT ntpsec). I was running refclock type 20 here - and using "integrated" PPS (i.e. I only had one source/refclock). This worked like a charm for years. Very steady, single digit usec offsets etc. I just reinstalled this machine with Debian 13 and I am trying to use the Debian ntpsec package(s) and am having a lot of trouble. It seems like the two refclocks I need to use (well maybe just one of them ?) are nmea and pps. Reading the docs it seems that I can do what I used to have and "integrate" PPS into nmea and just have one source ? (Bonus question: If that is true, and I were to do that, is there an ntpq command that would verify that PPS is being used properly ? Or would the source be prefixed with an 'o' in the billboard ?) It also seems that I can have an nmea + PPS source and these will work in concert. I currently have: refclock pps unit 2 minpoll 4 maxpoll 4 ppspath /dev/pps2 refclock nmea prefer minpoll 4 maxpoll 4 mode 1 baud 4800 path /dev/gps0 flag4 1 Which gets me: root at jetway:/etc/ntpsec# ntpq -pn remote refid st t when poll reach delay offset jitter ======================================================================================================= xPPS(2) .PPS. 0 l 9 16 377 0.0000 158.7602 0.0340 xNMEA(0) .GPS. 0 l 12 16 377 0.0000 0.3310 0.0525 Again, my hardware is solid. My NMEA output is good, as well as PPS (GPS location sanitized): root at jetway:/etc/ntpsec# cat < /dev/gps0 $GPRMC,224921.000,A,0.0,N,0.0,W,000.2,328.9,120825,05.2,W*53 $GPRMC,224922.000,A,0.0,N,0.0,W,000.2,328.9,120825,05.2,W*58 $GPRMC,224923.000,A,0.0,N,0.0,W,000.2,328.9,120825,05.2,W*53 root at jetway:/etc/ntpsec# ppswatch /dev/pps2 trying PPS source "/dev/pps2" found PPS source "/dev/pps2" timestamp: 1755038482, sequence: 1859, offset: -57088441 timestamp: 1755039046, sequence: 1860, offset: -58500396 timestamp: 1755039046, sequence: 1860, offset: -58500396 timestamp: 1755039047, sequence: 1861, offset: -58614668 timestamp: 1755039047, sequence: 1861, offset: -58614668 timestamp: 1755039048, sequence: 1862, offset: -58567599 timestamp: 1755039048, sequence: 1862, offset: -58567599 Can someone point me in the right direction here ? I figured I'd have some bumps getting this to work with ntpsec, but I didn't think it would be this hard. Thanks. -------------- next part -------------- An HTML attachment was scrubbed... URL: From vom513 at gmail.com Tue Aug 12 23:04:00 2025 From: vom513 at gmail.com (vom513) Date: Tue, 12 Aug 2025 19:04:00 -0400 Subject: Need help with NMEA + PPS refclock In-Reply-To: References: Message-ID: <10D93EFA-2ABA-4053-938C-4DEFC1ACD0ED@gmail.com> I might have figured this out :) I now have: refclock nmea prefer minpoll 4 maxpoll 4 mode 1 baud 4800 path /dev/gps0 ppspath /dev/gpspps0 flag1 1 flag4 1 And after a while I get ?o? in the billboard and the offset goes down. Would still like some feedback on if there is anything I should be configuring differently kowing my hardware and setup. Thankls. -------------- next part -------------- An HTML attachment was scrubbed... URL: