Re: NMEA but no PPS in ntp, Ubuntu 18.04.5

[Gary E. Miller]

Yo Steve!

On Fri, 4 Dec 2020 10:42:59 -0600
Steve Bourland <sbourland@swri.org> wrote:

> > Did you ever get aound to getting ntpd to listen to SHM(0) and
> > SHM(2)?  
> 
> Did try using 127.127.28.2 with no change.

Yes, but what did you see?  

> The SHM(2) only has a
> single entry at startup of ntpshmmon, only SHM(0) gets per second
> entries on the sick system.

And your earlier logs did whow a PPS sneaking out, before the "no fix"
kicked in.  So that is likely your PPS.

> The "healthy" system (Ubuntu 18.04.4
> LTS, Linux 4.15.0-72-generic #81-Ubuntu, gpsd: 3.19.1~dev (revision 
> 3.19.1~dev-2019-12-16T16:01:12), ntpd ntpsec-1.1.0+419 
> 2018-03-14T12:03:57-0700, using 127.127.28.0 and 127.127.28.1 
> successfully) reports entries for NTP2 and NTP3 at startup, then NTP0
> and NTP1 per second (I hope that makes sense).

Not without knowing your configuration.  But no matter, we know it all works
when it all works.

> The "sick" system was
> working just fine prior to my upgrade from 16.04 to 18.04.  The
> upgrade was done in-situ, so the cabling and receiver didn't move
> (ie, I have high confidence my issues are software not hardware.

Easy, just downgrade.  Execpt gpsd has lots of 18.04 users, so I doubt
that.

> Given we're seeing PPS signals with ppstest and cgps thinks we have a
> fix but pps doesn't, I think you're on board with me?

Yes, been around that road several times.

>  I haven't
> ruled out "permissions" issues that may have come up with the OS
> move, but have shutdown apparmor to no avail, and can't find a
> difference between the two systems in that regard).

I do not believe permissions either, but run as root, and no apparmor,
and none possible.

> > Depending you your GNSS receiver that change may help, or not.  The
> > benefit, depending on model is that gpsd may optimize the sentences
> > that your receiver sends.  
> 
> Both systems are using (hold your nose) Garmin 18x LVCs, so I suspect 
> there won't be much change if I drop the -b.

There will certainly be a change with the 18x, just not to this.  The
default 18x configuration is sub-optimal.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        gem@rellim.com  Tel:+1 541 382 8588

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    "If you can't measure it, you can't improve it." - Lord Kelvin

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