Yo Greg!

On Thu, 22 Jan 2026 09:38:58 -0500
Greg Troxel <[email protected]> wrote:

> > Ugh.  That will not work.  I find more them 2km and the benefits are
> > small.  
> 
> It's really hard to say.  You have much worse experience with RTK
> than I do.  While 40 km is a bit much, I have great positioning
> results with network RTK where the closest stations is 20 km, a
> friend getting sub-cm repeatable positions with a tripod, and me
> within a 4 cm diamater circle handheld prism pole watching the level.

By "network RTK", I assume you mean the type that uses a number of
base stations to compute an RTK feed adjusted for your position?

Those can work well.

Also SPARTNv2 can do better than meter accuracy world wide.

> I don't think it is at all clear that the RTCM stream accessed over
> NTRIP is "bad".

Just not "good".

>   Log the NMEA from the receiver, or gpsd'd processed version, for a
>   decent interval (min 4h) in autonomous mode, and then again with
> RTK. Graph  each of them to understand how tight positions are.  Look
> at fixmode and see if you are in float or fix.

Yeah, get to the root of the issuue, not several layers down the stack
as it affects your system clock.

>   If you really want to understand, get a stable 1 pps source, like a
>   budget GPSDO (e.g. Bodnar), and a way to compare that pps signal to
>   the F9P's, probably like the TAPR TICC
>   https://tapr.org/product/tapr-ticc/

The TICC is great.  ebay will sell you a Rybidum clock for around $100
to $300 these days.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        [email protected]  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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