ublox refclock

Gary E. Miller gem at rellim.com
Sun Nov 24 21:27:54 UTC 2019


Yo Udo!

On Sun, 24 Nov 2019 15:08:05 +0100
Udo van den Heuvel via devel <devel at ntpsec.org> wrote:

> On 24-11-2019 15:01, Eric S. Raymond wrote:
> > Udo van den Heuvel <udovdh at xs4all.nl>:  
> >> I have an M8N on order, would that be compatible enough to this
> >> driver? If so: I could help test etc.  
> > 
> > That can't hurt - they speak the same protocol - but the big deal
> > with the T variant os a stationary mode you don't have.  
> 
> Ah, OK.
> The M8N was cheap so perhaps a fake; I can try to identify this when
> it comes in.

If it speaks u-blox protocol it is almost certainly from u-blox.

That said, there are many GPS sold as "replacement for NEO-M8N" that
are not u-blox.  And sometimes cheaper/older u-blox remarked as newer
more expensive ones.  UBX-MON-VER will answer those issues.

> As it appears I need a (real) M8T:

Really?  For me to tell the performance between a NEO-M8N and a NEO-M8T
requires me to use a TAPR PICC and/or my Rb clock.

> What M8T board, cabling etc would I need to buy to interface to RS232?

So many to choose from.  If you are only using RS-232 to read the PPS
then the M8T is way overkill.

Both the NEO-M8N and NEO-M8T are very temperature sensitive.  To see
the added performance of the M8T over the M8N you need a very stable
ambient temperature.

With ntpviz I can easily see the heat go on and off in my house.  Even
when the GPS is in a room with NO connection to my house ducts.

I, and others, have built single oven, and double oven, enclosures to
remove the temp dependency.

> Would e.g. https://www.gnss.store/12-gnss-gps-modules be reputable
> enough?

Dunno about their reputation.  Their price on the u-blox 9's seem OK,
but their older stuff is way over priced.

See the discussion eariler this month where I recommended parts to
Richard Laager.

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

	    Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin
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