Yes, and the new uBlox timing GPS have a software jamming sensor and
indicator which the Motorola/iLotus products do not have, and they are much
easier to get to work at a users' site than the Motorola parts, and much more
robust against jamming than the Motorola timing GPS. We have done extensive
tests here on our products that use the LEA-6T to prove that.

There are significant advantages in performance and easy-of-use to the
ublox parts compared to all other alternatives in the market today.

Still the Motorola designed parts have the best timing performance with a
margin when properly operated, so they still have significant applications
for  many years to come - one reason we offer the uBlox parts in some of our
products and the Motorola parts in others (i.e. Fury GPSDO).

BTW:

I applaud the use of the eBay name in this thread.

I think many members here are doing a dis-sevice on this list by naming it
ePay, 3Pay or whatever. They don't seem to remember what it was like
getting equipment before Ebay was around, and while I curse the Ebay fees and
policies, Ebay offers a great service, and we should give  them the respect
they deserve in my opinion. If you don't like Ebay,  then don't use them, use
Craigslist or used-line etc.

bye,
Said

In a message dated 1/3/2012 10:25:26 Pacific Standard Time,
azelio.boriani@screen.it writes:

Oh no, I  was speaking always of timing version GPSes. For non timing
version GPSes  you loose the position-hold timing mode too. uBlox has T-RAIM
in the LEA6-T  version. In the block diagram of uBlox GPSes they show the
option XTAL/TCXO  for their receivers. Although not stated, I believe that
the TCXO option is  reserved for the timing version  hardware.

Thanks to the folk here for pointing out the ublox receivers.  I managed to
get one off eBay for ~US $30 with antenna on a board designed for hobbyists
with 3.3V serial and PPS outputs (I needed to add one wire for that) which
feed directly into a Raspberry Pi.  It's still to be completed, but the
serial 9600 baud and PPS outputs appear to be spot on.  My early notes are
here:

http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html#serial

I'm intending to use a second Raspberry Pi with the ublox NEO-6M, but I
don't expect to see any significant difference (at the microsecond level)
between it and the Trimble module I'm already using.

Cheers,
David

SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk

-----Original Message-----
From: paul swed

most interested in you progress.
What will be the total power consumption of the pi and gps rcvr?

---==

I've not measured the total, Paul, but the Raspberry Pi is about 700 mA and
the GPS receiver less than 100 mA, so the total is likely to be less than 4W
(5V at 0.8A).

Cheers,
David

SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk

oh thats my kind of basement wall wart. Place it on the wall and forget it.
I have nas drives that way. They spin down and power consumption is I want
to say 5-8 watts been a long time. May be lower. You access them they spin
up and get your data stay up for a while and back down.
A quite basement no heat and little power.
Regards
Paul.

---=======

.. and no noisy fans either, Paul!  The unit takes micro-USB power, so you
could perhaps power it from those junked mobile phone chargers!

Cheers,
David

SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk

-----Original Message-----
From: paul swed
Sent: Tuesday, November 20, 2012 9:34 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] eBay Ublox

any luck on the ntp server?

---=========

If it's me you are asking, yes, Paul, here's the server:

http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html

and here's the performance with the u-blox NEO-6M (I know that's a
Navigation and not a Time GPS).

http://www.satsignal.eu/mrtg/performance_raspi-1.php

When recompiling NTP /and/ installing SNMP, there was a +20 microsecond
transient, followed by a -14 microsecond transient during recovery.  That
was just before 16:00 UTC the day before yesterday, and is just disappearing
off the left end of the graph as I write (08:40 UTC, Wednesday).  Otherwise
well within 5 microseconds, with the unit just sitting out in the open.

Cheers,
David

SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk

-----Original Message-----
From: Bill Dailey

Very nice write up.  I went down a similar road with my fury and Ubuntu...
And then with FreeBSD on a soekris box.  Have you tried refclock drivers
instead of gpsd?  I use gpsd on Ubuntu but decided to use refclock route
instead for FreeBSD.  I have an overall feeling that at us and ns levels
gpsd doesn't perform as well... No evidence but is does seem like it should
be inherently slower... Probably much more important on the free bsd soekris
implementation.

Doc

---============

Thanks for your comments, Doc.  I try to make the write sufficiently simple
but comprehensive so that I can understand it next time I need to visit
Linux!

I only use gpsd on the Linux system, and then only because it was the first
thing I discovered when searching with Google.  As the precise timing is
from the PPS signal fed to the GPIO pin, with a GPIO interrupt handler, I am
forced to use that.  I don't think the interrupt handler talks to the gpsd
at all, but I might be wrong.  There is no DCD line on the Raspberry Pi for
gpsd to receive the PPS signal.

The FreeBSD system uses the type 20 driver (generic NMEA) for both coarse
and fine time (via kernel PPS).

As a lot of this is new to me, my understanding is not as complete as I
would like.  VMS device drivers I used to understand.  I think I have a
moderate knowledge of Windows and how .SYS drivers fit in, and how DLLs
might support them.  What Linux "modules" are I don't yet know, so why I
need both a revised kernel /and/ modules on Linux to support PPS is
currently unknown - although my guess is that the modules are the equivalent
of Windows device drivers.  Don't have the time to read up about this, but a
pointer to any easy-to-understand documentation about Linux, kernels and
modules would be welcome!  My FreeBSD understanding is even less.

Cheers,
David

SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk