[time-nuts] Followup (still want a GPS-type NTP refclock)

[Attila Kinali]

Hi Sarah,

I've just reread the old thread from august and i don't quite
get what you are aiming for. From what i gather, you want to have
an ntp startum 1 server for your internal network at home?
How accurate does it have to be? Sub-ms? Sub-us?


On Wed, 17 Oct 2012 03:50:41 -0400
Sarah White <kuzetsa at gmail.com> wrote:

> 1) iLotus M12M timing mode GPS (serial port version)
> 2) Aprox 10 meter antenna cable with apropriate connector(s)
> 3) active antenna which can handle being 10 meters from the module
> 4) power supply for above list, and much needed luck, all for under
> $100 USD


Should be possible. Though i doubt you'll find all together as one kit.
But the whole stuff is pretty much standard.

A lot of the puck antennas come already with a couple of meters cable.
Mostly in the range of 2-10m. You should be able to find an appropriate
one on ebay or other stores. 
The iLotus M12M comes with an MMCX antenna connector. This is a nice
and small connector, but IMHO unsuitable for home use. It's not very
sturdy and you can break it easily if you are not carefull. I suggest
that you'd rather look for a timing module with an SMA connector,
which is much less fragile (although still something you have to be
carefull with) and more standard (antennas and cable with SMA connectors
are very common for GPS).


> 
> Discovered something amusing about my sirf III GPS "mouse / puck" ---
> uses the same prolific 2303 chip internally (same driver) as the USB
> <---> Serial converter I dug out of my storage area and tested in the
> past 24 hours... At least I know it works with the various operating
> systems I'll be trying to time on...

You know that an USB Serial converter introduces an unpredicatable
non-white jitter in the ms range? An ntp server with good internet
connection gives you better results than that.

 
> Works fine for my crappy NMEA / sirf-binary GPS thingy... will this
> also work for the iLotus M12M or is there a new or comparable version
> of the same? (similar to the thunderbolt or sirf thingy) ...

Guessing from the name, i'd say the iLotus M12M uses a variant of the
Motorola M12 Oncore timing receiver.


HTH

			Attila Kinali


-- 
The trouble with you, Shev, is you don't say anything until you've saved
up a whole truckload of damned heavy brick arguments and then you dump
them all out and never look at the bleeding body mangled beneath the heap
		-- Tirin, The Dispossessed, U. Le Guin