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

[Hal Murray]

>> Does anybody have a favorite low cost timing mode unit?  How about
>> one with minimal soldering required?

kuzetsa at gmail.com said:
> http://www.ankaka.com/usb-gps-receiver-for-computers-laptop-worked-as-gps-nav
> igator_p46411.html
> "AGI-G217 USB GPS Receiver" 

That web page says:
  Uses SiRF Star III chipset to provide high accuracy and reliability

It's a typical low-cost GPS via USB navigation unit.  It's not a timing 
receiver.

SiRF has a huge chunk of the low cost  market.  Their receiver is sensitive, 
but it's horrible for timing unless you have a non-USB version so you can get 
the PPS signal.  The problem is wander.  (With my timing hat on, I'd call it 
a firmware bug.)  By wander I mean very low frequency jitter.  It's low 
enough that you can't filter it out by averaging a reasonable number of 
samples.
  http://www.megapathdsl.net/~hmurray/ntp/GPSSiRF-off.gif




-- 
These are my opinions.  I hate spam.