[ntp:questions] Re: All my servers rejected

Chris Stenton jacs at gnome.co.uk
Fri Jan 9 11:08:48 UTC 2004

At $30 I would go for the RadioShack GPS if it can generate a 1PPS.

I have both  Motorola M12 Timing and Non-Timing evaluation kits, both
generate 1 PPS signals. I have found that when connected to a bulk standard
motherboard the "M12 Timing" version is more accurate but nothing to write
home about. I think to get the best out of it you need a motherboard with
better crystals than you get on a std board.

Strangely, I have found that the "M12 Timing" picks up less satellites than
the non timing version using the same puck antenna. At my location I can get
24/7 coverage with the "non timing" but not the "M12 Timing" version. I've
got the external antenna but its cold and wet outside so its still in its


"Richard B. Gilbert" <rgilbert88 at comcast.net> wrote in message
news:Es-dnWKI0dwWlGOiRVn-jg at comcast.com...
> I believe that the RadioShack GPS receivers are navigation rather than
> timing.  Synergy Systems sells a Motorola M12 Timing Evaluation kit for
> $198.  This includes a circuit board with the M12 and support
> components, a wall wart for DC power, a hockey puck antenna with cable
> and an RS232 cable.  It has a one PPS output in addition to choice of
> NMEA or Motorola Binary output formats.  You need to mount the circuit
> board in a box of some sort and hook it up to a computer.
> I had hoped to have the one I've ordered in hand by now but no such
> luck; I just talked to Synergy and they haven't shipped it yet. <sigh>
> The RadioShack receiver would still be far superior to a satellite
> connection with two to three second latency.  A lot depends on how
> closely he needs to synchronize.
> Harlan Stenn wrote:
> >I recommend the following:
> >
> >- Can you afford $200 for a GPS clock?  I gathern RadioShack is closing
> >  some (apparently tolerable) GPS receivers for about $30...
> >- do what you can to get a local, reliable frequency source, so you can
> >  continue to have stable time when your link is down.
> >- use iburst and burst (in your specific case - in most cases
> >  burst is Unfriendly)
> >- use your pppup/pppdown scripts (or whatever) to handle enabling and
> >  disabling your ntp associations as your connection goes up and down
> >
> >This is somewhat discussed on twiki.ntp.org .  I would be Happy to see
> >more info there.  Please help.
> >
> >H
> >
> >

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