[time-nuts] Chooses for a desktop/server NTP external 1PPS reference

[Alexander Sack]

On Tue, Dec 8, 2009 at 3:46 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>> WHAT SHOULD I BE LOOKING FOR?
>
> I don't think we can answer that for you.
>
> What do you consider to be fun?  How much money do you want to spend?

I would like to spend less than 1k and I would consider something with
a little assembly as well as the ability to learn more about
timekeeping (I am also booking up sort of speak on the subject).

>
>>> Say I want nanosecond accuracy with respect to the PPS rising edge to
>> absolute UTC....I know that for sure.  My target system is FreeBSD ...
>
> There isn't much point in talking nanoseconds if you are going to connect it
> up to a computer, especially one running a normal OS.  Things get more
> interesting if the system has special hardware.

Right, I would assume the oscillator on a typical motherboard will
have too much variance to get down into the nanosecond range?  When
you say system has special hardare, do you mean like an Oregano PCIe
card that the system could use as a reference or something else.

>> Another issue is what governs the price of these units?  I'd like to
>> think its not going to be like the audio industry.
>
> I'll split the market into 3 chunks:
>  consumer gear, high volume low cost
>  telcom:  medium volume
>  lab: low volume, expensive
>
>
> If you want to get started, I'd suggest the GPS-18x and playing with ntpd.

I've done that already sort of speak at work (except using a higher
priced Endrun receiver).  I'd like to go to the next step.  I'd also
want to start graphing a bit some of my ntpd usage (I assume folks
basically grok peerstats and look at the offsets over time?).

Sorry for the flurry of questions, I am truly a n00b.

-aps