[hpsdr] Internet NTP useful for Ham freq measurement?

[John Ackermann N8UR]

Hi Dan --

I fully agree about the usefulness of NTP generally for timekeeping (I 
run four stratum 1 servers in my basement :-) ).  I was answering only 
the specific question about using it to create an "NTP-DO".

73,
John
----

Dan Mills said the following on 10/21/2012 05:32 PM:
> On Mon, 2012-10-15 at 12:05 -0400, John Ackermann N8UR wrote:
>
>> You could set something up that uses a good quality OCXO locally that
>> gets steered once a day or so to NTP, but I think you'd spend more and
>> get worse performance than other options.
>
> Actually NTP is quite useful for ham stuff, not so much as a frequency
> reference but as a way to get relatively accurate time without going to
> the extremes of something like a TBolt GPS timing rx.
>
> Some of the weak signal modes rely on the time at the transmitter and
> receiver being synchronised to within a few seconds, and NTP is more
> then man enough for this use.
>
> I don't know about Windows, but the Linux kernel actually locks a
> software PLL to the NTP reference and uses this rather then the RTC on
> the motherboard for wall clock time, it is not a case of comparing every
> hour or so and jam synching at that point, but of actually doing a long
> loop timeconstant PLL in software.
>
> man adjtimex(8) has some interesting comments, and the kernel
> timekeeping code is some very clever stuff.
>
> Regards, Dan.
>

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