[time-nuts] Is it sensible to update every few seconds from NTPserver?

[paul swed]

OK thanks for the pointer to joe taylor will look him up.
This would be familiar to the very weak signal work I was doing years ago
about 15 and I used discreet ICs to process very weak signals that were
slow. But we would use a common view reference such as wwvb or a am radio
station. These days you would do it all in a sound card.
Regards
Paul.

On Wed, Nov 7, 2012 at 6:53 PM, Alan Melia <alan.melia at btinternet.com>wrote:

> Hi Paul think synchronous data transmission where you cant detect enough
> signal to synchronise reliably via the bit edges received. Initially
> developed for LF (136kHz) where the ERP of amateur antennas is very low.
> Google Joe Taylor but not for his Nobel prize, who's original interest was
> Moonbounce communication. He has now generated modes for LF too.
> Alan
> G3NYK
>
> ----- Original Message ----- From: "paul swed" <paulswedb at gmail.com>
> To: "Discussion of precise time and frequency measurement" <
> time-nuts at febo.com>
> Sent: Wednesday, November 07, 2012 10:11 PM
> Subject: Re: [time-nuts] Is it sensible to update every few seconds from
> NTPserver?
>
>
>
>  Interesting I am unaware of any amateur service requiring that tight of
>> a timing relationship.
>> At least modern PC clocks do not drift that badly in a few minutes. So it
>> is pretty odd.
>> Without further detail I am at a loss for why you need to do that.
>> Maybe he is tinkering with spreadspectrum?
>> Regards
>> Paul
>>
>> On Wed, Nov 7, 2012 at 5:04 PM, David <davidwhess at gmail.com> wrote:
>>
>>  Some Windows NTP clients like Tardis can calculate and implement a
>>> clock frequency adjustment instead of stepping the clock if the time
>>> adjustment is below a specified limit.  If he was using an application
>>> that was upset by the time being stepped, then that might allow less
>>> frequent updates.
>>>
>>> If he is polling that often to maintain accurate time, then I would
>>> assume he is using a local known to be accurate NTP server.
>>>
>>> There are Windows NTP clients which will synchronize to GPS PPS time.
>>> That should be better than stock hardware and Windows can handle
>>> anyway.  Something like a Garmin GPS18 is specified to be within 1uS
>>> and has a pulse to pulse jitter in the 10s of nanoseconds.
>>>
>>> On Wed, 7 Nov 2012 21:41:36 +0000, David Kirkby
>>> <david.kirkby at onetel.net> wrote:
>>>
>>> >Someone at my radio club uses some mode of operation where accurate
>>> >time is required. He said the standard Windoze clock does not keep
>>> >sufficiently accurate, so he has software which updates from an NTP
>>> >server every 4 seconds or so. It's not exactly a denial of service
>>> >(DOS) attack, but seems almost close to it in NTP terms to me. I can't
>>> >really believe updating every few seconds is sensible myself, but he
>>> >assures me it works very well. (I'm rather hoping it does not use a
>>> >stratum 1 server!)
>>> >
>>> >I'm sure someone will say if you want accurate time on a PC, to use
>>> >some combination of GPS, rubidium or OCXO with a 1 pps pulse and a
>>> >serial port on a FreeBSD or similar computer. But that's probably not
>>> >practical if your software only works on Windoze.
>>> >
>>> >Any comments?
>>> >
>>> >Dave, G8WRB.
>>> >
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