DaveB wrote:
In article <[email protected]>, david-
[email protected] says...
On 31/07/2013 20:36, DaveB wrote:
[]
The server is using 5 'net based servers at this time (my original GPS
RX died) and is only just stable enough for what I'm doing. Sometimes
due to asymetric ping times, it "wanders a bit" for an hour or three.
[]
Oh... Though the time server is FreeBSD based, other boxes in my empire
are a mixture of Windows and Linux, various versions types and
requirements.
Cheers All.
Dave. (G0WBX/G8KBV)
Dave,
A small GPS with PPS I can recommend to you is this one:
http://www.adafruit.com/products/746
At least here, on the top floor of a two-storey house in Scotland, it
gets enough signal to lock consistently. Not too expensive, and
available from a UK stockist.
http://proto-pic.co.uk/ultimate-gps-breakout-66-channel-w-10-hz-updates-mtk3339-chipset/
A few hundred microseconds should be enough for your pulse, although
GPSs tend to use either 100 ms or 200 ms by default. Easier to see on a
non-storage 'scope as well! I'm pondering on making a driver and having
a terminated line running around the shack here (at pseudo RS-232
levels) for feeding PPS into all my PCs which have COM ports to get the
best time synchronisation. AT the moment, those PCs which aren't
stratum-1 have the poll interval set to 32 seconds to the local
stratum-1 servers.
I'm sure you know about the information on my site for FreeBSD, Windows
and Linux, but others may not:
http://www.satsignal.eu/ntp/index.html
Yes, well aware of your wonderful resource pages. And thanks for the
link to the adafruit site, I'd forgotten about them.
I now have a new-old-stock GPS-16 (with unmolested full length lead and
original connector) should I need, but I may end up using that for
similar needs in a mobile setting, hence my interest in using the TB to
drive the shack NTP box.
Took a look at the TB's PPS signal last night, & yes, 20ns duration, and
though it can be turned -ve (as in 0 to -5V) or off, the width can't be
changed.
Too many toys, so little time. :)
Hi
a simple monostable can give an extended pulse long enough to
be caught by DCD on a serial port. Yes it causes a delay but
not likely to be more than a few us.
I've tried with parallel port using atom driver but could not
see any difference other that I could use different pps source.
another David
73.
Dave G0WBX/G8KBV.
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