[ntp:questions] Sure GPS - PPS not working

Chris North chris at invalid.com
Mon Dec 9 21:56:13 UTC 2013

"David Taylor"  wrote in message news:l856os$9sp$1 at dont-email.me...


I very much share your own confidence level in Linux.  I find myself
even having to look up basic commands like how to move a file, delete a
non-empty directory etc.  However, the folks here and elsewhere have
been very patient, and very helpful, so the instructions on my Web site
are part of my way of saying thanks to the community.  I won't say
you'll have no problems, but there should be help or notes around.

I've not actually tried the Sure with a Raspberry Pi, as both my Sure
cards were tied up with "real" NTP servers, and I wanted to try
something a little smaller.  My current preference is a card which
requires no soldering at all:


and which can take an external antenna connection so you can use a
magnetic puck mounted in the best receiving location.  If you can get
your Pi within sight of some sky you can try the Adafruiut module:


which can also have an external antenna via a rather small connector.
There should be no trouble using the Sure card, though, but you would
need to attenuate the signal down to 0..3.3 V rather than having it at
RS-232 voltage level, or even TTL level.  The Sure board has 3.3 V PPS
output, so that should be OK.  I don't recall testing the USB port,
except perhaps in the very early days, but the RPi will take serial over
USB - you may need the right drivers, though.

You'll have fun with the RPi - any disaster with the OS simply reprogram
the SD card.  Get an 8 GB card if you intend to do much, for just an NTP
server a 4 GB card will be fine, but 8 GB allows more scope e.g. if you
want to do much recompiling.  You can backup the card onto a Windows or
Linux PC easily.
Web: http://www.satsignal.eu

David, many thanks for that.
I think this is a good project for the cold, dark days after Christmas.
I'll get the bits ordered ready.

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