an interesting experiment would be to see what the magnitude of the time 
drift is between a computer using an internet network time server 
(synchronised at regular intervals) and one using a gps time board.

It would also be interesting to then calculate what the typical 
positional error would be (of an epicentre) for a pc using an internet 
network time server, using gps time as a base line.

Ian Smith

Steve Hammond wrote:

>PSN members,
>I'm writing to report on a software network time client server software
>program that is compatible with WinSDR. I'm using Larry's serial connected
>A/D hardware with a Motorola GPS for data collection and realized that I
>could have my own home network time standard if I could find a compatible
>software package.
>
>After looking and trying three different products, I selected Net Time
>version 2.1 because it works seamlessly with WinSDR. You can obtain a trial
>version of the software from Http://www.han-soft.com I think you will find
>it to be compatible with all the MS operating systems.
>
>A few observation notes: While you can install the same copy of the trial
>software on two different systems, you need to purchase a server "Full
>License" for $25.00 for the time server (the machine running WinSDR) and a
>"Client License" for $12.99 for each client using the new network time
>service. The software includes a list of known Internet time servers and
>also allows you to assign the local IP address of your in-house network time
>server. The software is configurable with and support several different
>protocols. I'm using SNTP on port 123 which does not conflict with any other
>ports currently in use by the system. I had some issues with the initial
>install because I didn't understand the licensing methodology but was able
>to sort it out with the help of the Han-soft support rep who provide prompt
>and high-quality service.
>
>If you don't have a GPS, as I said, the software comes with an extensive
>list of network time servers that can be accessed via the Internet to obtain
>accurate time. Overall, the experience with this software package has been
>very positive and after 30-days of testing I'm now recommending it to other
>members of the Public Seismic Network.
>
>
>Regards, Steve Hammond, Aptos CA
>Public Seismic Network  San Jose California
>Http://www.publicseismicnetowrk.com
>
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