Hi Bryan,

If your A/D board was locked to GPS time your timing accuracy is closer to +-5ms. The 
filter delay is more or less constant and can be factor out by placing the filter 
delay time in WinSDR. In the Channel Settings dialog box you will see a "Filter 
Delay" edit box. For now use 50 ms. When I get some time I will measure the delay of 
one of my Amp/Filter board channels and place this information on my Web site.

Besides accurate timing you should also have an accurate location of you station. I 
noticed that the PSN files you placed on your web site did not have the Latitude and 
Longitude data filled out or the file only had the location too two decimal places. 
Since you have a GPS receiver you can use it to locate you station's location to a 
few meters.  If you run the current beta version of WinSDR you can use it to average 
the position information from the GPS receiver connected to the A/D board. See 
http://www.seismicnet.com/winsdr/betarelease.html for more information. If you let 
WinSDR average the data for a day or two you will have a very accurate latitude and 
longitude number.

Regards,
Larry Cochrane

Bryan wrote:
> Ok so what should I tell CERI   I am getting a lot of different numbers from the replies? Would I be ok 
 >to say with filtering I should be within +/- 50ms also will this be good enough to 
accurately locate
 >a local events with 3 stations less than 50 miles apart. This will explain why I 
ask is a clip
 >from a letter from Mitch.

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