In a message dated 02/02/2006, jonfr500@......... writes:

I have  set the raw data on digital filtering, but that one is on 5.5Hz
but the  online graphs are now on 4Hz. It appears that the noise is
somewhat above  10Hz (there is noise on 10Hz, but alot less then if i
record from 2Hz to  60Hz), maybe above 6Hz.  I just haven tested it
properly yet. I do not  know how this filtering will effect my abliti to
detect  earthquakes.


Hi Jon,
 
    Record 'sample' traces at the maximum bandwidth of  20 Hz, including 
noise at various times and a few local quakes.
 
    If you only view from maybe 3 to 5.5 Hz, you may  miss some quakes.  
 
    Then view these traces putting in varying  frequency low pass digital 
filters, using Winquake and see how to make the quake  traces easier to read 
against the background noise.
 
    Regards,
 
    Chris Chapman






In a message dated 02/02/2006, jonfr500@......... writes:
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  set the raw data on digital filtering, but that one is on 5.5Hz
but the=
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  online graphs are now on 4Hz. It appears that the noise is
somewhat abo=
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  10Hz (there is noise on 10Hz, but alot less then if i
record from 2Hz t=
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  60Hz), maybe above 6Hz.  I just haven tested it
properly yet. I do=
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  know how this filtering will effect my abliti to
detect=20
earthquakes.

Hi Jon,
 
    Record 'sample' traces at the maximum bandwidth=
 of=20
20 Hz, including noise at various times and a few local quakes.
 
    If you only view from maybe 3 to 5.5 Hz, you ma=
y=20
miss some quakes.  
 
    Then view these traces putting in varying=20
frequency low pass digital filters, using Winquake and see how to make the q=
uake=20
traces easier to read against the background noise.
 
    Regards,
 
    Chris Chapman