Hi,

you could try to isolate where the spikes are entering into your system. 

1: You could disconnect your geophone and short the input to your 
amplifier/filter.  Run it for a few hours to see if the spikes go away 
and if they do then it's the cable between the geophone and the amp/filter.

2: If you still have spikes, then disconnect your cable to the A/D, 
short the input there and run it for a while.

Your filter should eliminate spikes so it may be after the filter but 
best to do it systematically.

Once isolated you may be able to narrow further on what the problem is.

Cheers

Ian

Jón Frímann wrote:

>Hi all
>
>The spike problem still exist. :(
>I am out of ideas what this might be. Also, after I did change to
>screened cable I have been seeing alot of smaller spikes with regular
>intervals, those smaller spikes happen with 10 to 20 seconds spaces
>between them. That might becose of the computer (serial port issue), but
>I am not sure.
>
>Regards.
>  
>
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