In a message dated 14/08/2005, royb1@........... writes:

AS1 Seismometer, Excellent Condition
Item number: 6200926939      ends Aug 20

This is  a vertical but has a rather short period.
Bob



This unit has NO electronics, so it is limited to  it's natural response of 
~1.5 sec and shorter periods.
 
    A specialised amplifier + ADC + processor is  sold with these units to 
boost the low frequency response out to about  15 sec. I don't know of an 
available circuit for DIY. If the integral knife  edge on the boom gets damaged, it 
won't work properly. 
 
    I never pay more than 50% of the cost price of a  secondhand item which 
has no warranty. 
 
    Regards,
 
    Chris Chapman
 






In a message dated 14/08/2005, royb1@........... writes:
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20
  size=3D2>     AS1 Seismometer, Excellent Condition
=
 =20
    Item number: 6200926939      ends Aug 20

This=
 is=20
  a vertical but has a rather short period.
Bob


    This unit has NO electronics, so it is limited=20=
to=20
it's natural response of ~1.5 sec and shorter periods.
 
    A specialised amplifier + ADC + processor =
is=20
sold with these units to boost the low frequency response out to about=20
15 sec. I don't know of an available circuit for DIY. If the integral k=
nife=20
edge on the boom gets damaged, it won't work properly. 
 
    I never pay more than 50% of the cost price of=20=
a=20
secondhand item which has no warranty. 
 
    Regards,
 
    Chris Chapman