Hi Paul,
 
  Have you looked at my web pages at
 
  _http://www.jclahr.com/science/psn/mcclure/index.html_ 
(http://www.jclahr.com/science/psn/mcclure/index.html) 
 
  There you will find a description and picture of my vertical sensor,  which 
operates at a period of about 5 seconds. By the way, the coil is the most  of 
the mass.
 
  Also there is a page describing my spring calculator for use in  vertical 
seismometers. You would do well to download and experiment with the  
calculator. The trick to getting a long period is to arrange the geometry of the  spring 
so that a decentering force is created to offset most of the restoring  force 
of the spring. A zero-length spring automatically does this. You have to  
relocate the support point of the spring if it is not zero length. For an AS-1  
type of seismometer, the upper end support of the spring should not be directly 
 above the hinge, but back of it. This adjustment is very delicate if long 
period  is the goal.
 
  For a sensor of the type you describe, the following links may be  helpful:
 
  _http://quake.eas.gatech.edu/Instruments/LPVERT0.htm_ 
(http://quake.eas.gatech.edu/Instruments/LPVERT0.htm) 
 
  _http://www.eas.slu.edu/People/STMorrissey/index.html_ 
(http://www.eas.slu.edu/People/STMorrissey/index.html) 


Cheers,
 
Bob



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Hi Paul,
 
  Have you looked at my web pages at
 
  http://www.jcl=
ahr.com/science/psn/mcclure/index.html
 
  There you will find a description and picture of my vertical sen=
sor,=20
which operates at a period of about 5 seconds. By the way, the coil is the m=
ost=20
of the mass.
 
  Also there is a page describing my spring calculator for use in=20
vertical seismometers. You would do well to download and experiment with the=
=20
calculator. The trick to getting a long period is to arrange the geometry of=
 the=20
spring so that a decentering force is created to offset most of the restorin=
g=20
force of the spring. A zero-length spring automatically does this. You have=20=
to=20
relocate the support point of the spring if it is not zero length. For an AS=
-1=20
type of seismometer, the upper end support of the spring should not be direc=
tly=20
above the hinge, but back of it. This adjustment is very delicate if long pe=
riod=20
is the goal.
 
  For a sensor of the type you describe, the following links may b=
e=20
helpful:
 
  http://quake.ea=
s.gatech.edu/Instruments/LPVERT0.htm
 
  http://www.eas=
..slu.edu/People/STMorrissey/index.html

 
Cheers,
 
Bob


Get a snea=
k peek of the all-new AOL.com.