Hi all,

  I am presently using a pre-Lehman type sensor I built more than 44 years 
ago, after reading an Amateur Scientist article.  At that time, it was 
equipped with optical means for sensing pendulum displacement.  I recently 
retrieved the sensor from storage, and modified it for velocity sensing.  It 
really works well.  It is set for 11 seconds natural period, and I 
post-filter the data to simulate a natural period of 32 seconds.  My ability 
to pick up teleseisms is limited only by local noise and microseisms.

  The pendulum, magnet and coil design are unusual.  You can see it described 
at John Lahr's web page:

      http://www.jjlahr.com/science/psn/mcclure/index.html

Regards,

Bob McClure

 

Hi all,



  I am presently using a pre-Lehman type sensor I built more than 44 years ago, after reading an Amateur Scientist article.  At that time, it was equipped with optical means for sensing pendulum displacement.  I recently retrieved the sensor from storage, and modified it for velocity sensing.  It really works well.  It is set for 11 seconds natural period, and I post-filter the data to simulate a natural period of 32 seconds.  My ability to pick up teleseisms is limited only by local noise and microseisms.



  The pendulum, magnet and coil design are unusual.  You can see it described at John Lahr's web page:



      http://www.jjlahr.com/science/psn/mcclure/index.html



Regards,



Bob McClure