Isn't setting this period just a matter of
positioning the lever arm as close to
level as possible and still able to
get it to seek a zero point reliably ?

There should be a point where gravity will
fail to overcome friction.
That will be the limiting factor
in how long a free period you may achieve.

----- Original Message ----- 
From: "Jón Frímann" 
To: "PSN-Postlist" 
Sent: Wednesday, May 06, 2009 7:54 PM
Subject: Incresing the period of a lehmans seismomter ?


Hi all

Tomorrow I am going to make the final changes to my lehman seismomter. I
hope that this changes make the seismomter get down to 20 seconds period
at most.

The only thing that I need to know is this. What is the best way to
increase the period of my lehman seismomter ? Moving the boom down or
up ? Or do I have to do something else.

Regards.
-- 
Jón Frímann

http://www.jonfr.com

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