PSN-L Email List Message

Subject: RE: Changes to my Lehman sensor
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@.........
Date: Wed, 15 Apr 2009 23:26:28 +0000


There is a peak around 0.6Hz, it might be the sensor it self that peaks
like that. But it might also be natrual forces in my area that create
this peak. I am not sure yet what natrual frequancy of the sensor is.

J=F3n Fr=EDmann.

On mi=F0, 2009-04-15 at 15:53 -0700, Gary Lindgren wrote:
> Jon,
> What is the period length of your Lehman sensor. Were you able to measure
> how long it takes for the boom displacement to drop by 1/2 after giving i=
t a
> light touch and this would be without damping in place.
> Gary
> -----Original Message-----
> From: psn-l-request@.............. [mailto:psn-l-request@............... =
> Behalf Of J=F3n Fr=EDmann
> Sent: Wednesday, April 15, 2009 11:20 AM
> To: psn-l@..............
> Subject: RE: Changes to my Lehman sensor
> Hi
> Here are pictures of the latest changes to my lehman sensor. One of the
> change is that the top now has a hindge to make it more movable. In
> theory that should provide me with better frequancy. However. I
> continune to get the peak at 0.6Hz, even with thoise changes. The damper
> plate is now aluminum, not steel.
> I am not sure how well this works until I get a earthquake close to
> Iceland or some where in the world.
> Pictures.
> Regards.


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