J=F3n,

I have made a few attempts to make a working Lehman. I never finished a =
stable version, but I did record some quakes with a mockup based on the =
'plumbers approach'. Lack of time and poor workshop facilities was the =
reason my project stranded.
So I ended up buying the SEP model which I'm very pleased with.
Your system looks alright to me, but I can't see from your pictures how =
your pivot points are working. Could you please describe in detail how =
the boom and support are in contact with the frame?=20

As I'm writing an Indonesian M6,6 is rocking my SEP. Feel free to visit =
my heliplots from Norway http://vindkast.no/wx_seismo.php

regards
Audun




-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... =
On Behalf Of J=F3n Fr=EDmann
Sent: 15. april 2009 20:20
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.

http://www.jonfr.com/myndir/v/geology/seismometer/p4150001b.jpg.html

Regards.
--
J=F3n Fr=EDmann

http://www.jonfr.com

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