Hi

I did manage to get the Hz number down to 0.4Hz. I guess that I need to
rase the arm up a little. I am going to do that tomorrow.

Regards.
J=F3n Fr=EDmann.

On mi=F0, 2009-04-15 at 16:44 -0700, Gary Lindgren wrote:
> Jon,
> Without damping give the boom a light touch, what is the natural period.
> Count how many seconds it takes to make one cycle. Then count how long it
> takes for the displacement to go from one centimeter to 1/2 centimeter. T=
his
> will tell you how much friction you have in your sensor.
> Gary
>=20
>=20
>=20
>=20
> -----Original Message-----
> From: psn-l-request@.............. [mailto:psn-l-request@............... =
On
> Behalf Of J=F3n Fr=EDmann
> Sent: Wednesday, April 15, 2009 4:26 PM
> To: psn-l@..............
> Subject: RE: Changes to my Lehman sensor
>=20
> Hi
>=20
> 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.
>=20
> Regards.
> J=F3n Fr=EDmann.
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> 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 measu=
re
> > how long it takes for the boom displacement to drop by 1/2 after giving=
 it
> a
> > light touch and this would be without damping in place.
> > Gary
> >=20
> >=20
> >=20
> >=20
> > -----Original Message-----
> > From: psn-l-request@.............. [mailto:psn-l-request@...............
]
> On
> > Behalf Of J=F3n Fr=EDmann
> > Sent: Wednesday, April 15, 2009 11:20 AM
> > To: psn-l@..............
> > Subject: RE: Changes to my Lehman sensor
> >=20
> > Hi
> >=20
> > 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 dampe=
r
> > plate is now aluminum, not steel.
> >=20
> > I am not sure how well this works until I get a earthquake close to
> > Iceland or some where in the world.
> >=20
> > Pictures.
> >=20
> > http://www.jonfr.com/myndir/v/geology/seismometer/p4150001b.jpg.html
> >=20
> > Regards.
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