PSN-L Email List Message

Subject: Lehman advantages
From: "tchannel" tchannel@..............
Date: Sun, 24 Jun 2007 09:54:20 -0600


Hi Folks,  I am thinking about building another Lehman style Horz =
Pendulum sensor.  I don't really need to build another,
but I have some construction ideas I wanted to try.  Before I start, =
could you describe the benefits of these points.

1 FIRMLY ATTACHED THE SENSOR THE THE EARTH.   I wish to make the contact =
between the earth, and the sensor as firm as possible, in this case the =
concrete slab setting on the earth and the sensor.   Presently the =
sensor has three feet which just set on the concrete slab. I know some =
people use adhesive to the concrete.  If I found a way to bolt all three =
feet into the concrete, and a new way to make the necessary adjustments, =
what benefits would be derived?
I understand that even the concrete floor floats on the earth.  I am =
just talking about the benefits of a tighter connection between the =
sensor and the floor.

2 A RIDGED VERTICAL SUPPORT FOR THE UPRIGHT.  I know that on a typical =
Lehman the vertical needs to be ridged and minimize the flex between the =
vertical and the horz members.   If I found a way to minimize this flex, =
what benefits might I see?  The one I have has no flex that I can see, =
but If I added addition braces so the vertical was at 90 to the horz =
with the minimum of flex, What benefit would there be?

3 USING A LONGER ARM.  I used  a normal length arm, and I understand if =
space was not an issue a very long 100 meters arm would result in a =
longer period.  I am just asking if space was avail would a 5 foot arm =
result in any benefits, over a 3 foot arm?

The last question is, if I had a sensor which was firmly attached to the =
floor, with a very ridged vertical, and a longer arm.
(with all the other important factors aside) What kind of improvements =
might I expect?  I think I could build a new and improved sensor, =
addressing these three issues.  But would these three issues make much =
different.  If I would, see improvements would they only be for =
teleseimic events, or would the improvements be evident in recording =
regional as well.








Hi Folks,  I am thinking about = building=20 another Lehman style Horz Pendulum sensor.  I don't really need to=20 build another,
but I have some construction ideas I = wanted to=20 try.  Before I start, could you describe the benefits of these=20 points.
 
1 FIRMLY ATTACHED THE SENSOR THE = THE=20 EARTH.   I wish to make the contact between the earth, and the = sensor=20 as firm as possible, in this case the concrete slab setting on the = earth=20 and the sensor.   Presently the sensor has three feet which = just set=20 on the concrete slab. I know some people use adhesive to the = concrete.=20  If I found a way to bolt all three feet into the concrete, and a = new way=20 to make the necessary adjustments, what benefits would be = derived?
I understand that even the concrete = floor floats on=20 the earth.  I am just talking about the benefits of a tighter = connection=20 between the sensor and the floor.
 
2 A RIDGED VERTICAL SUPPORT FOR THE = UPRIGHT. =20 I know that on a typical Lehman the vertical needs to be ridged and = minimize the=20 flex between the vertical and the horz members.   If I found a = way=20 to minimize this flex, what benefits might I see?  The = one I have=20 has no flex that I can see, but If I added addition braces so the = vertical was=20 at 90 to the horz with the minimum of flex, What benefit would there=20 be?
 
3 USING A LONGER ARM.  I = used  a normal=20 length arm, and I understand if space was not an issue a very long 100 = meters=20 arm would result in a longer period.  I am just asking if space was = avail=20 would a 5 foot arm result in any benefits, over a 3 foot = arm?
 
The last question is, if I had a sensor = which was=20 firmly attached to the floor, with a very ridged vertical, and a longer=20 arm.
(with all the other important factors = aside) What=20 kind of improvements might I expect?  I think I could = build a new=20 and improved sensor, addressing these three issues.  But would = these three=20 issues make much different.  If I would, see improvements would = they only=20 be for teleseimic events, or would the improvements be evident in = recording=20 regional as well.
 
Thanks, Ted

[ Top ] [ Back ] [ Home Page ]