Hi All,    Two new questions from me today.

On the Folded Pendulum, which is now being tweaked and tested, there is =
a balance rod contains three weights or masses.
Large, medium and small.   After some minor adjustments I can change the =
period.  From maybe 2,  to maybe 10 seconds.
I am still working on how to make the longer, but for now I can set it =
where I want.

My verticals record more and smaller earthquakes.  To me there is some =
advantage to these shorter periods, but I am aware of the advantages of =
the longer periods as well.  On the verticals I often pick up 5+ that I =
don't pick up with the Lehman or Folded, as they are set for the longer =
period.   However when I record  a 7M like today the signal goes on for =
2 and sometimes 3 hours, because of the longer period, where the =
vertical will record much less, maybe 30 mins.

My question is where should I set the period for the best overall =
results?   Or is it just a personal preference?

My second question has to do with testing the resistance or friction of =
various hinges.
I have seen razor blades, roller on roller , wires, figure 8 wires, foil =
and so on.....Has anyone tested or qualified the different using one or =
more of these methods?

I did a simple test, using various hinges, foil, wire, razor blades and =
eyebolts.   I could and did see some difference in how long a pendulum =
would swing free.  I just moved the pendulum 6" and let it go counted =
the cycles until it stopped.
Not very accurate, but I could see only about 20 percent different, =
between what I would call good and better hinges.
I am not suggesting this test tell the whole story.   So if there is a =
study I would like to see it or hear about your own testing.   I was =
surprised there was not a greater different on my test.








Hi All,    Two new =
questions from me=20
today.
 
On the Folded Pendulum, which is now =
being tweaked=20
and tested, there is a balance rod contains three weights or=20
masses.
Large, medium and small.   =
After some=20
minor adjustments I can change the period.  From maybe 2,  to =
maybe 10=20
seconds.
I am still working on how to make the =
longer, but=20
for now I can set it where I want.
 
My verticals record more and smaller=20
earthquakes.  To me there is some advantage to these shorter =
periods, but I=20
am aware of the advantages of the longer periods as well.  On the =
verticals=20
I often pick up 5+ that I don't pick up with the Lehman or =
Folded, as they=20
are set for the longer period.   However when I record  a =
7M like=20
today the signal goes on for 2 and sometimes 3 hours, because of the =
longer=20
period, where the vertical will record much less, maybe 30 =
mins.
 
My question is where should I set the =
period for=20
the best overall results?   Or is it just a personal=20
preference?
 
My second question has to do with =
testing the=20
resistance or friction of various hinges.
I have seen razor blades, roller on =
roller , wires,=20
figure 8 wires, foil and so on.....Has anyone tested or qualified the =
different=20
using one or more of these methods?
 
I did a simple test, using various =
hinges, foil,=20
wire, razor blades and eyebolts.   I could and did see some =
difference=20
in how long a pendulum would swing free.  I just moved the pendulum =
6" and=20
let it go counted the cycles until it stopped.
Not very accurate, but I could see only =
about 20=20
percent different, between what I would call good and better=20
hinges.
I am not suggesting this test tell the =
whole=20
story.   So if there is a study I would like to see it or hear =
about=20
your own testing.   I was surprised there was not a greater =
different=20
on my test.
 
Thanks, Ted