I'm working on a sketch that I hope will help understand the spring =
terminations.  It is a bit "fiddly" to build, but it was designed in =
such a way that machine tools aren't required.  I should have an update =
in a few days.

My site is in Santa Rosa, CA, a mid sized city north of San Francisco.  =
My noise source are many, the worst (in amplitude) is thermally induced =
baseline drift.  Luckily, this is easily compensated and/or ignored.  =
Next in line is site noise.  I'm only about 40 miles from the Pacific =
Ocean, and whenever there's a storm brewing, I git big "swells" in the =
traces.  This could also be from barometric pressure changes, but I =
doubt it.  I'm also only about 1/2 mile from Highway 101, and even less =
from a very busy main artery.  These pretty much set my noise floor.

Thanks to all for the suggestions on how to publish the schematics.  I'm =
going to try a few of them and see how they work.

Cheers,

    Keith
  ----- Original Message -----=20
  From: ChrisAtUpw@..........
  To: psn-l@.................
  Sent: Tuesday, June 17, 2003 8:05 PM
  Subject: Re: Pictures and drawings of my system


  In a message dated 17/06/03, kpayea@........... writes:=20

  Hello Keith,=20

        Congratulations! It all looks very nice!=20
        I notice that on the schematic drawing you have the two spring =
suspensions vertically above each other, whereas in the apparatus photo, =
the top suspension is closer to the hinge. This last one looks similar =
to the arrangement used in a LaCoste suspension. I wondered if you had =
been able to get significant period lengthening?=20
        "One hint I can give is that the ends of the spring are pulling, =
not pushing"?=20
  But the horizontal hinge foils in the photo look as if they are in =
compression, rather than in extension? I wondered if you had tried the 2 =
thou Stainless Steel foil from KS metals, or 1.5 thou steel shim strip?=20
        You say "the limiting factor in this seismometer is not =
sensitivity, but noise". Is this geological, environmental or electronic =
noise, please?=20
        For circuit diagrams, I usually enter the components on =
QuickCad, save it either as .jpg or .bmp and then use Micrografx Picture =
Publisher to scale or convert to a .gif A4 image. Alternatively, you can =
draw it with symbols on paper and scan it. I use tracing paper over =
graph paper to give an easy hand drawing scale. Can you not print out =
the OrCad images and re scan them?=20

        Regards,=20

        Chris Chapman=20








I'm working on a sketch that I hope =
will help=20
understand the spring terminations.  It is a bit "fiddly" to build, =
but it=20
was designed in such a way that machine tools aren't required.  I =
should=20
have an update in a few days.
 
My site is in Santa Rosa, CA, a mid =
sized city=20
north of San Francisco.  My noise source are many, the worst (in =
amplitude)=20
is thermally induced baseline drift.  Luckily, this is easily =
compensated=20
and/or ignored.  Next in line is site noise.  I'm only about =
40 miles=20
from the Pacific Ocean, and whenever there's a storm brewing, I git big =
"swells"=20
in the traces.  This could also be from barometric pressure =
changes, but I=20
doubt it.  I'm also only about 1/2 mile from Highway 101, and even =
less=20
from a very busy main artery.  These pretty much set my noise=20
floor.
 
Thanks to all for the suggestions on =
how to publish=20
the schematics.  I'm going to try a few of them and see how they=20
work.
 
Cheers,
 
    Keith

  
----- Original Message ----- 
  From:=20
  ChrisAtUpw@....... 
  
To: psn-l@.............. 
  
Sent: Tuesday, June 17, 2003 =
8:05=20
PM
  
Subject: Re: Pictures and =
drawings of my=20
  system
  

In a =
message dated=20
  17/06/03, kpayea@........... =
writes:=20
  

Hello Keith,=20
  

      Congratulations! It all =
looks very=20
  nice! 
      I notice that on the =
schematic=20
  drawing you have the two spring suspensions vertically above each =
other,=20
  whereas in the apparatus photo, the top suspension is closer to the =
hinge.=20
  This last one looks similar to the arrangement used in a LaCoste =
suspension. I=20
  wondered if you had been able to get significant period lengthening?=20
  
      "One hint I can give is that =
the ends=20
  of the spring are pulling, not pushing"? 
But the horizontal hinge =
foils in=20
  the photo look as if they are in compression, rather than in =
extension? I=20
  wondered if you had tried the 2 thou Stainless Steel foil from KS =
metals, or=20
  1.5 thou steel shim strip? 
      You =
say=20
  "the limiting factor in this seismometer is not sensitivity, but =
noise". Is=20
  this geological, environmental or electronic noise, please?=20
  
      For circuit diagrams, I =
usually enter=20
  the components on QuickCad, save it either as .jpg or .bmp and then =
use=20
  Micrografx Picture Publisher to scale or convert to a .gif A4 image.=20
  Alternatively, you can draw it with symbols on paper and scan it. I =
use=20
  tracing paper over graph paper to give an easy hand drawing scale. Can =
you not=20
  print out the OrCad images and re scan them? 

      Regards,=20
  

      Chris Chapman=20