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

Hello Keith,

       Congratulations! It all looks very nice!
       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?
       "One hint I can give is that the ends of the spring are pulling, not 
pushing"?
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?
       You say "the limiting factor in this seismometer is not sensitivity, 
but noise". Is this geological, environmental or electronic noise, please?
       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? 

       Regards,

       Chris Chapman


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



Hello Keith,



       Congratulations! It all looks very=20=
nice!

       I notice that on the schematic draw=
ing you have the two spring suspensions vertically above each other, whereas=
 in the apparatus photo, the top suspension is closer to the hinge. This las=
t one looks similar to the arrangement used in a LaCoste suspension. I wonde=
red if you had been able to get significant period lengthening?

       "One hint I can give is that the en=
ds of the spring are pulling, not pushing"?

But the horizontal hinge foils in the photo look as if they are in compr=
ession, rather than in extension? I wondered if you had tried the 2 thou Sta=
inless Steel foil from KS metals, or 1.5 thou steel shim strip?

       You say "the limiting factor in thi=
s seismometer is not sensitivity, but noise". Is this geological, environmen=
tal or electronic noise, please?

       For circuit diagrams, I usually ent=
er the components on QuickCad, save it either as .jpg or .bmp and then use M=
icrografx Picture Publisher to scale or convert to a .gif A4 image. Alternat=
ively, you can draw it with symbols on paper and scan it. I use tracing pape=
r over graph paper to give an easy hand drawing scale. Can you not print out=
 the OrCad images and re scan them? 



       Regards,



       Chris Chapman