Larry, in response to your message sent to Charles about the stability of
the Lehman detector. In support of the stability of the Lehman or
modified lehman detector , here is what i do. I have one detector set up
at approximately 20 stable seconds and it has been running for over two
years .It is housed in a 8'x8' utility building on a concrete slab. It
requires only a minimum of adjustments. I have another modified Lehman
detector set up on a concrete slab in a bigger storage building that is
run at over 30 stable seconds with a minimum and acceptable amount of
adjustments . This detector has both upper and lower ball bearing pivot
points . If the Lehman detector is constructed on a good solid base and
is set up in a fair location then, it will have acceptable stability. As
a rule , i do not post to PSN the data from these detectors but from time
to time i do post from experimental detectors . I know of more than a few
amateur seismologist that are using the Lehman or modified Lehman and are
posting to PSN on a regular basis. JC  PS, Larry , you of all people
should know better than to try to set up and run a seismic detector on a
wood floor. Take care .JOHN

________________________________________________________________
Sign Up for Juno Platinum Internet Access Today
Only $9.95 per month!
Visit www.juno.com
__________________________________________________________

Public Seismic Network Mailing List (PSN-L)