Larry-and PSN Members (The Can-Do Folks),

I am in the process of developing seismic systems (as cheap as possible,
so I can get them in as many schools as possible) for Clark County
Schools, here in Las Vegas, which has over 200,00 students.  I am
thinking along the lines of PEPP, but with a much more affordable system.
 

Recording at UNLV:
I recently purchased your Amp/Filter (3 Channels) and the A/D board and
hooked it up to the UNLV, 20 year old, Lehman (E-W) and 3 S-13's (X,Y,Z).
The Lehman went thru your Amp/Filter (set at 2K gain) while the S-13's
went thru a Geotech amplifier of 1K gain, and all 4 were recorded on a
Gateway PC (8Mb Ram & 400Mb HD) at 50 sps.  I was able to record the
Scotty Castle sequence (M=5.7, 8/1/99), was I impressed, even the Event
Detector worked!  Now, all channels went off scale on the Main Shock, it
appeared either the Amp or A/D clipped on the Lehman, while it appeared
the S-13 seismometer, it self, was saturated, as the recording was very
peculiar looking, not the normal clipping.  We were 250 Km's away from
the epicenter.  The Lehman also has a 10hz oscillation which is small on
the seismogram and comes out as a spike on the spexa. 
Question 1.  Is it likely the S-13 seismometer itself would get saturated
from this Eq ?
Question 1a.  How do I tell rather the Amp or A/D board clipped?
Question 1b.  Does the Lehman have another resonant frequency at 10 HZ? 

 Geophone Testing (L-4):
 I live about 5 Km's from a recent M=2.5, May 6, which I felt.  UNR has
two sites 30 Km's and 50 Km's away in opposite directions from Boulder
City, (BC), (BC is 30km's South-East of Las Vegas), UNR recorded the
M=2.5, but they need a third site to get a better location.  I hope to be
that third site to pin down these small shocks which go unnoticed on
their Network, here in BC.  I just started testing 3 L4's, 2 H & 1 Z,
here at my house in Boulder City, NV . I have them on my patio with 100'
of coaxial cable which came with the sensors.  I borrowed them from UNLV
to determine if they would be good for detecting local EQ's. I put their
output directly into a DataQ  A/D board, (DI-194, 16 bit, 4 channel, 10V
FS, sells for $100)  thru the 100' cable, which hooks up externally to my
PC( HP 96 Mb Ram & 4 GB HD) thru the Com1 port.  I obviously need a
preamplifier as I don't even see road traffic, they do slightly  pick me
up when I walk by. 
Question 2.  What is the L-4 output?
Question 3.  Can I use your Amp/Filt board as a Pre-amp? and do I need to
place it very close to the L4 seismometer to keep a short input cable? 
Question 4. Should your  Filter board setting be something like 0.5 to 30
Hz for the L4.
Question 5.  I have a program, Atomic Clock, which calls Boulder or Fort
Collins, CO to reset my PC clock.  I am wondering if that is
satisfactory, as my main interest is just S-P values, to locate local
Eq's. 

At the present time I have the Lehman, 3 S-13's and 2 Z  L-4's recording
at UNLV using your Amp/filter board on the Lehman and L-4's.  I believe
you set two of the channels to 20 hz for the Geophones and 10 hz for the
Lehman. 

I am ready to order another Amp/Filter board unless someone can suggest a
cheaper pre-amp.....for the L-4's.

Jim O'Donnell
Retired Geophysicist

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