Hi Gang-
We have been using  Mark Products geophones that are 4.5 Hz and 40 Hz
(~$50 each) for geotechnical seismic surveys here at UNLV.  The 40 Hz are
made and even come with a kit to put the spike in a mode so they work
either in the vertical (Z) or  horizontal (H) directions.  The logic is
the Z has such a stiff suspension it can also work in the H.  The 4.5 Hz
definitely do not work in the H as some of the students have found out.

I bought some of the Gateway specials ~ 6 months back and found they were
~28 Hz (usually marked on the case, Res and Freq).  I bought them for
High School demos, and they appeared to work in either direction.  I
suspect they were originally made to be used to detect movement along the
Ho-Chi Min trail in Nam....

The 3 component geophones that Larry sells are one Z and 2 H's and are
4.5 Hz.  They work great for local earthquakes here in NV, but have a
very limited range.  Appreciate Larry's effort in getting these and
passing them on so cheaply.

Other Comments:
Most manufacturers state the Z's are only good to about a 5 deg variation
from the Z.  But it turns are they are better than that; You can test
them by putting two in the Z position in a bucket of sand and then vary
the tilt angle on one, as you tap the bucket.  Also this is called a
cluster test when you put all the phones together, preferably in sand and
see if they all have the same response to a common shaking. The logic use
to be, you could not get the phones close together because  it would
cause cross-talk, but this does not seem to be valid.  Now if your
talking about a 1 or 2 Hz phone none of the above may not be a valid.

Jim


 
..On Wed, 27 Jun 2001 16:26:02 -0700 Casey Crane  writes:
> Hi All,
> 
>         I was wondering if any could tell me if I can use a 
> geophone
> in a horizontal configuration . www.gatewayelex.com has a unit made 
> by
> GEOSOURCE.
> 
> Casey
> ________________________________________________________________
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Hi Gang-
We have been using  Mark Products geophones that=
 are=20
4.5 Hz and 40 Hz (~$50 each) for =
geotechnical=20
seismic surveys here at UNLV.  The 40 Hz are made and=
 even=20
come with a kit to put the spike in a mode so they work either in the =
vertical=20
(Z) or  horizontal (H) directions.  The logic is the Z has such a=
=20
stiff suspension it can also work in the H.  The 4.5 Hz=20
definitely do not work in the H as some of the students have found=20
out.
 
I bought some of the Gateway specials ~ 6 months back=
 and=20
found they were ~28 Hz (usually marked on the case, Res and Freq).  I=
=20
bought them for High School demos, and they appeared to work in either=20
direction.  I suspect they were originally made to be used to detect=20
movement along the Ho-Chi Min trail in Nam....
 
The 3 component geophones that Larry sells are one Z and 2 H's=
 and=20
are 4.5 Hz.  They work great for local earthquakes here in NV=
, but=20
have a very limited range.  Appreciate Larry's effort in =
getting=20
these and passing them on so cheaply.
 
Other Comments:
Most manufacturers state the Z's are only good to about a 5 deg =
variation=20
from the Z.  But it turns are they are better than that; You can test =
them=20
by putting two in the Z position in a bucket of sand and then vary the tilt=
=20
angle on one, as you tap the bucket.  Also this is called a cluster =
test=20
when you put all the phones together, preferably in sand and see if they =
all=20
have the same response to a common shaking. The logic use to be, you could =
not=20
get the phones close together because  it would cause cross-talk, but =
this=20
does not seem to be valid.  Now if your talking about a 1 or 2=
 Hz=20
phone none of the above may not be a valid.<=
/DIV>
 
Jim
 
 
 
.On Wed, 27 Jun 2001 16:26:02 -0700 Casey Crane <ogzax@........> writes:
> Hi=20
All,
> 
>         I was=
=20
wondering if any could tell me if I can use a 
> geophone
> in =
a=20
horizontal configuration . www.gatewayelex.com has a unit =
made=20

> by
> GEOSOURCE.
> 
> Casey
>=20
________________________________________________________________
> =
GET=20
INTERNET ACCESS FROM JUNO!
> Juno offers FREE or PREMIUM Internet =
access=20
for less!
> Join Juno today!  For your FREE software, visit:
=
>=20
http://dl.www.juno.com/get/tagj.
>=20
__________________________________________________________
> 
>=
=20
Public Seismic Network Mailing List (PSN-L)
> 
> To leave this =
list=20
email PSN-L-REQUEST@.............. with=20

> the body of the message (first line only): unsubscribe
> See=
 http://www.seismicnet.com/=
maillist.html=20
for more information.
>