Go to  http://insurance.ca.gov/error/free-document-readers.cfm to download
free reader software.

Bob



On Mon, Feb 6, 2012 at 1:18 PM, Geoffrey  wrote:

>
> The trouble with these government pubs is that
> I do not have a decent reader for their
> file types.
> I will never understand why they don't use rich text files
> or simply html or plain 7 bit text.
> Something more universal than a snobby DOC file
> which takes too much space on your machine
> or cost too much money for the software to read it.
> I do not like to MS stuff because they are too
> involved when it comes to installing the software.
> They almost always use special software
> to make their documents.
> I guess Ill stop crying now.
>
> Regards,
> geoff
>
>
> On 2/6/2012 5:39 AM, Stephen Hammond wrote:
> > Hi Geoff, I get the impression you are looking for a simple answer to a
> > complex problem. Here is a simple answer: I use three HS10 geophones on
> my
> > system and based on word of mouth input I received from a USGS tech in
> 1990
> > he told me to start with two  500 ohm resisters in a t-pad arrangement
> just
> > to get started and work up until I got the output I desired. That said,
> > Chris is right-- you will need the specs from the manufacture if you
> want to
> > setup your geophones with any kind of precision . Here are two links,
> one to
> > a USGS report describing setting the damping values for the S and T
> > resisters in a t-pad style damping  (one resister across the coil output
> and
> > one resister in series between the coil output and one of the inputs to
> the
> > filter/amp).  Here is a link to a USGS paper and calibration results for
> > their sensors. http://geopubs.wr.usgs.gov/open-file/of99-434/
> >
> > Here is the link to the Stanford Geo lab calibration procedure for the
> L4C
> > geophone.
> http://www-ssrl.slac.stanford.edu/lcls/technotes/lcls-tn-03-6.pdf
> >
> >
> >
> > I hope this helps, Regards Steve Hammond PSN San Jose, Aptos, CA.
> >
> >
> >
> >
> >
> >
> >
> > From: psnlist-request@.............. [mailto:
> psnlist-request@...............
> > On Behalf Of chrisatupw@.......
> > Sent: Sunday, February 05, 2012 4:42 PM
> > To: psnlist@..............
> > Subject: Re: Damping Resistor
> >
> >
> >
> > Subject: Damping Resistor
> >
> > Is anyone able to comment on this expression
> > to get a value for the damping resistor ?
> > .
> > Hi Geoff,
> >     Most geophones use a copper coil former, which also forms part of
> > the mass. Since this is moving in the magnetic field, damping currents
> > are induced in it, giving maybe 0.4 critical damping. I think that your
> > formula relates to a system with no inherent damping. The manufacturers
> > supply response curves for a range of damping resistors.
> >     Regards,
> >     Chris
> >
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSNLIST)
>
> To leave this list email PSNLIST-REQUEST@.............. with
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>
Go to=C2=A0
http://=
insurance.ca.gov/error/free-document-readers.cfm=C2=A0to download free =
reader software.

Bob





On Mon, Feb 6, 2012 at=
 1:18 PM, Geoffrey <gmvoeth@...........> wrote:




The trouble with these government pubs is that

I do not have a decent reader for their

file types.

I will never understand why they don't use rich text files

or simply html or plain 7 bit text.

Something more universal than a snobby DOC file

which takes too much space on your machine

or cost too much money for the software to read it.

I do not like to MS stuff because they are too

involved when it comes to installing the software.

They almost always use special software

to make their documents.

I guess Ill stop crying now.



Regards,

geoff





On 2/6/2012 5:39 AM, Stephen Hammond wrote:

> Hi Geoff, I get the impression you are looking for a simple answer to =
a

> complex problem. Here is a simple answer: I use three HS10 geophones o=
n my

> system and based on word of mouth input I received from a USGS tech in=
 1990

> he told me to start with two =C2=A0500 ohm resisters in a t-pad arrang=
ement just

> to get started and work up until I got the output I desired. That said=
,

> Chris is right-- you will need the specs from the manufacture if you w=
ant to

> setup your geophones with any kind of precision . Here are two links, =
one to

> a USGS report describing setting the damping values for the S and T
> resisters in a t-pad style damping =C2=A0(one resister across the coil=
 output and

> one resister in series between the coil output and one of the inputs t=
o the

> filter/amp). =C2=A0Here is a link to a USGS paper and calibration resu=
lts for

> their sensors. http://geopubs.wr.usgs.gov/open-file/of99-434/
>

> Here is the link to the Stanford Geo lab calibration procedure for the=
 L4C

> geophone. http://www-ssrl.slac.stanford.edu/lcls/=
technotes/lcls-tn-03-6.pdf

>

>

>

> I hope this helps, Regards Steve Hammond PSN San Jose, Aptos, CA.

>

>

>

>

>

>

>

> From: psnlist-reques=
t@.............. [mailto:psnlist-request@..............]

> On Behalf Of chrisatupw@.......<=
/a>

> Sent: Sunday, February 05, 2012 4:42 PM

> To: psnlist@..............

> Subject: Re: Damping Resistor

>

>

>

> Subject: Damping Resistor

>

> Is anyone able to comment on this expression

> to get a value for the damping resistor ?

> .

> Hi Geoff,

> =C2=A0 =C2=A0 Most geophones use a copper coil former, which also form=
s part of

> the mass. Since this is moving in the magnetic field, damping currents=


> are induced in it, giving maybe 0.4 critical damping. I think that you=
r

> formula relates to a system with no inherent damping. The manufacturer=
s

> supply response curves for a range of damping resistors.

> =C2=A0 =C2=A0 Regards,

> =C2=A0 =C2=A0 Chris

>



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To leave this list email =
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