Geoff, I=E2=80=99m glad the links helped. I teach computer science at a =
local college and we have our students use http://portableapps.com/ free =
software suit. It installs on several platforms, provides word =
processing, excel and may other support applications, and also has =
ongoing support and documentation. It even installs on a USB key if you =
want to move between systems.

=20

Regards, Steve Hammond

=20

From: psnlist-request@.............. =
[mailto:psnlist-request@............... On Behalf Of Bob McClure
Sent: Monday, February 06, 2012 10:33 AM
To: psnlist@..............
Subject: Re: Damping Resistor

=20

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

=20

Bob

=20

=20

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

=20














Geoff,
I=E2=80=99m glad the links helped. I teach computer science at a local =
college and we
have our students use http://portableapps.com/ free =
software suit.
It installs on several platforms, provides word processing, excel and =
may other
support applications, and also has ongoing support and documentation. It =
even
installs on a USB key if you want to move between =
systems.

 

Regards, Steve Hammond

 



From:=

psnlist-request@.............. [mailto:psnlist-request@............... =
On
Behalf Of Bob McClure

Sent: Monday, February 06, 2012 10:33 AM

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

Subject: Re: Damping Resistor



 

Go =
to 
http://i=
nsurance.ca.gov/error/free-document-readers.cfm to
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 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-t=
n-03-6.pdf

>

>

>

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

>

>

>

>

>

>

>

> From: psnlist-request@webtronics=
..com
[mailto:psnlist-request@webtronics=
..com]

> 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@SEISMICNET=
..COM
with

the body of the message (first line only): unsubscribe

See http://www.seismicnet.com/maillist.html
for more information.