You may find your info at:
http://www.jclahr.com/science/psn/roberts/index.html

Regards,

Jerry

 

From: Edward Ianni [mailto:edwianni1@............ 
Sent: Monday, September 17, 2012 5:52 AM
To: psnlist@..............
Subject: Re: Old hobby resurgence

 

Hi Chris;
      I see that you are still giving out great information and advice.
Could you possibly " point" me to the schematic of the serial AS-1 period
"extender". As I recall I built the Roberts circuit years ago with limited
success. I'm pretty sure I did not get the component values correct. I will
try the Roberts circuit again after I try the AS1 "electronics". I searched
for the AS1 schematic/detail but only found very general info on it. I
haven't "played" with this "stuff" for years but I feel a very strong
resurgence of interest in Seismology since I started this project again.
Thanks, Ed.



On 9/17/2012 5:22 AM, chrisatupw@....... wrote:

Edward Ianni   
To: psnlist   
Sent: Mon, 17 Sep 2012 0:53
Subject: Old hobby resurgence

Hi all:           

I have two very old seismometers and I would like to extend their "periods",
electronically and EXTERNALLY if that is possible. I tried this a long time
ago but I am not heavy into electronics and could not come up with the right
values for some of the circuits that I looked at. The two Seismometers are a
Kinemetric SH1 "Intermediate"(about 5 second period), and a Sprengnether
(square box type) with a 1.5 second period. Is it possible to do this easily
and is there a circuit somewhere with relatively simple instructions for
calculating component values? Thank You. Ed.

 

Hi Ed, 

    The short answer is Yes ! 

    You can extend the period of a seismometer electronically by about x10
with two stages of the parallel Robert's circuit, or you can use the simpler
serial type used in the AS-1. So the Sprengnether could easily go out to 15
seconds and bring in the surface waves fairly respectably. I suggest that
you extend the SH1 only to about 25/30 seconds and this is a bit more
difficult since you may have to suppress 1/f noise. You have the problem
with requiring a 1/f^2 amplifier characteristic and this gain has to go to
periods beyond what you require and the excess 1/f noise has to be filtered
out.

Regards, 

Chris Chapman

 

You may find your info =
at:  http://www.=
jclahr.com/science/psn/roberts/index.html
Regards,
Jerry
 
From: Edward Ianni [mailto:edwianni1@............ 
Sent: =
Monday, September 17, 2012 5:52 AM
To: =
psnlist@..............
Subject: Re: Old hobby =
resurgence
 
Hi =
Chris;
      I see that you are still giving =
out great information and advice. Could you possibly " point" =
me to the schematic of the serial AS-1 period "extender". As I =
recall I built the Roberts circuit years ago with limited success. I'm =
pretty sure I did not get the component values correct. I will try the =
Roberts circuit again after I try the AS1 "electronics". I =
searched for the AS1 schematic/detail but only found very general info =
on it. I haven't "played" with this "stuff" for =
years but I feel a very strong resurgence of interest in Seismology =
since I started this project again.  Thanks, Ed.



On =
9/17/2012 5:22 AM, chrisatupw@....... =
wrote:
Edward Ianni =
<edwianni1@...........>To: psnlist <psnlist@..............>=

Sent: Mon, 17 Sep 2012 0:53
Subject: Old hobby =
resurgence
Hi all: =
          
I have two very old seismometers and I would =
like to extend their "periods", electronically and EXTERNALLY =
if that is possible. I tried this a long time ago but I am not heavy =
into electronics and could not come up with the right values for some of =
the circuits that I looked at. The two Seismometers are a Kinemetric SH1 =
"Intermediate"(about 5 second period), and a Sprengnether =
(square box type) with a 1.5 second period. Is it possible to do this =
easily and is there a circuit somewhere with relatively simple =
instructions for calculating component values? Thank You. =
Ed.
 
Hi Ed, 
    The short answer is Yes ! =
    You can extend the =
period of a seismometer electronically by about x10 with two stages of =
the parallel Robert's circuit, or you can use the simpler serial type =
used in the AS-1. So the Sprengnether could easily go out to 15 seconds =
and bring in the surface waves fairly respectably. I suggest that you =
extend the SH1 only to about 25/30 seconds and this is a bit more =
difficult since you may have to suppress 1/f noise. You have the problem =
with requiring a 1/f^2 amplifier characteristic and this gain has to go =
to periods beyond what you require and the excess 1/f noise has to be =
filtered out.
Regards, 
Chris Chapman

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