PSN-L Email List Message

Subject: Re: Counts
From: Barry Lotz barry_lotz@.............
Date: Wed, 29 Apr 2009 19:20:21 -0700 (PDT)


Ted
2 cents:
The late Sean Thomas Morrissey emailed PSN on Nov 13, 1999 with expected se=
ismograph output. He related amplitude,magnitude and distance.Using his dat=
a I plotted distance on the x axis, my vertical sensor count on the y axis =
and had lines for 0.5 magnitude incriments from 3 to 8. It was plotted on a=
 log-log scale.My particular sensor was theoretically 2000v/m/s @ 5 vts=3D3=
2768 cnt. I then plotted individual points for each actual event I recorded=
.. It correlated pretty well. The four corners of my graph were: Clip @ M4.5=
@100km, and M8 @ 14000km. My winter microseism amplitude was about 300 coun=
t. This related to M2.5 @ 100km and M6 @ 14000km. I like the idea of record=
ing at two or more gains simultaneously and after reviewing the data, savin=
g the best.=20

Barry
--- On Wed, 4/29/09, tchannel  wrote:
From: tchannel 
Subject: Counts
To: "psn" 
Date: Wednesday, April 29, 2009, 8:02 AM



=20
=20

Hi Folks,=A0 I have two vertical sensors in=20
test, both using Larry's one channel board and DATAQ adc.=A0=A0 One of the=
=20
boards is set for low gain and one is set for high gain, using the=20
jumper.
=A0
The first earthquake records was the 5.6m in Mexico=20
April 27th.=A0=A0 Not unexpected the counts on the one using high gain was=
=20
10x the one using low gain.=A0=A0 Something like 70 vs 700.
=A0
Both traces looked fine and I could see little=20
different, aside for the counts.=A0=A0 My question is what should my count=
=20
target be?=A0=A0 Someone may have indicated about 100 to 300=A0counts=20
during the quiet of night?
=A0
The reason I ask is I see data files posted with=20
many using higher counts 700 or 800, instead of smaller=20
numbers.=A0=A0=A0 I know the higher gain feature on the board is for=20
lower voltage output.=A0=A0 My coil and magnets are similar to Chris's=20
quad magnet arrangement, and a coil of 4000 turns, so I have plenty of=20
voltage.
=A0
I would like your opinions and why.
=A0
=A0
Ted
2 cents:
The late Sean Thomas Morri= ssey emailed PSN on Nov 13, 1999 with expected seismograph output. He relat= ed amplitude,magnitude and distance.Using his data I plotted distance on th= e x axis, my vertical sensor count on the y axis and had lines for 0.5 magn= itude incriments from 3 to 8. It was plotted on a log-log scale.My particul= ar sensor was theoretically 2000v/m/s @ 5 vts=3D32768 cnt. I then plotted i= ndividual points for each actual event I recorded. It correlated pretty wel= l. The four corners of my graph were: Clip @ M4.5@100km, and M8 @ 14000km. = My winter microseism amplitude was about 300 count. This related to M2.5 @ = 100km and M6 @ 14000km. I like the idea of recording at two or more gains s= imultaneously and after reviewing the data, saving the best.

Barry<= br>--- On Wed, 4/29/09, tchannel <tchannel@............> wrote:
From: tchannel <tchannel@............ t>
Subject: Counts
To: "psn" <psn-l@..............>
Date:= Wednesday, April 29, 2009, 8:02 AM

=20 =20
Hi Folks,  I have two vertical se= nsors in=20 test, both using Larry's one channel board and DATAQ adc.   One o= f the=20 boards is set for low gain and one is set for high gain, using the=20 jumper.
 
The first earthquake records was the 5= ..6m in Mexico=20 April 27th.   Not unexpected the counts on the one using high gai= n was=20 10x the one using low gain.   Something like 70 vs 700.
 
Both traces looked fine and I could se= e little=20 different, aside for the counts.   My question is what should my = count=20 target be?   Someone may have indicated about 100 to 300 cou= nts=20 during the quiet of night?
 
The reason I ask is I see data files p= osted with=20 many using higher counts 700 or 800, instead of smaller=20 numbers.    I know the higher gain feature on the board is f= or=20 lower voltage output.   My coil and magnets are similar to Chris'= s=20 quad magnet arrangement, and a coil of 4000 turns, so I have plenty of=20 voltage.
 
I would like your opinions and why.
 
 
Thanks, Ted

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