Chris and Allen, Thanks for your interest. =20 To answer questions first Chris I am referring to the old Manual of = Seismological Practice Chap 4.5.1. It seems to provide an easy = calibration method using the instrument itself. You made a good call on = the filter section. I had considered maybe a capacitor was leaking = rather than doing its intended function. Because I don't get the step = functions shown in Fig 4.5.1a, I assume a correction can be calculated = to add the decay as a function of time and get the correct result = similar to 4.5.1e with dc being the initial jump in the trace. I hadn't = thought about it but maybe this decay can be used to calculate the = cuttoff frequency for the filter section. Allen, I have reread para 9 and remain confused. It seems to imply any = peaks in the entire train can be chosen as an and an+1. Ar isn't really = defined other than being later than a1 and then there is the " on the = end like a derivative. In my first attempts I have used the first peak = as ar and the next 2 as an and an+1. Other than these points I'm finding it quite easy to set up and have in = fact left everything connected for periodic checks or to check = sensitivity of various magnet configurations. I also believe the walk = up once a day is the best way to see how things are going.=20 I put together a file of my results and posted it at = http://www.santel.net/~randallpratts as testcal at the top of the page. = It will open in Winquake or you can download it first. The first = portion from 0118 to 0125 is boom locked as para 3. Minutes 28 to 34 = are para 6. 36 to 38 I have removed most of the damping to get free = period. From minute 53 to end is the best example for para 9 and is a =Chris and Allen,Thanks for your interest. =To answer questions first Chris I am = referring to=20 the old Manual of Seismological Practice Chap 4.5.1. It seems to = provide=20 an easy calibration method using the instrument itself. You made a = good=20 call on the filter section. I had considered maybe a capacitor was = leaking=20 rather than doing its intended function. Because I don't get the = step=20 functions shown in Fig 4.5.1a, I assume a correction can be calculated = to add=20 the decay as a function of time and get the correct result similar = to=20 4.5.1e with dc being the initial jump in the trace. I hadn't = thought about=20 it but maybe this decay can be used to calculate the cuttoff frequency = for the=20 filter section.Allen, I have reread para 9 and = remain=20 confused. It seems to imply any peaks in the entire train can be = chosen as=20 an and an+1. Ar isn't really defined other than being later than = a1 and=20 then there is the " on the end like a derivative. In my first = attempts I=20 have used the first peak as ar and the next 2 as an and = an+1.Other than these points I'm finding it = quite easy=20 to set up and have in fact left everything connected for periodic checks = or to=20 check sensitivity of various magnet configurations. I also believe = the=20 walk up once a day is the best way to see how things are=20 going.I put together a file of my results and = posted it=20 at http://www.santel.net/~randallpratts as testcal = at the top=20 of the page. It will open in Winquake or you can download it = first. =20 The first portion from 0118 to 0125 is boom locked as para 3. = Minutes 28=20 to 34 are para 6. 36 to 38 I have removed most of the damping = to get=20 free period. From minute 53 to end is the best example for = para 9 and=20 is a connection and disconnect with=20 V=3D346mv.