Thanks Angel, but I don't see exactly which part you are showing me. I was looking for information on a "McComb-Romberg seismometer", not a gravity meter. Thanks anyway. I get Sooooo frustrated trying to research online and just get dead-ended by sites that want payment or membership which I would not qualify. HOW is one to learn? Regards, Jerry ----- Original Message ----- From: Angel To: Jerry Payton Sent: Sunday, March 23, 2008 12:08 PM Subject: Re[2]: Channel, 1,2 and 3? Hello Jerry, Maybe this? http://www.physics.uq.edu.au/physics_museum/geophysics.html ar Sunday, March 23, 2008, 4:30:11 PM, you wrote: > Ahhhhh. A new term (at least to me). I get the usual dead-end by Googling for "McComb-Romberg seismometer." It always directs me to sites where you have to be a member or pay for a copy. Chris. do you know of a link showing this type of device? Thanks, Jerry ----- Original Message ----- From: ChrisAtUpw@....... To: psn-l@.............. Sent: Sunday, March 23, 2008 11:20 AM Subject: Re: Channel, 1,2 and 3? In a message dated 23/03/2008, johnjan@........ writes: My understanding of a long period physical pendulum is that sensitivity to ground motion is sacrificed in order to obtain the long period. Hi Ted, That is NOT my understanding in general. But you are using a nearly balanced pendulum, with a high moment of inertia but a small C of G to suspension distance, correct? This type have a long period but a LOUSY sensitivity to linear ground motion. They are however, sensitive to ground rotation. Longer period pendulums like the Lehman and the Romberg are very sensitive to linear ground motion and make good seismometers. Regards, Chris Chapman -- Best regards, Angel Thanks Angel, but I don't = see exactly=20 which part you are showing me. I was looking for information on a=20 "McComb-Romberg seismometer", not a gravity meter. Thanks=20 anyway.I get Sooooo frustrated = trying to=20 research online and just get dead-ended by sites that want payment or = membership=20 which I would not qualify. HOW is one to learn?Regards,Jerry----- Original Message -----=20From: AngelTo: Jerry PaytonSent: Sunday, March 23, 2008 12:08 PMSubject: Re[2]: Channel, 1,2 and 3?Hello Jerry,
Maybe this?
http= ://www.physics.uq.edu.au/physics_museum/geophysics.html
ar
Sunday, March 23, 2008, 4:30:11 PM, you wrote:
>
Ahhhhh. A new term (at least to me). = I=20 get the usual dead-end by Googling for "McComb-Romberg = seismometer."=20 It always directs me to sites where you have to be a member = or pay=20 for a copy.
Chris. do you know of a link showing this = type of=20 device?
Thanks,
Jerry
----- Original Message = -----
From: ChrisAtUpw@.......
Sent: Sunday, March=20 23, 2008 11:20 AM
Subject: Re: Channel,=20 1,2 and 3?
In a message dated = 23/03/2008, johnjan@........ writes:
My understanding of a long period physical = pendulum=20 is that sensitivity to ground motion is sacrificed in order to = obtain the=20 long period.
Hi Ted,
That is NOT my understanding = in=20 general.
But you are using a nearly = balanced=20 pendulum, with a high moment of inertia but a small C of G to = suspension=20 distance, correct? This type have a long period but = a LOUSY sensitivity = to linear=20 ground motion. They are however, sensitive to ground=20 rotation.
Longer period pendulums like = the Lehman=20 and the Romberg are very sensitive to linear ground motion and = make good=20 seismometers.
Regards,
Chris=20 Chapman
--
Best regards,
Angel