Ah hah. Thanks John. I'm always trying to find a longer period system as I
don't have the time to build one - but would really, really like to. My
system is a vertical 4.5Hz one. 

Kareem

-----Original Message-----
From: John or Jan Lahr [mailto:JohnJan@......... 
Sent: Sunday, August 14, 2005 1:53 PM
To: psn-l@..............
Subject: RE: ebay auction

Hi Kareem,

Without strong filtering to enhance the longer periods, this unit would be
unable to see teleseismic surface waves.  The filter/amplifier that is sold
with the AS1 does manage to pull out larger surface waves.

After a large event, check out the records posted here in near-real time:
http://jclahr.com/science/psn/as1/heli/allas1.php
(Many school stations are not operating during the summer.)

The Sumatra records are posted here:
     http://jclahr.com/science/psn/as1/indonesia04/as1indo.html
and records from a 6.7 in the Cayman Islands here:
     http://jclahr.com/science/psn/as1/heli/cayman.html

Often when a long period instrument picks up clear 20-second surface waves
the AS1 will only see waves in the 12- to 15-second range.

Cheers,
John

At 11:58 AM 8/14/2005, you wrote:
>This particular unit is more suited for local event records, right?
>
>Kareem
>
>-----Original Message-----
>From: John or Jan Lahr [mailto:JohnJan@.........
>Sent: Sunday, August 14, 2005 10:53 AM
>To: psn-l@..............
>Subject: Re: ebay auction
>
>The AS1 works amazingly well for such a simple mechanical system with 
>moving magnet.
>I've posted information here on the system:
>http://jclahr.com/science/psn/as1/
>
>However $150 is quite steep for a used transducer without 
>amplifier/filter/AD unit.
.. 

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