Hello Rick,

Water departments have a rather simple device used to precisely locate
leaks before digging up a street.  I think they also call it a geo-phone.
It worked very well the only time that I used one.  Configuration was like
a giant stethoscope.  Didn't appear to have any electronics.

Bob

>Rick,
>
>I'm not sure if a geophone would be good for this type of thing,
>maybe....I'm CCing the PSN mailing list. Maybe someone on the list has some
>ideas for you.
>
>PSN'ers, please CC Rick at seadog@....... since he is not on the list.
>
>-Larry Cochrane
>Redwood City, PSN
>
>
>----- Original Message -----
>From: "Rick Howard" 
>To: 
>Sent: Sunday, August 12, 2001 12:43 AM
>Subject: geophone for urban search work
>
>
>> Larry,
>>
>> Please advise whether you feel a geophone like the Mark
>> Products L10B you have for sale might prove useful as
>> a device to detect a person tapping on a collapsed structure
>> when buried under rubble.
>>
>> I'm a Technical Search Specialist for one of the FEMA
>> Urban Search & Rescue Task Forces, and we use a
>> sophisticated device (http://www.delsar.com) as a person
>> locator, but this equipment is expensive and limited as
>> far as access for training.  How might a geophone work as
>> as a detector if someone was tapping on a structure (pipe,
>> concrete, etc) 20-100 feet away?  The general frequency
>> range the Delsar unit calls for is 1-3000 Hz.  I'd love
>> to buy a geophone to experiment with.  I can solder circuits
>> pretty well, if you can recommend a circuit to go with it.
>>
>> Any advice would be appreciated.  I serve in search and
>> rescue as a volunteer; you'll incur no liability in
>> giving me your recommendation - I'm just looking to
>> experiment with other available, cheaper tools in a
>> quest to do my search job better.
>>
>> Thanks -
>>
>> Rick Howard
>> Tech Search Specialist
>> California Task Force 3, Menlo Park

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--- http://www.earthquakewarning.org ---


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