PSN-L Email List Message

Subject: Re: Teledyne Geotech BB13 Seismometer
From: Gary Thurmond w6str@.......
Date: Mon, 26 May 2003 21:15:25 -0700


"I have had an interest in setting up a seismograph for some time."

Likewise here Frank.

I was thinking about which system to build first when I found a BB-13.
It is a beautifully crafted  instrument.
The manual I have for it is dated "Revised 12 February 1990".
So far with a quick look I have not found a difference in the one you and Larry
posted.
I'll check again and see if there is anything different.

I was fortunate to find a problem with my BB-13 before operating it.
It arrived setup in the horizontal configuration.
The manual states do not ship it in the horizontal configuration. So this was a
concern!
However there is a modification in this BB-13 not described in the manual that
allows safe shipping in the horizontal configuration.
After the change over to vertical configuration I noticed there was a
stickyness to the vertical oscillation when perturbed.
That turned out to be some rusty iron particles rubbing between the coil and
the magnet poles.
Some disassembly and cleaning with toothpicks warped with Scotch Tape removed
the particles. There was only minor visible damage to the coil.
No cut or shorted turns.

A photo of the BB-13 with Can Removed -
http://www.mcn.org/m/w6str/bb-13.html

Gary Thurmond, W6STR


Frank Gentges KØBRA wrote:

> Hi,
>
> I have had an interest in setting up a seismograph for some time.  That
> interest was suddenly fired into full force when I happened upon a Teledyne
> Geotech BB13 broadband sensor on a hamfest swap table several weeks ago. I
> am now working on a seismograph setup in my spare time.
>
> I contacted Geotech (who is now free of the Teledyne connection) for a
> manual.  After some searching effort they provided me with a manual.  They
> indicated the unit is obsolete and this may be the last manual they
> have.  Geotech was kind enough to give me permission to post my scan of the
> manual to the internet for public access.
>
> Larry Cochrane agreed to post my file to the Redwood City Public Seismic
> Network web page at
>
> 
>
> For download.
>
> The manual includes a lot of advice on setting the unit up and detailed
> schematics of the mechanical structure and electronics.  Even if you do not
> have one of these you may find it instructive on the operation, design and
> construction of the unit.
>
> I have a nice high speed commercial scanner and I can scan other such
> documents for public use by the group.  We will need to obtain permissions
> to avoid putting Larry in an uncomfortable (or worse) position.
>
> Enjoy,
>
> Frank
>
> Frank Gentges KØBRA
> 
> LF web site at 
>
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