Hi George,

T think you got my name mixed up. 

Anyhow, I need thebig plug in the center. It should be a big knurled knob=
 with an O-ringand maybe a bubble level in it. This is the one that repla=
ces the long shipping plug which locks the mass. I have all the other plu=
gs (the two 1/2" ones).

As far as using the BB-13 for earth tides, I think it's possible but I al=
so think you'd have to have a very high quality seismic vault. My BB-13 i=
s inside an aluminum foil covered blue-board insulation box about 4" thic=
k all around and it still tends to drift, from either temperature or pres=
sure changes. The manual stresses airtight operation and that's why I'm l=
ooking for the original center plug with the O-ring.....to try and elimin=
ate atmospheric pressure changes.

If I cannot find a plug to copy, I may take Chris Chapman's advice and us=
e a rubber stopper with vacuum grease or some other air-tight scheme.

Thanks,

Bob Hammond
PSN-Alaska


Subject: Re: Looking for Teledyne Geotech BB-13 plug to copy
From: George Bush ke6pxp@....... 
Date: Fri, 20 Mar 2009 08:42:53 -0700

Hi Ted-


I have a BB-13 that is complete with manual I and have a plug on mine. It=

has standard NF 1/2"-20tpi threads and should be avilable from any
hardwre or auto supply store. Of course, the one that comes on it is a
really nice one with a knurled top, but a commercial bolt with an O-ring
on it should seal until you can get something better. You would need to
get the shortest bolt you could as the plug is 3/8" long (from face of
head to end) and that includes a 1/8" captive groove for the O-ring and
1/4" of threads. 


I would love to talk to you about your instrument and mine. I have been
fiddling with the filtering to detect earthquakes, and have wondered if I=

could use it to detct earth tides, I understand that the output goes down=

to DC. I built box of hard foam-core insulation around the istrument and
it has really helped with temperature control and has minimized
re-adjusting it.


Hope this helps- George

Hi George,

T think you got my nam=
e mixed up.  

Anyhow, I need the
big plug in the center.  It should be a big knurled knob with an O-r=
ing
and maybe a bubble level in it.  This is the one that replaces the l=
ong shipping plug which locks the mass.  I have all the other plugs =
(the two 1/2" ones).

As far as using the BB-13 for earth tides, I =
think it's possible but I also think you'd have to have a very high quali=
ty seismic vault.  My BB-13 is inside an aluminum foil covered blue-=
board insulation box about 4" thick all around and it still tends to drif=
t, from either temperature or pressure changes.  The manual stresses=
 airtight operation and that's why I'm looking for the original center pl=
ug with the O-ring.....to try and eliminate atmospheric pressure changes.=


If I cannot find a plug to copy, I may take Chris Chapman's advic=
e and use a rubber stopper with vacuum grease or some other air-tight sch=
eme.

Thanks,

Bob Hammond
PSN-Alaska



Subject: Re: Looking for Teledyne Geotech BB-13 plug to copy
From=
: George Bush  ke6pxp@....... 
Date: Fri, 20 Mar 2009 08:42:53 -0700
Hi Ted-


I have a BB-13 that is complete with manual I an=
d have a plug on mine. It
has standard NF 1/2"-20tpi threads and shoul=
d be avilable from any
hardwre or auto supply store. Of course, the on=
e that comes on it is a
really nice one with a knurled top, but a comm=
ercial bolt with an O-ring
on it should seal until you can get somethi=
ng better. You would need to
get the shortest bolt you could as the pl=
ug is 3/8" long (from face of
head to end) and that includes a 1/8" ca=
ptive groove for the O-ring and
1/4" of threads. 


I would l=
ove to talk to you about your instrument and mine. I have been
fiddlin=
g with the filtering to detect earthquakes, and have wondered if I
cou=
ld use it to detct earth tides, I understand that the output goes downto DC. I built box of hard foam-core insulation around the istrument and=

it has really helped with temperature control and has minimized
re=
-adjusting it.


Hope this helps- George