Hi Folks,   I added a heat source, light bulb, to the top area of my =
vault.   I could see at once this was a big big help.   In this pit are =
three sensors, each has a cover of some kind.
Ch 1 is a Lehman 20 seconds, covered with a large Styrofoam box, not air =
tight, just some butt joints and a bit of tape.  ( no noise problems)
Ch 2 is 22 seconds, covered with a large Styrofoam box, not air tight, =
no tape, butt joints.     (big noise problems)  with frequencies of 15 =
to 60 seconds
Ch 3 is a vertical, housed in its own plastic enclosure, fairly tight.  =
(no noise problems) other than the high frequencies stuff, which the =
vertical picks up.

I just added a heat source,inside the pit, did a before and after, FFT =
on all three sensors, and see a big improvement.   Especially on Ch 2, =
not much on the other two.   I can email images.

I know this may not be the only issue, but it made a 100% improvement.

To better explain this let me say the pit 4'x4'x6' lined with blocks.  =
Along the top edge of the pit, I added 4" of insulation batting.   On =
top of that I added 1" ridged Styrofoam panels taped to form a lid.
I added bricks to compress all and form a tighter lid.   The pit is =
under the house in the craw space, 24" from any footing.  The craw space =
seem quiet, I can not feel any air currents, no wind blowing.
No duct work, blowing air.   No temperature changes,  52 degrees for a =
low and 55 for a high, out side pit, less inside the pit.

Obviously, air must be circulating or otherwise influencing into the =
bottom of the pit.   The heat source in layering the air in the pit, and =
minimizing the turbulence.

Any similar observation?  and or advice.

I am surprised because I thought the boxes plus lid, would do the job.   =
Before I rework the boxes, taping, insulating etc.   Perhaps I should =
address the lid and make it thicker, from 1" to 6" batting, and improve =
the lid seal.   Maybe I should do all of it.

I could also leave the heat source, especially if that is the real fix.  =
=20

Merry Christmas,
Ted









Hi Folks,   I added a heat =
source, light=20
bulb, to the top area of my vault.   I could see at once this =
was a=20
big big help.   In this pit are three sensors, each has a =
cover of=20
some kind.
Ch 1 is a Lehman 20 seconds, covered =
with a large=20
Styrofoam box, not air tight, just some butt joints and a bit of =
tape.  (=20
no noise problems)
Ch 2 is 22 seconds, covered with a =
large Styrofoam=20
box, not air tight, no tape, butt =
joints.     (big=20
noise problems)  with frequencies of 15 to 60 seconds
Ch 3 is a vertical, housed in its own =
plastic=20
enclosure, fairly tight.  (no noise problems) other than the high=20
frequencies stuff, which the vertical picks up.
 
I just added a heat source,inside the =
pit, did=20
a before and after, FFT on all three sensors, and see a big=20
improvement.   Especially on Ch 2, not much on the other=20
two.   I can email images.
 
I know this may not be the only issue, =
but it made=20
a 100% improvement.
 
To better explain this let me say the =
pit 4'x4'x6'=20
lined with blocks.  Along the top edge of the pit, I added 4" of =
insulation=20
batting.   On top of that I added 1" ridged Styrofoam panels =
taped to=20
form a lid.
I added bricks to compress all and form =
a tighter=20
lid.   The pit is under the house in the craw space, 24" from =
any=20
footing.  The craw space seem quiet, I can not feel any air =
currents, no=20
wind blowing.
No duct work, blowing air.   =
No=20
temperature changes,  52 degrees for a low and 55 for a high, out =
side pit,=20
less inside the pit.
 
Obviously, air must be circulating or =
otherwise=20
influencing into the bottom of the pit.   The heat source in =
layering=20
the air in the pit, and minimizing the turbulence.
 
Any similar observation?  and or=20
advice.
 
I am surprised because I thought the =
boxes plus=20
lid, would do the job.   Before I rework the boxes, taping, =
insulating=20
etc.   Perhaps I should address the lid and make it thicker, =
from 1"=20
to 6" batting, and improve the lid seal.   Maybe I should do =
all of=20
it.
 
I could also leave the heat source, =
especially if=20
that is the real fix.   
 
Merry Christmas,
Ted