Hi,  I don't hear any 'creeks and groans'  and we have no appliances =
which operate (only) during this 8 to 5 period.
I have all but eliminated wind as a factor.  We do set near the =
mountains, could the sun warming the mountains 6 miles away cause this?
The noise is typical today, a Holiday with very little traffic on our =
streets.  The sun has just gone behind the trees in the west, at 4pm, =
yet the noise continues and will until about 5 pm, if the pattern holds =
and it will.  After that all will get quiet again. =20
Thanks, Ted
  ----- Original Message -----=20
  From: ChrisAtUpw@..........
  To: psn-l@.................
  Sent: Thursday, November 23, 2006 2:39 PM
  Subject: Re: Noise


  In a message dated 2006/11/23, tchannel@.............. writes:


    The sensor, a Lehman, is in my basement. It is on a concrete floor =
next to a concrete wall, and the house above is wood and brick.
    Could this noise be the sun?  At about the time the noise begins the =
sun rises above the trees and shines on the east side of our house, =
which is also the wall near the sensor.


  Hi Ted,

         Next to the concrete wall may not be the best place? General =
advice is to keep sensors away from walls.

         Does the house 'creek and groan' at all during the day? If it =
was direct sun on the house and things moving, I would expect you to be =
able to hear them, at least sometimes, if you try. Maybe run an audio =
tape recorder on high sensitivity in the basement to include one or more =
events? However, I would also expect house noise to be related to wind =
conditions.

         Now you have got the Lehman cosily enclosed in a thermally =
insulated airtight box haven't you?

         What is the construction of the Lehman suspension, top and =
bottom? What detector are you using?=20

         Do you have central heating or electrical appliances which come =
on between 8am and 5 pm? These times do sound suspiciously like work day =
activity of some type, or related to it in some way. Do you get =
increased environmental noise between these times?=20

         Do you have a geophone? I got mysterious thump type signals =
intermittently, of short but varying length, which did not seem to be =
related to anything obvious. I eventually connected an audio amplifier =
and headphones up to one of the geophones - no seismic amplifier. I =
found that I could hear fast traffic on the main road starting at ~1 km. =
The thumps seemed to be directly related to lorries when travelling =
round a bend in the road. When I checked the road, I found a sunken =
drain grating on the inside of the bend. When there was traffic in both =
directions, lorry drivers kept tight to the inside of the bend and ran =
over the recessed grating. I pointed out this traffic hazard to the =
authorities and they replaced the drain cover....

         Regards,








Hi,  I don't hear any 'creeks and=20
groans'  and we have no appliances which operate (only) during this =
8 to 5=20
period.
I have all but eliminated wind as a =
factor. =20
We do set near the mountains, could the sun warming the mountains 6 =
miles away=20
cause this?
The noise is typical today, a Holiday =
with very=20
little traffic on our streets.  The sun has just gone behind the =
trees in=20
the west, at 4pm, yet the noise continues and will until about 5 pm, if =
the=20
pattern holds and it will.  After that all will get quiet =
again. =20

Thanks, Ted

  
----- Original Message ----- 
  From:=20
  ChrisAtUpw@....... 
  
To: psn-l@.............. 
  
Sent: Thursday, November 23, =
2006 2:39=20
  PM
  
Subject: Re: Noise
  

In a=20
  message dated 2006/11/23, tchannel@..............=20
  writes:


  The sensor, a Lehman, is in my basement. It is on a =
concrete=20
    floor next to a concrete wall, and the house above is wood and=20
    brick.
Could this noise be the sun?  At about the =
time the=20
    noise begins the sun rises above the trees and shines on the east =
side of=20
    our house, which is also the wall near the =
sensor.

Hi=20
  Ted,

       Next to the concrete =
wall may=20
  not be the best place? General advice is to keep sensors away from=20
  walls.

       Does the house =
'creek and=20
  groan' at all during the day? If it was direct sun on the house and =
things=20
  moving, I would expect you to be able to hear them, at least =
sometimes, if you=20
  try. Maybe run an audio tape recorder on high sensitivity in the =
basement to=20
  include one or more events? However, I would also expect house noise =
to be=20
  related to wind =
conditions.

       Now=20
  you have got the Lehman cosily enclosed in a thermally insulated =
airtight box=20
  haven't you?

       What is the=20
  construction of the Lehman suspension, top and bottom? What detector =
are you=20
  using? 

       Do you have =
central=20
  heating or electrical appliances which come on between 8am and 5 pm? =
These=20
  times do sound suspiciously like work day activity of some type, or =
related to=20
  it in some way. Do you get increased environmental noise between these =
times?=20
  

       Do you have a geophone? I =
got=20
  mysterious thump type signals intermittently, of short but varying =
length,=20
  which did not seem to be related to anything obvious. I eventually =
connected=20
  an audio amplifier and headphones up to one of the geophones - no =
seismic=20
  amplifier. I found that I could hear fast traffic on the main road =
starting at=20
  ~1 km. The thumps seemed to be directly related to lorries when =
travelling=20
  round a bend in the road. When I checked the road, I found a sunken =
drain=20
  grating on the inside of the bend. When there was traffic in both =
directions,=20
  lorry drivers kept tight to the inside of the bend and ran over the =
recessed=20
  grating. I pointed out this traffic hazard to the authorities and they =

  replaced the drain =
cover....

      =20
  Regards,

       Chris =
Chapman=20