Hi Chris, You know these are great suggestions....I can't rotate the =
sensor, where it is located, but if I could???????
I do have another sensor I could set up and rotate.  I could perhaps =
setup a microphone/ amp/ headset, to see if I could pick up the noise =
and then isolate its direction.  I tried the am radio but could not hear =
the noise, I will try that again, at different frequencies.   Ted
    ----- Original Message -----=20
  From: ChrisAtUpw@..........
  To: psn-l@.................
  Sent: Thursday, November 30, 2006 4:21 PM
  Subject: Re: Noise


  In a message dated 2006/11/30, tchannel@.............. writes:


    Hi Jim,  At night time the noise stops as suddenly as it begins, I =
think it stops at around 4:30pm, starts at 8:35 to 8:50am.  Really quiet =
at night,
    I live 1/4 mile from a school, and crossing lights, but the noise =
continues during Sat, Sun and Holidays when the school is inactive.
    I did remove the magnet during the noise, and the trace was dead =
quite, all the noise stopped and started again when I replaced the =
magnet over the coil, so I don't think it is RFI.=20


  Hi Ted,

         OK. Can you identify any 'typical sequence' types of signal?  =
Can you log the ~amplitudes?

         Now you have evidence that the noise isn't RFI or pickup from =
the house wiring, can you re-orient your sensor, say 20 degrees at a =
time at first, to determine the direction that it is coming from? If it =
is an external fixed source, there should be a direction which gives a =
minimum response.

         It can be quite difficult to identify a source just from a =
seismic trace. If it is a local source, there are likely to be a lot of =
associated high frequency signals. Do you have a geophone, or a piezo =
accelerometer, which you can use as a sensor to drive an audio amplifier =
/ headphone system? Sounds carry quite a long way in the soil. I can =
pick up car tyre noise on the main road at about 1 km. This could help =
to direct your search.

         Regards,








Hi Chris, You know these are great =
suggestions....I=20
can't rotate the sensor, where it is located, but if I =
could???????
I do have another sensor I could set up =
and=20
rotate.  I could perhaps setup a microphone/ amp/ headset, to see =
if I=20
could pick up the noise and then isolate its direction.  I tried =
the am=20
radio but could not hear the noise, I will try that again, at different=20
frequencies.   Ted

  
  ----- Original Message ----- =

  From:=20
  ChrisAtUpw@....... 
  
To: psn-l@.............. 
  
Sent: Thursday, November 30, =
2006 4:21=20
  PM
  
Subject: Re: Noise
  

In a=20
  message dated 2006/11/30, tchannel@..............=20
  writes:


  Hi Jim,  At night time the noise stops as suddenly =
as it=20
    begins, I think it stops at around 4:30pm, starts at 8:35 to =
8:50am. =20
    Really quiet at night,
I live 1/4 mile from a school, and crossing lights, =
but the=20
    noise continues during Sat, Sun and Holidays when the school is=20
    inactive.
I did remove the magnet during the noise, and the =
trace was=20
    dead quite, all the noise stopped and started again when I replaced =
the=20
    magnet over the coil, so I don't think it is RFI. 

Hi=20
  Ted,

       OK. Can you identify =
any=20
  'typical sequence' types of signal?  Can you log the=20
  ~amplitudes?

       Now you have =
evidence=20
  that the noise isn't RFI or pickup from the house wiring, can you =
re-orient=20
  your sensor, say 20 degrees at a time at first, to determine the =
direction=20
  that it is coming from? If it is an external fixed source, there =
should be a=20
  direction which gives a minimum=20
  response.

       It can be quite=20
  difficult to identify a source just from a seismic trace. If it is a =
local=20
  source, there are likely to be a lot of associated high frequency =
signals. Do=20
  you have a geophone, or a piezo accelerometer, which you can use as a =
sensor=20
  to drive an audio amplifier / headphone system? Sounds carry quite a =
long way=20
  in the soil. I can pick up car tyre noise on the main road at about 1 =
km. This=20
  could help to direct your =
search.

      =20
  Regards,

       Chris =
Chapman=20