In a message dated 13/08/2005, dwieck@............ writes:

>     Is it a timber house or one with brick/stone  walls?
Its brick
> How many stories?
2
>      Are they the 4.5 Hz geophones?
yes
Hi Dennis,
 
    I would be optimistic about an underfloor location.  Just keep away from 
the water supply and waste water pipes and from the  foundations. Suggest that 
you try it out as your first option?

The good  news is I am 200 yards from the nearest road (except for what 
comes in my  driveway)
    That will probably be fine. 

> I  connected my geophones up to the amplifier in a portable radio and 
>  listened with headphones. OK, these signals aren't the seismic ones, 
>  but you can often recognise noise sources by ear easier than trying to  
> figure them out from the traces. I start to hear fast cars on the  main 
> road at about 1 km. There is a slightly depressed water drain on  the 
> main road about 100 yards away which gives thump signals  occasionally 
> with passing lorries..... Check for slamming doors and  windows, fridge 
> start/stop, cooking loads, central heating timing,  wind noise.....
    Do 'have a listen', see what you can pick up and  also take a seismic 
recording to find any associated signals. 

>     Trees may give broad band noise, but this  may be more serious for 
> the longer period instruments. Aim to keep  your sensors at a distance 
> equal to the height of the trees, minimum.  

This is about impossible on my lot. Even the under the house spot  would 
not meet this but would probably be the closest.
>     You have the problem of long cable runs and  probably 
> some lightning protection required for installations away from  the house.
>> I am used to this. I am a ham and have dealt with tower and  coax to my 
radios grounding.
 
    Great. There is a lot of ham literature on  protection for radio systems.

Is there  a problem with moderate (probably less than 100 ft) runs 
between the  geophones and the amp/filter/A/D or do I need to remote them 
(that adds to  the waterproof question)?
    This depends a lot on your soil conductivity.  Wiring under the house is 
likely to be partly shielded by the house 'earth'. 100  ft is quite a long 
external 'aerial'. I would be inclined to fit some lightning  protection where 
the cable enters the house, especially if lightning is a  'problem' in your 
area. A burnt out seismic system + computer would be  expensive. Remember that you 
get ground currents for quite some distance around  a lightning strike.
 
    Is the utility power wiring to your house below  ground or on poles?  
Elevated wiring does tend to pick up stronger  lightning surges, sometimes from 
many miles away.
 
    Regards,
 
    Chris Chapman









In a message dated 13/08/2005, dwieck@............ writes:
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20
  size=3D2>>     Is it a timber house or one with brick/st=
one=20
  walls?
Its brick
> How many stories?
2
>   &nb=
sp;=20
  Are they the 4.5 Hz geophones?
yes
Hi Dennis,
 
    I would be optimistic about an underfloor locat=
ion.=20
Just keep away from the water supply and waste water pipes and from the=20
foundations. Suggest that you try it out as your first option?
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>The good=20
  news is I am 200 yards from the nearest road (except for what 
comes in=
 my=20
  driveway)
    That will probably be fine. 
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>> I=20
  connected my geophones up to the amplifier in a portable radio and 
>=
;=20
  listened with headphones. OK, these signals aren't the seismic ones, 
&=
gt;=20
  but you can often recognise noise sources by ear easier than trying to=20
  
> figure them out from the traces. I start to hear fast cars on the=
=20
  main 
> road at about 1 km. There is a slightly depressed water drai=
n on=20
  the 
> main road about 100 yards away which gives thump signals=20
  occasionally 
> with passing lorries..... Check for slamming doors a=
nd=20
  windows, fridge 
> start/stop, cooking loads, central heating timing=
,=20
  wind noise.....
    Do 'have a listen', see what you can pick up an=
d=20
also take a seismic recording to find any associated signals. 
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20
  size=3D2>>     Trees may give broad band noise, but=
 this=20
  may be more serious for 
> the longer period instruments. Aim to kee=
p=20
  your sensors at a distance 
> equal to the height of the trees, mini=
mum.=20
  

This is about impossible on my lot. Even the under the house spot=20
  would 
not meet this but would probably be the closest.
>     You have the problem of long cable runs and=
=20
probably 
> some lightning protection required for installations away=20=
from=20
the house.
>> I am used to this. I am a ham and have dealt with tow=
er and=20
coax to my 
radios grounding.
 
    Great. There is a lot of ham literature on=20
protection for radio systems.
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Is there=20
  a problem with moderate (probably less than 100 ft) runs 
between the=20
  geophones and the amp/filter/A/D or do I need to remote them 
(that add=
s to=20
  the waterproof question)?
    This depends a lot on your soil conductivity.=20
Wiring under the house is likely to be partly shielded by the house 'earth'.=
 100=20
ft is quite a long external 'aerial'. I would be inclined to fit some lightn=
ing=20
protection where the cable enters the house, especially if lightning is a=20
'problem' in your area. A burnt out seismic system + computer would be=20
expensive. Remember that you get ground currents for quite some distance aro=
und=20
a lightning strike.
 
    Is the utility power wiring to your house below=
=20
ground or on poles?  Elevated wiring does tend to pick up stronger=
=20
lightning surges, sometimes from many miles away.
 
    Regards,
 
    Chris Chapman