Brett Nordgren brett3nt@.............
Subject: Re: Spring for AS-1 type vertical seismometer


Hi Dave,
   I agree, Richard has made a very nice looking instrument.
Regarding noise, I think it's the other way around.  Generally the=20
erticals are considerably less sensitive to local disturbances of=20
he ground (though much more sensitive to temperature and barometric=20
ressure changes). =20
Hi Brett,=20
    Vertical Seismometers which are NOT hermetically enclosed may be=20
quite noisy when compared to horizontals. They are strongly effected=20
by atmospheric pressure noise and by air convection, particularly if=20
they have low mass. A Lehman type commonly has a mass of 1 to 2 kg.=20
What mass does the FBV use, please?=20
    Can you direct me to the plans for the FBV, please ?=20
    What ADC do use, please ?
    I have some sheets of 3 thou mylar / polyester, which looks like=20
it could be used to make a seismometer bearing. Would you be=20
interested in having a sample ?
    I would be interested in trying to make a FBV. Can you confirm=20
the cost of the board + postage to the UK, please ? I will need some=20
help with the capacitors, the timing crystal and the ICs please.=20
None of the UK suppliers that I can find have a 3 MHz crystal. The=20
supplier which I was using has closed down. The pin spacings on=20
capacitors are very variable. I think that I am OK for everything=20
else. I do have a PayPal account.=20
   I am continuing to recover medically, but progress is very slow.
    Regards,
    Chris Chapman=20


















<=
TT>


=
Brett Nordgren brett3nt@bnordgren=
..org

Subject: Re: Spring for AS-1 type vertical seismometer





Hi Dave,
    I agree, Richard has made a very nice looking instrument.

Regarding noise, I think it's the other way around.  Generally the=20
verticals are considerably less sensitive to local disturbances of=20
the ground (though much more sensitive to temperature and barometric=20
pressure changes).  
Hi Brett, 
<=
FONT size=3D3>    Vertical Seismometers which are NOT hermetically enclo=
sed may be 
quite noisy when compared to horizontals. They are strongly effected =
by atmospheric pressure noise and=
 by air convection, particularly if 
they have low ma=
ss. A Lehman type commonly has a mass of 1 t=
o 2 kg. 
=
What mass does the FBV use, please? 
=
    Can you direct me to the plans for the FBV, please ? 
    What AD=
C do use, please ?
    I have some sheets of 3 thou mylar / polyester, which looks l=
ike 
it c=
ould be used to make a seismometer bearing. =
Would you be 
interested in having a sample ?<=
/TT>
    I would be i=
nterested in trying to make a FBV. Can you confirm 
the cost of the board + postage =
to the UK, please ? I will need some 
help with the capacitors, the timing crystal a=
nd the ICs please. 
None of the UK suppliers that I c=
an find have a 3 MHz crystal. The 
supplier =
which I was using has closed down. The pin s=
pacings on 
capacitors are very variable. I think that I am OK f=
or everything 
else. I do have a PayPal account. 
   I am continuing to recover medically, but progress i=
s very slow.
    Regards,
    Chris Chapman