Hi Chris- Thanks for the comment on Robert's Circuit- Equalizer Board as=
I have used Mauro's commercial version (SEQUA10 ) and found it to be qu=
ite good.
Question- =
Do you believe a digital inverse filter would work just as good?
BTW_ I enjoy reading all your comments...Thanks....Jim
Jim O'Donnell =
Geological/Geophysical Consultant
GEOTECHNICAL APPLICATIONS
702.293.5664 geophysics@..........
702.281.9081 cell jim@..........
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
-- ChrisAtUpw@....... wrote:
Hi Ian,
If you are using one of Larry's L15B units, you should be able to se=
al it with the "non acetic acid" type of silicone rubber sealant OK. Thi=
s should be good from -40 C to 70 C. The Geospace geophones seem mostly =
rated from -45 C to 100 C, but I am not sure about the plastic case for =
the higher temperature. An alternative sealant which I use is Blue-Tack =
/ White-Tack from a stationery supplier. It is a putty like, non hardeni=
ng adhesive sold for attaching posters etc to walls without damaging or =
staining the surface finish. It is not available in the USA.
I agree about the environmental noise, but you could get more wind =
noise in an outside location. This is likely in Iceland. I use a SEQ=
UA10 frequency extension board from http://www.sara.pg.it/prod04_04_e.ht=
mThey cost E30 and extend the low frequency response of a 4.5 Hz geophon=
e down to 1/10 the natural frequency, a bit like the low frequency boost=
circuit on a HiFi amplifier. This enables you to sense both P and S wav=
es, at 1.0 and 0.5 Hz, for local, regional and teleseismic events with a=
4.5 Hz geophone. It is a modified version of the Roberts' circuit. =
Hi Chris- Thanks for the comment on Robert's Circuit- Equalizer=
Board as I have used Mauro's commercial version (SEQUA10 ) and fou=
nd it to be quite good.
Question-
Do you believe a digital inverse filter would work=
just as good?
BTW_ I enjoy reading all your comments...Thanks....Jim=
&nb=
sp; Jim O'Donnell =
Geological/Geophysi=
cal Consultant
=
GEOTECHNICAL APPLICATIONS
702.293.5664 =
; geophysics@..........
702.281.9081 cell &n=
bsp; jim@..........
>&=
gt;>>>>>>>>>>>>>>>>>&=
gt;>>>>>>>>>>>>>>>>>&=
gt;>>>>>>>>>>>>>>>>>&=
gt;>>>
-- ChrisAtUpw@....... wrote:
Hi Ian,
&nb=
sp; If you are using one of Larry's L15B units, you should be=
able to seal it with the "non acetic acid" type of silicone rubber seal=
ant OK. This should be good from -40 C to 70 C. The Geospace geophones s=
eem mostly rated from -45 C to 100 C, but I am not sure about the p=
lastic case for the higher temperature. An alternative sealant which =
I use is Blue-Tack / White-Tack from a stationery supplier. It is a =
putty like, non hardening adhesive sold for attaching posters etc t=
o walls without damaging or staining the surface finish. It is not avail=
able in the USA.
I agree about the environmental noise, but =
you could get more wind noise in an outside location. This is likely in =
Iceland.
I use a SEQUA10 frequency extension board f=
rom http://www.sara.pg=
..it/prod04_04_e.htm
They cost E30 and extend the low frequency response of a 4.5 Hz&nbs=
p;geophone down to 1/10 the natural frequency, a bit like the low f=
requency boost circuit on a HiFi amplifier. This enables you to sense bo=
th P and S waves, at 1.0 and 0.5 Hz, for local, regional and teleseismic=
events with a 4.5 Hz geophone. It is a modified version of the Roberts'=
circuit.
Regards,
Chris Chapman