I just joined the list on Sunday, and would like to briefly introduce myself, and ask for some input. I'm from Alberta, Canada, and will be moving to the Bay Area soon to work for SegaSoft (well, OK, I was supposed to move in November, but who ever said getting a work visa was easy.) This move has prompted me to take a more active interest in seismic activities. I now have an irresistible urge to build things seismic (to the disdain of my wife). I have enough of a history in electronics to build and circuitry, etc, to drive the hardware, but I am trying to decide what would be the best type of sensor equipment to use. I wanted to build a Lehman sensor, but my wife vetoed it, due to size. Currently I am looking at possibly a geophone configuration, or a force balance accelerometer (if price is not prohibitive). A SG seismometer is also a possibility (or a modified design that I have been working on in my head - I have a preference for non-RF electronics). Does anyone know an approximate price for a decent FBA sensor (1-3 sensor - I'm guessing mega $ here...)? I have already contacted geospace for a quote on the GS-11 geophone, so I know what price range I would be looking at for that. I could also try a few more local surplus stores, as seismic surveys are quite active throughout Alberta. However, I have had no luck at any of these stores yet. I also have not seen any discussion anywhere on using an integrator in combination with a geophone. I would think that a geophone -> preamp -> low pass filter -> high pass filter -> integrator -> amp arrangement could be fairly sensitive for low cost, but would like to know some opinions about if it would be worth trying? If the high pass filter cutoff frequency were at aprox. 50-80% of the resonant frequency of the geophone, I would think that you could pull up low-end performance without inducing too much noise (from looking that the performance specs for the units). Well anyway, I seem to have rambled on enough for now, so till later, Eric __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>