Hi, thanks for that exhaustive analyses, I appreciate your efforts. The tilt meter is called an Electrolevel and is a "..closed tube containing a bubble of gas, an electrically conducting liquid and electrodes...". It is a metal cylinder about 3 inches long and 3/4 of an inch in diameter. It's made in the UK, vintage 1990, and has a range of +/- 0.5 degrees. The box that drives it produces a voltage of about 0.5 mV per arc second. I'll be connecting this signal to a Krohn-Hite 3322 filter and setting the band pass to 20 seconds to 10 seconds (arbitrary choice). I can switch in a gain of 1, 100 or 10000 to this, though it will depend on how much noise is produced by the drive box. My A/D is 12 bits and is set to +/- 20 mV. So my estimate of 5 urad is a bit of a guess. I'll know better when I get the filter (hopefully this weekend). I wouldn't be surprised if a lot of teleseismic events pass me by un-noticed as your analyses suggests. I think it may well depend on the integrety of the signal produced by the drive box. Thanks Ian Smith __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>