Hi, My Lehman looks much like the one described in the Scientific American article. = The main frame doesn't consist of pipes, but I used metal bars = instead. The piano wire is directly attached to the upper main = frame. I didn't use a turnbuckle. The boom is a curtain rod of ~ 75 centimeters long. The problem is, I can't get the boom in a center position. I didn't get much farther. Perhaps the soft soil I live on (clay and sand) causes = the boom proble,? Meredith, you say the SG sensor isn't that much of a problem to build, even for someone who has problems with the simple 'Lehman'? :) Best regards, Marchal van Lare -Nieuwvliet, The Netherlands _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>