I have always had the best luck adjusting the boom so it makes a 90 degree angle with the upright support. Then adjust the entire base assembly to get the period correct (which means you tilt the base so the base and boom make the same slight angle off of vertical). You are correct that the mass end should be slightly lower, but make this happen by adjusting the leveling screws on the base. Regards, Ted "D. Hill"
on 02/14/2000 03:30:56 PM Please respond to PSN-L Mailing List To: PSN cc: Subject: Lehaman boom position I was adjusting my Lehman and got wondering about something. How should the boom be set? Should it be level or should it have a slight downward drop at the at the mass end. If there were a drop at the mass then it would seem that re-adjustments would be less frequent. And as the movement of the base is what produces the wave forms then it would seem that as long as the boom did not touch any of the sensing/supporting hardware then there should not be difference in it's performance. Any comments from anyone? Regards, Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>