A Slave Pendulum for a Low Frequency Gravity Wave Antenna (Abstract)

Volume 24 number 2 (1996)

Casper H. Hossfield

Abstract

(Abstract only) A low frequency gravity wave antenna is a pendulum-based mechanical device similar to an acoustical musical instrument. Such an antenna must measure distance, or the length of a vibration caused by a gravity wave. On smaller antenna prototypes, this was accomplished by use of a push rod attached to one pendulum which moved a coil in a magnetic field on the other pendulum. The coil's small voltage induced by vibrations was amplified by an acoustical amplifier and recorded on a seismograph drum. It is not practical to build an 88-meter push rod, so I will use a slave pendulum to measure vibrations in the 88-meter antenna. The distance between the master and the slave will be less than one meter, so it will be a simple matter to mount the coil on one pendulum mass and the magnet on the other. Reference: Hossfield, C. H. 1992, J. Amer. Assoc. Var. Star Obs., 21, 157.