Abstract: A system of apparatus for use in a coring tool measures the height of a core sample being recovered and transmits data relative thereto to the surface of a formation concurrently during the coring operation. A transmitter of an electromagnetic ranging system rides atop a core sample being formed in the barrel chamber and a receiver member of the electromagnetic ranging system is fixed at a top end of the barrel it known distance above the transmitter. During the coring operation the transmitter transmits a fixed frequency signal to the receiver through drilling fluid disposed therebetween. The distance between the transmitter and receiver decreases and the amplitude of the transmitted signal changes as a function of the separation distance between the transmitter and receiver as the core sample enters the inner barrel and the height of the core sample within the barrel is determined as a function of time and depth.