1. A method of calibrating and operating a magnetic resonance tuning system, the method comprising: varying a tuning signal through a frequency range; at each of a plurality of sample frequencies, applying the tuning signal to a plurality of loads and determining a complex reflected signal value for each of the loads; using the complex reflected signal values to create calibration constants; applying a tuning signal at a specific operation frequency to an RF coil and receiving a reflected signal value for the specific operation frequency; using interpolated values of the calibration constants and the received reflected signal value for the specific operation frequency to calculate a corrected reflection signal value for the specific operation frequency.