Abstract: A method of tuning a radio frequency coil for use in MR imaging applications uses reactive shunts having a reactance in parallel with a switch to connect sections of the coil to ground thereby constraining the resonant mode of the coil to a known orientation. A plurality of measurements of the frequency of the resonances along different such constrained orientations is used to deduce the frequencies of the two unconstrained orthogonal resonant modes of the coil and its orientation. The shunts may also be used to tune the coil according to the deduced frequencies of the unconstrained resonance and the desired frequency and orientation by adjusting the reactance of the shunts. A shunt having a variable reactance and a switch for shorting the RF coil as required uses a PIN diode in combination with a variable reactance.