Magnetic position sensor and cable

A catheter comprising:

• an elongated catheter shaft configured to be received within a patient;
• a medical assembly coupled with the elongated catheter shaft and configured for use within the patient to diagnose and/or treat a medical condition of the patient;
• and
• one or more magnetic position sensors, wherein each of the one or more magnetic positions sensors comprises a magnetically permeable core and a coil, wherein the magnetically permeable core has a central axis and a core length along the central axis, wherein the coil comprises a wire wrapped around the magnetically permeable core and configured to output an electric signal in response to a magnetic field, wherein the coil has a coil length along the central axis that is less than 90 percent of the core length, and wherein the magnetically permeable core consists of a magnetically permeable material selected from a group consisting of mu-metal and a nickel-iron soft ferromagnetic alloy.