It is not the number of turns that matters to distinguish coil antennas from motors, though indeed a high number of turns in both motors and antennas leads to a high inductance, which ensures that any resonance frequencies will be low, so a received radio signal of high frequency will not be amplified by a resonance.
The magnetic circuit of a coil antenna has a very big air gap, because its ferromagnetic core usually has the form of a cylinder or of a prism and the magnetic circuit closes through the air between the opposite ends of the core.
The magnetic circuit of a motor has only small air gaps between stator and rotor, which are required to allow the rotor movements. Because of the small air gaps, the inductance of a motor winding is much higher than the inductance of a coil antenna with the same number of turns and using a ferromagnetic core made of the same material.
It is not the number of turns that matters to distinguish coil antennas from motors, though indeed a high number of turns in both motors and antennas leads to a high inductance, which ensures that any resonance frequencies will be low, so a received radio signal of high frequency will not be amplified by a resonance.
The magnetic circuit of a coil antenna has a very big air gap, because its ferromagnetic core usually has the form of a cylinder or of a prism and the magnetic circuit closes through the air between the opposite ends of the core.
The magnetic circuit of a motor has only small air gaps between stator and rotor, which are required to allow the rotor movements. Because of the small air gaps, the inductance of a motor winding is much higher than the inductance of a coil antenna with the same number of turns and using a ferromagnetic core made of the same material.