Originally Posted by
freexray
Any idea where that frequency component would originate? not a square wave harmonic surely? would be the 56th harmonic.
My earliest posts showed a strong second harmonic component in the output field of the older AMB transponder, most likely due to driving the tank single-ended. The RC4 probably also uses a single-ended drive. This would give plenty of even-order harmonics.
At higher frequencies, even short conductors become excellent antennae!