AFAIK radio waves can be influenced by magnetic fields (when not traveling through a vacuum). Electrical wires create a magnetic field perpendicular to the length of the wire, as a function of the current running through it.
In air, water, or other medium, would radio waves be influenced by this magnetic field (or conversely by the electric field)?
Say for this purpose I have a radar which scan through walls, and I am interested in knowing wether the wires in the wall are currently "on" or "off". Would this be possible? How weak, or strong magnetic field (conversley electric field) is needed to influence radio waves (when not in a vacuum)?
Or have I completely misunderstood something here :) ?