The first problem with the term "magnetic loop" is that no two people seem to use it to mean the same thing. One that halfway makes any kind of sense is the case where a resonant loop is inductively coupled to a feedline through a smaller loop within the plane of the main loop.One thing it definitely does NOT mean, however, is that a loop antenna "responds only" (or primarily or preferentially or any other qualifier) "to the magnetic component of the received signal," as one so often sees egregiously misstated. That's a blatant physical impossibility.
One explanation of this hard reality can be found at:
www.w8ji.com/magnetic_receiving_loops.htm
The text is both theoretically and empirically accurate, if a bit confusing to follow and possibly dwelling on the "field impedance" concept a bit too much. One would do well to ignore the bottom three fourths of the page which deals with examples, as many of these are needlessly confusing and therefore potentially misleading. The essential points--and ones which tie Maxwell in with quantum electrodynamics too--are:
* Forces which exist between stationary charged regions are electric fields, which diminish rapidly with distance.
* Forces exerted between moving charges are magnetic fields, which also fall off rapidly with distance.
* Forces created by the acceleration and deceleration of charges, and which in turn can cause other charges to accelerate and decelerate through forces that diminish in inverse proportion to distance, are propagating electromagnetic waves.
In quantum terms, the first two are manifestations of the action of photons exchanged between the particles at short range and for short time intervals, and hence are termed "virtual photons." The process of charge acceleration (and other physical phenomena not described by Maxwell, but later explained by relativity and QCD) results in the emission of "real" photons, ones which are not confined to a local "prisoner exchange" but which are free to travel through space forever, unless or until they encounter a willing and receptive charged particle to interact with...hopefully, for RF, an electron in an antenna wire into which it can impart its tiny packet of energy.
In Maxwellian terms, propagating EM waves are inseparable; if you stop the alternating electric field, you stop the associated magnetic one, and vice-versa. In quantum terms, there are no such things as "electric photons" or "magnetic photons," just virtual or real ones, which is itself merely a question of how long they remain in existence.
In practice, all antennas produce all three effects in one proportion or another. But it is totally irrelevant to the way in which they work as radiators or receptors of EM waves whether they have disproportionately greater electric or magnetic near field energy. A loop under some circumstances may be more receptive to locally generated near field magnetic QRM sources than electric ones, but its response to desired EM waves has nothing to do with filtering out "bad" electric fields and responding only to "good" magnetic fields.
By the same token, active whips also receive both components of an EM wave, not just the "e" component. And anyone who elevates one several meters in the air certainly has no "probe," either.