I have a very different reply from Guysonic's. I wouldn't recommend foil shielding for 99% of the people on this forum, and the 1% (if they exist here at all) know who they are. For one thing it is extremely important for the shield to have the lowest possible series resistance, but foil shielding has considerably higher resistance per unit length than braided copper, which is the preferred type for professional location recording. That's why the drain wire is included--but because it generally isn't wound symmetrically with respect to the signal pair, it can actually become a pathway for interfering signals to get into the audio.
In other words, if anyone assumes that foil shielding should be the ultimate in RFI protection because of the 100% shield coverage, there are plenty of seasoned professionals who can point out the error of that assumption. Big time.
Foil-shield cable is designed for permanent, built-in, physically protected installations--not for the situation in which the cable has to be unwound, might well get stepped on, and then gets wound up again at the end of the night. Stay well away, unless you are an electrical contractor (the possible 1% that I referred to earlier).
The whole shielding thing has been totally overemphasized; much if not most noise from RF interference isn't affected one way or the other by the presence of a shield. There are very widespread misunderstandings about this whole topic, and I hesitate to open the can of worms, but someone should at least say quietly and modestly (the way I always do) that most of the whole audiophile belief system concerning shielding and grounding is for crap.
The main responsibility for rejecting noise due to interference falls on the balanced input that your signal cable is connected to--but depending on the configuration of that input circuit, its ability to reject noise may depend considerably on how well balanced the driving circuit is as well (i.e. the microphone and cable). If those factors are well squared away then (and here is where the audiophile assumptions are so wrong) you can remove the shield from the cable completely, and the noise rejection of the balanced input will still work. (I'm not suggesting that anyone really do this; it's just to make the point that it's the balance that matters in most cases, NOT the shielding.)
The other thing that falls onto the shoulders of the input is exactly how the shield contact from the cable is connected to the chassis ground of the receiving equipment (the recorder in this case). This must be done at a single point as close to the connection point of the cable as possible; otherwise any current flowing in the shield will inevitably leak into the rest of the circuitry. And approximately 0% of the lower-cost, Far-Eastern-manufactured preamps and recorders that people use here are constructed appropriately in this respect (the so-called "pin 1" problem), so the production design of the equipment is pretty much begging for noise and interference problems. These can often be mitigated by the use of Neutrik "EMC" (XLR) connectors on the cables, but analog audio circuit designers need to do their homework better in the future.
Enough lecturing; you've got a well-known piece of troublesome gear (the MicroTrack) whose analog inputs simply suck, though they suck less when driven at line levels by balanced sources and cables than unbalanced sources and cables. Still, I would advise you to feed the thing a digital signal instead. Second choice is to use a preamp with balanced outputs and to feed a line-level signal through balanced cables to the analog inputs of the MicroTrack. I would never advise using that recorder for anything critical anyway--it's far too unreliable--but I certainly wouldn't advise connecting microphones to its analog inputs.