EFR,

Yes Copper {Foil} Alarm Tape can be put to use as
Loop Antenna around the Window about an Inch or
two away from the Metal Frame of the Window.

If the Loop does not work 'cut' the Tape in the middle
of the Loop and try it as a Folded {Bent} Dipole. The
Dipole-on-the-Window usually works better for FM Radio.

Also if the Copper {Foil} Tape is too much of a Eye
Sore - Then try very thin Magnet Wire with a few
pieces of Scotch {Clear} Tape to hold it in-place on
the Window. The Magnet Wire on the Window
usually allows for several turns about and Inch
apart either as a Loop Antenna or as a bent spiral
Random Wire Antenna.

just my two cents worth - iane ~ RHF