There is a loop antenna that was thrown around an attic interior several decades ago, of long forgotten dimensions.  I found the feed line.  Is there a way to measure what (U.S. amateur) bands on which it might radiate most efficiently (if at all) without physical access?

Possible resources:  A vintage Philmore FS-45 field strength meter.  An old Versa Tuner with an SWR meter.  Two portable SW radios.