Why A ground loop happens when two pieces of equipment reach ground by different paths, so RF or AC currents circulate between them and appear as hum or RF in the signal path. The fix is to tie all the equipment enclosures together with short, heavy bonding straps so everything in the station sits at the same potential and there is no voltage difference to drive current through the interconnecting cables. Good bonding practice is a single-point station ground with everything bonded, not a collection of separate ground paths.
Watch out Connecting grounds in series (daisy-chaining to one rod) is exactly what creates the loops and differing potentials; and tying the AC neutral to the ground wire anywhere but the service entrance is a serious code violation that can put current on your ground conductors.
Bond everything together, short and heavy. Equal potential means no loop current.