I have a hard time believing the whole AM and FM were hiss-filled by an iboc station.
As bad as iboc is, I don't think it can overload any radio at 28 miles.
There must be something else that was causing it.
How large of an area was impacted by this?
I can drive right by the towers of WGN 720 and WBBM 780 both in iboc and still hear anything clearly except the
2 channels above and below they wipe out.. Even AM 750 from Portage Indiana, 45 miles away, though they get a bit splattered
within 1 mile.
Of course, this is with a 1972 factory Motorola AM/FM. It has a true RF preselector tuned gain stage on AM.
Hospital on March 27th, huh?
I hope you have picked a hospital in Houston where you can open a window and throw a chunk of magnet wire out the window for
AM signal pickup, because most hospital are RF-shielded and noisy as all get out.
Maybe someone will bring you a helium balloon you can tie the magnet wire to and send it up over the hospital.
Tie off the balloon lead at the window, wrap 5 loops around the radio, then connect the end to a earth ground on one of the
ground pins on the many outlets found in a hospital room. AM should work OK then.