Can a AM Loop Antenna help with the signal?
I've heard differently from others but my personal experience is that my loop only helped with daytime reception when a station was very weak.
Didn't make a difference to me at all at night.
Maybe it would be different with some of those large loops people have made.
If you were using your PR-D5, it probably boosted the signals only by a DB or so, and it might not be enough to notice using the speakers. I can definitely tell with my PR-D5, the Select-A-Tenna boosts it by about a DB -- but a lot of times I really don't need a loop, the loop doesn't help as much on the PR-D5 as it does on other radios.
Also, the loop works best with mine when it's 5-6 inches from the side of the radio. Any closer, there's no help at all. Not sure why that is.