I've tried using reverb and it does improve am sound . Wabc during the 1970s used reverb on all their audio to give their station a fuller sound.
True, Diablo! Reverb makes an AM station sound 'bigger' which I guess might seem like 'more powerful'. In the 1960s WIL AM 1430 located near me used reverb and their DJ-rock format became No. 1 in the ratings. A few years ago when I used Winamp as an audio player for my station there was a reverb plugin that gave me reverb for awhile, but now that I use Zara for playlist there is no reverb app that I'm aware of, otherwise I'd be using reverb.
I remember that too. In the 60s listening to WLS and WABC with Cousin Brucie especially there was some reverb especially on the speech by the DJ.
I was just thinking, and have the idea that Hans Van Zutphen should build a reverb add-on to his great StereoTools Audio Processor. I'd pay some money for that.