Hate to be a party pooper, but I think KPLZ is probably running day power at night. Its something that's become more and more common as small AM stations strugle and as the FCC has become more and more focused on matters other than AM stations operating on higher than authorized power. We've been discussing it off and on here for the past several years.
That said, 2,500 watts on a crowded channel on the upper end of the dial at nearly 500 miles is still a fairly nice catch, so "a round of applause" is still in order. Even if it turns out that the good folks at KPLZ are "forgetting" to power down.
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