The term you're thinking of (since no one else seems to know or want
to answer) is "long delayed echo". As others have said, without
actually answering your question, no one has scientifically verified
the phenomenon, although of course there is quite a lot of anecdotal
evidence of it. I myself have never heard an LDE, so I have no idea,
firsthand, whether such a thing actually exists or is someone's idea
of an April Fool's joke.

Just so you're aware, Hank, don't believe everything you read in April
QST...there will be at least one April Fool's article in, along with
all the real stuff. The LDE thing was not, to my knowledge, posted in
an April QST, however. 
-- 
Buddy Brannan, KB5ELV
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