As soon as I posted, I did a search and it led me to some of the same places you went to. I did notice that my “several minutes”
interval was bogus, several seconds is more realistic. I suspect it was an artifact of Lunan’s book. I must have read it a long time ago.

However, I did remember that figure correctly, because I recall at the time doing the calculations and I determined that a Bracewell probe with those signal characteristics would have to be somewhere in the inner solar system.

Thanks for checking up on that for us.

I read about it in college. There’s a Wikipedia article about Lunan here.

When I was even younger, I read a cool book called Strangely Enough by C. B. Colby, which had enough bizarre mysteries in it to keep this particular board going for years. Some of them kept me awake at night. I still have an old hardcover copy.

One of these mysteries was the famous “KLEE call sign” mystery, which seemed to be a very strange LDE. Unfortunately, the real story is more mundane.

More on LDEs here.