(Crossposted to boatanchors because of common interest)

Spurious Noise wrote:

Two links to long delayed echoes at URL:
ttp://ac6v.com/propagation.htm#LDE

Never heard one myself.

Post yours here -- will add to the above links.

Wish I had a recording, but we're talking about the fall of 1974.
I remember, because I was still in high school.
I've never forgotten the details, because it was so weird.
Our 75 meter group was talking on 3915 KC about 7 PM.
There were stations in ( west to east)
Dallas, Paris and Longview Texas-
Shreveport, Ruston and Monroe, Louisiana
Vicksburg, Mississippi and one in Alabama (don't remember town).
The effect started on the station furthest west,
which was about 200 miles west of me.
After transmitting, he'd let go of the PTT
and you'd hear the last word or so repeated, like an "echo."
The effect moved like a "front" from west to east,
though there was no unusual weather at the time,
and the delay got longer as it "moved" over my location in north
Louisiana.

A strange aspect: the guy in Paris never heard it.
The guy in Longview heard it weakly, but only for a short time.
All of us in north Louisiana heard it, but it was strongest
and longest over Shreveport. It was as though it "echoed"
only those signals coming from the east, back to the east.
When the "front" passed over my location, I could key my mike,
say a couple of short words, unkey and hear it repeated back to me
with good signal strength.

Once the "front" passed over me, I couldn't hear it anymore,
but the guys east of me did. The effect continued east,
fading in intensity and delay length until it finally stopped.
The guy near Vicksburg was last to hear it. He said it was weak
and only repeated the last syllable, suddenly stopping entirely.
Another oddity: the guy in Alabama never heard it.
The whole thing took about an hour, so whatever it was moved
about 400 miles in an hour; no weather front could do that.

Never had a satisfactory explanation, nor have I heard it since.
The delay was far too long for it to be troppo or some other weather
related deal, nor could it be a "modulated magnetic flux line"
ala the whistlers on longwave, because there is was no doppler shift.
Easily the strangest thing I've ever heard on a radio.

73 Dave S.