Several people have e-mailed me suggesting that the weird echo I have been hearing on shortwave broadcast stations is in fact one of the fabled “Long Delayed Echoes” that radio amateurs have been hearing intermittently since about 1927. I was skeptical at first, but — at least in the case of the Radio China signal — I think LDE caused by the signal going around the globe several times does explain what I’ve heard. Each trip would add a delay of about .133 seconds, and that seems to match what we hear in my recording:
http://soldersmoke.blogspot.com/2014/08/strange-echo-on-china-radio.html
Compare that with what K9FIK recorded on 10 meter SSB (thanks Stephen!):
http://swling.com/blog/2013/10/hearing-the-speed-of-light-dx-double-echo/
(you can listen to the audio on this one).
It sounds very similar.
If this is in fact LDE, I’m lucky — this is pretty rare. And it is a eerie that I first heard it on on Regen receiver from the 1920s! Above is a picture of the regen used to study the FIRST LDEs. See: http://folk.uio.no/sverre/LDE/
Our book: “SolderSmoke — Global Adventures in Wireless Electronics” http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Well, you always USED to say in jest that “regens are possessed.” Perhaps this is not a LDE, but more a phenomenon worthy of Art Bell’s show of yore, that is to say, for wont of a better expression: an actual case of Regen Possession. The audio files and pix you put up are fascinating, nonetheless. OT: you may know about and enjoy BBC 4 radio’s “In Our Time”, hosted by Melvyn Bragg. Quite lightweight, but pleasant bus/train listening. The podcasts on RElativity 06-vi-13 and The Invention of Radio 04-vii-13 are worth listening to, however light. Going to listen to thE K9FIK 10m SSB file again. It’s…trippy 73 desde Guadalajara, JAL
Thanks, Bill. I found a link to some articles on LDE at http://www.df5ai.net/Material/articles5.html David WA1LBP