Around the World Twice (and maybe more) on 15 meters

 

John EI7GL has a great blog post about some experiments recently done by Salvador EA5Y.  Salvador was aiming his 4 element yagi in one direction, sending dits, and watching for the signal to come around the other side.  You can see the results in the display above.  I commented that this might be the time for one of those antennas with which you can instantly reverse the pattern. Or, probably better, have some other hams aim their antennas in the opposite direction so that they can catch the circumnavigating signals. 

Check it out: 

https://ei7gl.blogspot.com/2023/12/twice-around-globe-on-21-mhz-and.html

Two trips around is 80,000 km or about 50,000 miles!  That's quite a trip.  But how about 3 times around?  Or more? 

Thanks to John EI7GL and to Salvador EA5Y.  

Long Delayed Echo on Radio China International

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/


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