Hearing the speed of light: DX double echo

ionosphere-earth-radio-wavesTwo weeks ago, at the W4DXCC conference in Tennessee, I met Lyle Juroff (K9FIK). Not only did I find that Lyle and I had many radio interests in common, but he also told me a story about hearing, recording and analyzing a double echo on the HF bands. I asked if he would explain in an email and include the recording so that I could share it on the SWLing Post. He kindly agreed!

Lyle writes:

I worked a DX station [9A1A] on 10 meters this past spring.  As the band improved, I heard an echo develop on his signal and guessed it might be long path so I began recording the audio.   I then began to hear a double echo and looked at the waveform on AUDACITY.  The timing marks on AUDACITY indicated 140 milliseconds between echos.

I went to Wolfram Alfa, one of my go-to sights for things I can’t remember, and looked up the earth circumference.  It not only gave me the distance but also the time to travel it at the speed of light,  133 milliseconds.   Not sure if everyone working DX has heard this sort of thing, I played the recording at the next East Tennessee  DX Association meeting.  Nobody said they had heard that kind of double echo.

Click here to download an mp3 of Lyle’s recording or simply listen via the embedded player below (note that the second recording is .WAV format):

Have you heard a double echo this profound? Please comment.

Many thanks to Lyle (K9FIK) for sharing his story!

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4 thoughts on “Hearing the speed of light: DX double echo

  1. James, AB4D

    Hi. Lately, I’ve been hearing this phenomenon more often on the HF bands. Today December 29, 2013, I heard a station in New Mexico working IA0MZ (Antarctica) on the 17 meter band at 1756z. I was beaming long path @19 degrees to hear IA0MZ, and there was a profound echo effect on the signal from the New Mexico station (I did not pay attention to his call).

    I’ve heard the same effect as well on 10 meters several times this month. I do not believe that it’s intentional, because the effect does not seem to last very long. I’ve heard it show up mid-sentence and disappear before the OM completes the transmission.

    About 2-3 years ago during the winter, I heard an echo of my own signal while on 80 meters SSB. The effect lasted about 8 seconds and I could only hear the tail end of my transmission.


  2. Lawrence

    First of all I haven’t updated my website for some time as I am extremely busy.
    Re the echo, some 20 – 25 years ago I was tuning around either on the 60M or 49M band and the BBC was coming like that and actually with a longer time which I calculated at about half a second or slightly a bit more between the signals. Pity that I didn’t have the tape recorder operating at the time but I realy wished I had as this is not something that occurs every day and maybe you will get it once in a lifetime.

  3. W4ASZ

    I’ve not heard anything like that in 35 years on the ham bands. That sounds like sideband through a spring reverb. It also sounds like more than a double echo in places.

    Yoiks !


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