{"id":7486,"date":"2013-10-10T07:57:40","date_gmt":"2013-10-10T11:57:40","guid":{"rendered":"http:\/\/swling.com\/blog\/?p=7486"},"modified":"2013-10-10T08:01:16","modified_gmt":"2013-10-10T12:01:16","slug":"hearing-the-speed-of-light-dx-double-echo","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2013\/10\/hearing-the-speed-of-light-dx-double-echo\/","title":{"rendered":"Hearing the speed of light: DX double echo"},"content":{"rendered":"

\"ionosphere-earth-radio-waves\"Two weeks ago, at the W4DXCC conference<\/a> in Tennessee, I met Lyle Juroff (K9FIK).\u00a0Not 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!<\/p>\n

Lyle writes:<\/p>\n

I worked a DX station [9A1A<\/a>] on 10 meters this past spring. \u00a0As the band improved, I heard an echo develop on his signal and guessed it might be long path so I began recording the audio. \u00a0 I then began to hear a double echo and looked at the waveform on AUDACITY<\/a>. \u00a0The timing marks on AUDACITY indicated 140 milliseconds between echos.<\/p>\n

I went to Wolfram Alfa<\/a>, one of my go-to sights for things I can’t remember, and looked up the earth circumference. \u00a0It not only gave me the distance but also the time to travel it at the speed of light, \u00a0133 milliseconds. \u00a0 Not sure if everyone working DX has heard this sort of thing, I played the recording at the next East Tennessee \u00a0DX Association meeting. \u00a0Nobody said they had heard that kind of double echo.<\/p><\/blockquote>\n

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