Long Delay Radio Echos

Discussion in 'Amateur Radio News' started by W5TXR, Dec 1, 2010.

Thread Status:
Not open for further replies.
ad: L-HROutlet
ad: l-rl
ad: L-MFJ
ad: abrind-2
ad: Left-3
ad: Subscribe
ad: Left-2
  1. W5TXR

    W5TXR XML Subscriber QRZ Page

    During the geomagnetic storm of Nov. 27th, a brief but intense G2-class event, amateur radio operator Peter Brogl of Fürth, Germany, experienced a strange phenomenon. Forty-six seconds after he transmitted his call sign at 7 MHz, he received an echo of his own transmission. "At first, I thought someone was playing tricks on me," says Brogl, "but I changed frequency, re-keyed my call sign (DK6NP), and got another echo." This went on for more than an hour, enough time for Brogl to make several recordings. First reported in 1927 by Norwegian civil engineer Jørgen Hals, long-delay radio echoes are rare and poorly understood. Unusual propagation conditions linked to solar storms is one of many possible explanations. Radio operators, if you experienced any similar phenomena on Nov. 27th between 1800 UT and 19:30 UT, please report your observations to Peter Brogl for correlation."


    Link to the recordings: http://brogl.net/Audio/

    Possible explanations: http://heim.ifi.uio.no/~sverre/LDE/Shlionskiy15.htm

    report your observations: pb@brogl.net

    73's W5TXR[/FONT]
    ARRL Asst. Technical Coordinator, STX
    ARRL Instructor/Teacher


    mark@w5txr.net
    www.w5txr.net
    www.amateurradioeducation.org
     
  2. AA7EJ

    AA7EJ Ham Member QRZ Page

    47 seconds??

    Since it was on 7MHz I assume he did not use directional antenna.
    Can we confirm that?
    73 Vaclav
     
  3. N1RKW

    N1RKW Ham Member QRZ Page

    47 seconds would mean that his signal had traveled approximately 8.7 million miles. That would mean that his signal had gone around the globe roughly 364 times before he received it.

    I want to know what type of amp this guy is using! :eek::D
     
  4. K1LWI

    K1LWI Ham Member QRZ Page

    DELAY ECHO

    THIS HAPPEN TO ME MANY TIME 5 SEC DELAY ME CALLING CQ ON TEN METERS CW BACK IN THE 60S AND 70S HERE END OF MY CQ CQ CQ DE K1LWI MY ANTENNA WAS 6 ELE LONG JOHM YAGI ALSO HAPPEN ON SSB TO MY BUDDY HAD HAPPEN TO HIM K1RAW WEAK FAST ECHO

    WENDELL K1LWI
    73
     
  5. K1LWI

    K1LWI Ham Member QRZ Page

    DELAY ECHO

    PS ALL THE DELAY ECHO WEAK VERY FAST QSB SOUND SIG COMING OVER THE NORTH POLE THAT THE SOUND LIKE


    K1LWI WEN
    73
     
  6. N7TEE

    N7TEE Ham Member QRZ Page

    Long delayed echo

    I do not know how far the complete conversion went, but back in the 70's on the central Oregon coast we had it come back to us in about 50 minutes. There were two kids talking about going over to Corvallis about 55 miles. This was on the "chicken band". They were gone and here they came talking again about going there. And, they were already there.

    Dave
     
  7. KL7AJ

    KL7AJ XML Subscriber QRZ Page

    Although such explanations MAY be plausible, there is a far more likely (though much less romantic) explanation. LDE's can be consistently generated in plasma chambers using well-known Ion Acoustic properties, primarily MODE CONVERSIONS between normal EM waves and slow-wave ion-acoustic modes, sort of like a big reverb spring. In fact, it's quite common that ion acoustic propagation AND parametric amplification occur at the same time...which means not only are LDE's possible, but VERY STRONG LDE's are possible. Again, these can be created consistently under CONTROLLED laboratory conditions...someting the magnetosphere is not!

    Magnetospheric propagation paths would be EXTREMELY lossy, inconsistent with the rather strong LDEs observed by numerous amateur and commercial radio operators. Ion Acoustic phenomena needs no such "stretches" of imagination...or physics.
     
  8. KC8VWM

    KC8VWM Ham Member QRZ Page

    I measured approx. 33 and 39 seconds starting from the end of the first transmission to the very start of the repeated echo transmission in the recordings.

    33 x speed of light, results in a range of around a 6 million mile distance.

    If it were an echo from a planetary body located in space, it would have been located approx. 1/2 that distance away. So, in other words it's probobly not likely to be coming from the Moon or Mars.

    Mars is between 55 and 400 million miles away. (It rotates in space and it's distance from earth varies) However, Mars is much too far away to have created this echo.

    The Moon, like Mars, also varies in distance from Earth between 225,000 and 250,000 miles away.

    There are some interesting theories regarding LDE suggesting plasma clouds traveling to the earth from the sun as a potential source of echo reflections. It also seems according to space weather reports a magnetic filament in the sun's northeastern quadrant erupted on Nov. 30th.

    Previous studies also suggest the radio frequency used may have some effects in terms of the amount of time it takes for these reflections to occur. More notable are 40 second delays measured by F.W. Crawford in the 5 - 12 Mhz range.

    It would be interesting to get a copy of his book...

    F. W. Crawford, D. M. Sears, R. L. Bruce, "Possible observations and mechanism of very long delayed radio echoes," Journ. Geophys. Res., Space Physics, vol. 75, no. 34, pp. 7326-7332, Dec. 1970.

    My Best,
     
    Last edited: Dec 1, 2010
  9. W6PDL

    W6PDL Ham Member QRZ Page

    My LDE

    Back in the late 1960's I experienced a 24 second delayed echo on 15 meters. I believe that this was an asteroid bounce! This is a known casue of HF LDE's.

    On numerous occasions I have experienced 1-2 second LDE's that I attribute to propagation around the planet and back.

    Dale Winther
    W6PDL
     
  10. WB9SBD

    WB9SBD Ham Member QRZ Page

     
Thread Status:
Not open for further replies.

Share This Page