olemus
pika hilistusega raadiokaja, algab saatest üle 2,7 sekundi hiljem,
tekke põhjuste kohta on ainult hüpoteese
=
radio echoes which return to the sender several (at least 2,7) seconds after a radio transmission has occurred

ülevaateid
https://en.wikipedia.org/wiki/Long_delayed_echo

http://www.arp75.org/wp-content/uploads/2014/02/lde_la3za_arp_20090318.pdf

https://www.mn.uio.no/fysikk/english/people/aca/sverre/articles/shlionskiy15.html

https://www.mn.uio.no/fysikk/english/people/aca/sverre/articles/lde.html