While we are at it, did someone used PskMail for underground communications ? Things like that:
http://tech.slashdot.org/story/10/01/31/2114242/diy-texting-system-for-really-underground-radio http://nicola.sssi.fr/spip.php?article27"The British 73 kHz Band ... The amateur community's interest arose from a desire to investigate propagation through the ground by transmission from underground caves."
http://pe2bz.philpem.me.uk/ElectronicPrograms/-%20ELF-Programs/DosFFT/#e136 Le 16.05.2012 19:29, Bernard Dekok a écrit :
$250 $10/month World wide, pole to pole.... http://shop.delorme.com/OA_HTML/DELibeCCtpSctDspRte.jsp?section=10820&minisite=10020 <http://shop.delorme.com/OA_HTML/DELibeCCtpSctDspRte.jsp?section=10820&minisite=10020> KC9SGV