When a station from Argentina can be heard on 980 kHz, where Rádio Nacional de Brasília rules, stations from Argentina can be heard everywhere! The date for this specific happening was July 30, 2009, and for a few seconds the signal was really impressive: “LT39 AM 980 ... www.lt39am980.com.ar. ...".
A most welcome email from Angel Enrique confirmed my reception.
QSL #600 from Latin America - MW QSL #50 from Argentina