E10 ABC on 5339 kHz, jammed

ABC was discovered in a FTJ frequency. It is on air right now, on 5339 USB with a nice S8 signal. The strange thing is the existence of the Jammer, at the same frequency but with a weaker signal. How odd! Why to jam a station calling "ABC" and nothing else? Maybe the Jammer knows more about the purpose of ABC, with no messages so far... Here's a short sound sample!