Can you help Joel ID this Vietnamese station?

SWLing Post reader, Joel, writes:

"Is there a section of SWLing Post for SWL's who manage to catch a highly unusual broadcast about which some of your members may have information? I refer to catching an S4+ transmission in northern Vietnamese from 1600-1630 GMT on 11,840 kHz last November? As linguist, SWL, ham and retired foreign service officer, this one has me totally stumped."

Joel, I'm hoping a reader can assist you with your question. My only guess would be that this was a Vietnamese broadcast from KTWR Guam.

Please comment if you can help Joel identify this station!