The Raya ridge effectively marks the border between Malaysia and Indonesia; it has been used for centuries as a jungle highway. On it was a VERY big boulder; and we as a tracker team; sat on it, and used it  to spot cooking fires at dusk , inside Indonesia ; the fires would be plotted on a map and the positions radioed in code back to the batteries of heavy British artillery behind us inside Kalimantan. The guns would normally fire around 0300 hrs and the shells would pass over the top of us [all gathered on the big boulder] to watch the impacts. The Indons; with their tummies full of fish heads & rice , must have got a HUGE shock as out of the black night; a veritable mountain of artillery dropped on top of them.They would sometimes open up their radio network and we listened in as the s*** hit the fan. Our LZ was a long struggle through almost impenetrable jungle, but after a day or so; we had to call it quits and head off for a chopper; back to Bau. Those Indons must have wondered how they were detected; we were NOT about to tell them. Though , we did have abusive chats occassionally.