B747 LNDG VHHH EXPERIENCED COM NAV PROB AND IS ISSUED GAR.

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THE FLT WAS BEING RADAR VECTORED TO THE ILS RWY 7L FROM THE S. A HDG TO BASE LEG WAS GIVEN WITH A DSCNT CLRNC TO 1500 FT. THE QUALITY OF THE XMISSION WAS POOR (SCRATCHY AND GARBLED) COUPLED WITH AN ACCENT. THE ALT WAS NOT CLRLY UNDERSTOOD BY ALL IN THE COCKPIT SO A REQUEST FOR CONFIRMATION WAS MADE. THE ATC RESPONSE WAS STILL GARBLED AND SCRATCHY BUT THE ALT ASSIGNMENT WAS CONFIRMED ALONG WITH A TURN TO 045 DEGS AND SOMETHING REFING RWY 7L. A TURN TO THE ASSIGNED HDG WAS INITIATED. AS WE APCHED THE LOC; I ASKED ATC IF THIS HDG WAS INTENDED TO INTERCEPT THE LOC. THE XMISSION WAS NOW CLR WITH 'AFFIRMATIVE.' THE PF (IOE) IMMEDIATELY ARMED THE LOC WHICH ENGAGED AND BEGAN A TURN TO CORRECT FOR THE OVERSHOOT. THE AUTOPLT CONTINUED TO OVERCORRECT FLYING THROUGH THE LOC COURSE IN THE OPPOSITE DIRECTION. AS WE WERE CONCERNED ABOUT THE HIGH TERRAIN TO THE R OF THE LOC; THE PF DISCONNECTED THE AUTOPLT AND MANUALLY FLEW THE ACFT TO A PARALLEL COURSE TO THE LOC. DURING THIS TIME; THE ATC CTLR INITIATED SEVERAL DISTRACTING XMISSIONS REGARDING TUNING THE LOC; RECEIVING THE LOC; AND QUESTIONED IF WE WERE ESTABLISHED ON THE LOC. THE RWY WAS IN SIGHT AT THIS TIME AND I EXPLAINED THAT WE WERE CORRECTING BACK TO THE LOC. THE ATC CTLR THEN ASSIGNED A HDG OF 070 DEGS AND AN ALT OF 6000 FT. SINCE THE RWY WAS IN SIGHT AT THIS TIME IT WAS NOT CLR THAT THE CTLR WAS DIRECTING US TO MAKE A GAR. I CONFIRMED THE CLRNC AND A GAR WAS INITIATED. A RADAR VECTOR TO FINAL AND THE SUBSEQUENT LNDG WAS UNEVENTFUL. IT WAS INTERESTING TO NOTE THE SECOND TIME ON BASE; IN THE SAME LOCATION AS THE FIRST APCH; THE AUDIO QUALITY OF THE ATC XMISSION WAS AGAIN POOR AND GARBLED. WITH A HEIGHTENED AWARENESS OF ALL CREW MEMBERS AND ANTICIPATING ATC INSTRUCTIONS; WE CONFIRMED THAT WE WERE CLRED FOR THE APCH. A PHONE CALL WAS REQUESTED AND INITIATED TO THE APCH CTL SUPVR (WHO WAS THE ACTUAL CTLR) AND THE SEQUENCE OF EVENTS WAS DISCUSSED. IN THAT DISCUSSION; THE CTLR CONFIRMED THAT SEVERAL OTHER FLT CREWS HAVE RPTED THAT THE AUDIO QUALITY OF ATC XMISSION ON BASE LEG WAS DETERMINED TO BE OF POOR QUALITY. THE RESULTING CONFUSION OF ATC CLRNC AND THE RAPID SUCCESSION OF CONFIRMATION; REQUESTS FOR INFO; AND MULTIPLE CLRNCS; INCREASED THE COCKPIT WORKLOAD AND REDUCED THE OPPORTUNITY FOR ME TO HELP THE IOE PF TO ANTICIPATE THE FLT MANEUVER DURING A CRITICAL PHASE OF FLT. THE IOE CREW MEMBER AND I HAVE DEBRIEFED THE SEQUENCE OF EVENTS THAT LED TO THIS EVENT AT GREAT LENGTH.