DC10-30 ENRTE NAGOYA TO GUAM HAS CALL SIGN CONFUSION FROM ATC MIXING UP FLT NUMBERS.

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ON FLT FROM NAGOYA TO GUAM WE WERE IN COM WITH TOKYO RADIO. WE WERE TOLD TO SWITCH TO HNL RADIO AT NEXT POS RPT. AT NEXT POS RPT POINT WE CONTACTED HNL RADIO TO GIVE POS RPT AND SEL CALL CHK. HNL RADIO TOOK POS RPT BUT HAD PROBS WITH SEL CALL CHK. WE GAVE SEL CALL CODE AND THEN RECEIVED A GOOD CHK. ABOUT 100 MI AHEAD WAS TSTM OVERHANG SO CAPT REQUESTED TRACK OFFSET OF 10 MI TO R OF COURSE IN CASE WE NEEDED TO DEVIATE. WE RECEIVED ATC CLRNC TO DEVIATE FROM HNL RADIO. AS WE APCHED OVERHANG WE FOUND WE DID NOT NEED TO DEVIATE BUT MOVED ONLY 2 MI TO R TO MISS OVERHANG FOR 5 MINS THEN WENT BACK TO TRACK. ON NEXT RPT POINT WE RPTED OVER CHK POINT TO HNL RADIO. HNL RADIO THEN ASKED WHO WE WERE; FLT AB OR FLC AC. WE TOLD HER WE WERE FLT AB. HNL THEN STATED THEY THOUGHT WE WERE FLT AC GOING TO SAIPAN. HNL RADIO HAD MISTAKEN US FOR FLT AC AND TOKYO RADIO HAD SENT US OVER TO HNL RADIO ONE POS POINT EARLY BEFORE OAKLAND FIR. THERE HAD BEEN A COM MIX-UP BTWN TOKYO; HNL RADIO AND US. WITH VOICE COM IN THE FAR EAST AS DIFFICULT AS IT IS WITH DIFFERENT LANGUAGES IT SEEMS THE SAT COMS THAT IS AVAILABLE TODAY SHOULD BE USED INSTEAD OF HF. THAT COULD HELP COM CONFUSION. ALL PARTIES NEED TO KNOW WHEN YOU ARE LEAVING OR ENTERING A FIR AND TO MAKE SURE THAT BOTH CTLING AGENCIES KNOW YOU ARE ON AN OFFSET FOR WX. FLT NUMBERS SHOULD ALSO NOT BE SO CLOSE SUCH AS AB; AC; ETC; THAT THEY COULD BE MISSED. AIRLINES AND FLTS SHOULD BE REQUIRED TO HAVE TOTALLY DIFFERENT NUMBERS FOR FLTS ON THE SAME TRACK.