A11 CTLR DESCRIBES POSSIBLE OPDEV WHEN USING WRONG CALL SIGN TO ISSUE HDG ASSIGNMENT.

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I WAS WORKING S RADAR/SE RADAR AND S HDOF POS COMBINED DURING A BUSY PERIOD. FINAL RADAR WAS EXTENDING THE FINAL OUT 20+ MI; SO I WAS HAVING TO VECTOR ACFT TO AN UPWIND THEN DOWNWIND PRIOR TO HANDING OFF TO THE FINAL RADAR SECTOR. AT THE LATTER PART OF THIS SESSION; I WAS TRYING TO TERMINATE THE UPWIND VECTORS AS INSTRUCTED BY THE FACILITY AND THE OPERATIONAL SUPVR ON POS AND RESUME NORMAL OPS WHEN ACFT X CALLED INBOUND. I ISSUED ACFT X A 90 DEG HDG TO ACHIEVE ADDITIONAL SPACING WITH THE ACFT IN FRONT OF HIM. ACFT Y (A SIMILAR SOUNDING CALL SIGN) DEPARTED ANCHORAGE CLBING TO 4000 FT. MY INTENT WAS TO VECTOR ACFT Y TO A HDG OF 220 DEGS AWAY FROM THE TAIL END OF THE UPWIND/DOWNWIND PATTERN; WHICH WOULD ALLOW ME TO CONTINUE HIS CLB TO FL200 AND VECTOR HIM OUT THE ENA GATE. I WAS THEN GOING TO GIVE ACFT X A VECTOR HDG OF 020 DEGS TO KEEP ACFT X AWAY FROM ACFT Y. BUT IN THE CONFUSION OF MY SITUATION WITH SETTING UP THE DOWNWIND PATTERN; TRYING TO TERMINATE THE UPWIND PATTERN AND TUNNELING ACFT Y UNDER OTHER TFC; I ISSUED THE HDG I WAS GOING TO GIVE ACFT Y TO ACFT X WHICH WAS A R TURN TO 220 DEGS. IT WAS BROUGHT TO MY ATTN ACFT X WAS TURNING SWBOUND; SO I IMMEDIATELY ISSUED A L TURN BACK AROUND TO HDG 020 DEGS.