NMAC OF 2 SMA'S.

Narrative

I RPTED 5 MI S OF THE ARPT WITH THE INFO FOR LNDG. THE TWR REQUESTED THAT I RPT ON THE 45 FOR A L DOWNWIND ENTRY FOR RWY 26. I RPTED ON THE 45 AND WAS DSNDING 200 FT ABOVE PATTERN ALT. THE TWR RPTED TFC TO BE DEPARTING RWY 21 FOR A L DOWNWIND DEP. I ACKNOWLEDGED THE CALL BUT DID NOT RPT NEGATIVE CONTACT. THE TWR RPTED MY POS AS INBOUND ON THE 45 TO THE DEPARTING TFC. I SAW THE TFC AT MY 11 O'CLOCK; SAME ALT; AND LOWERED THE NOSE TO DSND SINCE HE APPEARED TO BE CLBING AND TURNING TO THE R. THE TFC PASSED OVER ME. WE BOTH RPTED OUR ACTIONS TO THE TWR AND CONTINUED. THE TFC AT THE ARPT WAS HVY WITH PLANES IN BOTH R AND L PATTERNS FOR RWY 26. THE TYPICAL PATTERN CALLS FOR ARRS ON RWY 26 AND DEP ON RWY 21. I FLY THE 45 LEFT ENTRY TO THE E OF THE EXTENDED CTRLINE OF RWY 21 TO KEEP DEPARTING TFC TO MY L. THE TWR SHOULD REQUEST THAT I STAY ON ONE SIDE OR THE OTHER OF THE EXTENDED CTRLINE OF THE DEPARTING RWY WHEN DEPARTING TFC IS IN CONFLICT. THE DEPARTING TFC SHOULD HAVE BEEN REQUESTED TO CONTINUE UPWIND UNTIL I WAS IN SIGHT OF THE CTLR CALLS THE XWIND. I SHOULD HAVE BEEN REQUESTED TO MAKE A 360 DEG TURN FOR SPACING IF THE DEPARTING TFC HAD TO LEAVE IMMEDIATELY. I SHOULD HAVE SPECIFICALLY RPTED NEGATIVE CONTACT OR REQUESTED THE PRESENT POS TO MY TFC; BUT DID NOT DUE TO THE HVY TFC.