ATC EQUIP PROB RADIO FREQ UNUSABLE.

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SLIGHTLY OVER ONE YR AGO I FILED AN ASRS RPT ON THE SAME PROB. ATC ADMINISTRATION; IN REACTION TO NASA INPUT; TRIED TO CHANGE THE FREQ BUT ENDED UP WITH WORSE PROBS. THEN THEY WERE SUPPOSED TO INSTALL FREQ FILTERS TO ELIMINATE THE INTERFERENCE. TO THIS DATE; PROBS STILL EXIST WITH NO HELP IN SIGHT. THE BLUFTON SUPER HIGH ALT SECTOR FREQ IS 133.52. THIS FREQ HAS A HISTORY OF INTERFERENCE HEARD BY PLTS AT ALL ALTS. THE INTERFERENCE AT TIMES IS SO STRONG AS TO BLOCK ATC XMISSIONS; AS WAS THE CASE TODAY. ACR X ENRTE TO YYZ WAS AT FL370. THE ADJACENT SUPER HIGH SECTOR WHICH ACR X WAS TO ENTER NEXT REQUESTED I DSND ACR X TO FL350 FOR TFC. IT TOOK NO LESS THAN 4 XMISSION AND A FREQ CHANGE TO GET THE CLRNC TO THE PLT. THIS IS UNSAFE. ANOTHER COMPANY FLT ON FREQ AT THE SAME TIME WAS ALSO COMPLAINING AND HAD TO BE CHANGED TO ANOTHER FREQ. THERE HAVE BEEN DAYS THE SECTOR IS CLOSED BECAUSE THE INTERFERENCE IS SO BAD. SEVERAL CTLRS BELIEVE THE INTERFERENCE IS CAUSED BY 133.37 WHICH IS THE LORAIN SECTOR WHICH IS ADJACENT BOTH PHYSICALLY AND AIRSPACE WISE TO BLUFTON. THE AIRWAYS FACILITY PEOPLE ARE NO HELP. THEY JUST KEEP ASKING FOR FREQ INTERFERENCE FORMS TO BE FILED OUT; BUT DO NOTHING TO RESOLVE THE ISSUE.