SMA ON LOC APCH DSNDS UPON PASSING OM. CTLR TELLS TO CLB TO ASSIGNED AS HAS NOT PASSED OM. FALSE SIGNAL.

Narrative

I CHKED IN AND INFORMED APCH THAT I WAS LEVEL AT 3000 FT ON THE LOC RWY 27 APCH. ABOUT 1-2 MINS AFTER I CHKED IN ON 121.0 I GOT THE LIGHT AND ORAL SOUND ON THE OM BEACON PANEL. I STARTED MY WATCH AND STARTED TO DSND. I CHKED MY TIME DURING MY SCAN AND :36 SECONDS HAD ELAPSED. ABOUT :30 SECONDS LATER ATC CALLED AND TOLD ME TO CLB AND MAINTAIN 3000 FT. I IMMEDIATELY APPLIED PWR AND STARTED A CLB BACK TO 3000 FT. I INFORMED ATC THAT I HAD GOTTEN AN OM LIGHT AND TONE AND HAD STARTED MY DSCNT ON THE APCH. APCH INFORMED ME THAT I WAS 3 NM E OF HOBO AND TO MAINTAIN 3000 UNTIL HOBO; CLRED FOR THE LOC RWY 27 APCH. I INFORMED HIM THAT I WAS LEAVING 2400 FOR 3000 AND WAS CLRED FOR THE APCH. FROM THE TIME APCH ON 119.3 INITIALLY CLRED ME FOR THE APCH 13 MI E OF HOBO UNTIL APCH ON 121.0 TOLD ME TO CLB BACK TO 3000; APPROX 7 MINS HAD PASSED. WHEN I GOT ON THE GND I STARTED TO LOOK AT THE ENRTE AND APCH PLATES. I KNEW PEACHTREE DEKALB WAS SE OFF MCCOLLUM. LOOKING AT THE APCH PLATES FOR PDK I FOUND THAT THEY HAVE AN ILS RWY 20L APCH AND THE OM IS CHAMB 5.5 NM FROM THE THRESHOLD. CHAMB WAS WHAT I WAS RECEIVING WHEN I STARTED MY INITIAL DSCNT AND NOT HOBO. I FEEL THAT THIS COULD BE A POTENTIALLY DANGEROUS SITUATION FOR PLTS THAT ARE NOT FAMILIAR WITH THE AREA AND THE DIFFERENT APCHS INTO THE OTHER ARPTS. SO THIS TYPE OF MISTAKE DOES NOT HAPPEN AGAIN; I THINK THAT ATC SHOULD ADVISE PLTS OF THE POSSIBILITY OF RECEIVING CHAMB OM WHEN ON THE RYY LOC RWY 27 APCH; OR PUBLISH A RADIAL OFF OF THE PDK OR ATL VOR FOR A MORE PRECISE IDENT OF HOBO OM.