A DEPARTING IFR TWIN CESSNA MAINTAINING 3000 FT PENETRATES THE 3 MI RING AROUND A TV TWR OBSTRUCTION BELOW THE ALLOWABLE ALT OF 3500 FT.

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LCL CTL; GND CTL AND CLRNC DELIVERY WERE ALL COMBINED AND I HAD JUST RELIEVED THE PREVIOUS CTLR. MY FIRST CALL WAS TO A VEHICLE ON GND. SECONDS LATER; TWIN CESSNA (NGA X) CALLED. HE HAD BEEN SHIPPED TO DEP PRIOR TO MY TAKING POS; BUT WAS STILL IN MY AIRSPACE. HE ASKED IF DEP WAS OPEN AT 121.5. I REPLIED THAT THE CORRECT FREQ WAS 120.1. HE THEN RETURNED TO THE CORRECT FREQ. THE PREVIOUS CTLR HAD GIVEN NGA X A 300 DEG HDG OFF OF RWY 32R; A STANDARD W HEADING FOR PROP DEPS; DESIGNED TO MISS TV TWRS W OF THE ARPT WHICH HAVE A 3 MI PROTECTED AIRSPACE AROUND THEM TO 3500 FT MSL. NGA X WAS LEVEL AT 3000 FT. AFTER I GAVE HIM THE CORRECT FREQ; I KEYED UP THE WEST CTLR AND TOLD HIM NGA X HAD BEEN ON THE WRONG FREQ AND WAS COMING OVER. I MADE THIS CALL BECAUSE NGA X WAS ALREADY PAST THE NORMAL POINT OF CTL TRANSFER. WEST SAID CLB HIM TO 4000 FT. I REPLIED HE WAS ALREADY ON HIS FREQ. I HAD NOT STUDIED NGA X'S TRACK AND HAD ASSUMED; GIVEN THE WIND (29 DEGS 08 KTS); HEADING AND OTHER FACTORS; THAT EVEN THOUGH HE WAS CLOSE TO THE 3 MI RING; IT WOULD NOT BE A FACTOR. I HAD MADE NO ATTEMPT TO TURN HIM AWAY FROM THE RING AND SUBSEQUENT DATA REDUCTION SHOWED THAT HE GRAZED THE NE SIDE OF THE RING.