GA SMT UNAUTH TKOF. PLT WAS OFF FREQ WHEN CALLING THE TWR.

Narrative

CONTACTED HAGERSTOWN GND. STATED READY TO TAXI. GND ASKED IF I COULD MAKE AN INTXN TKOF ON RWY 27 DOWNWIND; WINDS 060 /7. I STATED I COULD. I THEN SWITCHED TO TWR ON 120.3 AND ASKED IF CLRED TO TKOF. THE FREQ WAS CLR OF ANY XMISSIONS. I REMEMBER THINKING ABOUT GETTING BACK IN TIME TO WATCH A MEDIA EVENT. THE FREQ WAS STILL QUIET. BELIEVING THAT THE GND HAD CLRED ME FOR TKOF; I LINED UP ON THE RWY. I STILL HEARD NOTHING ON THE RADIO; THEN TOOK OFF. ABOUT 500' AGL; I SAW COMMUTER SMT CROSS MY PATH ABOUT 1 MI AHEAD AND 500' HIGHER. I RADIOED TWR THAT I HAD THE TFC IN SIGHT--NO REPLY. IT WAS THEN THAT I CHKED THE FREQ ON THE DIGITAL RADIO AND FOUND THAT I WAS OFF ON 120.5. YOU SEE; THE RADIO'S LED READOUT WAS NOT MAKING THE NUMBERS OUT COMPLETELY. WELL; AS SOON AS I DISCOVERED THIS IT TOLD THE TWR I HAD THE TFC IN SIGHT. THE SMT PLANE RESPONDED WITH 'THAT'S A NICE VIOLATION.' THEN TWR ASKED FOR MY FULL N# AND DEST; AND IF I KNEW WHAT I JUST DID. I REPLIED THAT I WAS OFF FREQ. TWR THEN TOLD ME I TOOK OFF W/O A CLRNC. MY INEXPERIENCE IN NOT IDENTING THE RADIO PROB ON THE GND AND BEING AT A STRANGE FIELD ASKING ME TO DO A DIFFERENT DEP THAN WHAT I WAS EXPECTING; AND THE FACT THAT THE ACFT HAD ONLY ONE RADIO; IN POOR CONDITION; ALL WERE CONTRIBUTING FACTORS.