PLT OF C175 TOOK OFF FROM MRY WITHOUT CLRNC.

Narrative

WHILE TAXIING FOR TKOF AT MONTEREY ARPT; GND CTL ADVISED THAT I WAS CLRED TO RWY 28L; THAT I WAS TO TURN R TO COURSE 060 DEGS PAST THE FREEWAY. HE GAVE ME A XPONDER CODE AND THE FREQ FOR DEP CT. I WAS USING MY NAV CASE AS A KNEE BOARD; AND IT SLIPPED OFF MY LAP AND DUMPED A LOT OF STUFF ON THE FLOOR; SO I HAD TO ASK THE GND CTLR TO REPEAT HIMSELF 3 TIMES BEFORE I GOT ALL THE INFO STRAIGHT; AND THE CONFUSION SORT OF MESSED UP MY NORMAL RHYTHM AND SEQUENCE. BY THE TIME I GOT THE COCKPIT SQUARED AWAY; I WAS AT THE TKOF END OF THE RWY. THE C340 AHEAD OF ME WAS TAKING OFF; AND THE GUY BEHIND ME WAS GETTING DEP INSTRUCTIONS. I INADVERTENTLY FAILED TO SWITCH TO TWR FREQ FOR CLRNC. THINKING BACK ON IT NOW; I ASSUME THAT; IN THE CONFUSION; I TOOK THE GND CTLR'S WORDS AS CLRNC FROM THE TWR. I PULLED UP SHORT OF THE RWY; CHKED VISUALLY FOR ONCOMING TFC; TOOK OFF AND SWITCHED TO DEP CTL. THE DEP CTLR ASKED ME IF I HAD GOTTEN CLRNC FOR TKOF AND; UPON REFLECTION; I REALIZED THAT I HAD NOT. AT FIRST; I TOLD HIM THAT I THOUGHT I HAD; BUT I REALIZED AFTER TALKING TO HIM THAT I HAD REALLY SCREWED UP. THIS INCIDENT REALLY GOT MY ATTN. I HAVE FLOWN FOR 30 YRS WITHOUT A BLEMISH ON MY RECORD OR A SCRATCHED AIRPLANE; BUT I BELIEVE THAT I NEED MORE TRAINING BEFORE I FLY INTO COMPLEX AIRSPACE. IT DIDN'T TAKE MUCH TO THROW MY CONCENTRATION OFF AND UPSET THE SEQUENCE OF A VITAL MENTAL CHKLIST.