STUDENT PLT HAS LOST COMS.

Narrative

I AM A STUDENT PLT. ON MAY/WED/02; I WAS ON MY FIRST XCOUNTRY FLT IN 2 YRS. I HAD PLANNED MY TRIP FROM 15G TO OSU FOR SOME MORE EXPERIENCE WITH A CTL TWR. I CHKED THE RADIO IN THE AIRPLANE WITH MY INSTRUCTOR TO BE SURE IT WORKED BEFORE DEPARTING 15G. I LISTENED TO ATIS AND WAS ABOUT 7 MI FROM THE OSU ARPT. I RADIOED THAT I WAS A STUDENT PLT; MY LOCATION AND PLANE NUMBER. I RECEIVED NO ANSWER FROM THE TWR. I WAS ABLE TO RECEIVE; BUT APPARENTLY COULD NOT XMIT. I CIRCLED JUST OUTSIDE THEIR AIRSPACE AND CONTINUED TRYING TO MAKE CONTACT. I HEARD THE OTHER TFC IN THE AREA; BUT WAS UNABLE TO GET A VISUAL ON ANY OF THEM. I WAS SCARED THAT I WOULD COLLIDE WITH THE OTHER TFC IN THE AREA. I PUT 7700 I MY XPONDER. I HEARD THE TWR CALL 'ACFT SQUAWKING 7700 YOU ARE CLRED TO LAND.' I CONTINUED TRYING TO CONTACT THE TWR. THEY REPEATED THAT I WAS CLRED TO LAND. THEY THEN REPEATED EMER ACFT YOU ARE CLRED TO LAND. I REALIZED THAT I HAD SQUAWKED 7700 INSTEAD OF 7600. I QUICKLY CHANGED THE XPONDER TO 7600. I CONTINUED TRYING TO MAKE RADIO CONTACT. JUST BEFORE LNDG THEY MUST HAVE FINALLY HEARD ME BECAUSE THEY RESPONDED WITH MY ACFT NUMBER AND ASKED IF I HAD ANY OTHER EMER OTHER THAN MY RADIO; I REPLIED; 'NO.' I LANDED AND SAID THAT I WOULD BE DOING A TOUCH AND GO. I DEPARTED STRAIGHT OUT FOR SOME TIME AND ASKED IF I COULD DEPART ON MY HEADING OF 056 DEGS. THE TWR REPLIED THAT I WAS CLRED TO TURN TO MY HEADING.