BEECH BE36 PLT ENCOUNTERS ICING; SWITCHES FREQ AND HAS LOST COM.

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I HAD FILED AN IFR FLT PLAN TO TRAVEL FROM DXR TO IND AT 12000 FT. I ENCOUNTERED SOME LIGHT ICING IN THE CLOUDS AND WENT TO 14000 FT. AT 14000 FT I ALSO ENCOUNTERED ICING IN THE CLOUDS AND RPTED THIS TO ATC AND ASKED FOR 16000 FT WITH A BLOCK WAS GIVEN A BLOCK TO FL190. AFTER ASKING PERMISSION TO SWITCH FREQS TO CHK THE WX; I CORRECTLY DIALED IN 122.0 AND CHOSE 122.0 AS THE ACTIVE FREQ. I WANTED TO USE THE VOR DME TO GET MY EXACT DISTANCE TO THE JOHNSTOWN VOR AND INSTEAD OF PUSHING THE PUSH C/V BUTTON/KNOB AND THEN TURNING TO THE VOR FREQ; I TURNED THE KNOB/BUTTON FIRST; CAUSING ME TO LOSE THE ATC FREQ. GOT MY WX BRIEFING; BECAUSE I WAS CONCERNED ABOUT BEING PUSHED UP HIGHER BY POSSIBLE ICING AND THEN WAS LOOKING FOR THE CORRECT ATC FREQ ON THE CHART AND NOTED I WAS AGAIN GOING INTO THE CLOUDS WHICH HAD TWICE PREVIOUSLY CAUSED ICING. TEMP WAS BELOW FREEZING. SINCE I HAD THE BLOCK TO FL190; I TRIED STAY OUT OF POSSIBLE ICING BY CLBING ABOVE THE WX BUT NEARLY STALLED THE PLANE. EXECUTED TURNS TO STAY OUT OF POSSIBLE ICING; INCLUDING A 180 DEG TURN. SINCE I HAD HAD ICING TWICE EARLIER IN THE FLT; MY JUDGEMENT WAS THAT MY PRIORITY WAS TO FLY THE PLANE AND I NEEDED TO STAY CLR OF POSSIBLE ICING. WHEN I BELIEVE I WAS CLR OF WX I RETURNED TO COURSE. DURING THE INCIDENT I TRIED TO RADIO IND APCH (THE FREQ WAS ON MY GPS) TRIED A VOR FREQ; AND AGAIN BRIEFLY TRIED FLT WATCH BEFORE I WENT BACK TO THE CHART TO FIND AN ATC CODE. I DID CONSIDER CALLING 121.5 BUT FELT THAT I WAS BACK ON COURSE AND; THEREFORE; THERE WAS NO EMER JUSTIFYING THE USE OF THE EMER FREQ. DURING THE INCIDENT THERE WERE NO TFC ALERTS SHOWN BY THE GPS. OTHER CONTRIBUTING HUMAN FACTOR WAS A LONG SINGLE PLT IFR FLT WITH NO AUTOPLT. ANOTHER JUDGEMENT BY BOTH ME AND ATC WERE CHKING THE WX WHILE APCHING THE CLASS B AIRSPACE AROUND PITTSBURGH. AN EQUIP ISSUE WAS HOW EASY IT WAS TO TWIST INSTEAD OF PUSH THE C/V BUTTON ON THE GPS AND; THEREBY; LOSE MY SECONDARY FREQ. IN THE FUTURE; I WILL ALWAYS KEEP MY BACKUP FREQ ON THE GPS AND DIAL FLT WATCH ON MY SECONDARY COM SYS.