NAV ERROR BY PVT PLT IN AN SMA DURING A NIGHT OP. UNAUTH PENETRATION OF CLASS B AIRSPACE; PROX OF APCH ROUTE TO SFO.

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FLYING FROM SJC TO HAF AT NIGHT; I LEVELED OFF AT 3500 FT AND WAS NOT CLRED INTO CLASS B. I HAD SET #1 NAV RADIO TO SJC AND WAS FOLLOWING 270 DEG RADIAL AS A PRECAUTION (AS A BACKUP TO PILOTAGE). AT THE POINT BEING HANDED FROM ONE CTLR (BAY) TO ANOTHER; I GOT NO REPLY. FOR 2-5 MINS I CONTINUED TO TRY TO CONTACT BAY APCH WITH NO RESULT. AT FIRST I COULD HEAR OTHER RADIO TFC; THEN ONLY SILENCE. WITH THE VOR NEEDLE CENTERED; I FELT CONFIDENT THAT I WAS ON COURSE AND NOT IN CLASS B AIRSPACE. AT SOME POINT; I LOOKED OUT A SIDE WINDOW AND REALIZED I WAS OVER THE BAY; 2-3 MI OFF COURSE. I TURNED L TO GET OUT OF CLASS B AND BACK ON COURSE. ON THE WAY BACK TO MY INTENDED COURSE; MY RADIO SEEMED TO START WORKING AGAIN. THIS MAY HAVE BEEN BY COINCIDENCE; OR A RESULT MY FLIPPING SWITCHES BACK AND FORTH; WORKING THE FREQ KNOBS BACK AND FORTH; JIGGLING CONNECTORS; ETC. I GOT A REPLY FROM BAY APCH AND CONTINUED THE REST OF MY INTENDED COURSE (SJC-HAF-CCR- SJC) WITHOUT INCIDENT. CONTRIBUTING FACTORS: LAST DIGIT OF VOR FREQ DISPLAY DEAD. POSSIBILITY OF WRONG FREQ SELECTED (BUT I DON'T THINK SO). #1 RADIO WOULDN'T XMIT (I WAS USING #2) COULD BE INDICATIVE OF LARGER PROB WITH THIS ACFT'S COM/NAV GEAR. DURING THE ENTIRE INCIDENT; IT IS POSSIBLE THAT I WAS XMITTING; BUT NOT RECEIVING COM OR NAV (HENCE DEAD VOR NEEDLE). AT THE POINT OF BEING HDOF; I MAY HAVE BEEN GIVEN THE WRONG FREQ; OR BAY MIGHT HAVE BEEN IGNORING ME. (WOULDN'T BE THE FIRST TIME). I FAILED TO 'AVIATE; NAV; COMMUNICATE;' I LET COM TAKE PRECEDENCE OVER NAV. LOST COM = STRESS. DID NOT REALIZE BOTH COM AND NAV WERE SIMULTANEOUSLY INOP; CONTINUED TO TRUST VOR NEEDLE.