DURING AN IFR XCOUNTRY; PVT PLT IN AN SMA ACFT EXPERIENCED ACFT ELECTRICAL PROBLEM CAUSING LOSS OF THE PRIMARY NAV AND COM RADIO EQUIP. THE PLT MADE AN UNSCHEDULED LNDG AT A NEAR BY VFR ARPT.

Narrative

FLYING IFR FROM WHITE PLAINS; NY; TO ATLANTA; GA. WHEN 20 MI W OF WINCHESTER; VA; ZDC NOTED THAT MY TRANSPONDER SIGNAL WAS LOST. AT THE SAME TIME MY LORAN WENT BLANK. CHKED AMMETER AND SAW THAT IT WAS DISCHARGING. ALSO; LOW VOLTAGE WARNING WAS FLASHING. SHUT DOWN MOST UNNECESSARY ELECTRICAL EQUIP; INCLUDING PITOT HEAT (BIG DRAIN) WHICH WAS ON BECAUSE A FEW MINS EARLIER I HAD BEEN IN AND OUT OF CLOUD TOPS AT 8000 FT; NOTIFIED CTLR OF PROBLEM AND REQUESTED VECTOR TO NEAREST ARPT; ALSO WX. WAS GIVEN VECTOR OF 090 TO WINCHESTER; VA; AND WX AT DULLES (GOOD VFR). TOLD CTLR I HAD HAND-HELD RADIO IN PLANE AND WAS TURNING TOWARD WINCHESTER. REQUESTED AND WAS GIVEN CLRNC DOWN TO 6000 FT. THEN RADIO WENT DEAD. DSNDED TO 6000 THROUGH HOLE IN BROKEN LAYER. WAS THEN IN GOOD VFR. CONTINUED DSCNT AND BEGAN LOOKING FOR WINCHESTER. GOT OUT HAND-HELD RADIO BUT HAD AN ANTENNA PROBLEM WITH RADIO. DECIDED BETTER TO CONCENTRATE ON FLYING THE PLANE AND LEAVE THE RADIO ALONE. FOUND WINCHESTER AND LANDED WITHOUT INCIDENT. AFTER LNDG; SPOKE BY TELEPHONE WITH FAA ARTCC AREA MGR; DULLES. PROBLEM TURNED OUT TO BE ALTERNATOR FAILURE; AS EXPECTED GIVEN THE SYMPTOMS. WHAT TO DO BETTER? 1) MORE FREQUENT SCAN OF THE AMMETER AND WARNING PANEL TO CATCH PROBLEM EARLIER. 2) SOME PRACTICE WITH THE HAND-HELD RADIO TO BE MORE COMFORTABLE WITH IT IN AN EMER. OTHER THAN THAT; I THINK I HANDLED THE SITUATION PROPERLY.