The optional reflector board heating system is designed for using the Model VT-1 in cold climates.  It includes a 12-VDC strip heater affixed to the underside of the reflector board, a snowfall sensor mounted on the side of the Model VT-1 electronics module, a three-way switch, and a heater power cable.  The system is designed to keep the reflector board clear of snow and ice, but it conserves power and makes it practical to power the unit by battery or solar electric power.  When in the Auto mode, the snowfall sensor activates the heater only when snowfall is detected.  When activated, the heater draws approximately 100 watts.  The snowfall sensor draws approximately 5 watts and operates on 12 VDC.  The three-way switch has positions for Auto, Off and Manual.  In the Manual mode, the snowfall sensor is bypassed and the heater is manually activated.  The underside of the reflector board is insulated to improve efficiency.