 
   // Enable the ADC
   ADCSRA |= bit(ADEN);
-  enableAdcPullups();
+  // The probe themistor voltage dividers are normally powered down
+  // to save power, using digital lines to supply Vcc to them.
+  digitalWrite(_pinProbeSupply, HIGH);
+  // Wait for AREF capacitor to charge
   stabilizeAdc();
+
   for (unsigned char pin=0; pin < RF_PINS_PER_SOURCE; ++pin)
   {
     if (PIN_DISABLED(pin))

  if (_pinLedRx != 0xff) pinMode(_pinLedRx, OUTPUT);
  if (_pinLedTx != 0xff) pinMode(_pinLedTx, OUTPUT);

  setupSupplyPins();

  // Force a transmit on next read
  memset(_previousReads, 0xff, sizeof(_previousReads));

// Digital pins for LEDs, 0xff to disable
const unsigned char _pinLedRx = 0xff;
const unsigned char _pinLedTx = 0xff; //9
// Digital pin used for sourcing power to the probe dividers
const unsigned char _pinProbeSupply = 4;
// Percentage (integer) of VCC where the battery is considered low (33% = 1.1V)
#define BATTERY_LOW_PCT 33
// Number of seconds to keep the "recent/new" bit set
