Understanding how Smartuners work helps all of us to use them better. The purpose of this note is to clear up misconceptions about what happens to a Smartuner when power is turned on and off. 

POWER ON - When a Smartuner is turned on, its microprocessor goes through a number of steps to initialize the tuner. When initialization is complete, the Smartuner is in the BYPASS or RESET state. In this state, all of the inductors and capacitors are out of the RF circuit so there is a direct connection from the feed line to the antenna system. This is the same state reached when the RESET button is pressed on a Smartlock box.

POWER OFF - When a Smartuner is turned off, all relays go to their power-off (OPEN) condition, so all of the inductors are IN the RF circuit while the capacitors are out of the circuit.