as mentioned above, set it to power.
setting it to radio, only keeps the wire powered up when FM and AM are the selected source, not HD. by having it powered up all the time, the antenna amp will be powered up durring all of the sources, including the HD radio.
however if the antenna is a power up and down antenna, the the antenna will always be rasied, even when the sources are turned off, so there will be no way to lower the antenna while the car is on (like going through a car wash) and as your antenna might not be like this i just wanted to make sure that if anybody is reading this with one they will know about it before its too late.
it is a little foolish that having the setting set to radio, does not keep the antenna wire powered up also durring the HD source, since that is techinally a radio input and would always need the antenna rasied or powered up to function. they are basiclly asking for a bunch of antennas to get broke for people driving specific car and radio combinations. once again pioneer, here is your FAIL award.