Does the Directed Electronics Sirius outdoor antenna (model #14240) need to be grounded? TV antennas and satellite TV dishes do, but the installation manual I downloaded from Crutchfield doesn't say a word about grounding. Assuming the answer is "yes," my next question is how? Where would I find a suitable grounding block with SMA connectors on it, and an SMA-to-SMA cable to go from the antenna to the block? 
