Each receiver must be connected to an external antenna, which is included with the receiver. Antenna placement is crucial to receiving a clear signal. In some locations users have experienced difficulty receiving the Sirius programming because the signal is not consistently strong. For the best reception, antennas should be placed such that they have an unobstructed view of the sky (preferably on rooftops without overhanging eaves or trees). If this is not an option, the antenna should be placed on an exterior wall. When placing on an exterior wall, the antenna should be mounted to a wall which faces the center of the continental United States in order to minimize the likelihood of the building itself blocking the signal.