 A transport can also carry radio and interactive television content.A typical American ATSC transport offers three to four channels, in most cases one of them is broadcast in HD (the station's main channel) and the rest of the channels are broadcast in standard definition, due to the limited 6 MHz 8VSB bandwidth used.In those cases when one physical channel transports more than one HD sub-channel, the data rate drops to the level of standard definition DVD-Video.