They are probably running a 1kW transmitter. Generally broadcasters will run two transmitters in tandem. These may be configured using a combiner to double the output power or could simply be a standby that switches over in the event of a failure. The former will route 1/2 of its remaining power into a resistive load and result in 1/4 power when one transmitter fails. This method is also used to make servicing the transmitter easier. Although many transmitters are solid state now usually comprised of power modules that are combined to give the required output power, there are plenty left that use vacuum tubes. Television generally uses separate transmitters for audio and video, but not always. If the broadcaster isn't on the air, it isn't making any money. :)