> 5 Megawatts is the maximum allowable power for the higher UHF's. 2 thru 13 are limited to 100KW.
Actually, 100kW is the max for channels 2-6 (LoBand VHF). Channels 7-13 (HiBand VHF) are allowed as much as 316kW visual. Remember, of course, that the aural signal power is well below that of the video.
5000kW ERP is the max for UHF, but, remember, on UHF, antennas can be made VERY high in gain. 5 megawatts can be generated ERP with much less than one might think. Most stations of that power level have actual transmitter outputs of between 100kW and 200kW (which still makes for a whoppin' power bill). And, the stations must deal with signal loss between the transmitter and antenna (it is UHF, after all), but, that's another discussion.
As an aside, don't get too close to a UHF TV antenna with this kind of ERP. Dangerous.
DE