Why is there no channel 1 on television in the United States?

In the U.S., virtually all sets for sale with screen size larger than 30 inches (diagonal) are capable of EDTV resolutions and the vast majority are actually HDTVs. In smaller set sizes there is a mixture of SDTVs and HDTVs. The FCC has mandated steps that digital tuners be included in various set sizes in specified proportions of sets produced, beginning in 2004. It is estimated that the year 2006 will be the first to have more HDTVs than conventional TVs sold. As of March 2006, all 25 inch and larger TVs for sale must have ATSC tuners capable of receiving the 8VSB modulation used for free terrestrial digital broadcasts in the United States. The final conversion step is a mandate that all televisions and TV-tuning devices have ATSC tuners by March 2007. Many of these will not be capable of displaying HDTV signals at their full resolution, but they will be capable of decoding and displaying these signals. No mandates exist for availability of digital set-top boxes enabling DTV reception and display on existing analog sets.