<P> Cable radio, a slightly older technology, has also become widespread; Music Choice is the market leader in this field, with its primary competitors being Sirius XM, Muzak, DMX, Sonic Tap and Canada - based Galaxie . CRN Digital Talk Radio Networks specialize in talk radio . Cable radio has the disadvantage that it requires a cable TV hookup, limiting its use outside the home . </P> <P> Unlike the mandated digital television transition, the U.S. government has not mandated a transition to digital radio, although it allows digital radio to be broadcast . The national standard is HD Radio, a proprietary in - band on - channel format that allows digital and analog signals to be broadcast simultaneously . Radio companies aggressively marketed HD Radio throughout the 2000s, touting its clearer signal and capacity for digital subchannels, but the technology never caught on with the general public . The negatives were cost, signal reception problems, a general lack of quality programming on the subchannels, and (especially on AM HD stations) adjacent - channel interference . HD Radio's primary use has been to exploit an FCC loophole to allow low - power broadcast translators to carry HD subchannels in analog, thus giving radio station groups the ability to program more program services in a market than the federally mandated maximum number of stations allowed . FMeXtra is another subchannel service authorized for use in the United States, although that service is generally limited to voice transmissions due to lower bandwidth . </P> <P> Internet radio, digital music players and streaming - capable smartphones are a challenge to terrestrial radio . Unlike satellite radio, most Internet stations do not require a subscription; several of the more popular ones use algorithms which allow listeners to customize the music they want to hear and select new music which may interest them . The proliferation of internet - based stations (which are more numerous and easier to set up than their television counterparts) creates a threat of audience fracturing beyond that experienced by television due to cable and satellite providers . </P> <P> Although not nearly to the extent that AM radio has declined in neighboring Canada, AM radio has also begun to decline in the United States . To partially combat this, radio ownership groups have increasingly moved their signals to FM, either through low - power broadcast translators (primarily on small, independent and / or rural stations) or through simulcast on full - market FM stations . The AM - to - FM phenomenon began primarily in mid-sized markets, where there is more bandwidth and less competition, but has since progressed even to New York City, where as of 2012 sports - talk AM stations WEPN and WFAN have both acquired FM stations with the intent to either move or simulcast their AM programming . By 2013 most of the AM / FM simulcasts had been discontinued, in part due to redundancy and the fact that most listeners to AM stations stayed with AM while very few new listeners were picked up on the FM side . </P>

The introduction of radio in the united states allowed