Sprint Nextel Inc. has started to fire up its 4G LTE networks in New York City and San Francisco. The operator said in November that NYC and San Francisco were among 115 markets that would launch in the "coming months." Sprint has said that it has 200 towns and cities where LTE is being installed all-told. The operator told The Verge that it has soft-launched LTE in some areas of San Francisco; New York City (and other parts of New York state); Washington, D.C.; and some parts of Florida. The soft launch is typical of the way Sprint is approaching its LTE deployment. Some users reported seeing LTE signals in the Bronx back in December. Sprint is racing to catch its larger rivals on LTE, announcing markets as soon as it gets street-level coverage and allowing users to access patches of 4G as soon as test sites are on air. Nonetheless, CEO Dan Hesse said earlier this month that Sprint is behind on Network Vision upgrades. Sprint now expects to cover 200 million potential customers with LTE by the year's end, with 174 LTE towns and cities due in the coming months. Clearwire LLC also said last week that it now has more than 800 LTE TDD sites ready to be connected to Sprint's core network. 2013 is a make-or-break year of transition for Sprint's 4G ambitions. By next January it will either have a faster 4G network that covers the majority of the U.S. populace and may offer even better mobile video performance in some cities, or it will be left behind. Fast 4G and unlimited data plans are still a winner for many mobile consumers. As you will see if you surf the Sprint user sites, however, many are already tired of waiting for 4G LTE to arrive in their cities. This will be among Sprint's key challenges for 2013. — Dan Jones, Site Editor, Light Reading Mobile