Maybe Sumocat is a little happier this morning. Sprint and Clearwire are announcing dates when they will flip the switch on WiMax in three big US cities. New York City gets lit up on November 1, Los Angeles on December 1, and San Francisco later in December. That last one is still a little porous, but the good news for those big city dwellers is that there is a time table. These will be big tests for Sprint’s version of 4G, assuming that there are large enough numbers of customers who have 4G devices. In the early going I’m guessing things will seem snappy, but we all know that at some point usage will reach a critical mass, and then we’ll know how well this plays out in the large urban environments.