the LTE on the default freq band (1900mhz) does not penetrate buildings very well because of the high frequency, in radio waves the lower the freq the farther the signal travels and better in building coverage, but lower bandwidth meaning a "channel" is wider and limits the number of channels. higher freqs go shorter distances but wider bandwidth so more channels available. Sprint has now 3 different bands of these freqs. They are adding 800 mhz and 2600 mhz for a great tri-fecta, hence the Spark. when it is done Sprint will have a great network using 800 for house penetration and distance, 1900 for normal use, and 2600 for dense areas to give many users fast data (limited range) such as a downtown area. All this is why we need to gravitate to the tri-band phones. The LTE and the CDMA (talk, text) are separate radios so you can get one without the other. i don't know about the iphone but most of the existing androids (except the G2 and the updated S4) get LTE on 1900 and CDMA on 800 and 1900. when buying a phone look for LTE and CDMA on all three bands.