Those 1300 towers have Samsung Dual mode WiMax/TD-LTE RRU's broadcasting WiMax for current users. The towers that are converted are most likely only the ones on the same towers that Sprint is co-located on, but could possibly be on towers that they aren't. Once 2015 hits, WiMax will be taken offline just like iDEN will be in 2 months, and all the old equipment will eventually taken down.
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