Midband 5G radios have been installed on half of the roughly 40,000 cell towers that Crown Castle owns, company officials said during a quarterly conference call. "To date, only about half of our sites across our top three customers [Verizon, AT&T and T-Mobile] have been upgraded with midband spectrum, providing a significant opportunity for additional revenue growth as additional sites are upgraded over time before their focus will likely shift to more infill with new co-locations," said Crown Castle CEO Jay Brown.