By Monica AllevenTower and distributed antenna systems (DAS) firm InSite Wireless Group received an undisclosed amount of funding from private equity firm Catalyst Investors.InSite, which owns about 350-plus tower and DAS sites, will use the funds to acquire and build additional towers and DAS facilities.The current and future demand for wireless, driven in particular by smartphones, is one reason the sector is so appealing, according to Catalyst partner Todd Clapp. Clapp, as well as Catalyst partner Chris Shipman, will join InSite's board."It's a business we've followed for many years and we like the key fundamentals," Clapp says. Besides industry trends pointing to more growth, Catalyst is familiar with the management team at InSite, going back 15 years or so. Members of the same management team, which includes President and CEO David Weisman, sold Mountain Union Telecom to Crown Castle back in 2006 for more than $300 million.Catalyst is an investor in Advantage Business Media, parent company of Wireless Week. Past investments include Alaska Native Wireless, Aloha Partners and Clearwire.Investment in the tower/DAS space appears to be picking up. A couple weeks ago, ExteNet Systems announced the closing of a $128.4 million investment round.