Lake Mary, Fla.-based Spectrum Bridge, which aims to create a secondary trading market for valuable spectrum online at SpecEx.com, has raised $7.38 million of an $8.15 million in a second round of funding, reports peHUB. According to a regulatory filing, investors include: Espirito Santo Ventures, Milcom Technologies, Telecommunications Development Fund and True Ventures. The site went live in September with an initial inventory of about $250 million in airwaves. The company, which previously raised at least $2 million, plans to take a cut of each transaction. Spectrum Bridge is headed by former Motorola (NYSE: MOT) executives, who are hoping to tap into this very fragmented market. Initially, spectrum is sold at auction by the FCC, but after that, airwaves can literally go unused. Spectrum Bridge wants to provide a one-stop shop where buyers can see what’s up for sale.