A startup wireless infrastructure company based in Greensboro will use about $800,000 in new angel investor funds to get its technology to the production stage, according to officials with the Piedmont Angel Network. PAN led the investment round with about $200,000 from its members, according to Fund Executive Andy Dreyfuss. Other private investors, mostly from Greensboro but not part of PAN, also took part in the funding, he said. Guerrilla RF was founded in 2013 by Ryan Pratt, an experienced…