Government officials and communications experts are assessing the public safety and security implications of a newly posted online article that provides directions for making cheap devices to jam Global Positioning System signals. Information in the article, in the current issue of an online hacker magazine called Phrack, potentially puts at risk GPS devices used for commercial navigation and military operations purposes, authorities said. The Phrack article provides a detailed guide to building a low-cost, portable GPS jammer out of components that can be easily obtained from electronics supply houses. Full Story