A jumpnet is an alloy mesh that surrounds a spacecraft like a Faraday cage. A Navigator in physical or very close proximity to a jumpnet can transition a spacecraft into or out of Am.
The field amplification effect of the jumpnet medium extends the HRV of any entity that makes contact with it – while this has a profound, civilization-defining benefit for Navigators, contact with a jumpnet mesh also boosts the abilities of telepaths and remote viewers.