Again, this is likely well beyond TL-15 in the OTU, and moot in most cases because empty-hex jumps are canon -- Ancients could pull it off if they wanted to. Maybe as a "drawbridge" to a world in the middle of a rift... you'd need the "key" to turn the grav field on to be able to cross the rift (though you can do it with matter-collector drives, or patience and a slew of drop tanks). It's better than a hidden mid-rift fuel cache because (if you can't do empty-hex jumps) you simply can't reach it unless the grav field is turned on, even if you know exactly where it is.Wow. I was intrigued by the idea of a possible Drop Tank Tender, and then you show me this.
How many Pirates are doing this to hide their refuel points?
Of course, the Imperial Navy would use this idea. Possibly even the Zhodani.
The annoying part is that you'd have to send the signal to turn it on at STL speed, and wait. Unless it's Ancients tech and they've got some kind of Jump Radio thing going on...
But if you're not sticking to OTU, this is a really nifty idea.