You have to edit the BlockBehaviorConfig file located in starmade -> data -> config. Open it with a text editor (notepad++ for example)
Search for JumpDrive and you'll find a a block with all settings about it.
Edit <DistanceInSectors>8</DistanceInSectors> the number in here to change the distance. Make sure to save once you're done with that. It will only work in singleplayer or your own hosted servers.
Oh and you can actually have jump shuttle that can immediately jump after exiting, no need for multiple jump drives.