I was contemplating jump gates.

How would I build one from a 'I'm a gearhead' view...

So, if we know how much energy it takes to rip open jump space for the largest ship that is going to go through, we assume that a gate needs to be fueled and powered to support that same level?

If the jump gate has an entry that could be physically dilated or contracted (to change the size of ship and the amount of power), that could be a handy feature of a higher tech jump gate.

Another mod could be the compute cycles and a much larger fuel and power capacity to be able to allow multi-ship jumps (like you saw sometime I think in B5).

Receiving wouldn't burn any power.

To defend your gate from incoming, you might have a Stargate SG-1 trick with a fancy alloy iris that prevents the jump field from disgorging vessels (that could mean you are stuck in J-space until that gate opens, or you might precip out at the nearest one, or insert fun dramatic outcome). 

You could also lay a bunch of mines (missile, gun, explosive) that could be activated if unwelcome folk came through.

You might be able to mount a lot of turrets or barbettes on the ring's outside so you can immediately get great point blank shots into incoming ships as they pop out....

If this was an Ancient-ish technology, you could just have the gates usable but not buildable until TL-whatever (18+?). If you were replacing standard jump travel w gates, then you could open them up at TL10 or TL12 (maybe all the space stuff that is interstellar is pushed up a few techs).

The gate using the fuel for an outbound jump means that there would probably be fees and you'd only be able to depart after satisfying outward clearance steps (including pay for the jump). It also mean non-jump engine shops could be jumped by a gate (recovery is left to the ship owner...). If you do take a jump capable ship through, it might mean they arrive with a full fuel load to jump out themselves. (In B5, ships had jump engines themselves at some point).

Why come through a jump gate? If you pay the power at the entry end or when your ship tears open the jump window, why go to an existing gate? Maybe the gate system is more well known and that improves odds of avoiding a mishap in a jump. Maybe other gates can only jump ships to other gates (not open space) or maybe they will only jump you to other known gates as a protocol unless you have a special permission.

Jump gates would want some armour and some electrical protection and multiple sources of power to drive the jump (fuel, solar, etc).

Jump gates could be taken in containers from one place via a jump to  a place without and ships jumping there with the containers and engineering crew could build a new jump gate there (likely a small one which is then fed loads and loads of resources and parts to build the big final one).

It'd make for a bit different of a TU, sort of making 'trade mains' more enforced by jump gate policy or limits. Only big military vessels might use their own jump window generators (other than the jump gates).

It also means a lot of trade could be done in 'm-drive only' ships freeing up a lot of space for extra cargo and thus making the merchant fleets much more viable (or the rates for shipping less).

Thoughts?

TomB