yes, yes, no, first, yes, yes, no

As I understand it, all trade ports in your empire earn the same amount - a base value, with a bonus for the longest trade route you have. Other than the trade ports that form your longest trade route, the positioning of other ports makes no difference. The only exception being 'planet specials' that offer a trade bonus or penalty.

I find the easiest way to ensure I have the longest route is to build one trade port on every planet. Then, if I need more income, I can build additional trade ports anywhere I want (preferably on planets with trade bonuses).


Yes, Culture is cumulative.


Yes, see above.



I don't think so - I think that Culture spread is slowed by passing through other planets, so building the broadcast centre on B (adjacent to C) will be more effective.

tradeports alone have their own ships and you can build say 5 (max i have managed to get in a planet) in one gravwell and they will bring in more money than just 1 in that gravwell...each one works on its own...so it doesnt matter if they are spread out or not (except for getting the distance bonus with each other when in the same gravwell)

broadcast centers......imagine them like giant containers containing fluid and the phaselanes are veins bleeding out. you can have 1 in a system and it spreads pretty slow. 2 in the system and it will spread a little faster and a little further. 1 in a system and one in an adjacent system..or even a few back..once their veins meet, they will start to increase slightly. when say an opposing vein reaches yours....they will push against each other and the stronger (say the one with more fluid going into it since we are using fluid as a visual) will push more against the weaker therefore pushing the weaker back where it came from. the more culture you have pushing against the opposing, the more and the faster it will push it back.

if you have any more questions pertaining to this..dont be afraid to ask...im not always good at putting to words whats in my head