The Thermal sensors are also likely a waste of space... they have a range of about 50 m-km against a typical Light Cruisers's thermal signature. What could they see that wouldn't already be spotted on RADAR? The EM sensor on the other hand is useful, for picking up enemy active sensors at a much greater range.
I do not understand the thing with passiv sensors. May I be a bit dorf but I dont understand the mechanic behind that. I only use them for the case they are vital and I simply don`t know it
First up, before I forget; you seem to have two of every sensor. This is really a waste of tonnage, because if the enemy has already taken out one, the ship is in dire straits already, and multiple sensors on the same ship has no other benefits.
Another thought is that sensor ships are the eyes of your fleet - vital to you and a target for the enemy. My sensor ships generally have a few extra layers of armor compared to combat ships.
-
The way passive sensors work is that their range is displayed against a signature level of 1000. So your sensors will detect a strength 1000 thermal signature at 44m km; larger signatures will be detected further away and smaller signatures closer to you. (I
think the increase and decrease is linear, since they don't have anything like the resolution of active sensors).
Thermal passives detect engine emissions - so anything moving (or idling with the engines on) will show up. EM passives detect enemy active sensors and shields - which usually don't come on until they've detected something via another means.
So really the problem here is that your thermal's range is a
lot less than the range of your active sensor's (179m km vs 44m km against roughly 'average' targets). What blue emu suggested - ditching thermals altogether - is a matter of doctrine. If you intend to run around with active sensors up all the time, then the thermals are pretty much useless. However, active sensors are a big blinking 'HERE I AM' sign, so if there's anything around it will probably see you. Thermals (particularly larger thermals) will allow you to detect enemies before they see you - although you'll still need to switch on your own actives to target them.