I didn't have any troubles using the ELINT sensors, but I've started some testing, just to be sure. And oh boy you're right, the ELINT sensor doesn't detect anything on its own. But if you detect the thermal signature, it will start detecting the EM signatures as well. Active sensor doesn't help, it needs to be passive (EM or thermal, either of them seem to work).
My ELINT ships have thermal sensors, that is why it worked with populations, but I probably missed many active sensor contacts when I didn't detect their thermal signatures. Thanks for pointing that out.
I agree, that we could use an indicator of intelligence points about sensors. And some better way to indicate that an ELINT sensor is gathering data from a source, would be useful. Perhaps just some text under the population's readout, that it's being monitored. It's just slightly better than checking it for intelligence points change, so probably a different approach would be better - maybe a toggle on the map view, to put a suffix after the EM source, something like
EM 40 321 ELINT-5 (with the sensor sensitivity after the dash). Both would probably be best. Maybe someone has a better idea?
So I SM-edited in my current compact EM sensor (and took out a big chunk of the fuel allowance) on my intel ship. It detects the targets. I'm still not seeing any evidence of intel points accruing after a few (grindingly slow) days of time advancing. The wiki claims the expectation should be one point per day?
The population intel points are still reporting zero. I'm not sure where I'd even find the points counted against "AS #8", but I'm certainly not seeing any reported.
Going to try flying away and then flying back, though I would be a bit surprised if that helped.
I've tested that SM-ing sensors on a ship in orbit, I didn't need to move it around. If your ship has only passive thermal sensors and the ELINT sensor, and you detect the EM signature of something, that probably means you're getting the intelligence data from it.