I would bet that smaller ships like fighters can't track ships into subspace. Just because smaller ships can't do it, doesn't mean that the bigger ships need to have a whole new device on board to be able to do it. You don't quite need to have a new piece of technology to track ships through subspace. To track things through subspace first formed as an idea, and then became an appliable method. It could be that only the bigger ships can track ships through subspace because they have bigger and much more powerful sensor arrays along with knowledge of the ancients to learn how to track things through subspace by modifying them.
I don't see how tracking technology is necessary for following ships in subspace. The subspace tracking technology was only necessary for being able to track ships in subspace from outside of subspace. Remember in the end of fs1, they learned two things, which was how to track ships through subspace, and that the lucifer's shielding didn't work in subspace. Nothing even close to tracking technology is necessary for physically following a ship into subspace.
And nightmare, what a horrible consensus technology you described as necessary for subspace tracking. What's the difference between a larger vessel witnessing a ship going into subspace versus not witnessing it going into subspace.
FighterPilot: sir a ship has jumped out using the knossos...track that ****er.
Command: ok well, since we, the bigger ship didn't witness it, we can't use our heavily advanced technology to track it.
FighterPilot: i witnessed it, it's going to the ****ing nebula beyond the gamma-draconis knossos here
Command: well kudos for you
A bigger ship needing to watch a ship jump out to be able to track is next to bull**** nightmare
Something rings of being able to use you're own head to figure out where a ship is going versus bogus technology. Why can't subspace tracking be like normal radar tracking? Except that it'd probably make use of quantum mechanics being needed to track a ship outside of normal space(effectively tracking a ship outside of space time and pretty much in a different dimension of space).
You know in fs1, when the taranis was captured, the only shivans present to witness that was the disabled and downed comm. of the taranis. That **** got tracked through subspace by the shivans without witnessing it no problem.