If the system involved bouncing the signal around with repeater stations or relays, I would assume Section 31 (or at least Starfleet Intelligence) would have some setup in Klingon Space to monitor their movements. Khan could bounce the signal of one of those as it be logical to have at least two beyond Qu'onos so Starfleet could always see what is going on in that system (or at least spot ship movements regardless of where the planet it in the system...can't have them use the planetary shadow or star as a way to jump ships out of the system to regroup for an assault on the Federation).
That is, if they use relays, rather than Scott's setup uses some other form of subspace were the universe is practically smaller, thus not needing a relay as, to the transporter pad, the planet is within 40,000 km or whatever the limit is.
That is, if they use relays, rather than Scott's setup uses some other form of subspace were the universe is practically smaller, thus not needing a relay as, to the transporter pad, the planet is within 40,000 km or whatever the limit is.