Short Victorious War, Chapter 17 wrote:"We could cover them fairly well against missile attack by tying them into our divisional tac nets, Sir," Honor countered. "There are only five of them. We could include one in each division's net and hook the odd man out into Nike 's and Agamemnon 's net. The Peeps won't be able to tell exactly where our defensive fire is coming from, so they shouldn't be able to ID them at any extended range. And for us to make the mines work, we'd have to use them before we got to beam range, anyway."
"And if they spot the mines?" Prentis was thinking aloud, not arguing, and Honor allowed herself a small shrug.
"Their fire control's a hundred percent passive, Sir. They don't have active emission signatures, and they're mighty small radar targets. I doubt the Peeps could spot them at much more than a million klicks, especially if they're busy chasing us ."
And then later on, in Chapter 30 so almost a full decade before Hemphill created "Ghost Rider" drones, Honor snuck an entire task group into 7 million km range from Admiral Chin's dreadnoughts (which were later upgraded by superdreadnoughts, which I find amusing)
"Contact!"
Admiral Chin jerked upright in her chair. DeSoto was bent intently over his display, and she frowned as seconds leaked away with no more information.
"I'm not sure what it is, Ma'am," he said finally. "I'm picking up some very small radar targets at about seven million klicks. They're not under power, and they're too small to be warships, even LACs, but they're almost exactly on our base course. We're overtaking them at about five-five-niner-four KPS, and— Jesus Christ!"
--- snipping to the segment about mines and their IFFs ---
"Our time to minefield is two-point-niner-six minutes, Ma'am," Charlotte Oselli said, as if the astrogator had read her mind. "The Peeps should enter attack range in . . . seven-point-five-three minutes."
Honor nodded in acknowledgment, never looking up from her plot. Now if only the mines didn't make a mistake where the task group's IFF was concerned.
--- snip again ---
"Crossing minefield attack perimeter—now!" Charlotte Oselli snapped, and Honor's eyes darted to Eve Chandler's back. The tac officer said nothing for a second, but then a green light flashed on her boards and her taut shoulders relaxed imperceptibly.
"IFF transponders challenged and accepted, Skipper! We're in clean."
She glanced back over her shoulder, and Honor raised one hand in the ancient thumbs-up gesture. Identification friend or foe circuits could always screw up, especially when ships had taken battle damage that could knock out their onboard transponders or change their emission signatures radically. But the minefield had recognized them; it wouldn't kill their own wounded ships, and, almost more important still, would not reveal its position to the enemy in the process.
--- snipping ---
Commander DeSoto stiffened as a faint radar return flickered in his display. Adrenaline flared as he remembered the last time his radar had picked something up, and he stabbed a key, interrogating his data base threat files. The computers considered dispassionately, then blinked an obedient reply.
"Minefield dead ahead!" he shouted.
"Roll starboard!" Admiral Chin barked instantly, and her task group swerved once more in the face of a fresh threat.
No where there, is any form of fusion generation making it easy to detect mines, or active scanners beyond "waiting for ship to enter attack range and get IFF checked" which is passive.