TL;DR: The antagonists in my story have made nearly unstoppable soldiers who, through nanites embedded in their brains, are able to experience the future and send memories back in time. Since the time machine in my story is the size of a small particle collider, these memories are transmitted through radio to the single time machine station, sent back in time and then redownloaded in the soldier's past mind. My protagonists, now having to fight these guys, are faced with a problem: Is it possible to make weapons or traps to shield the RF frequencies that pre-cog soldiers use to send their memories back in time? If so, what would these weapons be like?


This question takes place in the same setting as the post I detailed in “What limitations can I put on wings for more tense/risky action scenes?” and deals more with the antagonists’ creation: nanites. The rogue research group I mentioned has “developed” these nanites that are capable of changing a human into... something else. Keep in mind that these nanites are essentially handwaved except for basic laws of physics, since their design and origin are not from this time or even the near future of the story, and they’d be essentially impossible with today’s technology.

In the case of the main protagonist, the nanites were used to change him into an Arronian as a test (see the post). In the case of the research group’s main goal, they use the nanites to change subjects into similar creatures that are tentatively named SHARDs (name ideas anyone?). SHARDs are a modified (the research group would say “perfected”) version of the natural Arronian, with biological and nanite based additions to make them, let’s say, very lethal. They are wingless—unlike Arronians—and their skeleton has been completely replaced by nanites for extra strength, and to allow them to shift from human to SHARD relatively quickly. The nanites have also fused with their minds, connecting the nanites' individual AGI to the previously human host, as well as to a limited hive-mind of sorts.

The important feature of the SHARDs for this question is that the nanites enable them to be precognitive; as a result, single soldiers are almost completely unstoppable. The pre-cognition works like this: all of their feathers have lost their barbs and are basically hollow, quill-like shafts. These shafts are filled with nanite-built structures that act as long-range RF antennas. The antennas connect the SHARD’s mind through satellite to a single large warehouse complex with a machine that can send messages (encoded in streams of particles) back in time. Again, this machine is handwaved because it’s tech from the far future. If a SHARD dies, is injured, or voluntarily sends something back, the nanites will broadcast the last few minutes of the SHARD’s memories (recorded by the AGI) to the machine, and then download them back onto the SHARD, a few minutes back in time. The SHARD has now experienced the future and now can correct its mistakes accordingly. If you’ve watched Edge of Tomorrow, it’s just like that.

So this presents a real problem for my protagonists: how do you kill a pre-cog? In addition to the tactics posted in numerous questions on Stack Exchange about this, I’m thinking that the main weakness here is that the time-travel component is centralized, and connected through RF. If a SHARD can’t send its memories back to the machine, then it loses its precognition. They can then be dealt with like any other nanite enhanced shape-shifting assassin.

Now after all that, here’s my original question: is it practical to make Faraday cage/RF shielding weapons or traps, and if so, what would they be like? Tactically, what kind of device would work best against the SHARDs? Could you quickly place RF shielding mats or fabric in rooms to trap SHARDs? Are grenades that spray out webs of reinforced copper micro-wires/lattices practical? Is it possible to make a device that could destructively interfere with or even just flood their radio frequencies with noise so the signals never reach the machine? Just a reminder, the level of technology is in the near future, about the 2030s, so nanotechnology should have progressed quite a bit.

I’m not experienced with EM shielding and the physics behind Faraday cages past the Wikipedia page, so if this is completely impossible or impractical let me know; I’m here to learn.

  • 3
    $\begingroup$ That's quite a long explanation. Can you try to condense it a bit more? $\endgroup$
    – L.Dutch
    Jul 24, 2019 at 6:04
  • $\begingroup$ You could go a Edge of Tomorrow route and make the transmission time-limited backwards. If they have been in a trap for X minutes the Pre-Cog transfer will only go back to a time when they are still in the trap. Effectively ending their loop. $\endgroup$
    – IT Alex
    Jul 24, 2019 at 18:40

4 Answers 4


These shafts are filled with nanite-built structures that act as long-range RF antennas.

These will necessarily be pretty short wavelength... probably line of sight only. Outside of the sight of a receiving station, they ain't gonna work. Over-the-horizon radio antennae are somewhat larger... perhaps groups of the pre-cogs might carry suitable radio equipment for long-range comms (though bear in mind that longer-wavelength comms will have much, much lower bandwidth. You can send the key-points, but not high-res video!)

The antennas connect the SHARD’s mind through satellite

That's obviously the best solution to the line-of-sight issue, though it does rather encourage people to fight in underground complexes.

It also suggests that one of the best ways to fight them is to attack the satellites... in the limit, there's always kesseler syndrome to force everyone back down on to the ground with all of the associated line-of-sight issues that entails. You might not have to go that far, though. Building some big lasers seems plausible for people who can make these kinds of fancy nanite. Remember, if a precog can speak to a satellite, you can see it and you can shoot it.

Tactically, what kind of device would work best against the SHARDs?

Honestly? Probably none. Having your temporal feedback suddenly stop is suspious. Depending on how far back the loop goes, it seems easy enough to work around the situation where you "disappeared" in the future.

But there's another option.

All that technology you have? I bet you can build some really nice simulation equipment. Really immersive stuff. Indistinguishable from reality.

What you need to do is to spring a simulation on a pre-cog in such a way that they don't realise that what they're seeing isn't real... I'll leave that as an exercise for the reader (or separate question on this site). You won't have to do this very often for temporal intelligence to start being a risky proposition. Did your precogs really win that battle tomorrow? Did they really capture their target and destroy the rebel base? Or maybe they're all in simulation vats for long enough for their temporal intelligence loop to be rendered useless, and then they're shot.

Suddenly, one in a hundred of your precog missions is going wrong, inexplicably. Your use of precognition now has to be a lot more cautious... you can't believe your future eyes and ears anymore. Better than a horoscope, but don't bet your life or savings on it, hmm?

(Disclosure: idea taken from John Meaney's Nulapeiron sequence, Paradox, Context and Resolution, though the oracles there can see the whole of the rest of their lives, which is rather more difficult to fake)

  • $\begingroup$ I didn't think about the need for radio repeaters... seeing as though they are partially made of reconfigurable nanites, some of the SHARDs could adapt themselves specifically to extend the range of the radio transmissions. It's possible that they could create strings of repeater SHARDs to extend the signal from the surface through tunnels. Also, that's a great idea with simulations! Just to expand on that, these guys are almost continuously receiving a stream of "memories of the future"... if you could intercept that stream and replace it with your own simulated outcome, they would be (1/2) $\endgroup$ Jul 25, 2019 at 19:16
  • $\begingroup$ (2/2) completely blinded and decieved about the future outcome of the situation. They still "experience" the true future, and message of that still gets sent back in time, but it's replaced with a simulation. This false time machine could be placed anywhere. Even the satillites could be tampered with to send the simulated signal instead of the signal from the real time machine. $\endgroup$ Jul 25, 2019 at 19:22
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    $\begingroup$ Yes! Hacking it is better than jamming it. And you could jam it creatively: record the broadcast of the future sent to one SHARD and tweak the address, and send it to all of them. Constantly, over and over. And it is the Humps song by Black Eyed Peas. $\endgroup$
    – Willk
    Jul 26, 2019 at 3:12
  • $\begingroup$ @Willk Now that would be just plain evil. Good idea though $\endgroup$ Jul 26, 2019 at 17:29
  • In a battle scene, Faraday cages would be extremely impractical. If you managed to capture a SHARD they would come in handy.
  • Depending on the type of the RF communication a wideband RF noise source could render the communication with the relay station impossible, or render the signal quality useless. Since there is not much time to send the information to the tower, lowering the signal quality thereby slowing down the communication might just work.
  • Destroy the tower as you said, or at least its communication capabilities.
  • EMP: seems to me, that the nanites (or the tower communication) is sensitive to electromagnetic impulses. Might try to temporarily overload the communication device a few seconds before kill.
  • Microwires/lattices would work only if you are using short wavelengths for the communication, where direct line of sight is necessary. For lower frequencies, longer wavelengths it's improbable to work. Also, you might need to match the microwire lengths to the used wavelengths, which might be impractical if SHARD-s use spread spectrum radio.

Hit the precog computer

Fighting precogs is useless. They don't need constantly see the future so would have no need to transmit anything. They could download how the day plays out each morning. If you try and block it, they will already know and download earlier.

Instead of RF, what you're looking for is tachyons. Tachyons travel faster than light (theoretically) and could allow information to be sent back in time.

What you'd need is the equivalent of a radio jammer that uses tachyons. It just outputs masses of white noise that drowns out anything trying to transmit through it.

Anything in an area around the jammer can't be sent back. It's just overwhelmed by the noise.

To beat a precog there are only two ways.

  1. Take away their ability to see the future. In the movie Watchmen, Ozymandias uses a tachyons jammer to block Doctor Manhattan's precog ability
  2. Have your own precogs. If someone looks to the future they know how it will play out but if someone else looks after them, the future will be different than the first time because the second person will see what the first person's plan is and can react. If everyone is using precogs, the effect basically cancels each other out.
  • $\begingroup$ That's a good point about having your own pre-cogs... I had planned on having the protagonists "steal" that ability in the last book. However, just for clarification, the radio isn't doing the time travel: it's just transmitting raw memories in a "mundane" way. The time machine, which is about the size of the Beijing Electron-Positron Collider and is located at (spoiler), is receiving these messages and sending them back in time. $\endgroup$ Jul 24, 2019 at 7:32

Radio Jamming

When you jamm a communication device, you figure out its frequency and then you mess with it with a more powerful radio of your own.

Jamming may be obvious:

Obvious jamming is easy to detect because it can be heard on the receiving equipment. It usually is some type of noise, such as stepped tones (bagpipes), random-keyed code, pulses, music (often distorted), erratically warbling tones, highly distorted speech, random noise (hiss), and recorded sounds. Various combinations of these methods may be used, often accompanied by regular morse identification signal to enable individual transmitters to be identified in order to assess their effectiveness. - Wikipedia

Or stealthy:

Subtle jamming is jamming during which no sound is heard on the receiving equipment. The radio does not receive incoming signals; yet everything seems superficially normal to the operator. These are often technical attacks on modern equipment, such as "squelch capture". Thanks to the FM capture effect, frequency modulated broadcasts may be jammed, unnoticed, by a simple unmodulated carrier. The receiver locks on to the larger carrier signal, and hence will ignore the FM signal that carries the information. Digital signals use complex modulation techniques, such as QPSK. These signals are very robust in the presence of interfering signals. But the signal relies on hand shaking between the transmitter and receiver to identify and determine security settings and method of high-level transmission. If the jamming device sends initiation data packets, the receiver will begin its state machine to establish two-way data transmission. A jammer will loop back to the beginning instead of completing the handshake. This method jams the receiver in an infinite loop where it keeps trying to initiate a connection but never completes it, which effectively blocks all legitimate communication.

So your Protagonist simply needs a powerful portable radio and someone techsavy enough to set his jamming equipment up.

On a side note, fighting these guys in regions with poor signal might also do the trick. Especially if they are very reliant on their fancy technology. Your antagonists expensive time maschiene will be neutralized by equipment worth a few hundred dollars. Quite a similar story to how the Allies neutralized the fancy and expensive acustic torpedoes of the Germans in WW2 by dragging noise producing pipes along a few hundred meters behind their ships.

  • 2
    $\begingroup$ Wow, that's a really simple counter to the SHARDs. I might want them to constantly be shifting the geometry of their antennas so they don't get stuck on one frequency, but it would be easy to just cover an entire band with noise. Now the challenge for my characters is reverse-engineering the radio from no previous knowledge of the SHARDs, and how to stop them before it's too late. $\endgroup$ Jul 25, 2019 at 19:31

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