cthia wrote:First, none of that is necessary if your opponent does not have your frequency or frequencies. One frequency alone is enough security between the mothership and the missiles if your opponent has no way of obtaining said frequency. It requires an infinite amount of power to jam all frequencies unless you are right on top of the receivers or emitters. Plus, any complexity demands the appropriate amount of additional power for the communication. Complexity also decreases the solidity of the communication.
A spectrum analyser can quickly find any one frequency in use. You can't hide the use of the spectrum if your opponent can receive your transmissions (either because it's broadcast or because they've inserted a receiver in your transmission path).
The trick in FHSS is to not let the opponent know which frequency you'll use next, so their jamming, as you and I said, becomes impractical. Since this technique has been in use by the military since WW2 (20th century current reckoning), I see no reason why they'd have forgotten this little detail in the 20th century post diaspora. We don't know if gravcoms have such a thing as a frequency, though.
What you are missing is that to execute an effective jam, the frequency or frequencies required MUST already be known. Hint, these platforms analyze the frequencies used just like the Apollo system -- and any navy -- analyzes the frequency(s) used by the enemy's ECM.
Modulating frequencies on the fly will work fine in a closed system. (Like Star Trek's shields). But in an open system where there are separate objects in the system (warship transmitters and missiles downrange) it is impossible. A communication protocol must already be established beforehand. And any jamming platform worth its weight in chips will get the "pattern" that is used easily. It simply needs a good enough look at the pattern. That is already a necessity in the HV and we hear it all of the time. "We got a good look at their ECM."
I don't think you appreciate how difficult establishing the patterns in pseudo-random frequency hopping is. And you must be familiar with paired pseudo-random number generation, which we currently use in a lot of Two-Factor Authentication mechanisms in our world (Google Authenticator app or equivalent by other companies, the physical RSA ID tokens, etc.), and with a publicly-known algorithm. We don't know how fast a molycirc computer is and therefore how fast it could crunch the numbers to deduce the pattern, but both sides have effectively equally fast computers, so the difficulty is the same regardless, unless some mathematical or technical breakthrough made solving the problem much faster, like Shor's Algorithm is expected to do for prime-based cryptography in the advent of quantum computing.
They're far more likely to be limited by spectrum and the technical capabilities of their transceivers. In fact, the best way to jam a receiver, as discussed earlier in this thread, would be to send enough energy into it even in the wrong frequency so that it gets saturated and can't receive the actual transmission.
Also, the proximity of the jamming device is important. If the jamming platform is much closer to the missiles than the mothership, its power requirements to effect the jam decreases significantly. Hint: Any such platform will be much closer to the missiles.
Eh, kinda. For lasers, we're talking directed energy and the loss through dispersion is much less than the square of the distance. We still don't know how fast gravcoms decay and whether their transmissions are directed or not.
You also can't put the platform closer than half-way, otherwise those missiles can turn around and target that very bright emitting source pointing at them.