Some tech questions

Just Had some tech questions I was uncertain about that might lead to some new strategic directions for navies. How jammable and/or interceptible are grav pulse coms. How much of an acceleration advantage would a unmanned ship without compensators have over a regular one. Depending on what the answers are destroyer or light cruiser sized drone might be very useful, especially in the system defense role as they could be deployed for long periods in standby condition.

rlrapp wrote:Just Had some tech questions I was uncertain about that might lead to some new strategic directions for navies. How jammable and/or interceptible are grav pulse coms. How much of an acceleration advantage would a unmanned ship without compensators have over a regular one. Depending on what the answers are destroyer or light cruiser sized drone might be very useful, especially in the system defense role as they could be deployed for long periods in standby condition.

The author has said he has no interest in having drone warships in this series; so we're simply not likely to see those no mater what their theoretical acceleration advantages might (or might not) be.

I suspect that grav pulse coms should be jammable; somehow. But part of the issue is we don't know how they're encoded (for example for radio even on a single band it's easier to muck up AM than FM - and of course frequency hopping or spread spectrum become even harder to jam). The early "Morse code" transmitters on the recon drones Honor deployed in the 2nd book are simply "on" or "off" and you use pulse timing to determine the signal. Those could be pretty easily jammed if you could put a transmitter along the line of sight between drone and ship so you were sending random pulses down that same bearing. But if you were much off to any side the grav sensors seem to have more than enough directional resolution to be able to pick out the pulses coming from the drone despite any pulses you were sending from a different direction.

But how the grav coms and grav fire control are encoded now we just don't know.

Still, if nothing else high enough powered noise jamming should work; simply saturate the receivers so they can't "hear" the intended signal over all the racket you're making.

And in support of that concept we do know that in truly massive missile launches the grav signal from all those impeller wedges is bad enough you can only roughly estimate the size of the total launch; since you can no longer see point sources through the noise.

However, it's not at all clear how (or even if) you'd be able to generate massive enough grav events to cause that kind of whiteout effect and prevent at least one side of the conversation from hearing the other.

(One speculation I had, that the author shot down, was to do it via a ship or drone wedge that you put broadside on and then rotate at as high an RPM as you can manage so it's flickering between showing wedge and showing gap really really rapidly. A ship's wedge seems to be about the most powerful grav effect we know of, so I was hoping that fluctuation would create a useful level of noise. But apparently not)

Grav pulses are interceptable. It's mentioned several times in the series.

It's unclear how useful this is. It's also unclear how directional a directional pulse is. I'd guess a lot less directional than a UV laser, which has a pretty big cone (even if diffraction limited) at Honorverse ranges.

kzt wrote:Grav pulses are interceptable. It's mentioned several times in the series.

It's unclear how useful this is. It's also unclear how directional a directional pulse is. I'd guess a lot less directional than a UV laser, which has a pretty big cone (even if diffraction limited) at Honorverse ranges.

interesting... I'd sort of assumed that they were omnidirectional - thinking of the chatter in the Beowulf system between elements of the Moriaty system.
or have I got that completely wrong ??

isaac_newton wrote:

kzt wrote:Grav pulses are interceptable. It's mentioned several times in the series.

It's unclear how useful this is. It's also unclear how directional a directional pulse is. I'd guess a lot less directional than a UV laser, which has a pretty big cone (even if diffraction limited) at Honorverse ranges.

interesting... I'd sort of assumed that they were omnidirectional - thinking of the chatter in the Beowulf system between elements of the Moriaty system.
or have I got that completely wrong ??

I don't know how directional they are but it nowhere near omnidirectional.

Shadow of Saganami wrote:Of course," she cautioned, her expression sobering slightly, "there is at least a small chance Bogey One or Two will also pick them up. The transmitters are directional, and we've made a lot of progress since the first FTL coms came in, but we're still a long way from completely eliminating backscatter. There's going to be something to see. All in all, I'd say Guthrie's probability estimate is probably pretty close to on the money, but we could both be wrong."

War of Honor wrote:For Hellbarde to be reacting that quickly to Jessica Epps's heading changes, the communications links between her and her remote sensor platforms had to be FTL, as well.
Which meant the Andermani Navy had not only managed to produce its own grav-pulse communicator, but also engineered it down to a size it could fit into something as small as a recon drone.
And a drone which is so stealthy, and has such a good shield against backscatter from its transmitter, that Shawn can't find it even when he knows it has to be out there, she thought unhappily.

At All Costs wrote:Besides, we may not know where they are, but we sure as hell know what they are."
Tucker nodded again, not even tempted to play devil's advocate this time. The only thing those transmissions could be were scraps of backscatter from Manticoran directional FTL transmissions. Which, of course, meant the ships which had deployed the recon platforms producing them were still in the system receiving their reports . . . somewhere.

In Beowulf the Silver Bullets needed to get deep in-system, so they could sit, undetected, more or less between where the Mycroft relays and their control node was. And even then they needed to get lucky to pick up the occasional FTL comms associated with system checks. But once they'd found the initial one(s) they were able to slowly map out the rest of the network. So by now they're probably tighter than a 90 degree cone. Still far from a laser com, but enough that with care you can avoid transmitting along a path with a known enemy in it.

Jonathan_S wrote:In Beowulf the Silver Bullets needed to get deep in-system, so they could sit, undetected, more or less between where the Mycroft relays and their control node was. And even then they needed to get lucky to pick up the occasional FTL comms associated with system checks. But once they'd found the initial one(s) they were able to slowly map out the rest of the network. So by now they're probably tighter than a 90 degree cone. Still far from a laser com, but enough that with care you can avoid transmitting along a path with a known enemy in it.

Aye.

Strictly speaking, that's not back scatter. The term implies that the signal was scattered in the wrong directions (back) along the path, usually due to absorption and re-emission by stray atoms. Such a backscatter could theoretically be picked up anywhere, not just a narrow cone around the intended receiver. That is, a tight laser beam could still be picked up at 90° from the signal or from behind the transmitter if it flashed through an overdensity of interplanetary gas.

As far as we know, there's nothing on the alpha wall to reflect signals and scatter them. But we don't know that there isn't something either.

Pedantic mode off.

Don't know if they are still doing it but back in the 50's and 60's the USSR would decide that they didn't want people to use various frequencies and hook up massive power sources to transmitters and essentially blot out the frequency with interference. Some of the rumors were that these were ones use by things like Voice of America or for clandestine transmissions to agents- that sort of thing. So, theoretically you could hook up a strong powers course to a Grave Pulse transmitter and just hammer your area to override someone else's transmission. Probably would help if you could get between the transmitter and receivers of the people you wanted to deny gp transmissions too. Might want to use a RD since whatever starts blasting out pulses is painting a massive target on itself.

Space is big. So not so sure about noise jamming.

But if I was the MA I'd be looking at the possibility that someone might figure out a way to detect subtle grav activity. Like the spider.

So I'd figure out a way to produce quite similar spurious subtle grav signals, produce them cheaply and plan to have these jammers available in large numbers.

kzt wrote:Space is big. So not so sure about noise jamming.

But if I was the MA I'd be looking at the possibility that someone might figure out a way to detect subtle grav activity. Like the spider.

So I'd figure out a way to produce quite similar spurious subtle grav signals, produce them cheaply and plan to have these jammers available in large numbers.

Those sound more like decoys than jammers. But yes, having something that can pretend to be a spider ship sounds like a great idea. Just like Manticore has a variety of towed and then later free flying drones that can simulate the drive signal of various wedge powered ships.

Brigade XO wrote:Don't know if they are still doing it but back in the 50's and 60's the USSR would decide that they didn't want people to use various frequencies and hook up massive power sources to transmitters and essentially blot out the frequency with interference. Some of the rumors were that these were ones use by things like Voice of America or for clandestine transmissions to agents- that sort of thing.

Look up Duga or Russian Woodpeckers, most of these where just immensely powerful over-the-horizon (OTH) radars.