Psi-Wars Electronics I -- Comms

I've been working on Electronics in general when my post spiraled out of control.  Originally, this was meant to cover sensors and sensor jamming when I noticed I hadn't touched on Comms and Comm-Jamming.  I, at least, see the fight between ECM and ECCM as a fight between sensor systems and counter-sensor systems, but in fact, it began as comm systems and counter-comm systems. Furthermore, this makes sense: once you’ve begun an ambush (whether pirates attacking a shipping freighter or a fighter wing attacking a patrol), not only do you want to prevent yourself from being detected, but you want to prevent the target from calling for assistance, or communicating any intelligence back to an authority figure.  So this is where I want to start.

Normally I peel out the GURPS Vehicles stuff for my Patreons, but it's too small to really make into its own document, and perhaps you'll find it interesting, and they have the whole document, which will be updated to include this information, so see it as a preview.  I also talk about "Low, Patrolling and High Orbit," in the document; this arises from the sensors discussion and a post that will drop later this week.  If I may briefly summarize them: low orbit is 100 miles from the surface, safely above the atmosphere but still close to the action.  Patrolling Orbit is about 500 miles up, as close to the surface as one can get while still maintaining "sight-lines" with other ships that might be guarding the planet at equidistant locations in a band around the planet, and high orbit is 4000 miles, one planetary radius away, which has to do with hyperspatial dynamics.

Comm Systems

The standard Comm Systems of Psi-Wars have been determined since Iteration 3, but given some ranges I’ve determined based on sensors, planet sizes and orbits, I’m going to make a modest change. See, Psi-Wars has been using “Radio” the whole time, as “Radio” is pretty intuitive. You know things like electrical storms or being deep in a tunnel or underground can disrupt the communication system, and this is important, because GMs will often want to isolate the PCs, and radio offers an intuitive, commonly accepted way to do that. But I thought I needed more range, but now I’m not so sure.
The primary ranges worth worrying about are 100 miles, 500 miles, and 4000 miles. 100 miles is “low orbit,” 500 miles is a “patrolling” orbit, where a belt of ships might position themselves to maintain sight-lines on one another, and maximize response time, and 4000 miles (one planetary radius) is where most ships will enter or exit hyperspace. It’s also about the distance between ships in a patrol orbit. I would imagine that characters can communicate with their ship with a wrist-mounted device (thus, tiny), that you might need a palm-sized device to talk to a ship in patrol orbit, and that ships would mount large communication systems that would communicate up to 4000 miles.
If we look at gravity-ripple, we find these values are over-kill: a tiny GR-comm will communicate to low orbit, a small GR-Comm will communicate to patrol orbit, and a Medium GR-comm will communicate to “far” orbit, or the hyperspatial terminus. However, if we look at “Communicators with Different Ranges” we see that the larger comms of spaceships and docking stations will more than make up for the small size. For example, a micro GR-comm can talk to a ship in orbit, if that ship has at least a small comm on it, and to patrol orbit if the ship has a large comm, and a small can communicate to far orbit if the station has a large comm. This is probably “too small” for what we’re going for.
If we return to standard radio, which is more intuitive, then we find that:

• Tiny (Wrist-Comm): TL 11 can communicate up to 5 miles, to low orbit if the ship has a Large comm system, and patrolling orbit if the ship has a Very Large comm system. TL 12 can communicate to low orbit if the ship has a Medium comm, to patrolling orbit if the ship has a Large comm.
  
• Small (Handheld Holo-comm): TL 11 can communicate up to 50 miles, to low orbit if the ship has a Medium comm system, and patrolling orbit if the ship has a Very Large comm system. TL 12 can communicate up to 100 miles, thus to low orbit on its own, to patrolling orbit if the target has a large comm system, and to high orbit if the station has a very large comm.
  
• Large (Vehicular comm): TL 11 can communicate directly to high orbit, and can communicate between ships in patrolling orbit. It will pick up TL 11 tiny comms if in low orbit and TL 12 tiny comms if in patrolling orbit.
  

It seems, thus, that the simplest solution is to use Radio with TL 12 ranges, which is a step down from GR-comm, but still offers the sort of convenience that we might expect. The only remaining problem is that radio offers far lower bandwidth at 0.1 GB per second, but after some research, I found that 1080p real-time only consumes about 14 MB per minute, so radio is probably plenty for low resolution holographic communication. This might actually explain why holo images are small, full of static and have a relatively low resolution. The other problem is that the range is also lower (by 10 times) for holographic communication, but that just requires a +1 jump in size. Thus, a small hand-held need about a Very Large comm system to do a holographic conversation with someone in patrolling orbit (at TL 12), and two ships in Patrol Orbit would need Very large comm systems to have real time holographic communication with one another.

For building an arbitrary comm system, the stats are:

weight = R * 0.004

Where R = Range.

Cost is trickier to work out, as we generally work out cost by weight, and barring that, some other measure, but in or case, weight, range and power all follow the same multiplier of ten, only cost doesn’t. At its smallest, the cost per lb is $2500, and at its largest, $50 per lb. Frankly, I’d just keep the radio values as they are, since working out cost is far more hassle than its worth (you probably don’t need a 65.25 mile radio tower, and even if you did, the rules we’d create would be “stepped” so it would be cheaper pound for pound to just get a 100 mile radio, etc). Power-requirements can be determined, and are vanishingly small (it works out to 1 kilowatt for the largest radio), but I’ll simplify it and give it a small bump of 0.0001 kw per mile of range. This increases it to 10 kw for the largest radio.

FTL Comms

FTL communications needs to handle the extreme distances of Psi-Wars, but otherwise the FTL values on p 46 of Ultra-Tech are fine, just multiply the (TL 12) distances by 30 parsecs and not that nothing smaller than a Medium communicator is considered practical. 3 parsecs will talk to very nearby systems, and is close enough to hit a relay if its in or near system, a Large will communicate from one typical “Jump” to another, and a Very Large is able to transmit over multiple jumps, and is typical of relays, allowing FTL comm from rim to galactic center, assuming unbroken relay chain, instantly. The model weight is range in parsecs * 1.3333, cost is 20 times the cost of a radio comm, and power is range 33.33kw * range in parsecs (I’m treating it as a cosmic technology; even so, the power requirements are fairly slim compared to more serious hardware).

Comm Jamming and the Distortion Scrambler

What surprised me is that while Ultra-Tech has plenty of comm systems, it has no comm jammers other than expendable jammers! I’m not sure why this oversight exists. I don’t think the distortion jammer is meant to prevent communication. We have a “bug stomper” on page 107, but that’s clearly meant to stop audio surveillance, acting as a sort of portable privacy field. It doesn’t prevent communication systems. This surprises me, as it seems an extremely useful thing to have: it’ll stop bugs from transmitting back to their source, it’ll prevent patrols from communicating to base, etc. To find one, I went hunting through GURPS Action and there it was. A deeper investigation proved that it was found in GURPS High Tech, making it an odd omission.

Thus, we’ll have to create our own, using the High-Tech values as a base. It’s not really clear to me exactly how they’re calculated, but Vehicles divides their range by 100 and high-tech seems to more-or-less follow the same path, so the simplest approach is to simply treat a jammer as a comm system with 1% of the range. I think I would argue that it also consumes far more power. This is confirmed by the fact that a 35 lb TL 7 radio uses batteries, but a 25 lb TL 8 area jammer uses external power. So, I propose 10x power. Cost will be $100 per lb.

When I initially looked at the rules, I was skeptical, namely in that you could equip a fighter with a jammer and run it up to a capital ship and jam all of its communication. Was that feasible or even realistic? This is different from radar jamming, which only affects distorting the return signals that strike you, this is about cutting off all communications reaching or leaving a specific target. But it turns out that it is reasonable.

At the risk of belaboring the obvious, comm jamming does the radio equivalent of overloading the source, or cutting up a signal. Sound-equivalents are people screaming over a conversation (very obvious), introducing white noise to slice up the sounds of your conversation (slightly less obvious), or perfectly introducing counter-waves to cancel out your waves (comes across as just silencing the target, and is not obvious at all, but also very difficult to do). While communication is generally targeted, time-boxed and can afford to be relatively low-energy (it doesn’t cost much to talk to someone), it’s more exhausting to use any of the above solutions (it costs you more energy to constantly scream than to just whisper a quick message and stop.

My concern was that a sufficiently loud broadcast should be able to overwhelm a jammer, sort of like shouting over the screamer, but my research suggests that, at least, this sort of thing isn’t common, that with sufficient power, one could jam almost any communication so, yes, a fighter could jam a dreadnought if it was close enough. I suspect there really are nuances, but not nuances I really want to get into, otherwise, we’d need to compare power-levels, and I’d need to find said power levels, and that’s both more work than I’m willing to do, and more work than you should do for a game like this.

So, the version of a jammer I have is cinematic. It jams all communications, much in the same way a distortion jammer jams all sensors. This works well for a simplistic sci-fi setting where you flip a switch and it does its thing. We’ll follow the same rules: this requires an Electronics Operation (Comms) rolls vs your opponent’s Electronics Operations (EW) roll; up to 10x the listed distance, it requires an unresisted Electronics Operations (Comms) roll. It will be called a “Distortion Scrambler”

An example Distortion Scrambler:

Distortion Scrambler: This device scrambles all forms of electronic communication within a one mile radius. Anyone attempting to receive or send a signal within one mile of the scrambler must roll a quick contest of Electronics Operation (Comms) vs the user’s Electronics Operation (EW). Those within 10 miles must roll an unopposed Electrionics Operations (Comms). $400, 0.5 lbs, 2B/1 hour; LC 2.