Do ultrasound sights have a range limit, or an "effective" range limit? I'd think there would at least be some TN penalties beyond a certain distance from a target, due to lag since the signals only go at the speed of sound. Since ultrasound requires goggles like smartlinks, does that mean it would be incompatible with magnification scopes? I know that it reduces the TN modifiers for ruthenium by half(M&M114), but how would it stack up against invis and imp invis?.

I'm not an expert, but my read is that the practical range is equal to sight, or at least equal to the range of whatever firearm you might use.

As for the smartlink, you can always use on or the other. If your goggles had Ultrasound and SL, then no problem to combine them, or if you have an internal SL with Cybereyes again, no problem. The Game Balance is that you cant use magnification and SL together.

Now the last one, And Here I am without books again, but....The Ultra sound basically paints over everything that bounces sound. So invisibility is negated by it. There might be a slight TN mod because of the incongruos picture between the painted picture and the empty space. But on the other hand, a silence spell is the antithesis of ultrasound. The way I handle it is all sound is magically deadened so anything in or on the other side of the spell is invisible to Ultrasound. (Beyond it because the sound needs to go through or bounce back through it, so are killed)

There may be more canon answers, but that is how I handle it.

There's only a .29 second delay for trying to fire, though. The only delay that matters there is for the reflected sound to return from the target to you. Where that sound originates from doesn't matter.

It still is a huge disadvantage, though. When sniping at long distances, you're talking about a delay of 1-3 seconds, which would make most shots impossible.

He's saying that the travel time from the Ultrasound emitter to the target doesn't matter, it's only the time that the reflected sound takes to get back from the potential target that you count.

So, in your example, the .29 seconds for the sound to get to the other guy doesn't matter; that sound wave isn't carrying any useful information until it hits something and starts its way back to the receiver. When it bounces off the target is when you start the "delay clock".

Exactly. It doesn't matter where the target is at the moment the sound leaves the goggles, only where he is when the sound reflects off him and what happens between that moment and when the sound returns to the goggles.

If it's only the target reflection->receiver time that matters, how much of a delay would start screwing with aiming? .1 sec? .2 sec?

Would these be reasonable?
+1 TN for every 0.2 seconds of delay, meaning no modifier for 0-0.19
or
+1 for the first second, +2 for the second(+3 total), +3 for the third(+6 total), minimum +1

Again, would it be usable with image magnification?
And if using it with thermo, would it cut the visibility mods after thermo in half, or cut the base modifiers, and then choose the lowest?

Everything beyond about 0.03 seconds would start screwing with your ability to hit a moving target.

+1 TN per 0.2 seconds seems reasonable. That's about equal to +1 per 70 meters.

Whether you can use image magnification with it depends on how good you think the resolution is. I'm not even sure what I'd rule.

Of course, that's all going to be completely variable depending on how fast and/or erratically the target is moving.

In the same way that fog shouldn't matter at all at very short range, but could make sniping at 600 meters completely impossible. Exactly how much several things affect your accuracy should really depend on a number of other variables, but that's extremely difficult to factor in in a pen & paper PG.

I would say a TN modifier between +1 and +6 should be applied at the GM’s discretion based on distance and movement. because the character can observe the effects that cause the penalty it is reasonable to tell the player what it will be. Aiming can only remove half this penalty. If US is not the only system in use ether the US penalty or the normal penalty whichever is lower

Usually there will be no penalty within 50m. (Changed to meters rather than seconds for game simplicity)

Justification. It should never be as hard as blind fire. You can’t aim to counteract movement that changed after your image was taken but you can aim to correct for regular movement. Even at 2K (assuming it was loud enough) you should have no problem with a stationary target.

Edward

How about +1 per 50m for a standard(moving/walking) target, no extra mod for a stationary target, and +2 per 50m for a running target? That last one would be on top of the +2 for a standard running target.

The way I currently play it (I'm a GM) is the abovementioned +1 to TN per 50m of distance, with the maximum range determined by GM based on circumstances. The TN can suffer additional penalties in certain conditions, e.g. in a sandstorm (our characters *have* been in some).
All ultrasound systems in our game contain "combat mode" software that can filter the incoming signals and analyze it. The main result is that the TN for ranged attacks can almost never be higher than would be without the US system, because the signals with too low signal/noise ratio or with too high lag are filtered out in combat mode. About the only things that could raise the total vision modifier above +8 are sophisticated false signals, either from technology or from spells. A side effect of this is that the maximum base effective range of US systems in this mode is 200m under these rules.
In the non-filtered (well, *relatively* non-filtered) mode the visibility TN modifier (both to shooting and to perception checks) can go higher than +8, so you have a chance to spot invisible characters even in bad conditions, but the downside is that sometimes the unfiltered signal makes it *harder* to hit the target because of the false information it feeds you.
Switching modes is a free action for smartlinked weapons or DNI controlled systems, simple action for manual switches.

Maybe not a realistic system, but relatively balanced and easy to use.

I'd handle it a little differently, only applying the +1/50m when shooting. This is more of a way to account for the sonic delay, after all. For perceiving I would only use the standard modifiers, as the lag doesn't matter when you only want to see if something is there, rather than shooting it.

I agree time delay doesn’t mean you can’t see it. The system would also have iconography indicating the approximate age of the image.

Edward