EM wavelengths, and how they affect PDLCs and Laserheads

kzt wrote:

Somtaaw wrote:I thought the Honorverse lasers were basically very similar to current generation industrial lasers. Powerful enough to cut steel plates, but practically no range so the emitter has to be fairly close to what you plan to cut.

And in Honorverse, anything beyond a million KM is for all intents invulnverable to a pure energy weapon-armed ship, even without sidewalls. At least thats what the wiki says, fairly hard limit of about that range.

Think about this a bit. If the power density is sufficent at 100,000 km and 300,000 km, how much can if fall by a million km?

I don't think that anybody has ever said that power density was the limiting factor on range. I suspect that it has more to do with accuracy than anything else. At a million km, you have (assuming I did my math correctly) about .00008 degrees between when you shoot over an Invictus' bow and when you shoot past its stern. Assuming a Grazer is 50 meters long, (and it is probably not) that is a 70 micrometer variance between over shooting the front and over shooting the rear. Kind of hard to get that sort of accuracy that will stand up to battle conditions.

The fact that you have a different effective ranges against ships with different defenses kind of strongly suggests it is related to power density of the laser spot.

kzt wrote:The fact that you have a different effective ranges against ships with different defenses kind of strongly suggests it is related to power density of the laser spot.

Or that bigger ships are easier to hit at long range?

Weird Harold wrote:

kzt wrote:The fact that you have a different effective ranges against ships with different defenses kind of strongly suggests it is related to power density of the laser spot.

Or that bigger ships are easier to hit at long range?

which is why the effective range against SDs is less than destroyers?

kzt wrote:The fact that you have a different effective ranges against ships with different defenses kind of strongly suggests it is related to power density of the laser spot.

Or it could be that your opponent having a sidewall in the way makes it twice as hard to get an exact bearing on his ship? SD strangth sidewalls would scramble the data more than a cruse grade sidewall. And the larger and more powerful sensors on an SD, coupled with the increased computing power, would allow them to get a better target from further away. :shrug:

We have textev in the books indicating roughly 1 mil effective range for a down the throat or otherwise no-sidewall shot for broadside energy mounts, but I seem to recall somewhere RFC indicating that aiming gets very hard past that range.

One possibility, for a fairly soft target such as a missile, would be to go for the max beam widening that still allows you to wreck the missile.

At the risk of thread-jacking, I wonder about the current design of PDLC. Given that MDMs are so fast that PDLC get only one shot at each, I question the utility of the ability to rapidly fire from the cluster by using multiple emitters. If the missiles arrive in the traditional single wave, it seems like the quick recharge is largely wasted as no follow up shots would be possible. Would not smaller but more numerous installations be more effective? Or the ability to fire from two emitters at the cost of lower cycle time?

At a million KM you are shooting at a spot it will be at in 3 seconds based on data from anywhere from 3 seconds to 0.05 seconds ago. With the acceleration of the ships they can make it kind of hard to hit it you are shooting at them broadside. Given that honorverse ships maneuver like garbage scows, if you are shooting directly along the thrust axis the targeting problem would grow unfeasible much slower.

ericth wrote:We have textev in the books indicating roughly 1 mil effective range for a down the throat or otherwise no-sidewall shot for broadside energy mounts, but I seem to recall somewhere RFC indicating that aiming gets very hard past that range.

One possibility, for a fairly soft target such as a missile, would be to go for the max beam widening that still allows you to wreck the missile.

At the risk of thread-jacking, I wonder about the current design of PDLC. Given that MDMs are so fast that PDLC get only one shot at each, I question the utility of the ability to rapidly fire from the cluster by using multiple emitters. If the missiles arrive in the traditional single wave, it seems like the quick recharge is largely wasted as no follow up shots would be possible. Would not smaller but more numerous installations be more effective? Or the ability to fire from two emitters at the cost of lower cycle time?

PDLCs can also fire all lasers in a cluster at the same time at multiple targets, with somewhat less accuracy. See the Pearls: http://infodump.thefifthimperium.com/en ... gton/151/1

kzt wrote:"Weird Harold"]"kzt"]The fact that you have a different effective ranges against ships with different defenses kind of strongly suggests it is related to power density of the laser spot.

Or that bigger ships are easier to hit at long range?[/quote]
which is why the effective range against SDs is less than destroyers?[/quote]


--------------------

The big boys have armor measured in (layered) meters thick -- that's a lot of material to disburse and absorb energy.

The small boys -- DD's / CL's are comparative sheet metal. They are incapable of absorbing damage.

Same in our universe. The Exocets that hit a couple USN DD's and FF's would have resulted in a call of "Sweepers, Sweepers, man your brooms" on an Iowa Class.

-- Stewart

stewart wrote:The big boys have armor measured in (layered) meters thick -- that's a lot of material to disburse and absorb energy.

The small boys -- DD's / CL's are comparative sheet metal. They are incapable of absorbing damage.

Same in our universe. The Exocets that hit a couple USN DD's and FF's would have resulted in a call of "Sweepers, Sweepers, man your brooms" on an Iowa Class.

-- Stewart

So you agree it's power density of the laser spot?