PD guns and Final Defence range

[dersavage (OP)]

If I make Point Defence guns example lasers or gauss is there a minimum range? So can I design small fire control like 6400 km and they still work or should they be like 10k etc. If range is not a issue why design greater range FC at all for PD guns.

[brondi00]

10k km is the minimum.  Remember that the fire control has better accuracy the smaller the fraction of it's total range it's engaging at.  Ak longer range fc is more accurate at final fire..  but there are obviously diminishing returns.  You need to decide how much you are willing to tolerate.  Unless I'm high tech I usually have a PD fire co trip at 4x speed and 1x accuracy. 

[liveware]

If you are using lasers for PD then the extra range can be very helpful not just for improved accuracy at 10k km but for greater accuracy at all ranges overall. Lasers have quite good range for beam weapons.

[brondi00]

Yes.  That's a good point.  If I am using lasers as a dual purpose weapon I often go for 2x range if the weapon can shoot that far so that I can use it as a back up self defense weapon on the PD ships. 

I usually do this with lasers if I have decided to make it my main beam weapon.

[dersavage (OP)]

Thanks. Not sure how accuracy works.

So if final defence always fire at 10,000 km I'm looking for optimal or good range for beam PD guns/FC. So if range is like 40,000 km not sure how going even bigger range benefit at all. Range makes more sense when using area defence. If you choose max. Range 20k or 40k FC and turrets are smaller and you can install more of them than longer range turrets.

[kilo]

Thanks. Not sure how accuracy works.

So if final defence always fire at 10,000 km I'm looking for optimal or good range for beam PD guns/FC. So if range is like 40,000 km not sure how going even bigger range benefit at all. Range makes more sense when using area defence. If you choose max. Range 20k or 40k FC and turrets are smaller and you can install more of them than longer range turrets.

The hit chance modifier for range is:

1-(distance/BFC range)

If this value becomes negative, aka BFC range is < 10k km, the weapons will not fire at all. At 10k km, the weapons will have a hit chance of 0%. Being too cheap here will gimp your beam PD hit chance severely, as it is the upper limit of your hit chance against missiles. It can only get worse when the speed/tracking speed ratio gets added into the mix.
At your suggested 40k km BFC range your hit rate would be 75% tops, which is decent. If you want to use your PD as a secondary battery in beam engagements you could go with a bit more, but for me the size of the BFC depends on the type and size of the guns it is controlling. If you connect it with a or even two quad full size gauss @ > 2400 tons per turret, it becomes pointless to save 50 tons when it comes to the BFC. Just make sure it looks sensible to you.

[brondi00]

If I were only using the weapon for final fire PD then I would go for at least 50k km of bfc range.  I consider that a minimum.  Especially early game when you're already getting penalty to hit because stuff is moving faster than the gun can track anyway.

But this is heavily tech dependant.  At higher tech even the tiniest baby bfc will track at like 10-12km/s and range at 70k while being only like 5 tons. 

But since I only bring, usually, two of bfc (one for use and one for backup) Id rather have them each be more capable so the guns I do bring are more likely to score hits.  But not too much more.  Especially early game I don't see much reason to go for 95+% bfc accuracy at final fire.

[Rince Wind]

Thanks. Not sure how accuracy works.

So if final defence always fire at 10,000 km I'm looking for optimal or good range for beam PD guns/FC. So if range is like 40,000 km not sure how going even bigger range benefit at all. Range makes more sense when using area defence. If you choose max. Range 20k or 40k FC and turrets are smaller and you can install more of them than longer range turrets.

The turrets don't care about the range. Lasers are the same size, no matter the wavelength, and Gauss don't grow because you increase launch velocity (I think? Can't test right now). So longer range is "free" when it comes to weight and it makes the weapons more usable for antiship duties. If you ships are not pure escort vehicles you can swap the turrets to another fire control for anti ship work at longer ranges. Even if 10cm lasers only do 1 point of damage at the range you are fighting ships it still helps as they are fast firing and often in multi-gun mounts.