[blowfish]

 Do you think that after Terrans realized that their weapons and Hecate destroyers were rather weak, that could not even destroy a Ravana, even less than their Vasudan counterpart, they might have tried to reproduce shivan beams, weapons?

 Or since the GTI rebellion, that kind of thing is banned.

What are you guys talking about? The Ravana has four main beams (two SRed, two LRED), the Hecate has five (four TerSlash and one BGreen). It all depends on positioning. All the Ravana's firepower is forward, the Hecate has only one forward beam (the BGreen) but good flank protection. Overall the Hecate's main weapons actually overpower the Ravanas' in terms of simple damage/second by roughly 7000 points.

What are you talking about?  The Ravana has much more firepower than a Hecate.  A single LRed is more than 1.5 times as effective as a BGreen, taking refire rate into account, and while slash beams can be somewhat unpredictable, I find the TerSlash to be somewhat weak, even when compared with the SRed.  Even if all of a Hecate's firepower was on its frontside, I still bet the Ravana would win.

[Mustang19]

Source: FSWiki

Hecate: Four TerSlash and one BGreen. TerSlash damage/second: 1925. BGreen damage/second: 6,600. Total damage/second: about 14,600.

Ravana: 2 Sreds (1100 dmg/sec) and 2 Lreds (3,300 dmg/sec). Total: 8,800 dmg/sec.

14,600 Hecate > 8,800 Ravana.

Again, it all depends on positioning, since the Hecate's armament is dispersed while the Ravana's flanks are nearly undefended. Even head-on, however, the Hecate's BGreen is quite powerful and the Ravana would "only" have a 2,200 dmg/sec advantage. Every single one of the beams mentioned has a 4000m range, so range isn't that important, although the Ravana having all its beams up-front helps the Shivans in this department. The BGreen and the Shivan weapons are all direct-fire, non-slashing, so although the Ravana may scrape by in a head-to-head fight, it's at a disadvantage in every other situation. If you position the Hecate at just a slight angle in a bow-versus-bow situation, it would be able to bring even more firepower to bear from its broadside. Through all this, remember that through some odd twist of fate the Ravana and Hecate have exactly the same hitpoints, as does the Orion.

Contrary to popular belief, a lot of Shivan equipment sucks and often they're only able to overpower the GTVA through sheer weight of numbers. The Ravana and Demon are the worst destroyers in FS2.

[Kie99]

You're ignoring some crucial Facts

Beam Lifetime
BGreen: 4 Seconds
TerSlash: 2 Seconds
LRed: 7 Seconds
SRed: 3.8 Seconds

Recharge Time
BGreen: 30 Seconds
TerSlash: 10 Seconds
LRed: 10 Seconds
SRed: 25 Seconds

Not wanting to go into the maths of it, I'm pretty sure the Ravana would gain an advantage over the Hecate in terms of punishment dished out in short order.  The LRed can fire so much more frequently, and for longer than the BGreen that the Hecate's advantages will be nullified.

[blowfish]

Yes, Mustang, you're ignoring the beam lifetime and recharge time.  There's a column of the Weapons Comparison Table called sustained damage per second, and these are the numbers you want to look at.

The LRed and SRed do 1359 and 145 sustained damage/sec, respectively.  That means that the Ravana can do 3008 damage per second.

The BGreen does 776 and the TerSlash does 321, so the Hecate does 2060 damage per second, theoretically.  BUT slash beams are somewhat unpredictable so assuming they hit their target about half the time the Hecate's damage per second is more like 1418, less than half the firepower of the Ravana.  And that's all of its beams combined.

[Woolie Wool]

The FS2 beams were photon beam cannons while the Lucifer's were flux cannons. Either the GTA and PVN didn't understand the Lucifer's beam cannons at first or their beams are completely different.

Pointless semantics. The Lucifer used weaponry that fired big glowing massively powerful death rays in FS1. 32 years later, everyone is shooting weapons that fire big glowing death rays that do a similarly massive amount of damage. If you believe the Interplay cutscene, the beams even made similar noises. I think it's parsimonious and logical to consider the Lucifer's weaponry a more primitive form of their current beam weapons. I've always been of the opinion that the Lucifer was already obsolete in FS1 and that the Shivans only send the bare minimum that they think they need to defeat their opponent. They saw the Terrans as easy meat, so sent an old rust-bucket destroyer and an outdated support fleet. In FS2, the Shivans probably decided the Lucifer was pretty much useless because its capship shields would not protect it against beam cannons (why else would the Terrans be so bullish about the Colossus, since the cutscene indicated that they expected more Lucifers? Why else do AAA beams rape shields so well?), and decided to focus on firepower, and then sent what they thought was needed to smash the GTVA. Well, it didn't work. The massive Sathanas fleet wasn't even sent to attack the GTVA directly--if it was, the GTVA wouldn't have had time to secure Capella because the armada would have torn the entire GTVA navy a new one in record time. The combat in Capella seemed more a diversion to prevent the GTVA from interfering in their plan to turn the Capella system into a gigantic subspace node.

As for where the GTVA got beam cannons, convergent technological development is not impossible. Why couldn't the GTVA develop beams by themselves? The MX-50 tech description indicated that they were already working on shields before the Shivans showed up.

[eliex]

 Actually, speaking of the Lucifer, I was curious why the Shivans on their second incursion didn't make all the Sath juggernauts shielded as well, or they were except that the GTVA weapons were considerably more powerful 32 years later.

[Woolie Wool]

Because the advent of beam weapons made the energy for a shield better spent on bigger beam cannons.

[blowfish]

 Actually, speaking of the Lucifer, I was curious why the Shivans on their second incursion didn't make all the Sath juggernauts shielded as well, or they were except that the GTVA weapons were considerably more powerful 32 years later.

I think that the Lucifer was a special ship, designed to be invincible (though apparently not quite), and capable of wiping out civilizations, while the Sathanas's main purpose was to make Capella go boom (and creating a supernode).  I'd imagine it isn't easy to shield a vessel of that size, and the Shivans really didn't think it was necessary to shield the Saths (though it would have helped).