Errr. Ummm...
I applaud the attempt at radar dampening, and I agree, it'll keep snipers from laying waste to it. however, this roughly... errr... defeats the purpose.
Allow me to model this with an image...
You'll note from memory, I hope, that to hit most of the inbound wormholes, you need to leave 1-2k in range of overlap for the 'circle' of invaders. The image above presents a 'shallow' version. It would leave a good 1/3rd off of an inbound fleet, at least. Notice where the dampening line hits at 1000 less than its range (roughly). Over half the fleet is still going to be able to pound the crap out of it.
This helps in that ships can't sit outside their range and pummel them, but for a Basic to even be IN range, the Frigates are going to pound them to pieces. MLRS is basically defended from everything at range now, that's handy, but those were just really icing. Usually you'd drop them and their 15,000 range at about 12k out to cover the wormhole. Lasers, at 11k dampening and 12k range, have a similar problem as the basics, just less fleet can do it immediately and you'll need to position just right.
This will help a hair, but it certainly won't be anything near a cure to death by alpha strike. Dampening needs to be brought to a 4k - 5k range difference so you can cover the wormhole without inhaling the alpha, or it's moot. Under most circumstances, you typically drop a FF I (or 5) across the wormhole to disallow escapees. They're 4k across as well.
I see roughly no difference between these turrets and the old ones except that they won't be sniped down on non whipping boy worlds where you run the turrets close to the command station instead of the wormholes.
Sorry Keith. I realize you didn't go nuts with it for balance reasons and if that's far too much dampening I can understand, but without it you're not going to cure the issue you'd hoped to. You still will have to deploy outside of 'covering range' of the wormhole or eat the alpha.