Well there is probably no perfect defense for them but here are some tips to make life a lot harder for SBHs.
So for starters the most effective way to defend you base from nuke attacks is stopping the SBHs from arriving in the first place.
But first things first, there are 2 types of maps, those with base defences and those without.
In most maps there are 2 or 3 ways to get into a base, a main entrance and one or two side tunnels or entrances.
If there are base defenses present they're intended to defend the main entrance to the base and they're able to detect SBHs so unless someone's a complete dimtwit an SBH will not come in via the main entrance of the base.
That leaves just 2 locations at most where the SBHs will come from, yup you've guessed it! The side entrance!
Basically you can just mine these 1 or 2 spots like there is no tomorrow and you're pretty much settled in maps with defences.
As for maps without defences, that's a lot more tricky due to the mine limit but it's still possible to defend properly.
The main idea is to mine the exits of buildings first to prevent nukes inside the building, once that's done place any mines that may still be placed at the stairs to each building (3 is enough). The limit will probably only allow you to place mines at 2 more structures but if a nuke is planted in your base at least you can tell the likelyness of the nuke being plantred on the roof or not.
As for which buildings' roof to mine or not, well the Warfactory is probably the biggest must, it's a big roof with plenty of spots to place the beacon.
Your last mines should be placed on a building near the Warfactory, in most classic base setups that would probably be the refinery.
The idea is that when a nuke is planted now and it's at the WF or REF it's probably somewhere outside the building on the ground floor level.
When it's planted at the Power Plant or Barracks you'll need to sweep the roofs as well but at least the PP and Barracks have much smaller roofs where nukes are easy to spot.
Going through these steps is likely to make your life as a base defender a whole lot easier...
So now defuse that nuclear strike beacon! Just be carefull to not get shot in the back of the head by the SBH(s) who planted it.
