What are the triggers for aliens to start attacking bases & how do you minimize the aliens ablity to find/attack your bases or stop it from happening so soon in game? I've had 2 new campaigns w/ Dec downloads that the Aliens just seem to go nutzo after my bases early in the game (2-4 attacks each month at my 2 main bases) using Harvesters which I don't have anything that can shootdown one yet so that isn't an option to contain them. Having this many base defense missions & trying to go on others leads to way too many WIA/KIA leaving no healing time. IIRC missions pace were supposed to go down to allow some downtime but the pace of these past 2 campaigns has been greater.
Any ideas on how to go deeper underground?