... Wait! Did I say "conventional underground radar"? It's ridiculous. Underground radars are not allowed because it is impossible. ...
I have an idea for another scenario featuring these AWACS aircraft and the radars:
Underground radars work but the pile of mud used to hide them means they can't use the fancy spread spectrum tricks to hide themselves below the background noise floor. This means the aliens will be able to lock onto their signal and find your base pretty quickly once you prove to them you are more than a little nuisance for them. Expect to have so many aliens knocking at the door of your base(s) that you will be literally forced to dismantle them all and rely solely on AWACS to figure out where these pesky UFOs are lurking around.
Plus the pile of mud gets in the way of the radar's detection abilities. This means while AWACS sports a whooping 50% chance of detection in a small radar range, the small radar itself can barely get to the measly 20%. Long range radar has much higher range but at a pretty high cost: It has to use much stronger signal which makes the base where it is locate much more vulnerable to detection of the alien craft but even that does not help too much as the detection chance is only 10%
And don't think a mind shield is going to do you any good in avoiding detection. If the aliens can see your radar's signals, they can detect your base no matter if it has a mind shield or not.
Well, that could add an interesting twist to the game. If you like to invite aliens to bring their gear to your hideout and then perish, you can build a bait base equipped by radars. Then whenever aliens go out searching for your base(s), they will find your bait base and the carnage can begin ...
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I also would suggest AWACS crafts based on alien technology. Can hold hyperwave decoding circuitry, have 100% detection rate and huge range but are EXTREMELY expensive to build and operate (the 100% detection gear needs a lot of fine alien avionics and communication artefacts to build and the high range has its costs in Ellerium consumption as well). This would add an interesting strategic twist to the game: Am I going to pay to cover the important area with 100% accuracy detection or I am going to be content with 50% (standard AWACS uses human fuel and Hyperwave Decoder does not use any Ellerium as it is mostly passive decoding device able to operate on standard electricity).
