sensor question

The tachyon sensors do the same thing as the basic sensors - detect things - it's just that they are better at detecting cloaked ships (higher sensor level) and worse at detecting far-away things (lower sensor range). So for optimal effectiveness, you will want both types of sensors.

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Well, if you research sensors high enough, you can have Tachyon Sensors that cover the whole map. Then range is moot.

"Once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been and will always long to return." ~Leonardo DaVinci