About an hour ago, while on my way home, I was driving on the freeway doing about 120 kmph (PSL is 100 kmph). I got a Ka alert, repeating at a slow, steady rate. I slowed to 100 kmph and started looking around to find the source. I continued to drive for about another kilometer, with the alert remaining steady and not ramping up. As I moved over to take my exit, the alert ramped up slightly, and then I saw the lights of an unmarked Trailblazer who had just pulled over another vehicle, about half a kilometer past my exit.
So, I got a Ka alert easily of around 1 Km (estimate), from behind, with my STi-R Plus antenna mounted behind the bumper of my CTS-V. This speaks volumes with respect to both the sensitivity of the STi-R Plus, as well as the viability of mounting the antenna behind a bumper cover.
I'm appreciating this thing more and more all the time.