Due to a need for a new toy, plus a newfound habit of 'slightly' exceeding the posted speed limits, I went out and got an Escort 9500ix. It has been very educational to drive it around the South (San Francisco) Bay Area and see what it picks up and how truelock/autolock works.
What I notice is that there isn't a whole lot of speed enforcement on 237, 85 and 280. During a recent trip to Southern California, I managed several more confirmed hits. On the I-5, I had a couple of hits on the way down and a couple of more on the way back.
The most exciting hit was when I was traveling south on I-5 in Kings County. The Ka warning came up, and I was a bit slow to react. There was a CHP cruiser, coming north in his left lane, that flipped on his lights, and started to execute a high speed u-turn in the median. He finished the turn ~50 ft away from me and went after some other car.
What I think happened in retrospect was that he was running in constant on mode looking for speeders in either lane. It never occured to me that CHP would be looking for speeders in both directions at once.
The other hits were less exciting. One was a speeder getting picked up in the other direction. Another was a pair of officers blocking traffic in the other direction and they must have left their radar on.
My initial observation/understanding is that CHP uses Ka band. K band has always been speed signs. And X-band is always a door opener/motion sensor. I'm thinking about disabling X-band.