I'm the author of this post. I don't know why I had so much trouble picking up my own sensors. I agree, I've seen a lot of people say they can pick them up from pretty far away too. I'm still not sure about my antenna situation, but I just picked up a couple of Citroen sensors from a car driving by (~75 ft away) and they reported 130 and 131 kPa. I also saw one that was reporting 123 kPa during one of my drives while troubleshooting. Although my own "Citroen" sensors are definitely reporting the correct pressures, I'm thinking maybe there's another model that reports half of the actual pressure or something.

I'm also curious why they report a manufacturer of "Citroen". Isn't that a French automobile manufacturer? I wonder if someone originally observed this protocol on a Citroen car, but it's really just one of the main protocols used by the big TPMS sensor manufacturers like Schrader. I really doubt the sensors on my Dodge Ram are made by Citroen...