Very interesting thankyou. I am picking up the control channel which is 852.3625, but it sounds weak and noisy. I should be hearing it strong if it's coming from the tower about three miles away. My GRE600 used to work but not as good as the old Uniden scanners. It finally stopped working on the P25 and that's when I put it up on the shelf until a few days ago. I might try your test and take it for a drive to see if it starts working.