Hello! I have the sds200 detailed view turned on and it shows the noise. Normally when scanning it reads 38,000 to 40,000. When a system comes on it could range from 60 to 400. What would be acceptable? How to tell where the noise floor is and how much noise I have on the feed? I'm also using a 15 db cable amp with the scanner. I've noticed it helps weak signals come in better. Would this be hurting the noise floor or the scanner?