We ar using an ambit decoder box and recently we are having unusually high line noise. We have used this system for several years and has worked great.We are using this on our oval and offroad tracks. We have 14 gauge copper wire buried no more than 4 inches deep. We tried it with and without the resistor to no avail. The loop is way shorter than the max length that amb recommends. I have seen readings as high as 135. Has anyone had this problem? And does anyone have any suggestions. I hestitate to call amb because i know they will want to sell me expensive equipment to replace it with.