Just wondering if anyone out is using the tracker IV and can offer some advise on the discrimination settings. I have been using mine either on the Tone setting with the switch at the 11.30 position, which seems to pick up most decimal coins - particularly $1 and $2 and gives a fairly reliable broken tone for pull tabs. I use this when I am short on time. However when I want to search an area more thoroughly I have it on the discrimination setting at about 9.30 (1/4 turn) which finds all decimal and pull tabs. I have only had the machine for 2 months and just wondering if anyone who has more experience with this machine has any suggestions for discrimination settings for optimal results.