Rebar will give me a false reading but mostly along block/cinder walls. I can't say I've ever run into rebar in a sidewalk. I belong to a club. There are many members who have never found silver. Only difference, they don't hunt old neighborhoods and ask permission to hunt old homes. The last four houses I asked to hunt their yard, they all said yes. Yesterday at a 20's house no silver coins, but I did dig a silver thimble, only my second in 11 years of hunting. The house two days ago, the homeowner sitting on this porch said "there's nothing in my yard". I've heard that a bunch of times. I dug a 1917p dime, it was about 4 inches deep. At a city park where I've dug 30 silver dimes, I just dug another silver, it was where they pulled out a bunch of shrubs that were along a chain link fence and now it's just dirt. I've heard a lot of excuses why some can't find silver. Do you really believe every house in an old neighborhood has been hit. A lot has for sure, but not all. Not all because some people will not let you do their yard. Well, some of those people may have either died, or moved, and now the new homeowner will let you detect his yard. Whenever I go someplace, I will 90% of the time drive through older parts of town and I always have an eye out for places to hunt. Carry your detector with you everywhere you go. The best time to hunt is just after a rain when the ground is wet, your machine will go deeper. Too, my machine is programmed to find silver coins. I took one factory program, programmed it to be silent. Using the volume control, the machine is super quiet, except when I swing over a nickel, and when I swing over a copper penny or a dime or quarter the volume is very loud. I've heard if you discriminate metals you lose depth, that's why I use my volume control so I'm not discriminating metals. I know for sure, if you do not hunt in old places you will NOT find silver.