The BEST way to test the boosters is as Follows
1).go to a known low reception area
2).check and make a note of the reception level
3).take out the Battery
4).install the booster according to directions-avoid touching the sticky part of booster-and stick it on the inside of the phone-not on the battery-as close to and in the same direction(if possible)as the built in antenna.In especially low reception areas-AND if your phone can hold more than one booster-go ahead and install a 2nd.
5).replace the battery,turn on phone & check reception