If you have the squelch set to tight, not only will you get a very nasty exaggerated squelch tail on your scanner.. but youll not scan.. just be locked on one freq..... You want to set it the first time at the point hissing stops.. then play around till you get the best setting for your location. Remember- If your in an area where there are lots of transmitters,.. you do not need a tight squelch setting.... but for rural areas with most of your listening from distant stations.. set the squelch tighter....