Please stop telling people they need to put a mag mount on a fridge, a ground plane kit, or a cookie sheet for a scanner antenna as it is FALSE information. Receive antennas DO NOT require ground planes. If it were the case, you would never be able to set your handheld radio/scanner down as your body is the ground plane when you transmit using a handheld. Same goes for buying higher gain antennas for scanners--gain is a transmit specification and has zero to do with receive.
LISA...please try what POP says...if you need further assistance, please include what systems you wish to scan and where they are related to you (i.e., my window faces them and I'm on the first floor 20 miles away). Best guess if you don't know exactly. I took a peek at the database and York County is using VHF and UHF...the only 800 digital system is the statewide one that may or may not have anything of interest to you. You are a fair distance from the VHF and UHF towers but they are up fairly high. Try to get a clear line of sight to the west--best you can...then you can compare other antennas.