I still have my grandfather's 1953 Philco two band radio where it had AM from 530 to 1600 kc and "Special Services" from 1600 to around 3500 kc and in the 1600 - 1700 kc area, there is a Civil Defense symbol, now part of the extended AM band and around 2000 kc, there is a police badge symbol. There are also ship symbols and plane symbols too. My mother remember picking up police calls on it when she was a teenager."Anyone with an ordinary receiver at home could tune in and hear the calls at WDKX, at 1684 on the AM dial,” author Christopher Bonanos wrote, of the NYPD, when it started broadcasting to its police cars in the 1930s.
Growing up, we had an old AM Radio in a wooden case that had POLICE at the top of the dial.