Home and portable scanners are used by various individuals, including volunteers working for civil defense agencies to journalists who cover the police beat for the local newspaper. The retailer, Radio Shack, produced a number of Realistic scanner models that it sold to the public. The Realistic Pro 41 is a police and emergency services scanner that users can program to follow specific frequencies.
Install fully charged batteries. Turn the scanner on.
Press the button marked "Manual" on the scanner keypad.
Use the keypad to enter the channel number you want to program and press "Manual" again.
Press the "./Clear" button to clear the screen and prepare for the new frequency.
Use the Realistic Pro 41 scanner's keypad to enter a new frequency; when done, press the "Enter" button to save the frequency into the scanner's memory.
Repeat as necessary until you program all 10 channels on the scanner with frequencies you want to follow.
A good reference for active frequencies is Radio Shack's Police Call Directory, which includes fire and emergency services.