RadioShack Guide to Scanners

Comparing the Scanning Methods

Crystal-controlled Scanners

The earliest scanners were crystal-controlled. These scanners had one or more internal slots for a crystal which allowed the radio to receive a single frequency. Crystal-controlled scanners are not currently being sold through RadioShack; however, they still turn up in pawn shops and garage sales. For example, the PRO-25 (Cat. No. 200-0106), PRO-27 (Cat. No. 200-0108), and PRO-53 (Cat. No. 200-0122) scanners were of this type. Generally, if you are looking at a RadioShack scanner and it does not have a keypad or program button, it is probably crystal-controlled.

The disadvantage of crystal-controlled scanners is that they were slow to tune, expensive to set up for new frequencies or channels, and they could not follow the new trunked radio activity. Crystal-controlled scanners have been replaced by programmable scanners.

Programmable Scanners

In the mid-80's, programmable scanners were introduced which used integrated circuits to allow the radio to tune to a range of frequencies. These scanners were a marked improvement over crystal-controlled scanners, which required the purchase and installation of individual crystals which could only tune to a single frequency. Programmable scanners have a wide range of features and capabilities and can be distinguished from one another by the following features:

• The number of channels that can be programmed
• The frequency ranges the scanner can receive
• Frequency band and/or service band search
• The scan speed (measured in channels per second and/or steps per second)
• The type of transmissions the scanner can monitor:
  • Conventional only
  • Conventional and analog trunking
  • Conventional, analog trunking and digital trunking