Part 1: Technology

The type of scanner you will need will depend on the type of radio technology being used in your area. While all of our scanners are capable of monitoring local public safety, not all models are compatible with all radio systems. In order for a scanner to properly receive the type(s) of transmissions you are looking to monitor it must be compatible in these 3 areas:

  • Frequency Range

    • Also known as bands this is the range in which a frequency will fall on the radio spectrum. The radio spectrum is divided into chunks that are allotted to users for a specific use, such as aircraft, marine, ham radio, public safety, etc. If a scanner is not manufactured to include the band you wish you monitor then you will not be able to receive transmissions on that band.
    • Example: The Howard County Fire/EMS Talk-Around channel is 868.512, which is on the 800MHz band. The BC75XLT would not be able to monitor that channel since it has a max frequency range of ~512MHz.
  • Modulation

    • Wikipedia defines modulation as “the process of conveying a message signal, for example a digital bit stream or an analog audio signal, inside another signal that can be physically transmitted.” This is basically the type of technology that is being used to broadcast the signal. In terms of scanning this will either be analog or digital. A digital scanner is still capable of receiving analog signals however an analog model does not have the components necessary to extract the information from a digital transmission.
    • Example: You can listen to the AM or FM radio stations in your car with your standard radio and antenna but to listen to XM or Sirius (digital) radio you would need the special receiver.
  • System Type

    • A communication system can basically be divided into two types: conventional and trunked. In a conventional system each channel of conversation has a dedicated frequency, for instance police dispatch on one frequency and police car-to-car on another. In a trunked system many agencies or groups of channels can share a pool of frequencies by having one temporarily assigned to them as needed based on availability. Instead of having dedicated frequencies they have a dedicated Talkgroup ID (TGID).
    • Example: (conventional): Baltimore Fire Dispatch is 154.415, Baltimore Fire Main (tactical) is 154.145.
    • Example (trunked): Howard County has 17 frequencies assigned to their trunked system that the county’s police, fire, sheriff, corrections, services, public works, schools, and their Maryland State Police troop share. If a transmission comes through from that trunked system the frequency can be any of the 17 on the system but if you saw talkgroup ID 43248 displayed onscreen you would know it is the Northern District Disptach since that is their assigned TGID.

Of course if you're not sure where to find the information you will need to shop for a compatible scanner model or it's all Greek you can always give us a call or drop us a line. Tell us a little about who you'd like to hear and for where, we'll take a look for you and recommend the best compatible scanner for your interests.