For those who are starting to go to the radio as a hobby, one of the first real technical challenges is understanding channel radio systems. At first glance, it seems simple: The control channel allows users to share part of the bandwidth instead of occupying one full channel, which allows greater use of the frequency range. In practice, it may be difficult to continue, but it is now a little easier thanks to software-defined radio.
This guide comes to us [AndrewNohawk], which is located in San Francisco and uses its system to monitor police, fire and EMS activity. These groups are commonly used channel radio systems due to the large number of users. Listening requires nothing more than a RTL-SDR setting, and the guide guides us by using this setting to find the control channels, the center frequency, and then identify the “talk groups” for which organization you want to listen to.
The manual goes into great detail, including lists of software needed to run such a system and since [AndrewNohawk] is a self-identified “radio noob”, the guide is fully accessible to people who are new to radio and especially new to highway systems like these. Once you catch it, it is not too difficult to scale.