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Spectrum Sentry

Overview            [Click Here for Screen Samples]        [Click Here for Supported Receivers]

Monitoring radio communications in remote areas poses unique challenges. Remote access to receivers is frequently required in the news media, public safety, law enforcement, and two-way communities. By locating a radio receiver at a remote site, the coverage area can be extended beyond the existing radio horizon.  Spectrum Sentry simplifies the task of installing and operating remote receivers by utilizing existing network infrastructure to provide both control and audio features over a single data link.

Want to Try It?

Call or email us and we'll set up a live demo at your installation. All you need is a PC connected to the Internet (see System Requirements, below). You'll download and install a demonstration version of Sentry Net and connect to a receiver at the Signal Intelligence remote site.


A Spectrum Sentry installation has three points of presence:

1)       A Remote Monitoring Appliance (RMA) located at the remote location. Each RMA supports one, two or four receivers.

2)       A base station PC running the Spectrum Sentry Base Station control software. Each base station can control up to eight remote sites.

At the remote location, the PC or appliance communicates with the attached radio receiver over an RS-232 interface. Received audio from the receiver is digitized by the sound card in the PC (or the RMA). The PC/RMA accepts a connection over the network (Ethernet TCP/IP) from the base station. When connected, received audio is compressed and blended with status information, and then transmitted to the base station over the network link. Status information includes frequency, PL tones, and ID codes. Additionally, control and programming commands received from the base station are sent to the radio.

At the base station, connections to remote locations are initiated and monitored. As audio and status data is received, the audio is rendered on the base station sound card and speakers, and the status information is displayed to the user on a graphical user interface (GUI). Control commands, such as scan or pause, are sent to the remote receiver from the GUI. Individual volume controls are supplied for each remote receiver.

Radio programming is performed by the base station, and can be password protected.

The base station has a record and playback feature that allows received audio from each remote location to be stored on the base station hard drive for later playback. The recorder is full duplex, meaning that recording continues even when playing back an earlier sound bite.

Remote Monitoring Appliance (RMA)

At the remote site, either a PC running the Spectrum Sentry remote agent software, or an RMA device can be used. Using an RMA device has several advantages. Since it’s not a personal computer and does not have a hard drive, maintenance is simplified and you don’t need to be concerned about rebooting. The RMA device is small, rugged and low power, providing more installation options.


Spectrum Sentry has two licensed components, the base station and the remote agent or RMA device. The minimum system consists of one base station and one remote appliance. As additional remote sites or receivers are needed, remote agents or remote appliances may be purchased.

Supported Receivers

  • Uniden® BC-785, TRUNK/CONV/P25.
  • Uniden® BC-796, TRUNK/CONV/P25.

System Requirements

Base Station: Minimum 750 MHz running Windows® XP, 2000. Multiple active receivers will require additional CPU speed. Minimum of 256 megabytes of RAM. Disk space to install under 20 megabytes, audio recording may require more. Sound card and network interface. Minimum display resolution of 1024 by 768, 1280 by 1024 for optimum viewing when multiple receivers are used.

Network, Remote to Base: Any network that provides routed TCP/IP. This includes Internet, DSL, satellite, private microwave, wireless LAN. RMA devices uses RJ45 Ethernet.

Network Bandwidth, Remote to Base: Minimum sustained throughput of 35 kBPS per receiver, good practice is to allow 64 kBPS per receiver.