Main/Standby

Main/Standby: Automated Transmitter Backup

Nautel integrates reliability and redundancy into all its transmitters, ensuring broadcasters remain on air. Main/Standby systems help broadcasters maintain continuous on-air broadcasts, contributing to more dependable, efficient, and secure operations. A Main/Standby system offers broadcasters an option to ensure uninterrupted service by enabling a smooth transition to a standby transmitter when the primary unit fails, thereby minimizing off-air downtime. Additionally, it facilitates system maintenance and upgrades, making it possible to carry out these tasks without interrupting the broadcast and maintaining a steady on-air presence.

Main/Standby Features and Advantages

  • Maximum on-air performance
  • Dedicated redundancy
  • Automatic switchover backup
  • Full power backup transmitter
  • Automated AES/EBU audio input main/backup routing (Using VS-TC/ VS-TC-HP)
  • Remote or local control

Nautel Main/Standby Implementation Example


In this example two Nautel VX series FM broadcast transmitters (top and bottom) are setup in a Main/Standby configuration along with a Nautel VS-TC transfer controller (at the centre). Each transmitter operates individually at one frequency between 87.5 MHz and 108.0 MHz. The system is designed to allow the backup transmitter to be used in place of main transmitter in the event of its failure.

When the VS-TC recognizes a fault condition that has inhibited the output power of the main transmitter, the VS-TC inhibits the faulty transmitter and transfers it to a test load. Along with RF, the AES/EBU audio can be switched to the standby transmitter which begins broadcasting the faulty transmitter’s channel.

Main/Standby Controllers

Nautel offers a number of options for main/standby controllers:

  • VS-TC Transfer Controller
  • VS-TC-HP Transfer Controller
  • SC4 Controller

VS-TC and VS-TC-HP Transfer Controllers


The VS-TC and VS-TC-HP controllers are specifically designed for use with Nautel FM broadcast transmitters in a main-standby configuration, enabling precise control over the transmitters’ on/off status by managing their RF mute circuits. Packaged in a 2RU, 19-inch rack-mountable chassis, they feature a user-friendly front panel UI that displays Main/Standby settings , and status for real-time operational oversight. These controllers help maintain continuous broadcasts by smoothly switching between main and standby transmitters, saving space, supporting consistent content delivery. The VS-TC includes an internal coaxial relay suitable for transmitters up to 600W to route the RF output to the antenna appropriately. The VS-TC-HP supports control and monitoring of an external coaxial relay,  providing increased flexibility of what transmitter power levels are used in the Main/Standby system.

SC4 Controller


Nautel’s SC4 Controller, powered by Davicom, is an SNMP-based system controller pre-configured for Nautel transmitters and available in Main/Standby and N+1 configurations. It’s designed to offer advanced control and monitoring capabilities, featuring a sophisticated HTML5 remote user interface for instantaneous updates and remote changeover control management.

SC4 Remote User Interface

Product Family Support