Repeater Monitoring

Monitoring and Automated Tests

Two-way radio repeaters are unique and complex pieces of equipment. They sometimes aren’t used for days or even weeks on end, but when they’re needed, they must start-up instantly and retransmit the incoming radio signals. If lightning strikes, or the antenna gets damaged by a falling branch or ice during the repeater’s off-period, the problem won’t become apparent until the repeater is solicited for operation.

Cortex units can be set up to regularly start-up a repeater and run a complete test. This is not simply an on-off test. The Cortex can:

  • Generate an audio signal,
  • Inject it into the repeater’s mic input,
  • Key-up the PTT,
  • Measure the RF output and VSWR,
  • Detect audio (via a 2nd on-site or remote receiver), and even check for a specific tone,
  • Log the test,
  • Send a specific alarm if anything untoward is detected.

In addition, normal everyday operation can be continuously monitored for things such as:

  • PTT presence without RF power, or vice-versa
  • High VSWR,
  • Low RF Power,
  • 2nd opinion RF power (if the transmitter has its own RF output detector),
  • Power supply current,
  • RF Power Amp status.

Find out what sensors or features can be used to achieve this functionality



Davicom’s Bidirectional RF Power Sensors can continuously monitor forward and reflected power by being permanently installed in the transmission line.

Each sensor has two internal trimmers for field calibration of the output voltages of both forward and reflected powers.

The sensor comes in two versions: Model BPS1050 has a 30-500 MHz frequency range; while Model BPS5095 has a 500-950 MHz range.

These sensors are perfect complements for Davicom units, and allow users to take advantage of the pre-programmed VSWR measurement functions. They can be useful even for systems where transmitters have their own built-in RF Power sensors since they provide a precious “2nd opinion” in cases where transmission lines are damaged, but the radio doesn’t detect the problem.

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Amongst the Cortex’s many alarm transmission modes, one is of particular interest for repeater operations. This mode is the “Voice over PTT” mode. With this mode, when an alarm occurs, voice phrases are sent to the Cortex’s audio output jack and a pre-selected relay is used to close the PTT contacts on the radio. Alarm messages can therefore be transmitted out over the air and received by the concerned parties. This mode would obviously not work if the repeater is defective, and it shouldn’t be used if any alarm information is of a confidential nature.

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Davicom’s Cortex units have Reach-Through ports (also known as tunneling ports). These serial ports (RS-232 or RS-485) allow easy access to legacy equipment (such as older repeaters) that may not have other means of communication or configuration. Once a reach-through connection has been established with the radio, it can be remotely configured and controlled over a dial-up or network connection. A simple terminal mode (VT-100) is available or the radio’s specific communications application software can be run and remotely connected to the device. A Virtual Port software app is required on the PC, in this case.

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