Nautel XR12, Руководство по предварительной установке

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XR12 Transmitter Pre-installation Manual Accessories
Page 10-2 Issue 0.17 2005-08-31
For detailed information about surge protection, refer to the Nautel Site Protection Manual.
Automatic antenna transfer control unit
The automatic antenna transfer control unit is a 19-inch rack mountable assembly that is used in
conjunction with two Nautel AM or FM broadcast series transmitters that are to be connected in a
main/standby configuration. The control unit controls the on/off status of the transmitters by
controlling the status of their safety interlock circuits. It also controls the AC voltage applied to relays
or contactors to determine the routing of the RF output of the on-air transmitter to the antenna. See
“Automatic switching system” on page 10-3 . The control unit allows manual or automatic switching
of the main and standby transmitters. In automatic mode, the forward power levels of both
transmitters are monitored. If the main (on-air) transmitter's RF output falls below a preset threshold
(typically 3 dB), an automatic changeover to the standby transmitter takes place. An interlock override
feature allows the operator to enable the RF output of the standby (off-air) transmitter into a dummy
load for maintenance or troubleshooting.
Figure 10.1: Automatic antenna transfer control unit
RF contactor
The RF contactor is an RF output switching device for a main/standby control cabinet that interfaces
main and standby transmitters (less than 15 kW RF output power) between an antenna and a dummy
load. Typically, an automatic antenna transfer control unit controls the RF contactor's position by
applying AC voltage to the 'set' or 'reset' solenoid of the RF contactor. The RF contactor's position
determines the routing of the transmitter outputs to the antenna and dummy load. Micro-switches on
the RF contactor provide interlock control for both transmitters and prevent 'live' switching.