1
Safegua
rds
2
Terms and
Warranty
3
Principl
e o
f
Operati
on
4
Ins
talla
tion
5
Operati
on
6
C
ont
rol Syst
em
7
RF Componen
ts
8
Power
Supp
ly
9
Maintenan
ce
10
Troubleshoo
ting
Reflected RF power level in % or watts. Mimics data from
level bar. The VSWR fault occurs when the measured
VSWR of system exceeds the user-defined VSWR trip point
found in the RF Levels Menu (described later in section). If
VSWR exceeds the shutdown level, but is below 1.8:1 (or a
custom VSWR protection point), then attenuation is added to
the amplifier/transmitter input until a safe level is reached. If
the measured VSWR exceeds 1.8:1 (or a custom VSWR trip
point, then the RF carrier is turned off to protect the
amplifier/transmitter chain. Then the system will continually
check to see if it is safe to come back on. This scheme helps
ensure that the system stays on air as long as possible
before doing a complete shutdown. If high reflected occurs, a
warning is displayed in red text near the top of the
touchscreen and the event recorder logs the event.
Temperature from sensor mounted on heat sink surface.
Shutdown trip point is factory set at a predetermined level to
keep the amplifier/transmitter pallets safe. Should a fan fail
inside the power amplifier/transmitter enclosure, or air
conditioning fails inside the broadcast facility causing the
temperature to exceed the trip point, the control system will
lower forward RF power until a safe level of measured
temperature is achieved. The system will continually try and
bring the RF power back to the same level when the fault
occurred if it is safe to do so, a warning is displayed in red
text near the top of the touchscreen, and the event recorder
logs the event.
RF output power is determined largely in part by the amount
of attenuation that the control system places on the input of
the power amplifier/transmitter. Whether a fault occurs and
attenuation gets added or the user requests a change in RF
power level via the web/SNMP/Remote Port interface, the
attenuation section of the summary bar conveys important
operating information. If the user requests a change in
forward power level via the web interface, SNMP monitoring
and control, or simply via the Remote Port connector on the
back of the enclosure, and an asterisk (*) is placed next to
the attenuation value in the summary bar. This informs the
user whether or not the attenuation was added due to a fault
or simply because it was requested.
